[Jaytor]

Thank you.

Yes, this is my own design but there are various parts of the design that I borrowed from other people’s designs.

[BrandonB]

Thank you.

Yes, this is my own design but there are various parts of the design that I borrowed from other people’s designs.

I want to say it again.  You and everyone else on here is making some awesome looking gear!

[poseidonsvoice]

Jaytor,

As I commented on diyaudio, phenomenal work! This is a $20K preamp through and through! The EML20A is a sleeper of a tube. Congrats on your hardwork!

Best,
Anand.

[Early B.]

The EML20A is a sleeper of a tube.

Yep. I have a pair of them driving my 300B amp. Well-built, too.

[Jaytor]

Thanks for the kind comments. So far, I've only listened to it for a little while in my workshop system. I'm hoping to install it in my main system sometime this week but I have to move some components around to make room on my rack. I'm looking forward to hearing how it sounds.

[jmimac351]

I was fortunate to get the chance to purchase a 25th Anniversary Sony VFET amplifier from Diyaudio. I had no idea what to expect from this amp. It’s incredibly rare and there will be no more so I ordered one while I had the chance as it is the last run and they’re now gone forever. The moment I fired it up and music started playing I knew this amp was magical. The midrange is the best out of any amp I’ve heard SS or tube. It produces vocals more natural and realistic than any other amp I ever had. It’s a shame that there are no more Sony VFETs because this thing is the best 10watts I own.

As I'm sure you're aware, the 2025 Burning Amp event happened this weekend in Petaluma, CA.  I was at Road Atlanta this weekend, but there was a $5 ticket to be able to view presentations, with obvious especial interest in what Nelson had to share.  It was also possible to bid in the auction via the zoom call.  I was aware that there were 4 First Watt amps that would be auctioned, some prototypes Nelson built.  What I didn't know was there was also a Sony VFET Anniversary amp to be auctioned. 

Well, I got it - and I am very excited to have been able to snag one.  With how much I love the SIT-5 monos, I figured this was a can't miss buy. 

It turns out that Jim (6L6) built the amp.  Can't wait to hear it!  It will be very interesting hearing next to the SIT-3 I have.  I've found that I enjoy mixing that amp in, still - a lower powered, stereo amp with a different flavor.

Thanks for sharing this.  I'm glad I was able to catch the train! 

[mkrawcz]

jmimac351, congrats! You will love that little Sony amp.

[jmimac351]

jmimac351, congrats! You will love that little Sony amp.

Thank you for your helpful feedback! It is going to be very interesting to compare to the First Watt SIT-3... 2 different VFET amps.

It will not surprise me in the least if I like the Sony VFET better - and both still GREAT.

And one costs 5X the other...
 

[jmimac351]

@mkrawcz, looking at the pics of your VFET amp, it looks like we have the same N-channel VFET setup.

Stuff I'm digesting about it:

Reading thru the writeup from Nelson, it appears our N-channel setup means normal hookup for input and speaker (no reversing +/-), and that will have NEGATIVE 2nd Order Harmonic, correct? 

Still reading a lot, and see the various front end boards Mark Johnson designed.  Nice wormholes. And also very interesting about this same basic setup working with MOSFETs, JFETs, etc other than VFETs.  It almost seems like a little ecosystem of different configurations depending on the output devices you can get / want to use.  I guess there are more of those still to come.

These appear to be 10dB gain? I guess I'll swap resistors in the preamp to raise gain level again to +9db in my KX-5.  I know the value to raise to to +12dB, and I wonder what the limit is.  Going to check with Jake / Ariel. 

With the SIT-3 at 11.5dB input gain, SIT-5 at 19dB, and VFET at 10dB... I guess +9dB gain on the preamp may work out well for all three.

The other thing that occurred to me... I suppose the VFET amp can pretty easily run on batteries?  36v input?

I hope to have it by the end of next week.

[mkrawcz]

@mkrawcz, looking at the pics of your VFET amp, it looks like we have the same N-channel VFET setup.

Stuff I'm digesting about it:

Reading thru the writeup from Nelson, it appears our N-channel setup means normal hookup for input and speaker (no reversing +/-), and that will have NEGATIVE 2nd Order Harmonic, correct? 

The other thing that occurred to me... I suppose the VFET amp can pretty easily run on batteries?  36v input?

Yes, the N channel is normal. Mine is using some extra wire I had from Danny and I didn’t have enough red to do the positive side so it’s white. Can it run on batteries? Probably, the amp draws 1.6amps which isn’t too much on bigger batteries. I may give it a try at some point.

[mkrawcz]

Just got this little 20 watt class A amp that is allegedly a clone of the Musical Fidelity A1 without the preamp section. BRZHifi A1S, cost $225 on Amazon and I am shocked at how good it is. This beats all the cheap class D amps you will find on Amazon by a mile. I see some opportunity to tweak also. Playing it through the NX-Bravo Towers and it’s very much a high end sounding Class A amp. Still can’t believe this cost so little. Just the chassis alone is something that would cost about $200 for DIY.

[goggle1824]

But against the Zenductor II? 🤔

[mkrawcz]

But against the Zenductor II? 🤔

Zenductor II wins with slightly better imaging and more bass punch. This is mostly because they’re monoblocks. Both amps are actually similar sounding. Warm, vivid midrange.

[goggle1824]

Zenductor II wins with slightly better imaging and more bass punch. This is mostly because they’re monoblocks. Both amps are actually similar sounding. Warm, vivid midrange.

Interesting… remind me, did you do any “upgrades” on your Zenductor II or is it pretty much stock?

Thx!

[mkrawcz]

Stock. Not too much to upgrade. If it had twice the power it would be ideal.

[goggle1824]

Thanks. I’ve read that elsewhere as well.

I picked up a set of boards from Dan at DIYaudio because I saw you mention to Jim (different thread) how much you were liking yours and that he should check it out.

There are some builds over there that people are planning to have, and increased the power, though the choke needs to be bigger then as well, as I understand it 😬😅, and with bigger chokes comes bigger costs. Regardless… there are folks that are actively pursuing more output I believe. 🤔👍🏼

[jmimac351]

Thanks. I’ve read that elsewhere as well.

I picked up a set of boards from Dan at DIYaudio because I saw you mention to Jim (different thread) how much you were liking yours and that he should check it out.

There are some builds over there that people are planning to have, and increased the power, though the choke needs to be bigger then as well, as I understand it 😬😅, and with bigger chokes comes bigger costs. Regardless… there are folks that are actively pursuing more output I believe. 🤔👍🏼

Cool!  Evidently Dan is working on that for several people, including us. 

The Sony VFET shipped out today and I should have it by next Friday.  They had some good stuff up for auction.  The VFET amp is what I really wanted.

I am also having another look at the FM5 Redux.  Big Picture... I have learned what I like and think I know how to get it.  I am actively trying to cycle out of quite a bit of bigger / and bigger $$$ amplification... and into smaller, boutique, custom equivalents, at a fraction of the cost.  And so far, it all sounds better too... but it has to be properly paired to the speaker(s).   

Not touching source components, yet. I am very happy with my source gear and happy with the money I have in it. 

[BrandonB]

Just got this little 20 watt class A amp that is allegedly a clone of the Musical Fidelity A1 without the preamp section. BRZHifi A1S, cost $225 on Amazon and I am shocked at how good it is. This beats all the cheap class D amps you will find on Amazon by a mile. I see some opportunity to tweak also. Playing it through the NX-Bravo Towers and it’s very much a high end sounding Class A amp. Still can’t believe this cost so little. Just the chassis alone is something that would cost about $200 for DIY.

I think that is the same little amp that Steve McCormack with SMc Audio has taken and is starting to Hot Rod them. There is a YouTube video with Audiophile Junkie.

[mkrawcz]

I think that is the same little amp that Steve McCormack with SMc Audio has taken and is starting to Hot Rod them. There is a YouTube video with Audiophile Junkie.

I just bypassed the volume control which made a big difference. This amp is awesome.

[goggle1824]

mkrawcz, you have a nice little collection of amps, (mostly class A?), I’d be interested in a little pros/cons comparison 😇😎. Also, what are you listening on?