Next Amp Recommendation Solicitation

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#41
The details are trickling in. What else can we add to the list? What's incorrect?

The Last of the Sony VFETs
starring
- SE with mu-follower (I think)
- 5 daughterboard FE's; one with Toshiba/LS JFETS; no SMD
- Custom chassis
- desktop supply w/ nice filtering
- 200 N channels; 200 P channels (similar but not same circuit)
- Lottery method for right to purchase (last I saw from Jason)
 
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#45
Mark Johnson said:
You'll do new things, you'll learn new skills, you'll use new semiconductor devices (power BJTs! what a concept!), you'll expand your horizons. And oh by the way you'll get an amp with LOTS MORE power output, which may come in handy for future loudspeaker experiments, or just future This-versus-That amplifier comparisons.
Click to expand...

MJ's nudges towards getting DIYers out of their comfort zone is commendable. 🙂
 
#46
ppinto1 said:
Thanks Mark Johnson. I may do that in the future. Currently, I'm on assignment working from an apartment; so my listening is generally near field at low SPL's to keep my neighbors happy. I would certainly like to go through the exercise of choosing power supply components and heat sinks based on proper calculations.

Russellc, that's interesting. So, I'd have a different mono-block for each speaker to compare? Or, did I miss something?

Thanks Codyt. I don't have any distortion measurement equipment; so I wouldn't know how much H2 has been reduced after properly setting the bias. I think I was getting some odd order harmonics, because the sound is smoother now.

While I still prefer the mids in the Aleph J, the overall system with the F6 is the best sound I've ever heard. I haven't ever heard such finely detailed separation of instruments. When I try to work with music in the background, I literally get distracted by pieces I've heard hundreds of times.

Several years ago, when I first wanted to build from diyaudio, an audiophile friend encouraged me to buy McIntosh gear. I shelled out, big time, for a C50 and an MC275. The DAC in the C50 is a nightmare (e.g. locks up with format changes via USB); but I always thought the 275 sounded very good. In fact, it does sound very good and had brought my attention to detail previously unexposed in well known content.

That process is happening all over again; this time with added depth and phenomenal staging. That may be partly due to the B1K, but the resolving capability of the F6 is amazing. I'm in awe. Thank you, Mr Pass!
Click to expand...

The idea is that each amp has a board and outputs of the other. The switch lets you select which board is activated. Push the switch one way (with amp off!) and its a F6 mono block, the other way, it is a AlephJ mono block. Set the other amp the same way. Now you have either AlephJ or F6 as mono blocks.

I did it with M2 and AlephJ. I had a transformer fail in one of them, converted the other back to stereo and repaired the other. Now I'm about to switch them back.

The only thing I don't like about it is that I cant use the AlephJ or M2 in "separate" systems, now of course, they must be used together
 
#47
codyt said:
F6 is a great amp. I’m consistently swapping F6 and Aleph J back and forth in my system. If I didn’t enjoy building so much, I could easily stop with either of those amps and be happy the rest of my days.

Having said that, if you ever run into a pair of the semisouth parts, try putting them in the AJ. For me, an AJ with semisouth output is a perfect blend of AJ and F6.
Click to expand...

The original FIRSTWATT F6 used semisouths as well, I believe...
 
#50
Nelson Pass said:
Yes. Given the price and scarcity of the Sony VFETs, I am mounting the
output transistors and enough parts to protect them and allow a
functional test.

This kit is designed to be friendly to newbies as well as you sophisticates,
and this way there will be fewer tears.

Don't worry, there are parts to add, and you can still pick your own
caps. It's powered by a desktop supply and I designed a nice little
filter to take the noise out.

There will be options for five, count 'em, five front end designs,
one of which is my M2 input stage, and the others are Mark Johnson's.

(collect them all!)

And wait till you see the chassis....

:snail:
Click to expand...

So finally 2020 will not be as bad as expected 😀
 
#53
Russellc said:
The idea is that each amp has a board and outputs of the other. The switch lets you select which board is activated. Push the switch one way (with amp off!) and its a F6 mono block, the other way, it is a AlephJ mono block. Set the other amp the same way. Now you have either AlephJ or F6 as mono blocks.

I did it with M2 and AlephJ. I had a transformer fail in one of them, converted the other back to stereo and repaired the other. Now I'm about to switch them back.

The only thing I don't like about it is that I cant use the AlephJ or M2 in "separate" systems, now of course, they must be used together
Click to expand...

Thanks for the explanation. That sounds like an A/B solution with minimal cabling!
 
#54
In mono block, grounding seems better, ( more quiet) and stage expands and they sound a little more powerful than stereo format. This has led me to always building single chassis amps as dual mono...Like I did with my first FirstWatt clone, F5. Lesson learned.

Russellc
 
#56
There will also be an offering of both VFET projects without the VFET for those who
have them already. I know a couple guys who pulled them out of old dead Sony
amplifiers. The good news is no bias or matching issues.

Also, the designs will accommodate other TO-3 Fet parts, not just Vfets.
 
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