FS: Decent STK8040, STK8050 module clones - Page 1
Forum section: electronics / general

author: shakalnokturn
author_rank: Super Contributor
timestamp: August 06, 2024, 12:31:36 am
content: I have PCB's and components left from a repair project on a Technics SU-V4A amplifier.These will work on the SU-V2, SU-V2A, SU-V4, SU-V4A and a couple of models of stereo receivers.They're quite accurately based on the original schematic and perform almost identically.Will sell PCB's alone, as kits (SMD), partially or fully assembled.The GERBER's aren't going public until my remaining stock is sold.Edit: Adding links to related audio forum topicshttps://www.diyaudio.com/community/threads/build-stk8050-equivalent.319154/page-7#post-7512865https://audiokarma.org/forums/index.php?threads/technics-sa-425-plan-of-attack.873663/page-8#post-16775896

author: Zucca
author_rank: Unknown
timestamp: August 06, 2024, 05:46:44 pm
content: Nice job!interesting discussion also herehttps://www.diyaudio.com/community/threads/build-stk8050-equivalent.319154/

author: shakalnokturn
author_rank: Super Contributor
timestamp: August 06, 2024, 06:54:09 pm
content: Thanks Zucca.I went through the whole DIYaudio thread you linked a year ago before deciding to make my own version.I felt that no one had gone far enough on solving this obsolete component issue:Chinese copies all over the interwebs that often last merely seconds and won't adjust correctly. DIY solutions that are either bulky, require custom drilling or look like wild bodges and none have full compatibility with the original.When I finished my layout and placed an order at JLCPCB thinking that I'd be able to sell the extra 18 modules easily I was wrong... no one is interested.(Maybe 15 years ago?)I've been buying broken amplifiers to fit them in, even then people are asking crazy prices for these amplifiers in non-working condition now and being in the middle of nowhere ("the world's asshole" as the French say) I'm not in much luck with selling the repaired amplifiers either.

author: Zucca
author_rank: Unknown
timestamp: August 06, 2024, 07:38:44 pm
content: If not we EE, who else can do it?It is our responsibility to fix stuff so that others can continue to use good old amp/devices.I am sure what you have done/designed is the right thing to do, even if you can't sell as much as you would like.Your example is inspiring me to do the same in other projects.RRRR Repair Reuse Recycle Rejoy.

author: coromonadalix
author_rank: Super Contributor
timestamp: August 08, 2024, 06:00:04 pm
content: no offence, great job replicating theses, i did change a lot of thembut now it's buy use .. until they break, and many will trash them, because now theses are rare or obsoletea nearby electronic seller has closed after 45 years, and there was a ton of stk modules, they got sold for cheap, pretty fastonly a knowledgeable guy would know their valuesmaybe push some ads on Ebay ??

author: shakalnokturn
author_rank: Super Contributor
timestamp: August 08, 2024, 06:31:23 pm
content: Thanks coromonadalix.I swear no GMC DMM's were hurt during that projectThe amplifiers these are used in still sell for into the 100-150€ range, in contrast non working ones sell between 30 and 60€.The last amplifiers I've repaired were equipped with two of my clones so that left me with an original STK to sell separately (about 30€).It seems a shame that people should trash these amplifiers because of the STK hybrids, they're not that bad when working.I suppose that all the people aware of the problem sell them for parts or trash them, the less aware buy a Chinese STK then trash them.I think I missed the right time to tackle this, even 10 years ago I'm sure there would have been plenty more demand.I also think it is more important to a lot of audio people that the replacement component looks like the original and bears "new class A" although electrically rubbish rather than being electrically identical but looking less inspiring.Audio is all about blue lights salesman's jargon and aesthetics.I'm only looking to recover my time and component investment on this, after I'll be pleased to share the Gerber's with whoever wants to save their amp. or (more likely) make money on my back.Edit:I have an ad. up on eBay, a little expensive maybe, I'm going to remove it anyway, now I've been through most of the latest downsides to eBay it just isn't worth doing business with them.The biggest deception being that to transfer money from eBay sales to my bank account I must give them the right to draw money from my bank account when they decide. To hell with that.

author: FPALB
author_rank: Newbie
timestamp: June 10, 2025, 03:58:04 pm
content: Hi shakalnokturn,I have a repair that im considering taking for a client and I do believe the 8050s are the issue - do you still have these for sale?

author: shakalnokturn
author_rank: Super Contributor
timestamp: June 10, 2025, 06:01:42 pm
content: Hi FPALB,Yes I still have some of these I'm selling them pre-assembled and tested for 50€ each, with postage to USA that is like going to be too expensive for you.If you have a Hameg scope with component tester or Huntron tracker an email address I could start by sending you my reference curves for out of circuit testing.Regards,Paul