Hi everyone!

I've just built a dual rectifier 2 channel replica, using the schemes that i've found on the net. Everything seems ok with hi-gain channel, but i can't have a really clean channel. In fact the clean channel sounds always cruncy...
I've made some modification on amp, but if i get a really clean channel, i don't get very saturated hi-gain channel...
Any experiences on this type of problems??

Thank's in advice!

Hi! Are your sure, to have set the bias voltage correct? The Power-Stage might produce an unharmonic distortion, if the bias is too low.
Greetz.

I'm just investigating this strange behaviour... Tomorrow morning i will check the output stage bias, in fact I haven't check yet (don't know why!).
But using 6L6 must be something like -50V or -51V, if i'm not wrong...
In the next days I will post some photos of my replica!

I've checked the bias voltage for the output stage: -52V.
Everything seems OK, I've also checked all biasing of the other tubes and they agree with mesa schematic.
I've see some schematich of the new 3 channel dual recto and i've noticed that clean channel is in different path (it does not path on V2).
Any suggest?

Zitat von: colorblind am Aug 09, 2006, 04:17
I've made some modification on amp, but if i get a really clean channel, i don't get very saturated hi-gain channel...

That sounds very strange. The clean-channel is separated from lead/crunch in the DualRectifier.
What you could do:
- check your switching-LDRs / FETs
- could it be a bleeding of the lead-channel
- V1 too near to V2/V3 (lead channel). Just pull the lead-tubes to test

Could you post your scheme? It would make things easier

Bye, Marc

Hoi!

I think he used the old 2-channel recto schematics, so both channels share the same tubes and circuit. The old recto didn't have a real clean channel, that's why the 3-channel recto (with an own real clean channel) was invented.
Try to use very low gain settings and loud volume settings to get a clean rhythm sound, that's all you can do...

Greets
Mathias

Hi,

and don't forget to adjust the bias for the powertubes via the 1-ohm-kathode-resistor method.
Your -52 Volt- measurement says nothing about the correct biassetting of your powertubes.

The current through the tube matters!

Look here:

http://www.webervst.com/tubes/calcbias.htm

regards

jacob

@mac-alex_2003:
i'm just using old 2 channel dual rectifier, that share clean and lead channel, i think that you're talking about the 3 channel dual rectifier.

@Magasit:
you're giving me a very important information, so i'm thinking that i've done the circuit in the right way. I'm just planning to experiment the 3 channel dual rectifier. (if i have the budget!!!)

@jacob
You're really right! sometime i forget to be an electronic engineer! Thanks to remind me!

regards

Luca

Here some pictures of my construction...
It's a 3 channel amplifier based on the "2 channel dual rectifier" mesa schematic.

Hi Luca,

Your PCB looks very professional and the rest of the guts looks very good too. I hope that you've managed to get a clean sound out of it eventually!!

I sent you an email about this a few days ago - I'm building a 3ch 50w Rectifier inside a small case, and besides not being a fan of point-to-point, I would like to create a neat and tidy design.

Could you please post more pictures of your creation? (more hi resolution!!)

Many thanks