new build 36lite with vvr

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chaliapin
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Re: new build 36lite with vvr

Post by chaliapin »

Im not sure what's up with my soldering, I'm applying the iron, waiting for the bridge to flow, painting, removing solder, removing iron. Joint looks lovely solidifying then at the last second goes hazy. Eugh. 25w EDIT ANTEX iron, silverline cheap 60/40 solder.

Anyway, before I read your message Josh i was trying to improve joints. Basically removing excess solder then reflowing with a little fresh solder. Powered up to check my grid voltages, one pair very low, brilliant, one pair not. Anyway left the amp on a few minutes and came back to an unpleasant noise and burning smell. Powered off fast before I could see what was happening. No visible or smellable problems anywhere.

Used the bulb limiter, voltages roughly halved all over the amp except v2 - pin 1 and seven fine but the rest less than 5v. Switched tubes, same story. Powered up to the mains anyway, all voltages fine, no buzzy noise, no burning smell. Still a nasty glassy sound in the treble basically same as it's been for days. Worse at higher volume.

Ive chopsticked fairly firmly every single turret, socket pin and wire looking for a crackle of a cold joint. Nothing.

I know I need to post pictures and a recording of the noise.

Getting fed up. Thanks for your patience.
Last edited by chaliapin on Wed 02/08/23 4:26 am, edited 1 time in total.
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Re: new build 36lite with vvr

Post by chaliapin »

I also meant to say that c5 is a little microphonic, the 22n cap going to the grid of the PI (coupling cap?) I assumed that was simply because it's on the grid pin and sensitive. I don't have a spare cap of the correct value to try replacing it.
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Re: new build 36lite with vvr

Post by Bieworm »

chaliapin wrote:
Wed 02/08/23 3:32 am
I also meant to say that c5 is a little microphonic, the 22n cap going to the grid of the PI (coupling cap?) I assumed that was simply because it's on the grid pin and sensitive. I don't have a spare cap of the correct value to try replacing it.
There are caps and resistors in the signal path that make noise when you tap them. That's nothing to worry about.
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Re: new build 36lite with vvr

Post by JMPGuitars »

That iron should be good enough, but maybe you should try some better Kester solder.

You might also want to check on your 470p cap going to the tone control.
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Re: new build 36lite with vvr

Post by chaliapin »

Power tube grid acting strangely. Got them down to 0.03 or so volts but after a few minutes one pair is climbing to over 1 volt. Resistors measure as they should to ground,
i replacedsome wires to the pin sockets. what's going on and is it important? I'll try to attach pictures of the joints
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Last edited by chaliapin on Wed 02/08/23 6:17 pm, edited 1 time in total.
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Re: new build 36lite with vvr

Post by chaliapin »

The turret joining the two resistors but messy as I had the MV wires soldered onto the tops.
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Re: new build 36lite with vvr

Post by JMPGuitars »

Components should not be touching each other at all. The soldering could be a lot prettier, but make sure you separate everything physically too.
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Re: new build 36lite with vvr

Post by chaliapin »

It's just the camera angle. Think my caps are leaking DC?
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Re: new build 36lite with vvr

Post by JMPGuitars »

weirdcap.jpg

What's going on with this cap's connections? Are they wrapped around the turret and the camera angle is weird? Or is this weird on its own?
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Re: new build 36lite with vvr

Post by chaliapin »

The legs go down vertically then wrap around the turret. They are rated 400v, I have two others rated 600 which I am going to put in their place, I was getting intermittent short through one of them. Im really hoping this is the problem ive been looking for.
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Re: new build 36lite with vvr

Post by chaliapin »

So I had a dead coupling cap. When it died and whether I killed it I can't say. Whether it slowly leaked to death or suddenly failed I don't know. I replaced the caps and checked grid voltages, one pair low, the other higher and climbing. Very sad. Switched the pairs of tubes around, climbing pair now on the other side. Maybe the dying cap took them down with it. Switched them out. 90- 95 percent GOOD SOUND.

couldn't test it for long as my boy was going to bed but I managed to coax a couple of nasty noises when hitting the bass e hard with volume 2/3 up but it was sounding good. And loud. Did I mention it was quite loud? Tight controlled tone, not as wild and loose and raunchy as i remember the 18 watt but maybe just speakers very different. Something bassman ish about the sting in the lead tone with my starfire but maybe just because I'm a massive Freddie king obsession at the moment...

Thanks everyone. Hopefully when I play it again it hasn't gone back to being nasty...
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Re: new build 36lite with vvr

Post by Bieworm »

I would buy a pair of new tubes to rule that out… sounds like at least one tube is flakey
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Re: new build 36lite with vvr

Post by chaliapin »

I have two quads, funky ones are out...
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Re: new build 36lite with vvr

Post by chaliapin »

Put the chassis in the cab. Sound bad again. I'll start through robs trouble shooting systematically. It's not the combo or speakers as I tried it connected to another combo speaker.
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Re: new build 36lite with vvr

Post by Bieworm »

Post a recording… what is bad sound exactly?
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Re: new build 36lite with vvr

Post by chaliapin »

Bad guitar sound, no hum or weird noises with nothing plugged into the inputs. I'll try to post something.
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Re: new build 36lite with vvr

Post by chaliapin »

https://vimeo.com/797947700

This might be useless? Volume on 4, Guitar volume 2 or 3. Trying not to overpower the phone. I could clearly hear nasty tone on the A to B bend on the G string. I can't hear it much on the video though...
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Re: new build 36lite with vvr

Post by chaliapin »

https://vimeo.com/797991890

Maybe more useful
Amp vol 4, guitar 10. Seems to sound better on the phone than in the room. Crunchy glass sound.
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Re: new build 36lite with vvr

Post by JMPGuitars »

Lower the value of the treble cap (470pF in schematic). Try 220pF if you have that.
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Re: new build 36lite with vvr

Post by chaliapin »

I don't but I could try without the cap entirely? It's a high buzzy little crackly crunchy glassy noise in the guitar sound. Doesn't come up on the phone audio very well.
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