Don't worry roncagg, I'm in the same position but I'm confident I will be extra cautious!
I start last year but love the DIY! the only problem with me it's compulsion!
I discovered a thread how to make your own electrostatic headphone have been reading 160 pages in fews days! I read all the pages of this one too!
I start last year but love the DIY! the only problem with me it's compulsion!
I discovered a thread how to make your own electrostatic headphone have been reading 160 pages in fews days! I read all the pages of this one too!
I think if you are careful/methodical and have good soldering technique you are set. That combined with the illustrated build guide and Nelson's detailed pdf and test points makes the probability of success very high.
However, if you want an excuse to make an amp for warmup I can highly recommend the M2 both in terms of build simplicity and sound quality. You can recycle the case and power supply etc. for the VFET - just need a different transformer for slightly different rail voltage.
BK
Prior to this I'd only built an F6 amp Ron. In my opinion building the VFET wasn't any harder. Sure there are more parts and the initial adjustments take longer, but if you take your time and follow the excellent guide on here and Nelson's website you'll be just fine. Most of the work and testing is done prior to installing the VFET's anyway.
I'd suggest the F5 design as a "learning" amp, as the pcb's are available in the DYIAudio store and the front end tuning is similar to this design. A 4U case and PSU (with possibly a different transfomer), could be re-used with this design as well.
I promised to tell you how mine works out with the FQP drivers and about 7mA Idss JFETs.
I had to increse R34 and R35 3 times. 330ohm did not do the trick, neither did 470.
So now they are 787ohm ones and with the 500ohm trimmer very close to mid position I get the correct bias on the FQPs.
Now my issue is that the rest of my JFETs are like 3-6mA.
I could probably get quads with 5mA, but higher than that I only have pairs 🙁
So my stereo amp will have 7mA Idss JFETs, but the 4-ch VFET amp (for biamping) need quads of a suitable Idss.
Also I would like to avoid having different resistors between channels in my 4-ch amp.
I think you understand me 🙂
Is 5mA too low...I cannot increase R34-35 indefinitely 🙂
Anyone have experience or advice about minimum idss?
If you say 5mA is too low, I can get some higher Idss ones or maybe use the other, older drivers with lower VGS.
Thanks!
I had to increse R34 and R35 3 times. 330ohm did not do the trick, neither did 470.
So now they are 787ohm ones and with the 500ohm trimmer very close to mid position I get the correct bias on the FQPs.
Now my issue is that the rest of my JFETs are like 3-6mA.
I could probably get quads with 5mA, but higher than that I only have pairs 🙁
So my stereo amp will have 7mA Idss JFETs, but the 4-ch VFET amp (for biamping) need quads of a suitable Idss.
Also I would like to avoid having different resistors between channels in my 4-ch amp.
I think you understand me 🙂
Is 5mA too low...I cannot increase R34-35 indefinitely 🙂
Anyone have experience or advice about minimum idss?
If you say 5mA is too low, I can get some higher Idss ones or maybe use the other, older drivers with lower VGS.
Thanks!
For the 2SJ74 and 2sk170 I have 2 matched pairs from Linear and 2 from Toshiba.
Should I use the pair from Linear or Toshiba ?
Will it make a difference ?
Thanks !
Should I use the pair from Linear or Toshiba ?
Will it make a difference ?
Thanks !
Hi jlithen.
Idss- problem solved.
if i remind right there was wrote in M2 thread- paralleling JFet possibility to come to higher
Idss- problem solved.
Hello Mattworld
Is Idss difference for DiyVfet amp use only BL (not GR).
If your Toshiba is genuine nos BL with Idss~8mA that ok
but if you have doubt better choice is Linear Jfet´s with the same BL grade.
Sound performance are similar.
Have a nice day 🙂
Q11 replaced and both channels are now up and running. I'm going from my DDDAC direct to the VFET and it sounds very nice. Previously I was using an F6 and I'd say this amp is a clear improvement.
Thanks to Nelson and 6L6 for the supporting documentation - there's not a chance I would have managed the build without this info.
Thanks to Nelson and 6L6 for the supporting documentation - there's not a chance I would have managed the build without this info.
Soundhappy, thanks for the infos 😉
Rodeodave, this is a nice build ! From where is your power supply board, it's from the store ?
What preamp are you using with your Vfet ?