![]() ![]() |
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
69.120.52.234
Hi. In an attempt to fix noise from my Audio Research MCP33, I'm taking the shotgun approach and replacing/upgrading all the transistors & opamps.Schematics linked below.
Here's the list of whats needed. Any upgrade suggestions?
D40K1 - cant find this anywhere. Google implies its a Darlington Power transistor, possibly NPN. What can I upgrade this with?
TIP41 - available at Mouser. However, can this be improved on?
TL071 - going to replace this with 8dip socket. I have a bunch of 8dip opamps to play with.
2N5462 - FET - also available - Can this be upgraded?
Follow Ups:
You may want to have someone check and make sure the PCB hasn't been ionized in one spot. We have a dead ARC SP-8 at work that has been sitting for a LONG time, until we finally get enough time to either make and etch a new PCB for it, or cut that part of the board out completely and point-to-point wire that area.In other words, maybe the next decade we'll have a chance. :)
"D40K1 - cant find this anywhere. Google implies its a Darlington Power transistor, possibly NPN. What can I upgrade this with?"I don't know about upgrading, a lot depends on how it's used in circuit. But if you need a replacement this guy has single pieces:
http://www.mikesarcade.com/cgi-bin/store.pl?sku=TRNS268
I'm not related in any way to him.
Be careful about "improving" transistors. Sometimes that hot, fast, high Ft new number looks great on paper but ends up turning your amp into a high frequency oscillator! The D40K1 is pretty non-glamorous, it was used in things like doorbell chime driver circuits. But it is reliable and cheap.
![]()
Thanks Jim. I'll try fets & opamps first, and if still noisy, I'll get this. I'm ordering both the original as well as an 'upgrade' for each part, so I'll try rolling them as well..
![]()
Are you certain its not noisey tubes ?
![]()
Hi Yes. Has all these noise problems with no 6DJ8s installed, only the 7044 and 12at7. Also tried rotating all the tubes, and another set of tubes, problem only in 1 channel.
This post is made possible by the generous support of people like you and our sponsors: