Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: pogona06 on January 21, 2018, 11:55:57 am

Title: Mashup Vox AC30 + Slodano SLO into a single guitar tube amp
Post by: pogona06 on January 21, 2018, 11:55:57 am

Some purists might not like this approach and will treat me of heretic, but as I had big issues to choose which type of tube amp I could build, I decided to build one combing 2 very different styles:
I integrated 2 preamps:
– Vox Bright/Boost channel, to go from clean sound to smooth saturation
– Soldano Bright channel, to go from smooth to high gain saturation

Followed by an adjustable mixer to combine both signals.
The rest of the circuit, ie: phase inverter and power amp are from the AC30 schematics.

I integrated several mods that I grab from different forums and also added few other ones, to test the impact on sound.

Here are information & schematics (still under consolidation), as I'm still tuning the amp, and specially struggling with "some" hum, as expected, considering the complexity ...

Blog: https://tubeampblog.wordpress.com
Schematics & Pictures: https://tubeampblog.wordpress.com/schematic-ac30-and-slo-mashup/

Title: Re: Mashup Vox AC30 + Slodano SLO into a single guitar tube amp
Post by: VMS on January 21, 2018, 01:06:15 pm

I'm building single-ended amp with slo type lead channel and lp standard crunch channel.


In your build i would maybe connect the slo channel to the other side of the PI like in this matchless dc30 amp:


http://el34world.com/charts/Schematics/files/matchless/matchless_dc30_old.pdf (http://el34world.com/charts/Schematics/files/matchless/matchless_dc30_old.pdf)

Title: Re: Mashup Vox AC30 + Slodano SLO into a single guitar tube amp
Post by: pogona06 on January 21, 2018, 01:37:47 pm

Quote from: VMS on January 21, 2018, 01:06:15 pm

In your build i would maybe connect the slo channel to the other side of the PI like in this matchless dc30 amp:

Thanks VMS ; but if I connect the 2nd preamp signal to the other side of the Phase Inverter, it should be in opposed phase vs the 1st preamp, which is not the case in my schematic. I realized this when I plugged the 2nd preamp on the other PI side and the sound became very tiny and was loosing a lot of basses when both signals were at similar level.
In fact, my basic mixer with 2 resistances of 200k on each channel might not be great as it creates interactions certainly.
If there are more appropriate options, I take them !

Title: Re: Mashup Vox AC30 + Slodano SLO into a single guitar tube amp
Post by: VMS on January 21, 2018, 02:19:36 pm

Sorry my bad. I counted the gain stages wrong.