Article - Sony VFETs part 1

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#344
WOW

Hello all. Today I have connect to JFET BOZ. Now I have the gain I need.
FANTASTIC. A lot better than my T16 OTL Transcendent Sound.
Wonderful dynamic, amazing details and I feel the instruments sound real.
Complex music as Piano Concerto in G, Op. 83 or Symphony No 2 of Mahler are simply superb.
Now I know that I want to make a nice quality finishes. This, or one similar (Part 2 or ..), will be my definitive amplifier.
Thank very much Mr. Pass.
 
#345
permaneder said:
Better that way?
Click to expand...
Hi again Permaneder
Could be possible delete little hole on the track between 1K's and gates of Vfet's ?
Open possibility to use biger wattage resistors if supplementary holes on 1k but on side's of 5k trimmers ? Thank You !
dady said:
Good morning lazy frenchy-man
Best Regards
Click to expand...
Good day amigo !
jama said:
Wonderful dynamic, amazing details and I feel the instruments sound real.
Complex music as Piano Concerto in G, Op. 83 or Symphony No 2 of Mahler are simply superb. Now I know that I want to make a nice quality finishes
Click to expand...

Congratulations Jama ! Bravo for Your DiY amp !

Have fun gentlemans🙂:wrench:
Greetings
 
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#346
Hello soundhappy, congratulations to all us. It is a wonderful amplifier. I have never heard Krell,..., now the big question is: how much are similar between them?. The answer to this question is irrelevant, I know, but I will be always doubt.
Best Regards all.
 
#349
permaneder said:
No. They are the through-the-hole contacts from the bottom to the top layers.

Why use higher power Rs in that place?
Click to expand...


Bottom with top layers contacts is for soldered with jumper ah ok.

I agree standard vishay dales do the job well.
Higher wattage mean less thermal distortion.
For 3,50 $ Caddocks 1% To-126 package 1k or 100k TO-220 wake up my curiosity but is only for few resistors in output or buffer stage.
With supplementary hole we have space to try this things or others and don't be limited to one model of resistor hope other people like it 😀

Caddock resistors

http://www.caddock.com/Online_catalog/Mrktg_Lit/MP9000_Series.pdf

jama said:
.For my speakers, Proac Response One 1SC, 86dB it is a little small.
Click to expand...
Proac be very good speakers for powerfull Common Drain Vfet's Part 2 !
Naturaly higher efficience alnico speakers > 95 dB give much better sonic result with 20 to 30 watts amps imho.
Your CSX1 amp is shine new let them play 4 days more with nice music to become wonder 😀

Zen Mod said:
because they're fancy ?

:clown:
Click to expand...

Beacause they are cute :magnet::bulb:

Greetings to All Diyers
:up::cheers::wrench:
 
#350
Hi one more time Permaneder !
Can be possible bring this to layers contact to 1k 's resistors leg than be one hole less on track just two sides soldering ? Simpler and with entire track who go to gate...
What Your think about this ?
Thanks and best regards
:magnify: :car:
 
#352
#353
Yes, transistors are very hot. The four dissipate more of 100 watt. In half an hour the full heatsink is hot (0.25 ºC/W). Now I know that this amplifier like very much. I will do it again and now I take into mind the heat dissipation, but I do not think that transistors temperature will not be much lower.
I have used JFET BOZ adjusted to have a gain of 7 (more or less).
Best Regards
 
#354
Dear Happy S. In few minutes the Tº rise homogeneously if low thermal resistance between the surfaces of the aluminium parts in the heat sink. The better you can do is put metal with better conduction like coper between the transistors and the principal body of the heatsink. The other one is a fan or water cooling. You can make a water tank in other room and pump the liquid to the heatsink. I have a Zalman watercooler system in the computer for the audio aid for avoid extra noises but anyway my wife talking from the kitchen and I found another solution for an non-existent problem. Or better said, that's problem without solution.
For make a final point to our team is get the transformers, we are more than 120 souls without a good Shepard and remain the part Two of with Common Drain and nobody guess at the moment if we need another different parts or more advantages in adopt it or no transformers at all.
Best Regards
 
#355
dady said:
For make a final point to our team is get the transformers, we are more than 120 souls without a good Shepard and remain the part Two of with Common Drain and nobody guess at the moment if we need another different parts or more advantages in adopt it or no transformers at all.
Best Regards
Click to expand...

Hi Dady

Interesting question are we need input Jensen transformers for Common Drain Vfet part 2 ?

If yes is not too late and we can buy them at the same time with GB🙂

I have 18 pairs of Vfet's not matched is this sufficient for build one symetric amp ?

Hope Mr Pass send us answer

Greetings :lifesavr:🙄
 

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#358
SONY VFET

I did some minor changes. The negative input rail of the main supply (-32V) has been moved to the bottom side of the PCB. That dependably prevents any possible electrical shorting between the L profile and the supply voltage.

The rest seems to be OK so far and I’ll place the order to my board makers on next weekend.
 

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