SO, I've dabbled in a few simple amps now and im looking to build on that with a scratch build. The concept is to expand on a simple Champ design and add a seccond microphone channel and reverb. Rather than go the traditional spring route im planning to "Borrow" the internals of a small reverb pedal and splice these in as a paralel send so that both channels can adjust their ammount of reverb.
There is lots of headroom on heater supply of the transformer so i was planning to rectify and step up the voltage to 9v to power the "pedal" using a premade board. My concern is arround how to split and merge audio in general. Presumably for the send all i need is a pot deviding the signal between the next stage and the effect?
What about merging? I am aware of a shred anode being a method of merging 2 channels. That might make sense for the dry feed from the 2 preamps, But more valves to merge in the wet seems silly. Can i effectively connect 4 coupling caps from the various outputs to 1 power stage. but quater the value?
What are the considerations/methods I can use here? Are you aware of any schematics that demonstrate applicalbe concepts?
Cheers.
There is lots of headroom on heater supply of the transformer so i was planning to rectify and step up the voltage to 9v to power the "pedal" using a premade board. My concern is arround how to split and merge audio in general. Presumably for the send all i need is a pot deviding the signal between the next stage and the effect?
What about merging? I am aware of a shred anode being a method of merging 2 channels. That might make sense for the dry feed from the 2 preamps, But more valves to merge in the wet seems silly. Can i effectively connect 4 coupling caps from the various outputs to 1 power stage. but quater the value?
What are the considerations/methods I can use here? Are you aware of any schematics that demonstrate applicalbe concepts?
Cheers.
You mix signals with two resistors.
"Plate mixing" can work OK but max output level is well down and distortion is higher.
"Plate mixing" can work OK but max output level is well down and distortion is higher.
I've a spare PCB for the Belton reverb module if it'd be of use? They do exactly what you are after - basically taking a feed from the heater / spare 5V supply, rectify it to 9V and then power an internal 'pedal'. Trim pot for gain & tone (could be panel mounted) and pads for reverb mix.
You'd also need an effects loop to get the signal down to the right level. I've also got a spare PCB for that too!
Send me a message if interested.
On the merging - I've been playing about with something. Was reading up on virtual earth adders and came up with the attached schematic. The idea was to mix two preamp channels with a minimal interaction as possible - and not having to use another tube to do it. So this has an LND150. All the section in the dotted box is what I'm calling the mixer. The bits on the left are the feeds. Apologies for the overlapping labels...
I'd welcome any input on how well something like this would work.
You'd also need an effects loop to get the signal down to the right level. I've also got a spare PCB for that too!
Send me a message if interested.
On the merging - I've been playing about with something. Was reading up on virtual earth adders and came up with the attached schematic. The idea was to mix two preamp channels with a minimal interaction as possible - and not having to use another tube to do it. So this has an LND150. All the section in the dotted box is what I'm calling the mixer. The bits on the left are the feeds. Apologies for the overlapping labels...
I'd welcome any input on how well something like this would work.
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