Silvertone 1474 Resuscitation

[erobillard]

Thanks G1. All 4 supplying the 6CG7 plates were redone, and aside from the 1W 1.5k replaced with a 5W 3.3k, these are the only resistors that have been replaced. Others have drifted up (as carbon comps do with time), but are still within 10-15% at room temperature. So either something failed or this was an intentional mod. If it doesn't ring out to anyone as an intentional mod, then I'm inclined to think one or two failed, the old ones were read wrong, and these should be brought back to 100k, but this time 1W to avoid another failure.

It may not be until next week that I get back to it. Lost a good friend this week, there's a music fest on this weekend (Ween and Guided by Voices tomorrow), and work is looking a whole lot like work.

[g1]

Judging by the previous 'work' done to this amp as you have described, I wouldn't trust any of what was done for/by the previous owner.
10K for 100K at the plates would not be any kind of a mod.
Hope you enjoy the GBV show, I saw them at the opera house in the 90's and they were great!
Sorry to hear about your friend.

[The Dude]

I would think the person that put those 10K's where 100K's should be made an error with the colour codes.

Agreed. And, God forbid you would take a second to measure them before installing.

[DRH1958]

One other thing to keep in mind, these resistors don't have a 4th band indicating 20% tolerance, so a 100k could be in spec between 80k and 120k. If you want better, then get silver or gold band resistors but I've found both Silvertones I own(1474 and 1484) have 20% resistors and sound great. Close enough for rock & roll.

[erobillard]

I think The Dude was writing about whomever replaced the 100ks with 10ks and decided that "looks close enough" was as good as testing. And they are 10ks. Picked up 4x1W 100k's to put in, best guess is that the original 1/2W resistors took a surge and died.

[erobillard]

Parts lists: Resistors & Caps

Greetings,

The basement flooded last year, and rather than put the 1474 in storage it's now entrusted to a local shop to fix up the caps in the final stage. In the meantime, I see a few of my links are broken from moving files around, so reposting the bits that might be useful to someone down the line. This message has the lists of resistors and capacitors based on the schematic in this thread, plus a file with counts.

Cheers,
-Eli.

1474 Resistors.pdf1474 Capacitors.pdf1474 R+C counts.pdf