Just from memory it was in one of his build guides at tubelab.com. It was the first time I had heard of doing it. It cannot hurt in our type of use. It is not like our amps are in a moving object being jarred all the time. I have got to where I leave all components off the board somewhat. It makes it much easier to do test if necessary. I do a lot of building and most often I have to do some testing to get the dang thing to work. Easier to replace parts as well.
I suppose this makes you the index case.
This has been a much anticipated moment for me. I have been wanting to build this amp since about this time last year when you first mentioned it. The only reward you are getting out of this is hearing about successful builds and I am proud to be the first to do so. I am now waiting for the promised SE V-fet design. It is my next SS project to look forward to building.
After another hour of listening, quick and dynamic are what comes to mind. I honestly think it is settling in some and getting better if one believes in such and I do.
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HeatsinkUSA.com Serious overkill for this build but I bought them last year along with the store j-fets anticipating this build. I bought them before our store started selling just heat sinks. I would definately buy our store heatsinks now to build a case. I have drilled and tapped many a hole in my previous occupation so this task is not a big deal for me. Certainly the Deluxe 4U chassis is the best way for most to go and you will have an amp you are proud to show off. I live by myself without a lot of visitors and I am more interested in hearing the amp. I do not look at it while listening. If I had not already bought the heatsinks I would have probably bought this. It is a deal for a case with heatsinks.
http://diyaudiostore.com/collections/chassis/products/dissipante-4u
I paid over a $100 for the heatsinks and still had to make some kind of crude chassis for them.
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Here's the amp in the Store deluxe 4U chassis.
PS is Tea's super-size version with Panasonic 105C THA 39,000uF caps.
One image is with a 400VA transformer.
Other image is with a tasty 800VA 24V transformer. It's on the big size, but tempting because it's on hand already.
BK
PS is Tea's super-size version with Panasonic 105C THA 39,000uF caps.
One image is with a 400VA transformer.
Other image is with a tasty 800VA 24V transformer. It's on the big size, but tempting because it's on hand already.
BK
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I want to share my short listening experience with this new build. My go to preamplifier for all my amps that require a preamp whether tube or SS has been my SRPP tube build. Naturally I used if for the V-fet build. I was somewhat disappointed in the soundstage and after a few hours of listening I was getting a touch of listening fatigue. On a whim I decided to install my BA3 preamp I have in place of the tube pre. It is as though someone stepped on the turbocharger in your car. Day and night difference. Immediately my soundstage bloomed and vocals were much smoother and after hours of listening and getting listener fatigue with the tube pre I listened for another hour or two with no fatigue at all. I am going to let the technical guys explain the whys and why nots I can only assume there is some kind of impedance match explanation. The SRPP tube pre has always sound best to me with my other 2 FW amps and a tube amp I have that requires a pre. Everything you have heard about this build is true. Extremely quick and dynamic with a great soundstage now using the BA3 front end as preamp. My BA3 pre is not as complicated as others have built with the regulated PS section. I am sure it is a very good thing but I just built a scaled down typical FW PS, CRC nothing complicated. Front caps 2 10K, 2 .47 resistors and 2 2.2K caps. That simple and it is plenty quite enough. I could not measure any AC at the output of it. Elna silmic 11 as the output cap on the board no exotic boutique film cap for me.
I say go with the 400VA if it is 22V. With a load my voltage is 29V using a 22V 300VA Antek transformer. With a smaller transformer you will have less chance of hum problems. In my opinion 800VA is serious overkill. Like a new corvette for the little old lady who drives 50 mph on the interstate.
Agreed - only presenting for size comparison since I've yet to see the boards setup in the store 4U. The 800VA has the right secondaries and is only collecting dust, but alas it is simply too monstrous for this particular application!
BK
It should be OK if you do not have the B1 buffer that Nelson prefers over passive pots. I listen to a lot of mp3's on my computer so I definitely need an pre with gain and also with my turntable. The gain of the V-fet amplifier is in line with the other FW diy projects.
many thanks for the feedback. do you know what should be the input level (v rms) for this amp in order to get the full output power (15w @ 8 ohm ?) ?
With some research you should be able to find out but my guess would be that 2V's would more than do it. The gain is a closed loop 16db so Nelson say's in the article.
Transformer Volume Control for Vfet amplifiers
indeed, i have been using satisfactory both 10k resistive (2x vishay 533 precision wire-wound poti) and 2x TVC (sowter 9335 TVC) as passive pre-amp with my SET 300b mono-blocks
. so i was wondering if they do a good job with this amp too ;-)indeed, i have been using satisfactory both 10k resistive (2x vishay 533 precision wire-wound poti) and 2x TVC (sowter 9335 TVC) as passive pre-amp with my SET 300b mono-blocks
10k stepped attenuator works brilliantly with my F6.