Top rack, from L: Aurorasound Vida, Fosgate Signature, Almarro 205A; below: Yamamoto CA-04.
Review: Fosgate Signature Phonoamp
NYC Analog Log (23-4): Sun Valley EQ-1616D, Part II
Fosgate Signature Phonoamp
First Impression Very soon after it came out in 2010, I bought one. It's amazing that I have not formally reviewed this, one of my staples, even though I have commented on it many times, starting with my 2011 Retrospective
...Ever since it came out it has garnered much attention, including a review in TAS. There is also a nice review in Audio Beat. This is one of those rare phono preamps with a fully active MC pre-pre section. As noted in the Audio Beat review, the 60 db gain for MC may be a little low for some people but it is perfectly fine in my case, even with the very-low-output Denon DL-304 (0.2 mV), since I mostly use preamps with high gain and efficient speakers. I am happy to report tube rolling is a breeze as the phonoamp does not seen to run the tubes unduly hard and many NOS tubes sound quiet in it. One thing that puzzles me about the industrial design: the two round cans flanking the tubes lead one to think they are input transformers; no, they aren't, this is a strictly active device and those are for decorations only. Incidentally, I think there is a new 10% price hike, but you can still find many selling at the original price of USD 2500. Review later...
Design A word on the patented, and unusual design (the Manual can be downloaded here), in Fosgate's own words:
- All amplification is accomplished with the SRPP (push pull) configuration for the best possible linearity, lowest noise and distortion.
- No solid-state devices are placed in the signal path and a tube is used for the high voltage rectifier.
- The power supply is very different and contributes to the high performance. There are no regulated power supplies. Each tube stage is powered by a separate storage capacitor that acts like a battery. These storage capacitors are very large (10 to 20 time's oversize). The power supply simply holds the voltage across the capacitors like a "trickle charger". PC board layout is "Dual Mono". The channels are located on opposite sides of the circuit board in near mirror image with dual triodes in a row down the center.
- The first stage has no NFB to interact with the cartridge. The second and third stages are enclosed in a single feedback loop incorporating both positive and negative feedback.
- The RIAA network is divided into two sections, one passive and one active. The upper half (above 1KZ) is accomplished with a passive network between stage one and two. The lower half (below 1KZ) is accomplished with an active network around stage two and three
...The next day I connected the Linn/Koetsu rig to the Fosgate and, as they say, the rest is history. In this system, the Koetsu did even better than on the AQVOX, and perhaps even better than on the Aurorasound. The Koetsu did everything the PC-1 did, but at a somewhat smaller scale, but I feel it has been optimized. What amazes me is that the all-tube Fosgate yields not one iota to either the AQVOX or Aurorasound in the transient portrayal of the leading edge; every emphasis is microdynamically portrayed, no mean feat, with the additional benefit of a smoother sound...
And in this article I said:
...I have never really written a formal review for the Fosgate, but it was in my Best of 2011 article. It has been one of my mainstays and here I have to sing its praise again. Its superb design allows pure tube MC amplification without the use of SUTs, a feat rarely accomplished (this also meant tube rectification for lower noise). A bargain and wonder, but one that is little appreciated. The world is not fair, right?
vs Sun Valley SV-EQ1616D
After I thoroughly evaluated the Sun Valley (SV), it was only natural that I made the comparison with the Fosgate. In design and ergonomics, there are superficial similarities and differences. Similar: both are tube-rectified, not so common at any price; both have tube MM sections. Different: critically, the Fosgate has an all-tubed MC section (a rare beast) and the SV a FET Headamp (common); usefully, SV has 2 inputs while the Fosgate only has 1; usefully, the Fosgate has Loading Selector (100, 300, 500, 1K and 47K ohms), while the SV has none (the MC is loaded at 50 ohm); not so usefully (for most people), the SV has various bells and whistles for EQ; of debatable efficacy, SV also has a Mono button (taken from the L channel).
Sonically, please first refer to the SV review, Part I linked at the top. I used mostly my Yamamoto CA-04 Line Preamp, AES SE-1 and Elekit 8300 300B amps driving various LS3/5As. All I have to do here is to tell you how the Fosgate trumped it:
- Macrodynamics (and Gain) This is the most important difference (the divide is big). Now, remember I use the SV's own FET headamp, and have an active Line Preamp with Gain to help. They have probably about the same gain, but the Fosgate sounds much better, unfolding loud passages with more force, yet with more detail, air and refinement, and even less noise. As mentioned in Part I the SV does better by dynamics with a SUT, yet it loses much finer details, especially compared with Fosgate.
- Microdynamics WIth classicals, in the softer passages, such as the Tapiola mentioned in Part I, SV regains a little ground. Its more overt manner (within its comfort zone) makes the Fosgate sound a tad cool, yet the Fosgate is no slouch and within the whole sweep of music this is not at all sufficient to turn the tide. Add the dynamic findings together, I'd think the SV, with or without SUT, is more suited to smaller scaled music, like jazz or vocals, whereas the Fosgate can do everything well.
- Loading I note that with the Fosgate I loaded the 2 Denon DL-103 (stock and with Midas) at 300 and 500 ohms (little difference), a theoretical advantage over the SV when its FET section is used (50 ohm). Yet it should be noted that I still prefer the Fosgate over the SV used with SUT (when there is little loading concern). The performance of SV surely can be improved by using more and more expensive SUTs, but is that the way to go?
- Resolution and Air The SV in any configuration is a little less resolved. And both have very good tubes in them.
- Mod Potential I note that Andy's SV already has V-Caps in them (Kevin opted for Mundorf instead), and the Fosgate is stock, with WIMA caps (pic below). Upgrading them is a definite possibility.
- Fosgate Signature This is a Masterpiece. Achieving this level of quietness with pure tube circuitry is a miracle! Jim Fosgate had passed at the end of 2022 and it's regrettable we shall not have more innovative designs from him! It's too bad that it has long been discontinued. Second-hand units are probably not too hard to find if one is patient. I don't think it was that popular in its time. One reason for that is likely because a few users in forums posted on the lack of gain in their systems. In this world where many people use Passive Preamps or Preamps with little Gain, that can happen quite often (and indeed with that Audio Beat reviewer). I always say, and I repeat, if you are into vinyl, you should have plenty of gain at the preamp. Little or no gain at the Preamp ruins a lot of analog and SET experience, and people never learn. Just numbers won't do, and Straight Wire with Gain is no more than wishful thinking. My Denon DL-103 is nominally 0.3 (often a bit higher) and I never have any problem. Have you noticed that almost all reviewers now just use their SUTs? This is to sidestep precisely this problem, and also why many more people use SUTs now with MM phonoamps, though I prefer an active MC stage whenever I can. There have been very few notable all tube MC Headamps (whether standalone or built into a phonoamp or full function preamp). Tall achievement! If the SV is Class A in Stereophile, the Fosgate is A++!
- Sun Valley SV-1616D While I think this is a very good tube MM (and a competent hybrid MC) phonostage, I think it's on the pricey side (even as a kit). If you add SUTs for MC use it's even pricier. Its Bells and Whistles are likely to be under-used, if at all. On the other hand, if you already have good tubes and SUTs on hand, it's a better proposition. If you see analog in the long term, buying tubes and SUTs are likely worthwhile anyway, just that it could be a lot of money (and no end to it, but that's part of the fun). If you go the way of SUT, I'd advise buying an external one rather than having some custom made ones built into the SV. This allows for flexibility. Personally I do not buy the SV because in terms of MM phonostage, many of the built in phono sections of vintage full function preamps are just as good, or even better. The Citation I is the best example. If you use its Tape Out it is a formidable phonostage. Similarly, excellent phono sections are the rule rather than the exceptions in older preamps. Just to toss off a few in my collection: MFA Magus, various Counterpoints and ARCs, Melos, etc. And among more recent stuff, second hand markets can still offer good value. An old Shindo Preamp not only offers a great preamp, but one with an exceptional phono section. Not cheap, but worth consideration for a vinyl lover. Of course, there are those unwilling to navigate through the vagaries of the second-hand market - I understand. I personally puzzle at the Stereophile Class A rating, when the FET headamp is basically brushed over, and contingent upon using a SUT and expensive cartridge as HR did. But then, many other things in Class A probably shouldn't belong there in the first place!
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