new build 36lite with vvr

[chaliapin]

Only very minor changes to previous voltages. Had a go with the strat, pretty good but definitely a little bit of something ugly going on in the distortion. I'm very happy with pretty clean tone up to halfway round the volume but I want to know if that's normal. Also feel like I'm missing top end chime, it's quite raw and abit brutal! I'll try in with an open back v30 with another combo in, it might be my weird open back, detuned front and ported sides can design. Got one g10s50 and a blue frame eminence fender in it now as a 2x10. V1 and 2 are JJs the others are the 6n14p from Ukraine. They're not new but were tested.

Oh, the voltages were kindly written in by my eight year old boy...

Oh and my attempt at improving my soldering to ground on the power tube grids seem to have made matters worse...

Voltages were taken with nothing plugged in and volume on 2 not that it probably makes any difference.

[JMPGuitars]

Only very minor changes to previous voltages. Had a go with the strat, pretty good but definitely a little bit of something ugly going on in the distortion. I'm very happy with pretty clean tone up to halfway round the volume but I want to know if that's normal. Also feel like I'm missing top end chime, it's quite raw and abit brutal! I'll try in with an open back v30 with another combo in, it might be my weird open back, detuned front and ported sides can design. Got one g10s50 and a blue frame eminence fender in it now as a 2x10. V1 and 2 are JJs the others are the 6n14p from Ukraine. They're not new but were tested.

Oh, the voltages were kindly written in by my eight year old boy...

Oh and my attempt at improving my soldering to ground on the power tube grids seem to have made matters worse...

Voltages were taken with nothing plugged in and volume on 2 not that it probably makes any difference.

From your description, this is a guess, but you may wish to try the Paul Ruby mod. It's in grey in this schematic: files/JMPGuitars_18_Watt_Superlite_TMB_Schematic.pdf

IME a V30 is too bright, and chances are your speaker is not causing the ugliness. Though I do recommend not using a highly efficient speaker.

You should desolder the path to ground from pin2 of the power tubes, and clean them, then resolder them. You need a proper heat bridge before applying solder. Let your tiny dot of solder melt into the turret before painting on the solder. Make sure it's concave when you're done. Too much solder is not helpful.

Thanks,
Josh

[chaliapin]

I might try the ruby mod, I did have a quick browse about blocking distortion but the description was a noise 'outside' of the guitar tone, this is a hint of unmusical crunch IN the guitar tone. I'll resolder tonight, thanks for the detailed instruction. What would be the symptoms of the DC on the grid?
Thanks.

[JMPGuitars]

I might try the ruby mod, I did have a quick browse about blocking distortion but the description was a noise 'outside' of the guitar tone, this is a hint of unmusical crunch IN the guitar tone. I'll resolder tonight, thanks for the detailed instruction. What would be the symptoms of the DC on the grid?
Thanks.

Too much voltage there is often a sign of bad soldering. Bad soldering can cause noise issues. Typically, I shoot for less than 20mV, I usually see between 7 to 12mV.

For your noise issues, I'd suggest making a demo and sharing it so we can hear what you hear. Try more than one guitar, and more than one guitar cable to see if the noise is consistently there.

[chaliapin]

So I played it this morning, sounded perfect. Decided I was imagining things. Fitted chassis into combo etc. Went to play it after lunch, bit of buzzing and nasty crackle back in the sound. Am I looking for lead dress or a bad solder joint do you think? I also removed the power tubes and refitted them with wire retainers.

Edit, took it back out of the cab and cranked it up, sounding ACE again for five or ten minutes, sudden momentary nasty noise and v5 and 6 lit up inside very briefly, sounded fine after but I obviously stopped playing! Obviously an intermittent fault is the worst thing to be looking for, should I even try or just start from one end trying to improve my solder joints? Guess vacuuming the inside could help for stray drips of solder etc.

I suppose it rules out lead dress at least...

[JMPGuitars]

That's a tough one. Definitely make sure the amp is clean, and if you see any obviously bad joints fix them...but it could just as easily be the tubes. Try playing through the amp so you can see the tubes. If only one or two of the tubes light up differently, replace only those tubes. If the tubes light up weird only in specific tube sockets, then that might also be a clue. You can try swapping a tube that lights up goofy with a tube in a different socket, and see if the goofiness follows the tube, or stays in the same socket.

[chaliapin]

Thanks Josh. Let's face it, my soldering/ wiring is the most likely culprit... especially seems to me as it was a pair of tubes briefly plating simultaneously.

I tried tidying the path to ground on the two grids for the two that flashed, replaced the wires as the two I used previously were thicker and harder to solder. Forgot to take voltage readings on pin 2 afterwards.

Amp sounded great again sat on top of the combo.

Put it into the cab, bit of nastiness in the treble again with volume approaching halfway. Really sounded like something in the cab or speaker, so tried the v30 in the 8 ohm output. It was a lot darker and smoother and a little quieter than the 2x10 weirdly... anyway, nasty sound still there. Chassis was still in my homemade combo cab at this point, I just put the two back to back so the cable would reach. Very frustrating, no plating but when that happened it was after a good twenty or thirty minutes of loud playing.

Also I added the simple stupid volume control. It works and isn't noisy, but I don't really see the point of it! it doesn't seem to act significantly different to the normal volume control! With volume cranked and mv at 1 or less you get some overdrive at civilised volume but it doesn't sound that great. Need to try attenuation and vvr s maybe next.

[JMPGuitars]

Thanks Josh. Let's face it, my soldering/ wiring is the most likely culprit... especially seems to me as it was a pair of tubes briefly plating simultaneously.

You could be right, but rule the tubes out first. If 2 out of 4 tubes do the funky plating thing (tubes A and B), then swap them with the tubes that don't (tubes C and D). If the funky plating happens in the tubes you moved (still A and B), then it's the tubes. If it happens in the original sockets on the other tubes instead (C and D), then it's not the tubes.

[Bieworm]

Thanks Josh. Let's face it, my soldering/ wiring is the most likely culprit... especially seems to me as it was a pair of tubes briefly plating simultaneously.

I tried tidying the path to ground on the two grids for the two that flashed, replaced the wires as the two I used previously were thicker and harder to solder. Forgot to take voltage readings on pin 2 afterwards.

Amp sounded great again sat on top of the combo.

Put it into the cab, bit of nastiness in the treble again with volume approaching halfway. Really sounded like something in the cab or speaker, so tried the v30 in the 8 ohm output. It was a lot darker and smoother and a little quieter than the 2x10 weirdly... anyway, nasty sound still there. Chassis was still in my homemade combo cab at this point, I just put the two back to back so the cable would reach. Very frustrating, no plating but when that happened it was after a good twenty or thirty minutes of loud playing.

Also I added the simple stupid volume control. It works and isn't noisy, but I don't really see the point of it! it doesn't seem to act significantly different to the normal volume control! With volume cranked and mv at 1 or less you get some overdrive at civilised volume but it doesn't sound that great. Need to try attenuation and vvr s maybe next.

That type of MV is only useful to bring down the volume slightly. I always put a 10k resistor between the turrets and the pot ( one on each wire to the pot). This will eliminate the nasty artefacts in the overdrive, for it prevents you from dialing the volume too low to get in the nasty territory. It will also be even less lowering the volume this way, but there is a better sweep control of the pot. I added one on my most recent Tremolo TMB last weekend, just to see how that turns out. I like it though… it gives me a little extra control over the volume, just enough for my purposes. That is for playing in smaller venues… but we’re talking about an 18 watt here. The 36watt is just too loud for me.
If you want mire volume control with a master volume I advise you to add a LarMar type 2 PPIMV. That works reasonably well. But I don’t know how it acts on a Marshall type of amp.. I use it in most Fender type builds, where it shines on some amps and sucks on others…

[chaliapin]

Thanks bieworm,

With hindsight I should have built am 18 watt and tweaked for more headroom but here I am...

Seems to me all the post PI MVs are doing is cutting the signal, and therefore there overdrive, to the power tubes. And that's where the interesting stuff happens...

Having said that I'd love to hear from someone who has built the 36w lite, break up on mine is a lot later than the 18 I built and definitely significantly less distortion available overall.

Just played the amp again this morning. It's a glassy rattle in the treble, only with the volume up near half so with slight breakup and more noticeable on certain notes, it almost sounds like a rattly tube or something. Now I think of it I'll tighten all the nuts and bolts...

[Bieworm]

Thanks bieworm,

With hindsight I should have built am 18 watt and tweaked for more headroom but here I am...

Seems to me all the post PI MVs are doing is cutting the signal, and therefore there overdrive, to the power tubes. And that's where the interesting stuff happens...

Having said that I'd love to hear from someone who has built the 36w lite, break up on mine is a lot later than the 18 I built and definitely significantly less distortion available overall.

Just played the amp again this morning. It's a glassy rattle in the treble, only with the volume up near half so with slight breakup and more noticeable on certain notes, it almost sounds like a rattly tube or something. Now I think of it I'll tighten all the nuts and bolts...

Hey... there's a "hear it" section in the forums link. There are a lot of soundclips there from various posts.

For example:
viewtopic.php?t=21354
viewtopic.php?t=19618

Here's a link to my 36W tremolo TMB... overdrive for days!
viewtopic.php?t=25859&hilit=tremolo+tmb&start=105

[chaliapin]

Mine sounds similar to the second of the three but no one tells you what volume setting they're using!

[Bieworm]

Mine sounds similar to the second of the three but no one tells you what volume setting they're using!

I don't know what the volume settings on the first 2 amps is, but mine was set at 8 or so

[chaliapin]

I could tell yours was cranked! Ha ha! Your circuit has an extra gain in the preamp though doesn't it? Im more into colourful dirt than raunchy rock tones, I'd just like to know it's working right...

[Bieworm]

a lot of the way your amp presents itself when it comes to dirt is the way it's biased and the B+ voltage. It's a matter of balance... and yes , the tremolo TMB has some delicious preamp dirt, more than the Lite for that matter.

The 'break wind' attenuator could be interesting for your purposes...

[chaliapin]

Have you built one bieworm? Where did you get parts? You're in Europe aren't you?

[Bieworm]

I’m from Belgium, yes. No I haven’t built one for there’s no need for me to have one.. yet
I source my parts from tubetown and jukeboxrevival.nl. The latter will probably supply most required parts

[JMPGuitars]

With hindsight I should have built am 18 watt and tweaked for more headroom but here I am...

What's stopping you from removing 2 of the tubes and rebiasing it for 18W? If that's what you really want, then do it. Cover two of the sockets with some masking tape so you know not to use them.

[chaliapin]

I may end up doing that Josh but I really want to get it working properly as 36watt. The nasty noise got worse after my last attempt at soldering improvement... im planning on working on all the joints then posting more pictures so you guys can hopefully tell me which are the worst...

What all I aiming for on the valve sockets solder joint wise?

I understand the irony and futility of amplifying an acoustically quiet electric guitar to wonderful, roaring, ear splitting levels... then putting a lot of effort into making it quieter again...

[JMPGuitars]

I may end up doing that Josh but I really want to get it working properly as 36watt. The nasty noise got worse after my last attempt at soldering improvement... im planning on working on all the joints then posting more pictures so you guys can hopefully tell me which are the worst...

What all I aiming for on the valve sockets solder joint wise?

I understand the irony and futility of amplifying an acoustically quiet electric guitar to wonderful, roaring, ear splitting levels... then putting a lot of effort into making it quieter again...

If that's what's happening when you try to improve the solder, I think we need to pause for a moment. What equipment are you using for soldering? What kind of solder? What temperature are you soldering at?

Forget your amp for a moment, and practice soldering like the videos. Work out the heat bridge and see it melt every time before you paint the solder on. If you have something to practice on besides the amp, that would be ideal.