Vox Gremlins (90's AC15 TB).

[pdf64]

Remember how I’ve been saying about failing solder joints in these things? These stupid, annoying issues may keep popping up until that’s dealt with

[Sea Chief]

Remember how I’ve been saying about failing solder joints in these things? These stupid, annoying issues may keep popping up until that’s dealt with

I do, but cover my eyes.. because if this be so, then me identifying it is about as likely as me suddenly understanding what gain is.

Its worth asking tho: is this bad solder joint idea of yours pdf relevant to my dicky ticky trem?

[pdf64]

Maybe.
eg if oscillator decoupling cap C1 was bad we might expect that issue. But similarly if C1 was actually ok but a connection to it was wonky.

[Sea Chief]

Maybe.
eg if oscillator decoupling cap C1 was bad we might expect that issue. But similarly if C1 was actually ok but a connection to it was wonky.

Ok pdf.. hmm, well as you say it did only start when I undid pcb to resolder input 1. And Ive gone over/ reseated all cable connections.

The pot does now seem a bit 'noisy', like a vol pot with a bit of crud in, across its range but Id think just showing up the problem wherever it lies, rather than the pot suddenly doing so itself. Not sure if thats a helpful symptom?

many thanks- SC

[Chuck H]

The scratch on the pot either means that the pot actually is dirty OR it's because there is DC voltage across it. There is DC voltage on the power tube grids which the pot is connected to. Are you certain the pot didn't always make this noise?

[Sea Chief]

The scratch on the pot either means that the pot actually is dirty OR it's because there is DC voltage across it. There is DC voltage on the power tube grids which the pot is connected to. Are you certain the pot didn't always make this noise?

Hi Chuck- certain the pot didn't make this noise, nor the ticking (the two happened concurrently) before I took preamp pcb out > in to redo the input lugs. The power tubes and other xyz on separate pcb's which I didn't touch.

I can give it a servisol pot clean see if that rids it.. but doubt it as it seems definitely connected to the pre pcb removal. Which does seem odd, I'm always very careful with it. All wire connections double-checked seated well again back onto it.

[pdf64]

The scratch on the pot either means that the pot actually is dirty OR it's because there is DC voltage across it. There is DC voltage on the power tube grids which the pot is connected to. Are you certain the pot didn't always make this noise?

The output valve control grids should be at 0VDC?
Of course they are likely to have much more grid current than an ECC83, so a bit of voltage (eg 0.1V) may appear, especially at high trem intensity settings, as the grid circuit resistance increases.

[Chuck H]

The output valve control grids should be at 0VDC?
Of course they are likely to have much more grid current than an ECC83, so a bit of voltage (eg 0.1V) may appear, especially at high trem intensity settings, as the grid circuit resistance increases.

Right. Of course. I wasn't complete in my post, sorry. I'm considering that Sea Chief has been experimenting with more power tube overdrive at which point some grid conduction will occur. I suppose there's also a possibility of a leaky coupling cap. I don't do repairs but I don't usually suspect that in newer amps. I'm sure you guys see it all the time.

[Chuck H]

I think it couldn't hurt to clean up/de ox any connectors and pins as well as touching up solder joints. But I guess you'll need to get your solder game back on point before that can happen effectively. Pretty sure that amp is built with lead free solder. That doesn't preclude you from using plain ol 60/40 rosin core solder for the touch ups. Much easier to get good, lasting results. I wouldn't attempt it with a no flux solder at all.

[Sea Chief]

I think it couldn't hurt to clean up/de ox any connectors and pins as well as touching up solder joints. But I guess you'll need to get your solder game back on point before that can happen effectively. Pretty sure that amp is built with lead free solder. That doesn't preclude you from using plain ol 60/40 rosin core solder for the touch ups. Much easier to get good, lasting results. I wouldn't attempt it with a no flux solder at all.

No I got servisol, & the contact cleaner. Is it servisol for pots, contact cleaner for connector pins-?

I'll get your recommended 60/40 rosin core solder today too. Used up my lead free stuff no there's no possible debate on that anymore! thx.

[Chuck H]

Well there are several Servisol products. But I'll assume that you've purchased two purpose specific products for different contact types (those that get lube and those that need de ox). So you're probably right. Info on the containers should be clear enough.

[Sea Chief]

Well there are several Servisol products. But I'll assume that you've purchased two purpose specific products for different contact types (those that get lube and those that need de ox). So you're probably right. Info on the containers should be clear enough.

Crumbs.. I don't know what I've bought lube or ox. Switch cleaner my servisol says, & i bought the contact stuff for tube sockets. Anyway thanks again Chuck- will use common sense. I think the idea is not to use lube on pots due to it gumming the moving contacts, but will refresh my memory 1st.

[pdf64]

CPC has a good range of useful stuff, and shipping becomes free with fairly small order values.
And Mouser’s free shipping min order value isn’t much more.
They’re a far better option than ebay or amazon, as you’re purchasing from a global distributor, with an assured supply chain back to the manufacturer. So eliminating the risk of fake product / shyster vendors, life being far too short to waste on either.

[Sea Chief]

CPC has a good range of useful stuff, and shipping becomes free with fairly small order values.
And Mouser’s free shipping min order value isn’t much more.
They’re a far better option than ebay or amazon, as you’re purchasing from a global distributor, with an assured supply chain back to the manufacturer. So eliminating the risk of fake product / shyster vendors, life being far too short to waste on either.

Hi pdf.. I'd love to have the best/ an array of xyz cans, but I am always watching my wallet: are my servisol & wd40 contact cleaners not sufficient in your opinion then?

[Chuck H]

Opinions may vary, but pots are typically cleaned with a product that includes lubricant. Switch and contact cleaner often has a de ox agent in it. I love my reading glasses. They work for reading information on line as well.

EDIT: I think it's funny that WD40 has a "contact cleaner" now. Since regular WD40 lubricant has always been considered a no no for the purpose.