Review: BBC LS5/1A, Sheer Brilliance
Kondo disciple Preamp vs DIY Kondo clone
Review: Robert Koda Takumi K-10 Preamplifier
Review: Studer A807 Reel-to-Reel
Review: Line Magnetic LM-126 Integrated Amplifier
Talk R2R: Re-issue Tapes from Tape Project and Analogue Productions
Revised Sept 30, 2017 (Forsell taken into account)
The BBC monitors that we regularly encounter are the ubiquitous LS3/5A and the larger LS5/9. This is because these are relatively small, as large boxes with large footprints are out of fashion anywhere where real estate prices are high. Recently, Graham Audio has also "re-issued/replicated" a much larger LS5/8, bigger brother of the more home friendly LS5/9 (reviewed in this blog here) and descendant of the even larger LS5/1A. Aside from these, earlier BBC monitors are seldom seen or heard, although their influence can still be felt in various Spendor (e.g. SP1/2, SP100) and Harbeth loudspeakers (e.g. HL5, M40).
pic from internet.
From Elsewhere, likely original BBC info (typo's unedited; LS5/1AC is the active version of the LS5/1A):
"LS5/1, and LS5/1A
The studio versions of the LS3/1 and A, designed to replace the LSU/10. The cabinets were larger than the LS3/1 and the tweeters were mounted above the woofer, rather than in front of it.
The following units were used: Plessey (LS5/1) or Goodmans C129/15pr (LS5/1A), 15-inch paper cone woofer 2 x Rola-Celestion HF1300 tweeters.
KEF /BBC DESCRIPTION FOR LS 5/1AC:
BBC MONITOR SPEAKERS
The speaker system employs three units, which together cover the audio range available from present day records and broadcast programmes. The enclosure is constructed from high-grade veneered chipboard of a quality, which has been found by experiment to possess the smallest degree of self resonance of all suitable construction materials. The structure is reinforced by internal partitions which restrict the vibration of the back and sides and also by a metal strut between the front and the back panels. Mudocel damping is applied to the top panel.
The internal volume of the enclosure is 4.7 cubic feet and a small vent resonating with the volume of about 50c/s is used to give a slight boost to the low frequency output. Standing wave effects are damped by internal pads of absorbent material.
The lowest frequency unit is a 15 inch paper cone type with a 3 inch diameter voice coil and PVC roll surround. Its axial frequency response extends smoothly up to about 2 Kc/s and it is relatively free of colouration effects. The sound output for this unit radiates through a vertical slot 7 and a half inches wide to ensure good horizontal dispersion up to the crossover point with the high frequency unit s at 1750 c/s.
Two identical HF units are fitted each having a phenolic impregnated diaphragm. The frequency response extends smoothly up until 13kc/s above, which it dies away in a regular manner. Tests have shown that the output to be free from prominent low damped resonances. The two HF units are mounted in a vertical line above the LF unit in such a way that the separation between high and low frequency sound sources is not noticeable to listeners located over four feet away. Both units are operated in parallel at middle frequencies to increase power-handling capacity in the region close to the crossover point.
Above 3Kc/s the input to the upper HF unit is reduced to induce dispersion in the vertical plane and the phase is retarded as to direct the combined radiation pattern upwards
A thirteen element printed circuit crossover network incorporates facilities for equalising minor irregularities in the LF unit as well as providing for adjustment for relative levels of LF and HF units in 1 DB steps. An additional network corrects the diffraction effect at low frequencies due to the finite size of the cabinet, as well as the low frequency loss due to the motional impedance.
There are two versions, one a floor standing cabinet for studio and control room work and a suspended model for use in television control rooms.
The floor standing speaker model LS5/ 1A is intended to be operated on a 15 inch plinth above the floor which positions the HF unit at optimum listening height. The plinth is designed to accommodate the equalised power amplifier conveniently beneath the speaker enclosure.
The suspended model is equipped with metal suspension gear, which enables the entire speaker to be tilted downwards at the required angle The LS5/2A requires additional equalisation at low frequencies to compensate for the loss of floor reflections. A suitable equaliser is available which can be incorporated with the power amplifier if required.
Both cabinets are available in a choice of oiled teak veneer or hammer grey lacquer.
SIZE: LS5/1AC 33 X 19x 17 inches
Weight: 82 Lbs
Nominal Impedance 25 Ohms
Maximum input: 35 watts R.M.S
Frequency response : 40 –13 K/cs +_ 5db
Directivity index: Better than 54 db up to 3 Kc/s reaching 7db at 10 Kc/s
Calibration Accuracy: The axial frequency response checked against a BBC approved standard sample is adjusted so that the curve of the loudspeaker under test does not differ from that of the reference loudspeaker by more than the following amounts:
50 c/s - 200 c/s +_ 1.5 db
200 c/s – 400 c/s 0db
400 c/s – 13000 c/s +_ 1.5 db
13000 c/s- 15000 c/s +_ 2 db - infinity
The reproduction of the Loudspeaker under test is also compared with that from the reference speaker using high quality programme sources and white noise.
LF Unit: 15 inch Heavy paper cone with plasticised P.V.C. Roll surround.
Fundamental resonance: 25 c/s
Flux density: 9000 oersted on a 3 inch dia centre pole
Total Flux : 16000 maxwells
HF Unit: 1.5 inch diameter direct radiator with Phenotic impregnated - fabric diaphram
Flux density : 10,000 oersted
Total Flux : 25,500 maxwells
Crossover Network 13 Element printed circuit network employing Radiometal - - cored inductors and closed terminal metallised foil capacitors. - Completely enclosed and shielded in a steel case.
Other Useful Links:
Wireless World Article on developing replacement for LS5/1A
BBC Paper on Design of LS5/1's successor's LS5/5 and LS5/6
Japanese Site with Great pics of the Active LS5/1AC
- At the Shop The shop sells clone-Dartzeel's and has only a solid state preamp. Even with their solid state amp or a cheap Chinese amp, the LS5/1A sounded good enough. But with my pair of Western Electric 124 that jules had been auditioning and which we brought with us, it became a revelation. Needless to say, since this is a BBC design, the midband was immaculate, rendering vocals perfectly. The treble was just a bit grainy with the ss amp, but this was largely ameliorated by the WE amp. Most impressively, there was great presence, creating the illusion of a live event; indeed, the palpability bore an uncanny resemblance to the Graham LS5/8 (here). My one reservation then centered on the quality of the bass, quite slow, one-note and somewhat truncated. I was weary of possible driver deterioration and urged caution, but jules bit the bullet anyway. As we find out later, that was due to the partnering electronics. Read on...
- Chez Jules I - pre Koda Jules' place is very familiar to me (last reported: the Dahlquist DQ20 here). Equipment Orpheus Zero SE cd transport; Totaldac d1 twelve dac; Van Alstine Pat 5 Preamp (solid state, fully modded dynaco); Line Magnetic LM 126 power amp or EAR 519 power amp. Sound With this setup I heard the LS5/1A twice, once as pictured, the other time with the loudspeakers more or less in the same positions but turned around firing towards the couch (as I heard the Dahlquist DQ20). The sound had improved since last reported (no wonder as the tube amps replaced the ss amps). Now, the LS5/1A really shone! Needless to say, there was just more of everything good. The bit of grain in the treble heard at the shop was gone - one only heard the surprising energy of the dual Celestion tweeters, which worked seamlessly with the 15" Goodmans woofers in the midband. The bass anomaly heard at the shop basically vanished - perhaps it was still a trifle slower than ideal and not the lowest reaching, but it was tuneful and tactile. Old loudspeakers sometimes need to be re-run-in (again, why all the difference from the shop? Read on...) vs Dahlquist DQ20 I wished Jules still had the DQ20's for me to compare. Alas, the small space had necessitated their removal. If my recollection serves me, both had a lively presentation, and excellent midrange presence. To my mind, the Dahlquist DQ20 (at least the treble) suffered a little from being partnered by ss electronics. Let me just say, the Dahlquist DQ20 costs a lot less than the LS5/1A and I miss it.
- Line Magnetic LM 126 Among the Chinese manufacturers I have always regarded Line Magnetic (official site) to be among the best. I have heard their amplifiers, particularly the SET behemoth LM-219IA, perform well at the HK AV Show. I have also heard at friends their WE Horn Replicas and Field Coil Amps and they look decent (hard to individually assess the sound in a horn system, but I know there is a European fan base). They make a bewilderingly huge range of products and in the West it seems only certain products (higher-priced; manageable size) are offered. The LM 126 at hand seems to have limited distribution. One can understand why - it is a another imposing behemoth, not expensive and hard to ship! Design wise, it is a potpourri - said to be based on WE circuit, with inclusion of a clone WE 618C input transformer (definitely not a necessity), but upping the power by using KT66 instead of 6L6. I understand this is a move to accommodate modern "real-world" loudspeakers but, if you ask me, there is no way one can duplicate 6L6 based WE amps with higher power - just not the same things (even for WE, the more powerful 142 is not as good as the 124), not to mention the sheer impossibility of cloning the WE transformers! The LM 126 performed well enough but, even though Jules had installed the best NOS tubes, I still had my doubts - a powerful sound, yes; but not quite an even response, especially when... vs EAR 519 There is no if's and's or but's: disregarding the substantial price differential, the EAR 519 completely outclassed the LM 126. Even with generic tubes, the EAR is much more even across the frequency spectrum and controlled the bass with an iron grip. That said, the LM 126 is quite good for the money and probably more than satisfactory for those who do not need full-range amplification. However, if you are patient and discerning, I'd wait for a good second-hand pair of the 509/519 and you will be settled for life (see also my most recent appraisal of the equivalent EAR 509 MkII) - until you get to know WE, that is...:-)...vs WE Jules did not hook up the WE this time (I never asked for it), but my take by memory is that some of the magic we heard at the shop with the WE is still missing.
- Chez Jules II, post Koda Just as this article was about to be finished, a few days ago, I called Jules and was flabbergasted that he had acquired the Robert Koda Takumi K-10 Preamp and a Studer R2R. Of course this article would have to be extended to incorporate these important new acquisition. So, after yumcha, Trazom, KC, Pluto and I all went to visit. We tested a lot in a few hours, so read on...
- Robert Koda Takumi K-10 (and Forsell Air Reference II Transport) There were two significant changes in the system from Jules I (listed above): the Forsell Air Reference CD Transport substituted for the previous Orpheus; and of course the Robert Koda K-10 Preamp. As a Kondo man, I was of course very interested in this very expensive solid state preamp from a Kondo cohort/disciple (a man who has gone on records saying he has never preferred a solid state preamp), which has won some accolades (see official link, which has review links; avoid the garbage HK magazine). Sound I have to say that what I heard might have been a combined effect of the Forsell and the Koda. The sound actually quite fascinated me. It sounded a tad slower than before, was more upfront, but quite warm, utterly devoid of the nastiness of lesser solid state components. Images were taller and larger than usual, with a fleshiness that I liked. Perhaps because of the warmth, I felt it to be a little less airy than the usual tube preamp in soundstage (not something of utmost importance to me) and depth, The reviews mentioned ultra low noise and distortion, which I agree with, but as usual with designs that place utmost importance in these parameters, a little liveliness may have been sacrificed (I dealt with this important topic in my lengthy review of iFi's iPhono). Although some of this (like reduction in speed, warmth and larger image) might also be properties of the Forsell, much as I appreciated the K-10, I was thinking I'd prefer a tube preamp (like my EAR 912, now relegated to the rear; but more to come, read on...).
- Surprise! David vs Goliath? As it happened, our yumcha friend davewong had been building a Kondo-clone preamp based on the very simply laid out boards by thomasfw. Since it is said to be a Kondo-clone, I expressed an interest to hear it (a very rare occurrence). Suffice to say, davewong geared up and had the prototype ready that day (click on right pic to enlarge), so we took it along to Jules. The DIY preamp employed 6X4 rectification and MOSFET regulation. For the line section, the two triodes of the 12AX7 were coupled and output was cathode follower. No exotic components were used - Dale resistors and Wima red caps for the line section; Philips caps for the power section. Sound The Kondo clone actually sounded quite decent. It seemed to be modern sounding, with a surprisingly fast leading edge (methinks faster than the Koda). Immediately, there were more air and a deeper soundstage, and the front corners were better illuminated. With the jazz CD, virtues were more split: the percussion had better rhythmic expression and exactitude with the Kondo clone; the saxophone and guitar sounded much fuller with the Koda - a surprise as usually one would expect the reverse. A Little Tube Rolling As there were Europhiles present, Valvo long plate's were swapped in for the RCA (D getter, grey plates). Immediately, the saxophone and guitar sounded much fleshier and much closer to the Koda, but at a cost - the percussion lost almost all of the snap (a price I personally would not pay). The Votes Though still a flawed prototype, some of us preferred the DIY tube preamp, but pluto, a DIY man, admired the Koda. As you see, it was not quite a David vs Goliath scenario. Suffice to say, both the DIY kit and the solid state Koda met with our approval, and (except for pluto and maybe jules) this is a rather hard-core tube crowd! After this, we reconnected the Koda and listened to analogue playback.
- Detour: Kondo Clone vs Kondo/Audio Note Japan M7 After I got home, I actually briefly compared it to my own Audio Note Japan M7 (the one in the pic). Both are quite neutral sounding so it is hard to say whether they sound alike, but the challenger was obviously a little on the lean side and rhythmically a little too insistent, without the M7's subtle and articulate nature. Still, a respectable showing!
- Analog Rig I This consists of the Thorens TD-125 with the Linn Ittok arm fitted with an EMT TD-15 cartridge, fed into EAR MC4 and a ss phonoamp (can't remember brand, but it was of some vintage). We listened only to a few cuts. Sound during the visit was a little on the sharp side. I was told after we left a swap to Gotham DGS-1 ameliorated the problem.
- Analog Rig II The big surprise! After my dear friend Robin left for Taiwan, I thought I'd never hear another R2R, but here it is in the form of the Studer A807 (info on this classic here)! And we heard two new tapes, one from Tape Project (Bill Evans Waltz for Derby, link) and one from Analogue Productions (Rickie Lee Jones It's Like This, link). These are both USD 450 a pop. Is it expensive, yes; is it worth it, even I have to say yes! Yes, the R2R playback absolutely trumped the vinyl, according to jules. We didn't really compare but the playback of the two tapes via the Studer was simply breathtaking. Of course I had long known this to be true. This time I shall not waste words, but instead re-direct you to my previous impressions of R2R (under the Label: Talk R2R) - everything said about Robin's R2R applies to jules. That is how good it is! The A807 is a professional two-track only machine, and cannot play four-track tapes. I predict there will be a second R2R deck chez jules soon.
- LS5/1A The LS5/1A is simply magnificent, the best BBC (or BBC-derived) loudspeaker that I have ever heard. How is that for direct utterance? And I know my BBC and BBC derived loudspeakers! Epitome of 2-Way I have always preferred 3-way's to 2-way's, but the LS5/1A is an exception that challenged my views. It is the best large 2-way I have ever heard. Indeed, I don't think the best BBC-derived 3-way's, like the Spendor SP-100 or the earlier BC-3 can match it. That is TALL accolade. Also, once again, a 15" paper cone woofer proves hard to beat; and it is very rare to have a two way that employs a 15" woofer! This is basically one of a kind.
- Robert Koda Takumi K-10 Since we heard also the Kondo clone vs Koda, I am confident I can separate the effect of the Forsell and come to the right conclusions. This is likely the best solid-state preamp I have heard (It sounds better to me than the Cello Suite [a bit too electronic], Mark Levinson ML-6 [not enough resolution], to name two, and jules had owned these before too I think). I think the K-10 would be a godsend with solid state or even hybrid amplifiers, like Koda's own K-70. But while I admire its rock solid steadiness and imperturbable nature, I am too hardcore a tube man and in general prefer a more lit up, livelier presentation, but then, as we witnessed, others may not think so. In the end, no question, it plays everything well! I'd like to listen to it more next time to get more impressions. So, there may yet be a Part II!
- Forsell Air Reference II CD Transport This is a classic that I have heard before on multiple occasions. In spite of, or because of its "deficiencies" indeed it makes CD's sound more musical, more analogue if you will. Since I know jules' system quite well, I have to say I like this transport a lot better than the expensive Orpheus (which makes things sound like digits). It is still amazing to me that transports make such a difference (some of my other favorites are the Audiomeca Kreatura, Roksan DP1 and Theta Data)!
- Reel-to-Reel Although I don't plan to own one, I am very happy the R2R Renaissance shows no sign of waning; rather, it is going from strength to strength. Price of new tapes are expensive, but not really overpriced, if you ask me. You may want to read this interesting interview of Tape Project's Dan (also known as Bottlehead's Doc B, whose cheap products I admire and have had some experience with) to gain some perspective. How does Vinyl Compare? Well, even the most expensive vinyl rigs I have heard have to yield to R2R, in every parameter. The tape advantage is decisive. And Digital? This year is the 35th year of digital, yet sonically it is still inferior to a good vinyl setup, not to mention R2R. Think, 35 years of continual "advances" and it is still a distant third. Don't you think all those data people and critics are laughable?
- DIY Advice The success of the DIY challenger reminds me once again that simple is best. Using simple, cheap and reliable components (like the Dale resistors) more often than not bring better results than stuffing it with expensive boutique components (like expensive caps).
I cannot even briefly tolerate this kind of front-end, but obviously some people do! In my years of hifi wandering, I have heard plenty of way-off stuff, but this experience belongs in the top ten. It made me feel I must write this article:
HiFi Basics VI: Know Your Source(s) and Digital Front-End Buying Guide (coming soon)