I am working on a couple of different JFET Beast DIY designs that can be used to drive headphones. None finished yet. Mr Pass is working on some new JFET Beat designs; none released yet.
Something similar. Details of mounting, biasing and such. The Tokins being N channel parts would look more like part 2 of this project, where the polarities are reversed. One interesting result for N channel follower is that you don't have to reverse polarity twice to get the 2nd harmonic phase negative.
Big upside is the potential for more power.
There will be a version for those devices forthcoming.
Thanks 6L6. I thought so, but wanted to be sure. I ordered a matched pair of the Tokin THF51S SITS from watanabletomoaki. I considered repurposing the Sony VFETs in my Pass DIY VFET amp using complementary Sony VFETs, but I cannot bring myself to gutting such a beautiful amp. I will place my entry in the lottery too. Maybe I’ll come away with a total three SIT amps after all is said and done!
Marvelous project.
The design is with an EDCOR 1:5.
I have JT-123FLP pin version transformers (that give not 1:5 but 1:3, but that will be enough I think, a few dB difference).
Would it be possible to use that in the design?
Probably the EDCOR has more headroom? Say 26 dB?
The Jensen and Cinemag are great transformers, but will not deliver the gain you likely want for part 1 version as there an autoformer won't do the phase inversion.
The Edcor was chosen for cost and gain and gain. In spite of somewhat inferior specs it has a popular sound as seen with the M2. Also ZM likes it.
Tokin SIT usage
@rhing:
"This might be a silly question, but would the Tokin VFETs (2SK180, 2SK182 andTHF51S) work in this design as well?"
Is there such a thing as a silly question? Nope.
I am wondering the same thing. As the chance to be gifted one of the VFET amplifiers (and such a wonderful gift!) is far from certain, I am interested in using my Tokin SITs in a similar circuit.
In Nelson's SIT-3 article he describes careful gate-voltage matching between the Mosfet and the SemiSouth SIT. For a Tokin SIT this might be a challenge for us non-experts. And there must be other issues. But I'm hopeful Nelson's design may accommodate such variations, and both Jim (6L6) and Christophe (SoundHappy) have made encouraging remarks. And of course Nelson's most recent comment.
@rhing:
"This might be a silly question, but would the Tokin VFETs (2SK180, 2SK182 andTHF51S) work in this design as well?"
Is there such a thing as a silly question? Nope.
I am wondering the same thing. As the chance to be gifted one of the VFET amplifiers (and such a wonderful gift!) is far from certain, I am interested in using my Tokin SITs in a similar circuit.
In Nelson's SIT-3 article he describes careful gate-voltage matching between the Mosfet and the SemiSouth SIT. For a Tokin SIT this might be a challenge for us non-experts. And there must be other issues. But I'm hopeful Nelson's design may accommodate such variations, and both Jim (6L6) and Christophe (SoundHappy) have made encouraging remarks. And of course Nelson's most recent comment.
Ohh sh!!!tttt yesss! Wow, 22 thread pages in under 24 hours, that's got to be some kind of record.
Better get off my @ss and move this excess audio equipment I've been meaning to sell for months to find this.
Thanks so much Papa! You da man!
P.S. I've been mentally planning my first Pass DIY amp for several months...I was planning for it to be an Aleph J, but is there any reason not to build this one first instead? I do have a good bit of experience building DIY headphone amps and a version of Mauro Penesa MyRef though, so it's not like it'd be my first ever DIY amp build.
I see the new VFET only produces 10 watts/ch vs 25 of the Aleph J...anyone have thoughts on how the 2 differ in sound characteristics?
Better get off my @ss and move this excess audio equipment I've been meaning to sell for months to find this.
Thanks so much Papa! You da man!
P.S. I've been mentally planning my first Pass DIY amp for several months...I was planning for it to be an Aleph J, but is there any reason not to build this one first instead? I do have a good bit of experience building DIY headphone amps and a version of Mauro Penesa MyRef though, so it's not like it'd be my first ever DIY amp build.
I see the new VFET only produces 10 watts/ch vs 25 of the Aleph J...anyone have thoughts on how the 2 differ in sound characteristics?
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@rhing:
"This might be a silly question, but would the Tokin VFETs (2SK180, 2SK182 andTHF51S) work in this design as well?"
In Nelson's SIT-3 article he describes careful gate-voltage matching between the Mosfet and the SemiSouth SIT. For a Tokin SIT this might be a challenge for us non-experts. And there must be other issues. But I'm hopeful Nelson's design may accommodate such variations, and both Jim (6L6) and Christophe (SoundHappy) have made encouraging remarks. And of course Nelson's most recent comment.
As I have said in the article, the Vfet is a prima donna, and each has an environment that brings the best performance. So yes, you can use the part 2 circuit as presented but you are better off with some variations that will be explored. This will be true for the 2sk60 and 2sj18 as well.
Thank you Papa, and thank you for designing the amps to accommodate other SITs like the Tokin THF51S in case we can’t get the unobtainium Sony VFETs. I’ve built the previous Sony VFET kit using complementary Sony VFETs, and it’s a great amp. I am really looking forward to trying the SE SIT amp design.
Too funny! I've never heard that description used before but yes it's true. More so with the Tokins than the Sony and Yamaha V-FET's I have which were match picked for use in complimentary pairs back in the day.
I have both AJ and SONY VFET SE (L'amp). Yes, AJ is more powerful, and it sounds more powerful. It's probably not too far from the difference between Pentode vs Triode tube amps, but AJ still sounds unmistakably single ended. Build both, and you'll be happy.
Rough dimensions coming in at a very tidy and svelt—
in inches:
11.5 Wide x 12.5 Deep x 7.5" high from the floor
metric:
292mm W x 318mm D x 190mm H
Add some depth for the VERY nice jacks.
Incidentally—around 115F on the top of the sinks, dropping to mid 90s midway down, about 108F on the body of a Vfet. Brick is tepid to the touch. Sweet! Been running this for a couple of days, all types of music. Vinyl and hi-res digital (plus movies)—it's fabulous (and an honor to get to play it ahead of the curve so to speak).
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