yamaha t50c hum

[roberto]

Thank you Mario,
I always try to do the best I can.

[Marioverkill]

Robert !

I changed the 2 coupling caps(22nF).The lower distorted note is almost all gone.I can hear a slight hum on the drive channel still there when I play a note(again after the amp is warm;20-30 minutes)I will wait to see if the changing the smoothing caps will correct the problem.

I did your 470K//470uF on the clean.HUGE IMPROVEMENT !I have ordered some 270 pF caps and will try the 1M//270uF.
However,I would like the clean to remain clean further on the gain setting.I biased the stage with a 47K Plate Resistor and a 1.2K Cr,biasing at 1.6 volts.I temporarily installed a 120K resistor//gain to try to limit gain.

1)Do you think it is a good idea to replace the gain pot with a 50K ?What do you suggest to keep the clean from breaking up to soon?

Thanks again

Mario

P.S I also replaced the feedback with 47K

[roberto]

Happy to read you are very satisfied.

1M//270p (you can use 220p if you prefer) sounds more clean than 470k//470p, this is the reason I suggested it. Don't lower clean gain pot resistance, it's easier to use a 100-220k resistor in parallel with it (maybe a SLO clean/crunch switch?).

I prefer 100k 2k2 (no bypass) on 2nd clean stage, try that with the 1M//270p and with the resistor in parallel to the clean gain pot.

As for the 5M6 - 2M2//120p - 1M//270p - 470k//470p effect, take a look at my pdf in attachment (50mV into a 100k 2k2 stage to 22n to x.xM//xxxpF to 470k voltage divider.

[Marioverkill]

Thank you for your time Roberto.

I'll let you know how it turns out.Hopefully I'll get the parts this week.

Mario

[Marioverkill]

Roberto,

Handy those spice simulations.

I liked your idea of the crunch switch.As I always play the clean channel with the bright on,I hardwired the bright.I installed a 100K//gain instead on the pot switch as a crunch instead.Works great !!

Mario

[roberto]

That's good. If you use a DPDT switch, you can choose to add some brightness to the crunch (or the clean) only by adding a cap on the gain pot.

[chopstuck]

So what kind of overdrive tone have you gotten out of the dirty channel ?

I can apply those changes to the clean channel but the dirty side has no redeeming qualities, it just sounds brash, loud and painful. Though it seems to work right.
I have wanted to do something with my T-50 now that I got the nasty smell issue solved. (A small piece of blue 3M masking tape on back of a power tube base).

I was thinking I wanted some kind of AFD tone or a scooped kind of SLO tone. Something that would fit within the footprint.

[roberto]

chopstuck,
what mods have you done and what do you want to obtain from lead?
AFD and scooped SLO are totally different tones.

[chopstuck]

Well I like the amp footprint, the iron is pretty good and I like the reveb.
I was looking for a rounder clean tone.

I have done no mods other than the choke, reverb and PS upgrade done by Soldano.
Geezers' Hosa 56 has a killer clean with a pentode but I was wanting to get a triode clean to keep from changing the achitecture toooo much.

I guess there is too much rewiring and parts density to get a SLO sound. What about getting something close, is that reasonably possible ?

Otherwise I was thinking an AFD or Emplexador channel. Not rip your face off gain.


These amps aren't worth much but the parts are too good to sell cheap.

Chops

[roberto]

Have you read the mods I've suggested before?

[Marioverkill]

Chopstuck,

I like gain.I play a Splawn quickrod.I have this amp rockin on the gain channel.Lots of gain and usable up to 8 or 9.I removed some bass from the preamp and added a resonance(dept) mod.I can post a clip if you are interested.

I am drawing a blank: what is AFD?

Appetite For Destruction? Slash marshall?

Mario

[roberto]

Yes, SIR mods.

[Marioverkill]

Did you get my PM Roberto ?

Mario

[chopstuck]

Yes Mario I would like to hear a clip of your mods.

I don't know what M Soldano wanted this to be. I know He was on a budget but it's got a lot of stages for a (to me) unmemorable sound.

I have played with an Atomic 16 too that kind of reminded me of this amp. I have heard some demos of the SLO and another similar 50 watt amp that I do like.

I have a few preamps like a Voodoo labs, a Rockmaster, a Realtube and a Prototype Hafler T-1 that get oodles of gain, but I like the hot rodded Marshall tone like the AFD.

[Marioverkill]

O.K.

I am waiting for some parts(hopefully this week).As soon as I get them and do a little work,I'll make one.I'll PM you.

Mario