A few years ago I purchased Sony VFETs, I have now 6N and 8P. Then I've have read on Papa’s article from 2014 where we can read about CSX1:
"Ah yes, the sound. Well, it's different. A lot of clarity without annoyance. For a little amplifier it holds up well at your higher volume levels, and certainly doesn't get harsh with abuse, and is better than a lot of my other little amplifiers at complex symphonic pieces, probably due to the largely third harmonic character. It is very non-fatiguing, the kind of piece that makes you go through most of your record collection."
That sounds delicious! It is actually what I am looking for. I am happy with F2J which has 2nd dominant harmonics, this one is more into the 3rd.
Now I am not trying to be a smartass… 🙂
My understanding why Mr. Pass used transformers in CSX1 and CSX2 is:
I am not trying to say that they are not necessary but for me personally I would sleep better not having them in the signal path (also having just a bit of the ego tickling having own(ish) design) I thought it could be a bit of mine till I found Zen V5... well… that was at least a confirmation that it wasn’t foolish of me to remove the transformers from the circuit. As Zen Mod pointed out this design is more prone to the PSU ripple. But using the PSU circuit from the Zen V5 I got -109dBFS 100Hz at 1W 8 Ohm 1kHz on the simulation, comparing to -93dBFS on the CSX1 with a "smaller" PSU.
So the rest of the measurements from the simulation are:
Total Harmonic Distortion(1W, 8Ohm, 1kHz): 0.090558%, 2nd -99dBFS, 3rd: -60dBFS
Frequency response: 1.5Hz - >1MHz @ -1dB
Gain (1W, 8 Ohm, 1kHz): 2.8x
Output impedance: 4.16 Ohm
Without the buffer on the input I am getting up to 89kHz at -3dB (1kOhm source), hence the buffer.
Since Zen Mod banned me for disliking transformers 😀 I have to ask others for their opinions:
Am I risking anything here starting the project and not adding the transformers here?
Is there anything I am missing here/not seeing the problem?
Do you think it's worth trying?
Any ideas to change/improve something?
"Ah yes, the sound. Well, it's different. A lot of clarity without annoyance. For a little amplifier it holds up well at your higher volume levels, and certainly doesn't get harsh with abuse, and is better than a lot of my other little amplifiers at complex symphonic pieces, probably due to the largely third harmonic character. It is very non-fatiguing, the kind of piece that makes you go through most of your record collection."
That sounds delicious! It is actually what I am looking for. I am happy with F2J which has 2nd dominant harmonics, this one is more into the 3rd.
Now I am not trying to be a smartass… 🙂
My understanding why Mr. Pass used transformers in CSX1 and CSX2 is:
- Use of simpler and cheaper PSU that makes life easier for DIYiers
- Possibility of using balanced input
- Floating input hence no ground loops
- Signal on the amplifier output is not inverted.
- Transformers might have (or rather have) some impact on the signal
- As a result of the electromagnetic field radiation from PSU transformer they may introduce a hum
- I appreciate the minimalist approach 🙂
- I believe the transformers are not absolutely essential (same phase on the both VFET gates)
I am not trying to say that they are not necessary but for me personally I would sleep better not having them in the signal path (also having just a bit of the ego tickling having own(ish) design) I thought it could be a bit of mine till I found Zen V5... well… that was at least a confirmation that it wasn’t foolish of me to remove the transformers from the circuit. As Zen Mod pointed out this design is more prone to the PSU ripple. But using the PSU circuit from the Zen V5 I got -109dBFS 100Hz at 1W 8 Ohm 1kHz on the simulation, comparing to -93dBFS on the CSX1 with a "smaller" PSU.
So the rest of the measurements from the simulation are:
Total Harmonic Distortion(1W, 8Ohm, 1kHz): 0.090558%, 2nd -99dBFS, 3rd: -60dBFS
Frequency response: 1.5Hz - >1MHz @ -1dB
Gain (1W, 8 Ohm, 1kHz): 2.8x
Output impedance: 4.16 Ohm
Without the buffer on the input I am getting up to 89kHz at -3dB (1kOhm source), hence the buffer.
Since Zen Mod banned me for disliking transformers 😀 I have to ask others for their opinions:
Am I risking anything here starting the project and not adding the transformers here?
Is there anything I am missing here/not seeing the problem?
Do you think it's worth trying?
Any ideas to change/improve something?
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"Things should be made a simple as possible, but no simpler"
Albert Einstein
"Less is more"
Ludwig Mies van der Rohe
"High quality sound can be obtained with simple and accessible circuits."
Nelson Pass
Now to the point. I think the amplifier from the DIY store will satisfy more diyiers than CSX Zen V5 (if I can call it like that), more speakers will be happy with this amplifier, the VFETs works here in a common drain mode, giving (probably) quite low output impedance.
But I am into full-range, high efficiency light paper cones where even 4Ohm output amplifier should be a perfect match.
EDIT: BTW I don't have the parts, I have two perfectly matched P pairs, but I'm missing one matched N pair 🙂
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OK then 🙂
Don't forget to: regulate supply's and apply bias supply before main power, ect.
It wont be as simple once that is all included but you will get there.
Don't forget to: regulate supply's and apply bias supply before main power, ect.
It wont be as simple once that is all included but you will get there.
You don't need to match P to N, as they have separate bias voltages, but if you don't match P to P and N to N... well 🙂
we are changing the subject
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Isn't you who complain first about unmatched Vfet's ?
Matched is necessairy for Vfet Part2 with two parallel pairs for one mono channel.
Good luck to your project(s)
Matched is necessairy for Vfet Part2 with two parallel pairs for one mono channel.
Good luck to your project(s)
But this was no subject 😀 better find what you can build..
Botte proposition in post # 2 is interesting.
Stereo amplifier with 2 Vfet pairs only, pcb in the store, and great front end included 😉
Edit: With 4 not perfectly matched pairs you can build two DIY Vfet amplifiers post #2
Connect them in two balanced signal mono blocks
Again good luck build what you enjoy anyways 😀
Botte proposition in post # 2 is interesting.
Stereo amplifier with 2 Vfet pairs only, pcb in the store, and great front end included 😉
Edit: With 4 not perfectly matched pairs you can build two DIY Vfet amplifiers post #2
Connect them in two balanced signal mono blocks
Again good luck build what you enjoy anyways 😀
Please note that I did not ask for a recommendation on what amplifier to build. My questions and concerns are specified in # 1.
@ Ripson
Yes was not clear post # 3 is about DIY Vfet amp or Vfet Part2.
Ok you have your own idea so go for it! Enjoy
Have a nice day 🙂
Yes was not clear post # 3 is about DIY Vfet amp or Vfet Part2.
Ok you have your own idea so go for it! Enjoy
Have a nice day 🙂
ripson, as I said somewhere ( in PM?), just go for it
though, if your speakers are so efficient, it would be clever at least to think about making a follower with these
do you have any specific measurements or findings - how much power you need?
of course you'll make what you choose ( I'm leaving you that freedom, generously
) , I'm just broadening perspective
though, if your speakers are so efficient, it would be clever at least to think about making a follower with these
do you have any specific measurements or findings - how much power you need?
of course you'll make what you choose ( I'm leaving you that freedom, generously
) , I'm just broadening perspective
of course you'll make what you choose ( I'm leaving you that freedom, generously
that's very kind of you Aleks 😛
"go for it" was probably for F5 with Hitachi mosfets and Nec jfets 🙂
I am afraid I would need some voltage gain if I would use VEFTs in a common drain mode, then I would probably add something F5-ish on the front ending up with something similar from VFETs part 2 🙂
By the way, do we "squeeze the sweetness" out of VFETs when they are working as a follower?
The new Vfet amplifier will 1) require only one Vfet per channel, 2) those can be either P or N, and 3) will have available no less than FIVE input stages, and some of those input stages have no signal transformer.
I’m sure you’ll be able to find a combination you will be delighted with!
I’m sure you’ll be able to find a combination you will be delighted with!
well, frankly, I shared same suspicion with you , but later did learn to appreciate VFets "even" in follower role; you're getting some wakoo sense of speed and easiness, whichever way you use them
The new Vfet amplifier will 1) require only one Vfet per channel, 2) those can be either P or N, and 3) will have available no less than FIVE input stages, and some of those input stages have no signal transformer.
I’m sure you’ll be able to find a combination you will be delighted with!
funny - I know how tricky and looong lasting things can be , due to logistic details, especially when process is shared between few or several parties ..... but I can't stop laughing observing unavoidable consequence - Greedy Boys more and more looking as that funny and adorable creature, often lured with Carrot on Stick
been there, been done that, and I will always find new Carrot for my self
my own Carrot - these are meanest of all !