Click pics to enlarge. This is the internal pic of doctorjohn's sample. Note the extremely crowded components around the 6F3, making it hard to modify. The quirky B+ Relay Board is to the right of the power transformer, up north of the electrolytic.
Review: APPLauseAudio 300B amp
Editor: This article is an unusual one in that it is co-written by the THREE of us! In fact, it was the APPLauseAudio 300B amps that tied us together. This was the second tube amp I bought after I became rejuvenated in audio. I wrote about it briefly in this article. Shawn P somehow read it and decided to take his plunge. Meanwhile, R Salamat left a comment that he has one too, acquired long before I did mine. Our communications started from there. This has turned into an end-all mega-review. It is VERY long, but I'm proud to say, worth every second of your time. Without much ado, It is a fine sounding amp with many quirks, as you shall read below. We shall begin with the person who gambled on this one first.
R. Salamat (LA, US)
Editor: This article is an unusual one in that it is co-written by the THREE of us! In fact, it was the APPLauseAudio 300B amps that tied us together. This was the second tube amp I bought after I became rejuvenated in audio. I wrote about it briefly in this article. Shawn P somehow read it and decided to take his plunge. Meanwhile, R Salamat left a comment that he has one too, acquired long before I did mine. Our communications started from there. This has turned into an end-all mega-review. It is VERY long, but I'm proud to say, worth every second of your time. Without much ado, It is a fine sounding amp with many quirks, as you shall read below. We shall begin with the person who gambled on this one first.
R. Salamat (LA, US)
During the initial phase of the pandemic, I had some time in my hands to reflect back on all the equipment I’ve had over the years that gave me the most pleasure using and listening to. I also had the thought of maybe reacquiring these same equipment as “endgame” (as young folks like to say) purchases for me. And when I say endgame, I don’t necessarily mean high-ticket, I just mean highly desired. Hence, the Nait 1, Rega Planet (love the hinged lid opening), NOS DACs purchases.
I have been missing the sound of single-ended 300B (mine was at various times a Cary, Audio Note’s. and custom-made mono’s using Tango transformers) for quite a while now. What led me to sell them before was, I think I got tired of the preponderance of second-harmonic distortion which fattens up everything, albeit making everything sound mellifluous. So back to the present, I was browsing Aliexpress, and happened upon the AppluaseAudio [sic] 300B amplifier. I immediately liked the styling cues from old Western Electric amps (mine even have a Western Electric logo plate on the front by special request, instead of the stock one), liked that it has a choke, tube rectifiers, and also the use of 6F3 front-end tubes instead of the usual 6SN7. I believe Shindo uses something similar or exactly the same configuration. Price, even with the higher shipping cost, was very reasonable. I actually was initially interested in the 211 version but was apprehensive about the higher voltages involved and, as you will see later, my feelings were validated.
When I got the amp, I plugged it in using beater speakers first, in case something goes awry. No smoke, good clean sound was obtained. I proceeded to break it in and noticed some tinniness to the sound which I attributed to the stock tubes, especially the front end. I initially got some Russian 6F3 tubes from eBay as my research concluded that those were equivalent tubes. But…not at all, the gain was all wrong. The available volume was very insufficient, and I don’t even listen that loud. Further reading educated me on the 6F3 tube actually being the correct equivalent one. So I scored a pair of RCA 6F5/6GV8 (obscure tubes = low price) and put those in. These gave the amp some of the inviting warmth in tone that I was looking for. I then proceeded to get a pair of Gold Lion PX300B to replace the Chinese 300Bs that came stock with the amp. Doctorjohn in an earlier response to a comment mentioned that changing out the stock 300Bs is not an urgent need, and I would have to agree. On some music, the PX300B sounds a bit too “damped”, whereas the Chinese may have some brightness, but it is also replete with more liveliness and “jump”.
I noticed some electrical quirks early on, like on my third week of use. Fuses popped; changed them out, ready to go again. But then the two tube rectifiers burned out. Hmmm, I thought, cheap tubes. I replaced them with some new production equivalent ones (5AR4), and it was good for a while. Then one day, the fuse popped again and I smelled something had burned. I opened it up to see a small capacitor in the PSU section that basically had exploded, with some wax from the transformers seemingly oozing out from the holes (where wires are routed) when inspected inside. Took it to my whiz of an electronics repair man (who actually makes his own SET and PP amps, by the way). He is in his late sixties, trained in Old World Vietnam, and knows his way around any circuit, tube or solid state without need for schematics. A real gem of a guy, I’m thinking in the same way as Déjà vu Audio’s resident Vietnamese amp-maker. Anyway, even he was, at first, stumped as to what was going on. Then, after various tests, he finally figured out that AppluaseAudio used a 100V transformer, which would be fine if used in Japan, but wholly inadequate for the US. He rigged me up a mild step-down trannie (120V to 100V) in a separate nice box, power switch, LED, the works, and everything has been fine since. So let this be a cautionary tale for someone from the US buying this amp [Editor Note 1].
Otherwise, this amp is grand. I don’t get too much of the “fat” that I associate with my old 300B amps (and partly what I miss if I’m being completely honest with myself), but I do get that 300B single-endedness that is characterized by that forwardness in drive accompanied by overall weight in sound, but light and quick enough that all points of the music are in cohesion with each other. It connects the dots well, in the words of the late, lamented Audio Writer Extraordinaire, Art Dudley. In contrast, 2A3 single-ended sounds to me to be more monitor-like [Editor Note 2]. More neutral, but also not neutered. So, it depends on what you’re in the mood for…Horses for courses. Different strokes for different folks. To each their own. One man’s meat, another man’s murder. Anyway, you get the gist, right?
Currently, I have mesh (or more accurately perforated) balloon 300B’s and a globe 80 rectifier (with an adapter) in there and it brings more clarity and delicacy to the sound. Soundstaging / imaging, for people who care about such things, is pulled off beautifully, often images will play way beyond and outside of the speaker’s plane: Chet Baker blowing his trumpet startled me one time when he began playing five feet to the left and twenty feet from behind the left speaker (but maybe I exaggerate. It was late and I did have a nice glass of Hibiki in my hand) as I was listening intently to Bill Evan’s quiet but purposeful piano, to illustrate this point.
You can use this amp as an integrated amplifier with passive line control, but I prefer to use a preamplifier ahead of it. I loved it in combination with some of my speakers (I don’t have horns): old, original Sequerra Met7, Spica Angelus, and Reference 3A de Capo. These three speakers are efficient enough to extract the measly 8 watts from this amp and release them as music with gossamer wings. I also tried it with my audio buddy’s JBL Hartsfields, who normally uses his own custom 300B monoblocks or Mark Levinson ML-2’s with his classic horn speakers. He declares the AppluaseAudio “Gooood” with a nod, which is short-hand for him to mean “Unexpectedly Very Good” and “I can live with it” [Editor Note 3].
So there you go, if you like a “gooood” amp that “you can live with”, able to drive efficient-enough two-way speakers, with a taste that lies between Rubenesque and Junonesque, a 300B amp with some of the umami held back for a subtler flavor, and have a good electronics tech that you can call on for quirky electronic puzzlers like popping fuses, you might want to try the AppluaseAudio before it gets too popular or they stop production.
I have been missing the sound of single-ended 300B (mine was at various times a Cary, Audio Note’s. and custom-made mono’s using Tango transformers) for quite a while now. What led me to sell them before was, I think I got tired of the preponderance of second-harmonic distortion which fattens up everything, albeit making everything sound mellifluous. So back to the present, I was browsing Aliexpress, and happened upon the AppluaseAudio [sic] 300B amplifier. I immediately liked the styling cues from old Western Electric amps (mine even have a Western Electric logo plate on the front by special request, instead of the stock one), liked that it has a choke, tube rectifiers, and also the use of 6F3 front-end tubes instead of the usual 6SN7. I believe Shindo uses something similar or exactly the same configuration. Price, even with the higher shipping cost, was very reasonable. I actually was initially interested in the 211 version but was apprehensive about the higher voltages involved and, as you will see later, my feelings were validated.
When I got the amp, I plugged it in using beater speakers first, in case something goes awry. No smoke, good clean sound was obtained. I proceeded to break it in and noticed some tinniness to the sound which I attributed to the stock tubes, especially the front end. I initially got some Russian 6F3 tubes from eBay as my research concluded that those were equivalent tubes. But…not at all, the gain was all wrong. The available volume was very insufficient, and I don’t even listen that loud. Further reading educated me on the 6F3 tube actually being the correct equivalent one. So I scored a pair of RCA 6F5/6GV8 (obscure tubes = low price) and put those in. These gave the amp some of the inviting warmth in tone that I was looking for. I then proceeded to get a pair of Gold Lion PX300B to replace the Chinese 300Bs that came stock with the amp. Doctorjohn in an earlier response to a comment mentioned that changing out the stock 300Bs is not an urgent need, and I would have to agree. On some music, the PX300B sounds a bit too “damped”, whereas the Chinese may have some brightness, but it is also replete with more liveliness and “jump”.
I noticed some electrical quirks early on, like on my third week of use. Fuses popped; changed them out, ready to go again. But then the two tube rectifiers burned out. Hmmm, I thought, cheap tubes. I replaced them with some new production equivalent ones (5AR4), and it was good for a while. Then one day, the fuse popped again and I smelled something had burned. I opened it up to see a small capacitor in the PSU section that basically had exploded, with some wax from the transformers seemingly oozing out from the holes (where wires are routed) when inspected inside. Took it to my whiz of an electronics repair man (who actually makes his own SET and PP amps, by the way). He is in his late sixties, trained in Old World Vietnam, and knows his way around any circuit, tube or solid state without need for schematics. A real gem of a guy, I’m thinking in the same way as Déjà vu Audio’s resident Vietnamese amp-maker. Anyway, even he was, at first, stumped as to what was going on. Then, after various tests, he finally figured out that AppluaseAudio used a 100V transformer, which would be fine if used in Japan, but wholly inadequate for the US. He rigged me up a mild step-down trannie (120V to 100V) in a separate nice box, power switch, LED, the works, and everything has been fine since. So let this be a cautionary tale for someone from the US buying this amp [Editor Note 1].
Otherwise, this amp is grand. I don’t get too much of the “fat” that I associate with my old 300B amps (and partly what I miss if I’m being completely honest with myself), but I do get that 300B single-endedness that is characterized by that forwardness in drive accompanied by overall weight in sound, but light and quick enough that all points of the music are in cohesion with each other. It connects the dots well, in the words of the late, lamented Audio Writer Extraordinaire, Art Dudley. In contrast, 2A3 single-ended sounds to me to be more monitor-like [Editor Note 2]. More neutral, but also not neutered. So, it depends on what you’re in the mood for…Horses for courses. Different strokes for different folks. To each their own. One man’s meat, another man’s murder. Anyway, you get the gist, right?
Currently, I have mesh (or more accurately perforated) balloon 300B’s and a globe 80 rectifier (with an adapter) in there and it brings more clarity and delicacy to the sound. Soundstaging / imaging, for people who care about such things, is pulled off beautifully, often images will play way beyond and outside of the speaker’s plane: Chet Baker blowing his trumpet startled me one time when he began playing five feet to the left and twenty feet from behind the left speaker (but maybe I exaggerate. It was late and I did have a nice glass of Hibiki in my hand) as I was listening intently to Bill Evan’s quiet but purposeful piano, to illustrate this point.
You can use this amp as an integrated amplifier with passive line control, but I prefer to use a preamplifier ahead of it. I loved it in combination with some of my speakers (I don’t have horns): old, original Sequerra Met7, Spica Angelus, and Reference 3A de Capo. These three speakers are efficient enough to extract the measly 8 watts from this amp and release them as music with gossamer wings. I also tried it with my audio buddy’s JBL Hartsfields, who normally uses his own custom 300B monoblocks or Mark Levinson ML-2’s with his classic horn speakers. He declares the AppluaseAudio “Gooood” with a nod, which is short-hand for him to mean “Unexpectedly Very Good” and “I can live with it” [Editor Note 3].
So there you go, if you like a “gooood” amp that “you can live with”, able to drive efficient-enough two-way speakers, with a taste that lies between Rubenesque and Junonesque, a 300B amp with some of the umami held back for a subtler flavor, and have a good electronics tech that you can call on for quirky electronic puzzlers like popping fuses, you might want to try the AppluaseAudio before it gets too popular or they stop production.
Shawn P (Hong Kong)
My world of power tube was simple during my early tube years - EL34 and EL84 were all I knew. In fact, I had no idea what SET meant.
I read “膽機世界” (The Tube World Monthly) in the early days and 300B was the one tube that kept appearing in the magazine. I thought it must be a powerful tube as it is much larger than the EL34 and little did I know that most 300B SET amplifiers were, and still are, 8W.
From reading these articles, I knew that any 300B amp would not be cheap, but I still decided to tour Mong Kok and see if I could find something “affordable”. Cary Audio’s CAD-300SEI had the lowest price tag but it was still out of my budget.
I still want a 300B After all these years, I still want a 300B amp but, of course, only if the price is right and that I can provide the accommodation.
Initially, I had my eyes on the Line Magnetic and Elekit 300B amps. They were affordable but their pre-amp sections seemed unusual. Elekit has only two 12AU7s and Line Magnetic has two 12AX7s and two 12AU7s. I am not in a position to comment as to whether those amps will sound good or bad, I simply did not have any relevant knowledge or experience with 300B. Nevertheless, while they were affordable, I did not want to fork out ten grand just to find out 300b was not for me.
Purchasing APPL 300b, the Caveats and Hiccups While doctorjohn’s article only briefly mentioned the APPL 300B (more like a teaser), the amp caught my eyes. But nothing I read was conclusive and, worse, no price. I was eagerly waiting for more information from doctorjohn but the next article was on something else. No APPL.
Knowing APPL could be the 300B I was longing for, I went to Taobao searching for the amp and I would (as I did) pull the trigger without doctorjohn’s further review if the price was right. Searching the amp was not easy, the name of the brand was funky “APPLuaseAUDIO”. The brand name was not helpful and my initial searches only yielded unrelated results. Eventually, I searched for 300B tube amp, went through the list and finally found it.
The price was lower than I expected and, yup, I could finally get a 300B amp! Contacted the seller, found out it could be shipped to Hong Kong and pulled the trigger. I waited for a week but found out it was shipped to the wrong address. Not a good start but the courier delivered the package eventually.
The package looked “makeshift” inside and out, I was not so sure how a heavy amp could survive. The amp was protected by pieces of uneven sized Styrofoam which attempted to fill up the space. It seemed that the Styrofoam could shift around, and the amp could lose its protection. Fortunately, that did not happen, and the amp was OK. The tubes were well packed but they were on the top of the amp and I wonder what would have happened if the box was flipped upside down, as the box had no marking whatsoever.
So, the amp and tubes were OK, but when I opened the box, it was like opening a can of paint and the odor filled up the living room quickly. I immediately summoned my wife to help me relocate the amp to a different room in order to mitigate the smell. The paint was dry but it smelled fresh. The makeshift packaging and strong odor perhaps indicated that this 300B may not be for everyone.
Lo and Behold, Other Issues and Very Unusual Ones See, I like tube rolling and was delighted to find out on the seller’s Taobao page that the 6F3 tube is equivalent to 6BMB which is equivalent to Russian 6F3P. Great, Chinese 6F3 must be equivalent to Russian 6F3P. It could not be wrong, right? Wrong, Chinese 6F3 is different from 6BMB and Russian 6F3P. I plugged in the Russian 6F3P and immediately noticed something was seriously wrong, no sound! XXXX!
While the electrical characteristics of 6BM8 may be similar to those of 6F3, the pinouts are different. The triode and pentode are essentially flipped with the 6BMB. I read the seller’s information again and again and even the info on his other amps with 6F3. I found nothing which would indicate these two tubes have different pinouts.
The story did not end there: from the get-go, I noticed a small amount of AC output at start-up, which was strong enough to move the bass driver of the speaker. Ahhhh! That still annoys me. In fact, I mentioned this annoyance to doctorjohn repeatedly.
My world of power tube was simple during my early tube years - EL34 and EL84 were all I knew. In fact, I had no idea what SET meant.
I read “膽機世界” (The Tube World Monthly) in the early days and 300B was the one tube that kept appearing in the magazine. I thought it must be a powerful tube as it is much larger than the EL34 and little did I know that most 300B SET amplifiers were, and still are, 8W.
From reading these articles, I knew that any 300B amp would not be cheap, but I still decided to tour Mong Kok and see if I could find something “affordable”. Cary Audio’s CAD-300SEI had the lowest price tag but it was still out of my budget.
I still want a 300B After all these years, I still want a 300B amp but, of course, only if the price is right and that I can provide the accommodation.
Initially, I had my eyes on the Line Magnetic and Elekit 300B amps. They were affordable but their pre-amp sections seemed unusual. Elekit has only two 12AU7s and Line Magnetic has two 12AX7s and two 12AU7s. I am not in a position to comment as to whether those amps will sound good or bad, I simply did not have any relevant knowledge or experience with 300B. Nevertheless, while they were affordable, I did not want to fork out ten grand just to find out 300b was not for me.
Purchasing APPL 300b, the Caveats and Hiccups While doctorjohn’s article only briefly mentioned the APPL 300B (more like a teaser), the amp caught my eyes. But nothing I read was conclusive and, worse, no price. I was eagerly waiting for more information from doctorjohn but the next article was on something else. No APPL.
Knowing APPL could be the 300B I was longing for, I went to Taobao searching for the amp and I would (as I did) pull the trigger without doctorjohn’s further review if the price was right. Searching the amp was not easy, the name of the brand was funky “APPLuaseAUDIO”. The brand name was not helpful and my initial searches only yielded unrelated results. Eventually, I searched for 300B tube amp, went through the list and finally found it.
The price was lower than I expected and, yup, I could finally get a 300B amp! Contacted the seller, found out it could be shipped to Hong Kong and pulled the trigger. I waited for a week but found out it was shipped to the wrong address. Not a good start but the courier delivered the package eventually.
The package looked “makeshift” inside and out, I was not so sure how a heavy amp could survive. The amp was protected by pieces of uneven sized Styrofoam which attempted to fill up the space. It seemed that the Styrofoam could shift around, and the amp could lose its protection. Fortunately, that did not happen, and the amp was OK. The tubes were well packed but they were on the top of the amp and I wonder what would have happened if the box was flipped upside down, as the box had no marking whatsoever.
So, the amp and tubes were OK, but when I opened the box, it was like opening a can of paint and the odor filled up the living room quickly. I immediately summoned my wife to help me relocate the amp to a different room in order to mitigate the smell. The paint was dry but it smelled fresh. The makeshift packaging and strong odor perhaps indicated that this 300B may not be for everyone.
Lo and Behold, Other Issues and Very Unusual Ones See, I like tube rolling and was delighted to find out on the seller’s Taobao page that the 6F3 tube is equivalent to 6BMB which is equivalent to Russian 6F3P. Great, Chinese 6F3 must be equivalent to Russian 6F3P. It could not be wrong, right? Wrong, Chinese 6F3 is different from 6BMB and Russian 6F3P. I plugged in the Russian 6F3P and immediately noticed something was seriously wrong, no sound! XXXX!
While the electrical characteristics of 6BM8 may be similar to those of 6F3, the pinouts are different. The triode and pentode are essentially flipped with the 6BMB. I read the seller’s information again and again and even the info on his other amps with 6F3. I found nothing which would indicate these two tubes have different pinouts.
The story did not end there: from the get-go, I noticed a small amount of AC output at start-up, which was strong enough to move the bass driver of the speaker. Ahhhh! That still annoys me. In fact, I mentioned this annoyance to doctorjohn repeatedly.
I do want to mention something on the rectifier arcing issue. On certain occasions, the rectifier arcs; my understanding is that in many cases, a large C1 filter capacitor is the culprit. I could not find any schematic from the seller’s page but doctorjohn informed me that Aliexpress does have it. The Aliexpress schematic shows a 47uf C1 capacitor which should be ok for 5u4 but likely too large for the 5Y3 and 5R4. Interestingly, only the stock 5Z2P and RCA 5U4 arced and perhaps the arcing was caused by something else or something else in addition. The relay mentioned above may also contribute to the arcing as it arcs right when the relay connects.
The setup Enough of the hiccups, let’s dig in further. A few weeks earlier, I had a casual discussion with doctorjohn about streaming and Bluetooth. I thought it would be interesting to use streaming exclusively for this review, perhaps Bluetooth as well if I could get it to perform within acceptable parameters. In addition, my room is tiny, and the APPL 300b and APPL 845 (more on the 845 below) are getting in the way between the listening chair and the CD player; this unfortunate setting makes streaming even more appealing.
At the beginning of conducting this review, I had already subscribed to Spotify but did not have Tidal. Spotify was ok for mobile playback but when compared side by side with CDs, it became obvious that Spotify would not do the APPL any justice. Hence, I subscribed to Tidal again and noticed that Tidal is now much different from 2014, when I first subscribed.
Anyhow, the setup is as follows: Android App USB Audio Player PRO (Bluetooth and USB); ifi Zen Blue (Bluetooth); S.M.S.L. Sanskrit 10th MKIII (USB); Audio Experience Symphonies as preamp; Reisong 1:1 audio transformer; APPL 300B. Speakers were Beydas "Stirling" LS3/5a.
(Note: I have around 8 years of experience with USB Audio Player PRO and I think it is a great App. Perhaps I should share more on BT, Tidal later. Let’s focus on the APPL for now.)
How does it sound? As mentioned, this is my first experience with 300B and I had no idea how 300B should sound. From reading all these 300B articles, the 300b is airy, sweet, warm, of good bass etc.
First, listening to Leonard Cohen’s “Live in London”, Cohen’s deeper than ever voice came alive, his voice was in front of me but was not in my face. It had density and was warm but not overly so. It was clearer than what I expected though not as clear as my other SET, Decware Zen. The APPL has plenty more power than the Decware however. Listening to another “vocal” album, Diana Krall’s “Wallflower”; I could find similar characteristics, but the sound stage was smaller as this album is more vocally oriented.
What about symphonic materials? The wattage of the 300B did concern me when it came to symphonic materials. But how could a review be completed without some? Perhaps something not too “full-blown”. Joe Hisaishi’s “The Legend of Ashitake” from “Symphonic Suite Princess Mononoke” went through without issue. There was no shortness of breath or running out of juice even with the double bass and bass drum. It finished the entire piece without much issue but please do not expect anything like the Maxell “Blown-away guy”. Another piece from Joe Hisaishi, “The Eternal Tree of Life” from “Symphonic Suite Castle in The Sky”. This piece was more challenging for the APPL, the brass was more demanding and it was overall busier The APPL could still manage but clearly it was reaching its limit.
OK, something more challenging. “Disarm” from Smashing Pumpkins’ “Siamese Dream”. It was OK for this piece but the APPL was not able to get to the sound level I was hoping for. It started to run out of breath, at least at the sound level this type of music would call for. I also tried “Soma” from Smashing Pumpkins and “Sabotage” from Beastie Boys, all I can say is that I will unlikely use the APPL for these pieces again.
Do I like the amp? Yes, absolutely. The best indication was that I spent hours with the amp listening, without leaving the room or changing tracks. But do I recommend it is another matter. More below.
Tube rolling As mentioned, I like tube rolling and how can I skip the same? Having said that, the only tube I could roll was the rectifier. I suggest getting rid of the stock 5Z2Ps right away. While they did sound ok initially, the APPL started to sound like crap after around 5 hours of use and the observation is repeatable. Once I plugged in different rectifiers, the issue was gone.
You will also need to be careful with the number of rectifiers. Stock uses 2x 5Z2P. But, when using 5U4, which draws 3A instead of the typical 2A (not all, please check) of other rectifiers, only one is needed. As you may have noticed, there are two sockets for rectifiers.
I have tried 5U4, 5R4WGB (potato masher), 5Y3 and 80 (essentially a 5Y3) and they were all in single operation. The 80 sounded the best of all and it produced the widest soundstage, the 5R4 was the runner up. To my surprise, out of all the 5U4s I tried, the Russian made 5U4 (year 1969) was the best 5U4. The 5Y3 sounded ok but nothing special.
Should you Consider? The APPL 300B sounds nice but it has some issues. I also acquired the APPL 845 not long after the arrival of APPL 300B. Compared to the APPL 300b, the APPL 845 sounds cleaner, more powerful (in fact, it is), a bit faster. In addition, the APPL 845 is also smooth. Does the APPL 845 have any issues like the 300b? Unfortunately, yes and perhaps a bit more. Hence, it appears that the seller can make good sounding amps but you will need to also consider these unusual issues. Perhaps, if you do not mind waiting a bit, I can share more on the 845 and you can then decide whether to purchase from the seller and, if so, which amp to purchase."
Doctorjohn (currently China)
First, I'd like to tell you that I wrote what's below before I received the detailed input from R Salamat. It pleases me that we think amazingly alike on several fronts. And then, Shawn P and I, being kinda neighbors with wechat media app, have been in constant contact over the APPL quirks, and we try to cover this aspect in detail.
At the beginning of conducting this review, I had already subscribed to Spotify but did not have Tidal. Spotify was ok for mobile playback but when compared side by side with CDs, it became obvious that Spotify would not do the APPL any justice. Hence, I subscribed to Tidal again and noticed that Tidal is now much different from 2014, when I first subscribed.
Anyhow, the setup is as follows: Android App USB Audio Player PRO (Bluetooth and USB); ifi Zen Blue (Bluetooth); S.M.S.L. Sanskrit 10th MKIII (USB); Audio Experience Symphonies as preamp; Reisong 1:1 audio transformer; APPL 300B. Speakers were Beydas "Stirling" LS3/5a.
(Note: I have around 8 years of experience with USB Audio Player PRO and I think it is a great App. Perhaps I should share more on BT, Tidal later. Let’s focus on the APPL for now.)
How does it sound? As mentioned, this is my first experience with 300B and I had no idea how 300B should sound. From reading all these 300B articles, the 300b is airy, sweet, warm, of good bass etc.
First, listening to Leonard Cohen’s “Live in London”, Cohen’s deeper than ever voice came alive, his voice was in front of me but was not in my face. It had density and was warm but not overly so. It was clearer than what I expected though not as clear as my other SET, Decware Zen. The APPL has plenty more power than the Decware however. Listening to another “vocal” album, Diana Krall’s “Wallflower”; I could find similar characteristics, but the sound stage was smaller as this album is more vocally oriented.
What about symphonic materials? The wattage of the 300B did concern me when it came to symphonic materials. But how could a review be completed without some? Perhaps something not too “full-blown”. Joe Hisaishi’s “The Legend of Ashitake” from “Symphonic Suite Princess Mononoke” went through without issue. There was no shortness of breath or running out of juice even with the double bass and bass drum. It finished the entire piece without much issue but please do not expect anything like the Maxell “Blown-away guy”. Another piece from Joe Hisaishi, “The Eternal Tree of Life” from “Symphonic Suite Castle in The Sky”. This piece was more challenging for the APPL, the brass was more demanding and it was overall busier The APPL could still manage but clearly it was reaching its limit.
OK, something more challenging. “Disarm” from Smashing Pumpkins’ “Siamese Dream”. It was OK for this piece but the APPL was not able to get to the sound level I was hoping for. It started to run out of breath, at least at the sound level this type of music would call for. I also tried “Soma” from Smashing Pumpkins and “Sabotage” from Beastie Boys, all I can say is that I will unlikely use the APPL for these pieces again.
Do I like the amp? Yes, absolutely. The best indication was that I spent hours with the amp listening, without leaving the room or changing tracks. But do I recommend it is another matter. More below.
Tube rolling As mentioned, I like tube rolling and how can I skip the same? Having said that, the only tube I could roll was the rectifier. I suggest getting rid of the stock 5Z2Ps right away. While they did sound ok initially, the APPL started to sound like crap after around 5 hours of use and the observation is repeatable. Once I plugged in different rectifiers, the issue was gone.
You will also need to be careful with the number of rectifiers. Stock uses 2x 5Z2P. But, when using 5U4, which draws 3A instead of the typical 2A (not all, please check) of other rectifiers, only one is needed. As you may have noticed, there are two sockets for rectifiers.
I have tried 5U4, 5R4WGB (potato masher), 5Y3 and 80 (essentially a 5Y3) and they were all in single operation. The 80 sounded the best of all and it produced the widest soundstage, the 5R4 was the runner up. To my surprise, out of all the 5U4s I tried, the Russian made 5U4 (year 1969) was the best 5U4. The 5Y3 sounded ok but nothing special.
Should you Consider? The APPL 300B sounds nice but it has some issues. I also acquired the APPL 845 not long after the arrival of APPL 300B. Compared to the APPL 300b, the APPL 845 sounds cleaner, more powerful (in fact, it is), a bit faster. In addition, the APPL 845 is also smooth. Does the APPL 845 have any issues like the 300b? Unfortunately, yes and perhaps a bit more. Hence, it appears that the seller can make good sounding amps but you will need to also consider these unusual issues. Perhaps, if you do not mind waiting a bit, I can share more on the 845 and you can then decide whether to purchase from the seller and, if so, which amp to purchase."
Doctorjohn (currently China)
First, I'd like to tell you that I wrote what's below before I received the detailed input from R Salamat. It pleases me that we think amazingly alike on several fronts. And then, Shawn P and I, being kinda neighbors with wechat media app, have been in constant contact over the APPL quirks, and we try to cover this aspect in detail.
Why I picked this Amp This deserves close scrutiny. It was actually quite rationalized (from my viewpoint).
System As usual with my SET amps, I max out the volume and use a Preamp. This adds oomph (I’m a firm believer of The First Watt). Mine is the Chinese 6J4/6V6 Preamp (here). At first, I used my Sansui floorstanders, later the “Stirling” (Beydas) LS3/5A.
General Sound From the start, the sound was quite good. It seemed not much run-in was needed. I have had quite a few 300B amps and have heard even more, from Holy Grail WE91A to DIY efforts and I can tell you all modern 300B tubes (including re-issue WE) do not hold a candle to the original WE 300B/A. The modern tubes can be very good-sounding but the sounds of the Amps are all over the place. I say this because, for some reviewers, the 300B tube has a "rich sound”. IMHO, it depends on the system and implementation, I think. 300B is to me actually usually on the neutral side, with just a hint of tube sheen; it also has a somewhat lean but ultra-high-quality bass. Of course, the transformers influence the sound greatly. So, in my experience the sound ranges from somewhat lean (AN Kit One and Conqueror, Audion Silver Night, not to mention Canary) to possibly over-rich (Cary) and even fogged (HK Allegro and the Japanese Advance kit of many years ago). So where does the APPLause fit in? Well, based on my sonic memory, it ranks at least in the middle, better than those I mentioned above. Take the most important thing, bandwidth, and this amp is very good. There’s no higher praise than to say the sound is highly organic and coherent. One just doesn’t think of treble, bass or whatever other parameter and just wallow in the music. And so, I’m ready to proclaim that the Output Transformers are of good quality. Another testament to the sound nature of the amp is that one easily hears the difference of tube rolling. A useful comparison is to my other 2 amps. The APPLause has a little more power, the best soundstage and fleshiest images. It is clearer than the Aosibao 6P1 PSE amp. My FU-50 amp has almost as much detail, but in comparison is not so see-through perhaps, and it is also not quite as sensitive to tube rolling nor as fleshy (I won’t say lush as it is not) and musical as the APPLause. I have been wordy. Perhaps I can just say: The APPLause delivers excellent SET Sound. And this is from someone who has experienced basically the majority of SE amp configurations. Just for 300B, I have owned and listened to tens.
Tube Rolling As above, both RS and SP have written about the vagaries of tube rolling the 6F3, and that is critical. What I did was roll in the ECL805, a premium type of the ECL85. Mine was Siemens from TB, with original box, RMB 290 (USD 42) for the pair. You can buy used old-stock and good quality ECL805 and 85 on Ebay for less if you want. The difference in sound? It's not subtle, but not quite what you expect. My friend hifienthusiast (older UK regular Pinkfish Media netizens may recall him) was with me when I swapped it in. He initially preferred the 6F3. Indeed, the Chinese 6F3 has more air. But, with breaking in, it was obvious the Siemens ECL805 has better texture, and since then I had kept it in (but quirks, see below). Now, I'd not be eager to change out the Linlai 300B, as my experience tells me the Chinese 300B's are very good. So are the Russian ones. Just have the patience to run them in. For me, re-issue so-called "WE 300B" and the many "boutique" ones are over-touted (by inexperienced reviewers) and lose out in many aspects to these Chinese and Russian tubes. No need to fuss. BTW, where do you think they get the vacuum tube parts. I can tell you - China. They may deny it, as the West always does (including the US sabotage of the Nord-Stream), but just look at the parts of a Shuguang tube and a "WE" re-issue and you shall see what I mean. Concentrate on the other tubes! Now, the rectifier(s). With the stock 2x 5Z2, the meter shows 150 mA. I have tons of 5Y3 in NYC and HK, but not here, so I'm not going to buy it. As R Salamat relayed to me that I could use just one socket, in conjunction with considerations of my other SE amps of similar output, I bought what I considered to be reasonably priced tubes, the potato smasher 5R4WGx (Mine is Chatham WGA, RMB 145 USD 21) and a Philips GT bottled 5R4 (RMB 165 USD 24). I also splurged on an ST 80 (Tung-Sol engraved, RMB 244 USD 36). Results are mixed, and vary from amp to amp, as a matter of course. In this amp, the 5R4WGA delivers oomph, very pacey. The 80 is more yin than yang, but very enticing. In my specimen, I noticed the meter indicates around 130-140 mA, around the limit of the 80's spec's (it may also have a larger voltage drop). But I'd not worry even if the tube is pushed, as it is robust. I also inserted the Russian 5U4M that came with my Aosibao. It sounds great and energized. This 5U4M is GT bottled and in my experience does not sound as good as the ST bottled equivalents (which I don;t have here). But as I right now don't have a good supply of Directly Heated rectifiers here, I'd just test the waters. I have always favored direct rectifiers. And the situation will change soon when I get back to HK to retrieve some of my tubes. It should be noted, that as a matter of course, the current draw of direct-heated tubes is higher. For the Russian 5U4M it's 170 mA, at least 20 mA higher than usual, but the sound is excellent.
Issues So all is smooth sailing? I wish I could say so! From my perspective, there are several problems with this otherwise fine piece of kit.
- As my Sansui floorstanders are efficient, I decided I will stick to SET. That’s par for the course, as I am a vintage aficionado (vintage gear have superior trannies) and am not interested at all in modern PP amps (e.g., I have a Shindo preamp but have never been interested in owning their amps). Also, SET amps are by far more reliable than PP amps. My LS3/5A clones acquired later are reasonably SET friendly as well.
- As all my (great) old stock tubes are in NYC and HK, I am heavily disinclined to buy too many tubes here in China, So I pick amps that would not force me to roll tubes too much. Like I’d not pick an amp with the popular 6SN7 as driver tube, as they are too expensive. This amp comes with very good pair of Linlai 300B, so no need to change that. Its driver tube is Chinese 6F3, which has reasonably priced equivalents (see below). For rectifier, it comes with 2x 5Z2P (see below).
- I like the use of the triode-pentode 6F3. I have always liked this class of tubes, which combine a triode front section with a power pentode (most popular example is 6BM8/ECL82, followed by 6GW8/ECL86). Just one tube can make an SE amp and they are good sounding (I have the early Eleikit TU-870 and an old San-Ei, both 6BM8 amps). Small and good sounding Vintage PP amps use these tubes too, as just 4 tubes can squeeze in tone controls and phono stage (most famous is Rogers Cadet, which uses ECL86; I still have a MkII). The disadvantage of these tubes is that with direct hard-wiring, without terminal strip (as in most US amps), it's difficult to change components (see top pic) as so many components are cramped around the socket. And, unlike the all-triode crowd, I have increasingly preferred pentode/tetrode driving SETs (yes, it still holds that no SE pentode sounds as good the great Triodes). Witness my Yamamoto 45 (driven by 717A, here) and my Wavac MD-300B amp. The latter has a 2-stage driving topology with 2 stages before the 300B (12AT/U7 triode and 6Y6, here). These are 2 of my best 300B amps. You can see the APPLause is kinda like a Wavac on the cheap (minus the latter’s luxurious interstage) There are too many 300B amps out there using 6SN7 double triodes (including my Sun Audio; there are many Chinese clones of it). Keep in mind the most famous of 300B SE Amp, the much copied WE 91A, uses 310A pentode driver (close to 6J7/EF37A).
- I like the WE-like hammertone looks, and the price is very low for what it offers. One reason is that the seller also markets his transformers, thereby saving costs (and boost confidence in the trannie quality). An excellent chassis, good RCA connectors and speaker binding posts. What’s not to like (turns out there are a few)?
System As usual with my SET amps, I max out the volume and use a Preamp. This adds oomph (I’m a firm believer of The First Watt). Mine is the Chinese 6J4/6V6 Preamp (here). At first, I used my Sansui floorstanders, later the “Stirling” (Beydas) LS3/5A.
General Sound From the start, the sound was quite good. It seemed not much run-in was needed. I have had quite a few 300B amps and have heard even more, from Holy Grail WE91A to DIY efforts and I can tell you all modern 300B tubes (including re-issue WE) do not hold a candle to the original WE 300B/A. The modern tubes can be very good-sounding but the sounds of the Amps are all over the place. I say this because, for some reviewers, the 300B tube has a "rich sound”. IMHO, it depends on the system and implementation, I think. 300B is to me actually usually on the neutral side, with just a hint of tube sheen; it also has a somewhat lean but ultra-high-quality bass. Of course, the transformers influence the sound greatly. So, in my experience the sound ranges from somewhat lean (AN Kit One and Conqueror, Audion Silver Night, not to mention Canary) to possibly over-rich (Cary) and even fogged (HK Allegro and the Japanese Advance kit of many years ago). So where does the APPLause fit in? Well, based on my sonic memory, it ranks at least in the middle, better than those I mentioned above. Take the most important thing, bandwidth, and this amp is very good. There’s no higher praise than to say the sound is highly organic and coherent. One just doesn’t think of treble, bass or whatever other parameter and just wallow in the music. And so, I’m ready to proclaim that the Output Transformers are of good quality. Another testament to the sound nature of the amp is that one easily hears the difference of tube rolling. A useful comparison is to my other 2 amps. The APPLause has a little more power, the best soundstage and fleshiest images. It is clearer than the Aosibao 6P1 PSE amp. My FU-50 amp has almost as much detail, but in comparison is not so see-through perhaps, and it is also not quite as sensitive to tube rolling nor as fleshy (I won’t say lush as it is not) and musical as the APPLause. I have been wordy. Perhaps I can just say: The APPLause delivers excellent SET Sound. And this is from someone who has experienced basically the majority of SE amp configurations. Just for 300B, I have owned and listened to tens.
Tube Rolling As above, both RS and SP have written about the vagaries of tube rolling the 6F3, and that is critical. What I did was roll in the ECL805, a premium type of the ECL85. Mine was Siemens from TB, with original box, RMB 290 (USD 42) for the pair. You can buy used old-stock and good quality ECL805 and 85 on Ebay for less if you want. The difference in sound? It's not subtle, but not quite what you expect. My friend hifienthusiast (older UK regular Pinkfish Media netizens may recall him) was with me when I swapped it in. He initially preferred the 6F3. Indeed, the Chinese 6F3 has more air. But, with breaking in, it was obvious the Siemens ECL805 has better texture, and since then I had kept it in (but quirks, see below). Now, I'd not be eager to change out the Linlai 300B, as my experience tells me the Chinese 300B's are very good. So are the Russian ones. Just have the patience to run them in. For me, re-issue so-called "WE 300B" and the many "boutique" ones are over-touted (by inexperienced reviewers) and lose out in many aspects to these Chinese and Russian tubes. No need to fuss. BTW, where do you think they get the vacuum tube parts. I can tell you - China. They may deny it, as the West always does (including the US sabotage of the Nord-Stream), but just look at the parts of a Shuguang tube and a "WE" re-issue and you shall see what I mean. Concentrate on the other tubes! Now, the rectifier(s). With the stock 2x 5Z2, the meter shows 150 mA. I have tons of 5Y3 in NYC and HK, but not here, so I'm not going to buy it. As R Salamat relayed to me that I could use just one socket, in conjunction with considerations of my other SE amps of similar output, I bought what I considered to be reasonably priced tubes, the potato smasher 5R4WGx (Mine is Chatham WGA, RMB 145 USD 21) and a Philips GT bottled 5R4 (RMB 165 USD 24). I also splurged on an ST 80 (Tung-Sol engraved, RMB 244 USD 36). Results are mixed, and vary from amp to amp, as a matter of course. In this amp, the 5R4WGA delivers oomph, very pacey. The 80 is more yin than yang, but very enticing. In my specimen, I noticed the meter indicates around 130-140 mA, around the limit of the 80's spec's (it may also have a larger voltage drop). But I'd not worry even if the tube is pushed, as it is robust. I also inserted the Russian 5U4M that came with my Aosibao. It sounds great and energized. This 5U4M is GT bottled and in my experience does not sound as good as the ST bottled equivalents (which I don;t have here). But as I right now don't have a good supply of Directly Heated rectifiers here, I'd just test the waters. I have always favored direct rectifiers. And the situation will change soon when I get back to HK to retrieve some of my tubes. It should be noted, that as a matter of course, the current draw of direct-heated tubes is higher. For the Russian 5U4M it's 170 mA, at least 20 mA higher than usual, but the sound is excellent.
Issues So all is smooth sailing? I wish I could say so! From my perspective, there are several problems with this otherwise fine piece of kit.
- As Shawn P mentioned, the Relay Jolt at Start Up is highly perplexing. At turn on, the meter shows ambient current around 30 mA. After about 3 seconds (Shawn's is around 12 seconds), the B+ comes on and the meter transiently hits the ceiling (meter maxes out at 300mA) and instantly re-bounces back to near-steady-state level of 150 mA or so (for 2x 300B tubes, dependent on rectifier used). But what truly perplexes me is that even with indirectly heated rectifiers (with their delayed B+), such as my 5R4, it also happens. This Relay Board is definitely suspect.
- There is also the problem of Rectifier Arcing. With directly heated rectifiers, such as the stock 5Z2P, arcing is pretty consistent, but it happens too with my direct-heated 5U4M and the indirectly heated (GT) Philips 5R4s too. BUT, no problem so far and all our amps have worked well.
- Socket Woes Why am I the only one? Initially, my 6F3 socket worked OK. BUT, when I swapped in the Euorpean ECL805 I began to get popping sounds (like firecrackers) in my left channel. Sometimes quite loud! The reason is pin diameter may be different, and hence cause contact issues. If I were not an experienced tube user, I'd have been jolted out of my chair! I just knew it was a contact problem. Proof: Wiggling the ECL805 tube resolves the pop, though it will happen again! Now, unusual for a modern tube electronic, Chinese or not, it uses a tube socket with a shield, like what we got in vintage phono's. I usually shun these shields, as I think they dull the sound. In this case, it got so annoying that I put them on. The pressure of the top spring in the shield helps in seating the tube properly. Yes, it got better, but problem is not completely ameliorated. Much less popping, but still occasionally. These sockets have bad spring clips that sometimes fail to do their job. If you are a DIY'er, change them out. Maybe this is just my specimen, as I don't see my 2 colleagues having the same problem.
Summary by Doctorjohn
- Sonically, the APPL is beyond reproach. Awesome Value. With my two colleagues' opinions in, I'm very confident about this aspect. There is no question the designer has a good ear. He's likely only compromised by cost constraints, but I do think he has put money in the right places (like an above-average pair of 300B). It beats many famous names imho. Those interested only need to consider the caveats.
- For those who can solder, KITS are likely still available and that'd be the way to go, as one can easily upgrade and change things (add a terminal strip around the 6F3 if u can). For me, parts quality is not bad at all (except for the 6F3 sockets). Aside from the relay quirks and arcing, our amps have proved reliable. In fact, on more than one occasion, as it sits recessed on the lowest shelf of my rack, I had forgotten to turn it off before going to bed, and I just continue to use it the next morning. The bias is rock steady (attesting to the good 300Bs) and the power transformer just lukewarm even after almost 18 hours of use! American customers need to ensure they get a 120V trannie, or provide their own, or use a Variac. For those who use older equipment, a Variac is a must, as US voltages have gotten out of hand. The more electronically versed you are, the more you will like this offering.
- In case you want to tube roll the 6F3, just go for the ECL85/805 (or as Salamat mentioned, the US 6F5/6GV8). The stock Linlai 300Bs are already very good. Roll rectifiers!
- We would welcome comments on the caveats! Electronically savvy readers please chip in!
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