First Watt F3 compared to my Cary Tube Amplifiers(modified)

[Deang]

Good post. I agree.

[Ski Bum]

Good post. I agree.

With the coffee and Bailey's part, presumably?

[NOSValves]

The J-FET has similar curves to a triode tube, I would expect them to sound similar.

If anyone wants to DIY, NP provided all the details after the first 100 units were sold.

If you have trouble buying the J-FET I have some.

I also have some of the higher power IXYS FETs used in the newer designs, although they are easy to find at Digi-Key.

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10-21-2001 2:08 AM djk

"I hope I dont sound like a complete dolt here but exactly what is the advantage of a low power tube amp vs. solid state stuff. "

Are you sure there is an advantage for tubes?

In the beginning there was the phonograph.

And it was good.

And then came the tube.

And it was, well it was louder.

But not necessarily better.

Feedback. Push-pull. FETs. Then bi-polar transistors.

The first transistor amps were copies of tube amps, just made with transistors. They inherited all the warts from the tube designs and picked up a few of their own. Notice that I haven't said anything bad about the transistor yet.

Lack of odd harmonic distortion in tubes.

False.

All feedback amps have higher odd harmonics. The feedback only cancels even harmonics. This is true whether it is a tube, transistor, or MOSFET.

A single ended amplifier with no feedback does produce predominantly second harmonic distortion driven just into clipping. Beyond 6dB into clipping the spectrum analysis shows the odd harmonics start to rise and look the same as a feedback amplifier.

Electrolytic capacitors don't sound good. The dielectric absorbs part of the signal passing through. When used as a coupling device the electrolytic gives up this charge when the signal goes through the zero crossing point. That means when it is supposed to be dead silent (the zero crossing point) all the hash comes out. Because of the high voltage in tube circuits they don't have electrolytic caps in the signal path. This is one of the main reasons cheap tube gear from the 50's and 60's sounded better than early solid state gear, they didn't have electrolytic coupling caps. When you hear tube freaks looking for 'Black Beauties', 'Orange Drops', and "Vitamin Qs" they are talking about coupling caps. They also didn't need electrolytic caps in the power supply either.

Electrolytic caps in the power supply have poor transient response. In transistor amps this translates into muddy bass. A choke input filter in a tube amp requires only a small high voltage filter cap. A 170W triode amp I used to own only had a single 9µF filter cap, a 'paper-in-oil' type (another tube freak gaga item). A cheap 2A3 based amp found in a console type hi-fi used a choke input filter and was single ended with no feedback. The first transistor amps were electrolytic coupling cap renditions of high feedback push-pull tube amps. They had the extra warts of electrolytic capped power supplies and electrolytic output coupling caps in addition to their electrolytic input coupling caps.

Remarks by 'homeless' tube freaks about the superiority of their glorified 2A3 juke box amps should be taken in this context. The solid state examples they have given as their 'reference' (B&K and Bryston) use un-bypassed electrolytic caps in their signal path and power supply, not to mention high negative feedback. Adding about $4 worth of film bypass caps in the right spots and $1 worth of emitter de-generation resistors to the diff inputs to reduce open loop gain will totally change the sound of these kind of amps. At this point in time the only affordable way to hear a solid state amp without electrolytic caps and feedback is to DIY. The http://www.passlabs.com/ site has good DIY content.

I wish I had the time to write about 12 paragraphs that it would take to straighten out this techno-babble generalized hogwash.... but sorry to say I don't at this time. Some of the above is correct, some of its dead wrong but most of all it is way too generalized to take as serious fact. In its entirety at the very least it is highly misleading as is the listening test that started this thread.

[djk]

Not sure how you got from "The J-FET has similar curves to a triode tube, I would expect them to sound similar." to "If not, then how can they possible sound "the same"?"

The voltage transfer function is very similar to the triode, as well as the harmonic structure. The DF is also similar to a tube amplifier. "If so, who needs it." only someone that can't afford good SE output transformers and the tubes required. The SET sounds very different than most amplifiers, ignoring the miniscule differences in amplitude response that do not account for the difference in sound.

[Deang]

LOL. Well, I saw that you had posted, and scrolled down until I saw the schematic, and then started reading after I saw...

10-21-2001 2:08 AM djk

...which is where I thought your comments started. I didn't even see your comment about J-FET having similar curves to a triode amp.

[Cornman]

With the highest respect for Cask & Mikes opinions - they have more audio experience & understanding of the science of audio then I do, but I must say I disagree, my listening experience is completely different. For me there is a huge difference in sound between the F3 and a tube amp (ie. 300B) on the K402 horn. My wife rarely comments on my different sound experiments, but even she said the F3 did not sound as musical. I can only conclude this is another one of those great examples in the variation in folks ears & taste, or my hearing is far from experienced or golden. [].

This has been another great thread.

Cornman

[The Dude]

Mike thanks for the write up I thought it was very good. It seems the more I get into this hobby the more I like to read about different things.

[Deang]

Good post. I agree.

With the coffee and Bailey's part, presumably?

Yes, absolutely.

[mikebse2a3]

With the highest respect for Cask & Mikes opinions - they have more audio experience & understanding of the science of audio then I do, but I must say I disagree, my listening experience is completely different. For me there is a huge difference in sound between the F3 and a tube amp (ie. 300B) on the K402 horn. My wife rarely comments on my different sound experiments, but even she said the F3 did not sound as musical. I can only conclude this is another one of those great examples in the variation in folks ears & taste, or my hearing is far from experienced or golden. .

This has been another great thread.

Cornman

Hey Cornman I suspect there will be many who will disagree with me because audio is subjective with many variables at play such as system equipment, room acoustics, etc... . So you and I have just added our experiences to the collective for whatever it might add to our understanding of a technology and human subjectivity. Just "maybe" if we removed the variables our ears and taste might be the same or maybe not but the variables have to be accounted for to draw more complete conclusions.

miketn[]

[mikebse2a3]

Mike thanks for the write up I thought it was very good. It seems the more I get into this hobby the more I like to read about different things.

Thanks duder1982.......All I can say is it was my listening experience along with a friend I had invited over during part of the listening test(he owns many amplifiers from McIntosh MC225, Marantz 8b, Cary CAD805c as well as Krell and McIntosh ss amplifiers so he has a good range of amplifiers to compare with) and he also expressed the same perceptions and conclusions when we discussed our thoughts about the comparisons. I also have another good friend(whose listening opinions I respect greatly) that tried the F3 against his 300b tube amps and he said that he and his wife both thought the 300b amp was the better amplifier in their system and again there are variables at play that "might"explain why we came to different conclusions and I hope to hear the F3 in his system soon for myself which should be interesting and part of the fun for me anyway.

miketn

[rigma]

Mike thanks for the write up I thought it was very good. It seems the more I get into this hobby the more I like to read about different things.

Thanks duder1982.......All I can say is it was my listening experience along with a friend I had invited over during part of the listening test(he owns many amplifiers from McIntosh MC225, Marantz 8b, Cary CAD805c as well as Krell and McIntosh ss amplifiers so he has a good range of amplifiers to compare with) and he also expressed the same perceptions and conclusions when we discussed our thoughts about the comparisons. I also have another good friend(whose listening opinions I respect greatly) that tried the F3 against his 300b tube amps and he said that he and his wife both thought the 300b amp was the better amplifier in their system and again there are variables at play that "might"explain why we came to different conclusions and I hope to hear the F3 in his system soon for myself which should be interesting and part of the fun for me anyway.

miketn

That be me Mikey is talking about. Yes, my wife and I both think the 300B is
definitely more musical than the F3 and it only took a few minutes to come to that conclusion, though we did listen much longer. I do have a very different setup
than Mikey, no digital other than CD player for one thing.

I have
heard
Mike's system prior to the F3 and it sounded great and I am sure if he
says the F3 sounds as good or the same as his 2A3s it does in his
system, he knows his stuff.[Y]

I can't explain why we have different opinions other than
our unique systems or maybe even taste. I will say the F3 is the best
SS I have heard and I will be using it for the front Jubilees in movie
mode.

rigma

[erik2A3]

Mike: I enjoyed your honest review, the flurry of subsequent graphs, schematic, and opinions of various topologies, output devices, and passive components (all of which I understand, though with which I do not completely agree) not withstanding.

I've heard others comment similarly about the First Watt amplifiers, many users of which also prefer crossover-less, "full-range" single speaker systems. I have a very good friend who is classically trained professional musician (before retirement) who mentioned to me the similarity between a few of his valve amps (one of which is a Leak St20 that I now own and am restoring) and his recent acquisition of a solid state amp modeled after another Pass design. He ultimately preferred the Pass, but described some of his preferences in terms of human-related attributes such as mood, music choice, listening environment (or rather the response to it). He said the amplifiers all had some really noteworthy -- positively noteworthy -- characteristics that didn't necessarily disqualify the others in terms of very satisfactory performance.

Ultimately what matters, and only what matters, is not response curves or people's differing opinions (that's all they are, including my own) about the use of electrolytic capacitors (which IMO and arguably those of others do not always sound bad and do not always benefit from bypassing with small percentages of film -- I've read lengthy, professional papers arguing in some instances quite strongly to the contrary) but what you found based on your listening. Regarding input to filter choices, capacitor or choke, I would submit that the use of a choke input has advantages beyond the value of capacitor following it. And I would like to qualify this as being based on my own years of experience, and more particularly the experience of others much older than I who have openly and humbly shared their many decades of knowledge with me. But certainly there are times where, depending on the type and characteristics of rectifier chosen (hollow or solid), where a cap input works perfectly well. I've used them both, but am not homeless. Great review! edit: should add, too, that I have a couple of very, very good sounding components that in fact do use an electrolytic cap in a coupling position. I have also used them, everyone avert your eyes!, as the series capacitor in a first order crossover. The reason was the original poly film type sounded too bright, whereas the electrolytic, probably in part due to mildly higher ESR, provided the same level of audible transparency but with the unpleasant edge dulled a bit. An adjustable L-pad could have done the same thing. And YES! I have loved Orange Drops at times, and like the electrolytic in the tweeter branch, preferred it to the much more expensive Teflon whatever-brand-it-was (can't remember anything beyond it being Teflon).

[Deang]

Speaking of electrolytics - does anybody make good ones suitable for loudspeaker use? I built some Type AAs once using the ones available from partsexpress and thought it sounded pretty bad.

[mike stehr]

Speaking of electrolytics - does anybody make good ones suitable for loudspeaker use? I built some Type AAs once using the ones available from partsexpress and thought it sounded pretty bad.

Xicon!! Nice and gritty...

[Deang]

lol. I thought there might be some hope when I found out Blackgate made some for loudspeaker applications, but then by the time I found out about them they discontinued them!

[erik2A3]

Some of the Blackgates were really fine sounding, particularly one series, which was also extremely expensive. There are lots of brands that might be suitable, but you might have to look around a it and experiment. You certainly don't need high voltage types in a passive network; even a 50V cap will work for most instances -- but wouldn't be best for really big amps. Non-polar types, as you know, can be really cheap, cost-wise, and some equally bad in terms of performance. But that said, as hard as I tried, I installed a pair of .1uf high voltage Auricaps in a pair of 300B amps I built last year...no the year before, that were just really rough around the edges. I know some have suggested break in time is needed, but I suppose I wasn't patient enough. I used some built-like-a-tank (maybe for a tank?) Russian PIO that I really liked. I tend to look for low inductance electrolytics, as well. Panasonic produced some that have worked great in cathode resistor bypass positions. Those big Blackgates PSU caps were incredibly well made, sounded liquid and detailed at the same time, were very expensive, and I would absolutely invest in them if available now -- I think! There is a bit of a price sticker shock with those things, as there are with the likes of Mundorf and some others.

[erik2A3]

Xicon - nice and gritty can Be the case, for sure. Just SO much depends on the application, circuit, hearing differences....the usual ancient stuff we've hashed over a billion times.

[erik2A3]

I've used these a number of times, both In power supplies and for a certain single-ended output connection. I have also used them in crossovers, though the voltage ratings are far above what's needed. If you're looking for a decently-priced cap for the AA squawker, might be a possible contender.

http://angela.com/angelaascpolypropyleneandoilcapacitors.aspx

[erik2A3]

And FWIW: I've paralleled motor run types with plastic films for specific values of capacitance. My own very subjective take on this is that paralleling in this way not only provides the reactance needed at X frequency, but can (here's the subjective part) also sound good. For shunt position use, such as across a woofer, I admit I am comfortable with a decent but inexpensive non-polar electrolytic. Back when I was suffering from audio capacitor neurosis, I remember using one of the ASC types above to bypass the cathode resistor on one of the glorified 2A3 juke box amps I built..................never mind, it's a long story. Bottom line is that I have liked the polarized Sprague electrolytics from Tubesandmore.

[mike stehr]

In my breadboard experiences with single ended tube amps, I tend to prefer a good quality film and or polypropylene for cathode bypass. I've used older oil caps...which seemed a bit better than a good electrolytic but not by much. I notice a tighter bass to my ears using plastic caps.