V-fet Repair of a WEGA V4810 solid state heaven - Page 3 - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 24th September 2009, 05:51 PM   #21
Helmuth is offline Helmuth  Netherlands
diyAudio Member
 
Helmuth's Avatar
 
Join Date: Oct 2008
Location: Winterswijk
Quote:
Originally Posted by Bakmeel View Post
Hey Hemuth, that looks like a job well done! I hope your amps are sounding well now... It seems they do ;-)

I especially like the good craftsmanship on the wooden side panels. How did you get the high gloss and keeping the dust away while the paint dries? I always get small specs of dust when trying to do a high-gloss paint job.
Hi Bouke,

How are your Passlabs amps playing?

The sound of the V-fet amp is a real exceptional nice transistor for audio, they meet most the straight amplifying characteristic of a Triode tube. And the strange thing is it really has the warm low sound of a tube amp although it has a damping factor of 40. Compared to a Mosfet the V-fet has less capacity on the gate and is there for less dependent on frequencies.

It started out to have a nice vintage set, and now I have a very rear V-fet Wega version of the rear V-fet sony TA 5650 and ST4950. http://www.thevintageknob.org/VFET/VFET-main.html
There are a lot of V-fet fans around but you have to be 50 years plus to have known the introduction and end of the V-fet 1974 to about 81.

It is on solid state what comes the most close to tubes.

About paint

There is always dust in the paint. I sprayed them outdoor you can spray the environment with water to prevent dust.
The real professionals sand of the last dust and bums, and after that they polish them again to get the real piano gloss finish. I tried that but did not get a good result you have to know the right tricks I guess.

Result after one can of varnish.
Click the image to open in full size.

Result after sanding and second can of varnish.
Click the image to open in full size.

Result after sanding and third can of varnish.
Click the image to open in full size.

I already have a new project I managed to buy a Graetz Profi 306 (1975-1978) the receiver my father hat in the seventies and I became the audiophile-bug by it. I play it now as second set it sounds great. The electronics are very conventional and very nice build. The selector switches a dc voltage that superponates the selected input on the preampstage, so no bad audio contact!.
Click the image to open in full size.
Click the image to open in full size.

Regards Helmuth

Last edited by Helmuth; 24th September 2009 at 06:15 PM.
  Reply With Quote
Old 24th September 2009, 08:19 PM   #22
miklos is offline miklos  Canada
diyAudio Member
 
miklos's Avatar
 
Join Date: Jul 2004
Location: toronto
Thanks Helmuth, very educational. I refurbished my 5650 about a year ago and now in the process to fix a 4650, with the V-Fet's from HK. I wonder if the batch numbers 53/52 won't be a problem? I assume you got the same kind of transistors as I got.
__________________
miklos
  Reply With Quote
Old 24th September 2009, 08:55 PM   #23
Helmuth is offline Helmuth  Netherlands
diyAudio Member
 
Helmuth's Avatar
 
Join Date: Oct 2008
Location: Winterswijk
Quote:
Originally Posted by miklos View Post
Thanks Helmuth, very educational. I refurbished my 5650 about a year ago and now in the process to fix a 4650, with the V-Fet's from HK. I wonder if the batch numbers 53/52 won't be a problem? I assume you got the same kind of transistors as I got.
Hi Miklos,

Yes I got,

The 2SK60 are from the same ranking 52, and the
2SJ18 are from the same ranking 53 too.

Bought on ebay.

Works good on my amplifier, only there is some difference in the right channel set, the left bias was stable the right drifted more when the ballast was on for a longer time. So I would wait for more then 3 hours and check the bias again.

Cheers Helmuth
  Reply With Quote
Old 25th September 2009, 03:31 AM   #24
miklos is offline miklos  Canada
diyAudio Member
 
miklos's Avatar
 
Join Date: Jul 2004
Location: toronto
Thanks for your reply, I will post my experience.
__________________
miklos
  Reply With Quote
Old 25th September 2009, 04:12 AM   #25
miklos is offline miklos  Canada
diyAudio Member
 
miklos's Avatar
 
Join Date: Jul 2004
Location: toronto
Here's a picture of the TA-4650 PA board, recaped and cleaned in the shower, with the four defective V-Fet's.
Attached Images
File Type: jpg Recaped2sm.jpg (248.6 KB, 219 views)
__________________
miklos
  Reply With Quote
Old 25th September 2009, 04:52 AM   #26
diyAudio Member
 
Wavebourn's Avatar
 
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
Hi Helmuth;

your avatar looks very similar to my current bass guitar combo prototype that I keep in secret.
__________________
The Devil is not so terrible as his math model is!
  Reply With Quote
Old 25th September 2009, 12:12 PM   #27
Bakmeel is offline Bakmeel  Netherlands
diyAudio Member
 
Bakmeel's Avatar
 
Join Date: Jan 2002
Location: The Netherlands
Quote:
Originally Posted by Helmuth View Post
Hi Bouke,

How are your Passlabs amps playing?

(....)
Regards Helmuth

They're doing great! Fantastic powerful, rich sound. Lots of control over the bass and very good placement. have you seen the results on the final build thread?
Final pics are here: Aleph 2 - The Final Build
__________________
More Power Igor! More Power!
  Reply With Quote
Old 25th September 2009, 03:21 PM   #28
Helmuth is offline Helmuth  Netherlands
diyAudio Member
 
Helmuth's Avatar
 
Join Date: Oct 2008
Location: Winterswijk
Quote:
Originally Posted by miklos View Post
Here's a picture of the TA-4650 PA board, recaped and cleaned in the shower, with the four defective V-Fet's.
In a normal situation only one end stage is defective so all the fets defective is strange. Are sure you did the diode test? The V-fet measures short with out negative gate voltage.

@Wavebourn

It is a La Scala.


@Bouke

Good to hear your labour payed back at the end, the build looks professional perfect to the detail. When is the party to celebrate it


Regards Helmuth
  Reply With Quote
Old 25th September 2009, 04:53 PM   #29
miklos is offline miklos  Canada
diyAudio Member
 
miklos's Avatar
 
Join Date: Jul 2004
Location: toronto
Yes I did, it was a relatively cheap amp, I paid $65 on the Bay. The seller said it's needing repair, but one channel is working. It turned out non was working, for obvious reasons. Now it is not cheap anymore. I have some V-Fet experience, I fixed my 8650, 5650 and built a class A amp with the 2SK82.
My first ever Class A amp.
__________________
miklos
  Reply With Quote
Old 25th September 2009, 10:35 PM   #30
Helmuth is offline Helmuth  Netherlands
diyAudio Member
 
Helmuth's Avatar
 
Join Date: Oct 2008
Location: Winterswijk
Quote:
Originally Posted by miklos View Post
Yes I did, it was a relatively cheap amp, I paid $65 on the Bay. The seller said it's needing repair, but one channel is working. It turned out non was working, for obvious reasons. Now it is not cheap anymore. I have some V-Fet experience, I fixed my 8650, 5650 and built a class A amp with the 2SK82.
My first ever Class A amp.
Cool design that hybrid amp Miklos.

Regards, Helmuth
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Wega-Elektronik amplifier Wega PV400 ash_dac Solid State 4 5th December 2010 06:01 PM
The Solid State Wiki - Your solid state reference guide Jason Solid State 0 25th June 2002 06:26 PM
Solid State DIY doktor Solid State 28 8th June 2001 12:03 AM


New To Site? Need Help?

All times are GMT. The time now is 04:19 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2