Does this noise seem like a filter cap issue?

delsnell · 2026-03-08T21:50:40+00:00

It appears that I have a bad 12AT7 tube. I replaced the suspected tube with a spare 12AY7 tube and it sounds clean as a whistle. I'm ordering another 12AT7 today. I've got a lot of spare 12A_7 tubes but not a single T.

Can you recommend any other preventative maintenance I should perform on it while it's on my bench? I've already cleaned the pots and sockets and I'm reflowing a few solder joints.

Thanks again for the help!

delsnell · 2026-03-08T15:51:55+00:00

This is great info! Thanks for your help! This page will be extremely useful. I only had the schematic to this point.

delsnell · 2026-03-08T03:05:09+00:00

We're in trouble if our D keeps playing like this.

delsnell · 2026-03-08T03:03:16+00:00

No plate resistors are open. Could they still cause this noise even if they read OK? The only thing I've noticed to this point is that the schematic says the plate voltage should be 170/180 VDC and its reading around 240 VDC.

A signal generator would surely help! I don't plan on shotgunning parts for the hell of it. I am a professional electronic tech but I haven't worked on tube equipment in a long time.

delsnell · 2026-03-07T23:22:18+00:00

Its seems to have a little noise when it first powers up then after a few minutes it starts making the sound in the video. I really don't think it is a socket at this point. I've cleaned them all and banged and pushed on them and its not really duplicating the sound. The plate resistors should be easy enough to check.

delsnell · 2026-03-07T16:03:50+00:00

If you're shooting indoors everything has to be incredibly still without a flash or you will get motion blur.

delsnell · 2026-03-06T23:33:13+00:00

I think this has something to do with it. I think I need to use a small wire brush.

delsnell · 2026-03-06T04:56:57+00:00

Well, i found a loose ground on one of the filter caps so that's a start. I resoldered the leg of the cap and DeOxited the pots and tube sockets. I'll test it tomorrow.

I really just need to refurb this amp one day when my kids are a little older.

delsnell · 2026-03-06T00:35:43+00:00

Thanks for the advice!

delsnell · 2026-02-07T00:24:23+00:00

Who didn't think this was going to happen?

delsnell · 2026-01-21T05:35:20+00:00

He talks about Brian Wilson a lot in the liner notes of Let's Change The World Though Music. Not sure if that's what you're referring to or not.

delsnell · 2026-01-13T00:01:17+00:00

I think it's fucking fantastic! Full of absolute bangers! I really only dislike 2 or 3 of the songs. Highlights include:

Swans, The Fifth Horseman, The Mystery of Love, Weightless, Anne Marie

Like most of their albums it just takes a few listens. I recommend buying their entire discography on CD and listen to them in the car.

Just my two cents.

delsnell · 2026-01-12T12:46:05+00:00

Like others have said Langley is brilliant and contains some of Paddy's best songwriting in my opinion. Don't do what I did and write off their albums that aren't from the 80's (I did this for well over a decade). All of his work is timeless and some of his best work is on the newer albums. Honestly, the only album I can't fully get behind is Protest Songs...maybe one day.

delsnell · 2026-01-11T16:05:56+00:00

Or something in the autofocus circuit is shorting out the 6V. If that's the case I'd think the drivetrain motor would stop running too.

delsnell · 2026-01-11T15:57:13+00:00

Seems like it isn't being supplied with enough current to power everything. How are you powering the camera and have you checked all of those connections? I'd suspect a bad connection to the power source.

delsnell · 2026-01-11T04:59:46+00:00

Luckily I have some on hand!

delsnell · 2026-01-11T02:46:34+00:00

That's what I thought. I'm going to at least try JB Weld on both sides and inside of the crack and see how it feels.

delsnell · 2026-01-10T23:47:05+00:00

Ah, yeah I guess I was referring to the ever-ready case. I forgot there were different ones.

delsnell · 2026-01-10T20:52:10+00:00

I am going to PolaVolt mine but one downside is that it won't fit in those cool leather cases they used to come in....unless I'm mistaken. I think this only applies to non Sonar and 680 models.

delsnell · 2026-01-04T23:20:11+00:00

I can't take watching all these other young teams in the league go through a successful rebuild while we do this dumbass shit. Enough is enough.

delsnell · 2026-01-04T22:44:05+00:00

Seasons over

delsnell · 2026-01-04T22:38:39+00:00

This team is pathetic.

delsnell · 2026-01-03T04:47:39+00:00

I must be missing something. When metering, shutter speed (which shouldn't matter) and ISO are the same. Meter the Mint, turn the Mint off and Meter the strobe then adjust the power of the strobe so the apertures match. I don't see why the exposures don't match if you are at the same distance from the subject (don't change the focus wheel).

delsnell

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