18Watt.com

Ok sorry, I'll go again

Ok, I calmed down and started thinking. It was working near perfect before I started messing with removing the ppmv and putting there grid stopper in. Cleaned up where I had the mv temporarily and jumpered the resistor. Back sounding pretty good. Need to send you an outdoor clip because basic sound is close to right but is hard to assess with everything rattling! The grid stopper I mounted p2p between the board and valve socket. I must be misunderstanding somewhere because it has silenced my normal input and made my hot input weird and noisy...

If you did the grid stopper correctly, it can't effect more than 1 channel.

This 10K is a grid stopper resistor on V1:

Ok grid stopper gone, I can live with a little interference for now. Had a play amp is sounding slightly better than so far ever. I now have a little colour on the tone at 2 on the volume in the hot input with HB guitar up full. Very nice. Very hard to get a video of the nasty noise with the volume up high as my pickups are microphonic and feedback real easy. Here it is with the amp volume around 8 andthe guitar volume just over one.

https://vimeo.com/804697911

Hope that's clear this time, basically sounds like an angry static woodpecker trapped in my amp when I play the low strings at close to full amp volume.

Put grid stoppers in correctly, and use a terminal strip to secure them, see below. I'd still use 10K resistors, but you can go up to 33K if the effect is only partially effective. I'm assuming you followed your schematic for series/parallel input jacks. Use a 3 lug terminal strip:

Then try again.

Thanks,
Josh

Thanks Josh,

I have 47k or 10k in quarter watt. Is mounting the tag on the valve socket bolt bad practice?

chaliapin wrote: ↑

Sun 03/05/23 12:39 pm

Thanks Josh,

I have 47k or 10k in quarter watt. Is mounting the tag on the valve socket bolt bad practice?

However 1/4 watt is no problem in that position it might be noisy to use those. Higher wattage resistors are more quiet. But given the current and voltage there it should withstand the power

Thanks guys, I installed them covered in heat wrap. So far quite a lot worse, hummy and bad distortion but im hoping it's lead dress around the tag strip, gonna chopstick that now.

Chopsticked for a bit, managed to get rid of most of the buzz, treble a bit glassy and not sounding as good as last night. Nasty noise still there when turned up. Some little bit of radio static with no guitar plugged in and the volume up full.

I am puzzled about you trying to tune the amp and always mention you turn the volume at max. All my amps are noisy at max, even without anything plugged in. Why are you testing the amp at max volume?

I guess to make it easier to notice if something changes the noise and to make it as quiet as possible? I think since adding the grid stoppers I have no improvement in the sound and a new 100-120hz buzz I can't reduce or get rid of. I assume the way I have installed them is ok? It's Only there with a guitar plugged in and is exactly the same with guitar volume up or down, checked all the grounds, no effect. Buzz volume goes up and down with the amp volume.

I think I'll try the bigger 47k resistors and how they go. I wouldn't mind losing a little treble from this amp anyway...

chaliapin wrote: ↑

Sun 03/05/23 6:20 pm

I guess to make it easier to notice if something changes the noise and to make it as quiet as possible? I think since adding the grid stoppers I have no improvement in the sound and a new 100-120hz buzz I can't reduce or get rid of. I assume the way I have installed them is ok? It's Only there with a guitar plugged in and is exactly the same with guitar volume up or down, checked all the grounds, no effect. Buzz volume goes up and down with the amp volume.

I think I'll try the bigger 47k resistors and how they go. I wouldn't mind losing a little treble from this amp anyway...

I'd think it's not the best way to search for noise issues at levels you will never play the amp anyway. Any amp will make noise when on full volume.
The buzz that appeared when you put in grid stoppers... are those the 1/4 watt resistors? Like I said, they tend to make more noise than higher wattage resistors. I use at least 1 watt metal film or 2 watt metal oxide resistors in those spots. And really make sure you use a heat sink when soldering them. Over heated resistors are bound to make noise as well...
Please show on a schematic where you've put the grid stoppers.
By the way, I don't think 47k is going to make a lot of difference. When you start tweaking this kind of stuff you need to make bigger jumps and dial back. Try 220k or even 470k and go down from there... But at V1a I wouldn't go higher than 68k.
And for Pete's sake, roll down the volume to acceptable levels. You're chasing ghosts the way you're addressing this... I always do this at 3 or 4 on the volume

Thanks bieworm,

Im normally working around volume 3, only up high with nothing plugged in. Buzz came with the quarter watt grid stoppers yes. Ive only been using a heat sink when soldering caps... although I doubt they toasted as I was soldering them with the sheilded cable which is really easy to melt...

They're inline with the inputs.

Input Jack- sheilded cable- solder strip- resistor- grid v1.

chaliapin wrote: ↑

Mon 03/06/23 3:56 am

Thanks bieworm,

Im normally working around volume 3, only up high with nothing plugged in. Buzz came with the quarter watt grid stoppers yes. Ive only been using a heat sink when soldering caps... although I doubt they toasted as I was soldering them with the sheilded cable which is really easy to melt...

They're inline with the inputs.

Input Jack- sheilded cable- solder strip- resistor- grid v1.

I would avoid the tiny resistors in an amp. They are best used in applications where there is no space (i.e. pcb boards in electronic devices such as TV, radio,...)
The best way to succes is the use of proper, oversized parts, which will grant you more reliability and sturdiness.
FWIW, some builders put a cap at the input. I think it's mainly for blocking DC on the grid that would sneak in when you run certain FX pedals into the front. The tone king imperial has one. Look at the 1st schematic in the 1st post of this thread:
https://el34world.com/Forum/index.php?topic=25123.0

Thanks bieworm.

Would that block dc on my guitar pots when using the vvr as well? Smallest I have is .01uf.

chaliapin wrote: ↑

Mon 03/06/23 4:52 am

Thanks bieworm.

Would that block dc on my guitar pots when using the vvr as well? Smallest I have is .01uf.

The cap would block any DC coming into the amp.

Got 47 and 56k stoppers in. Clean sound at low volume ok but no nice distortion and nasty crackle up high...

chaliapin wrote: ↑

Mon 03/06/23 6:15 am

Got 47 and 56k stoppers in. Clean sound at low volume ok but no nice distortion and nasty crackle up high...

Order 1W metal film resistors. 10Ks and 33Ks. Your 1M input resistor also needs to be metal film.

Are you using humbuckers? Is the guitar volume up all the way?

Guitar volume mostly low when I put the amp up around 8 so I don't blow my ears. I will order more resistors soon, they may be adding noise but they're not the thing making the amp sound crap...?