Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Jennings on December 14, 2023, 04:59:45 am

Title: What to do with a spare triode?
Post by: Jennings on December 14, 2023, 04:59:45 am

Recently I’ve been doing some work on my modified Ceriatone Rock-It (Trainwreck Rocket) based amp, which reminded me that is has a spare triode unused. Seems a shame to leave it there doing nothing…what would folks suggest/recommend to use it for?

Title: Re: What to do with a spare triode?
Post by: Dave on December 14, 2023, 10:10:27 am

You could... move the connections from the V1B over to that unused triode and then parallel the V1A and the V1B. Some people like a paralleled first stage. Some think it is a waste of resources. Either way, it is something you could experiment with.


Or, you could use it as a series gain stage.


Or. you could drill out another preamp tube hole and with three stages, implement a fender-type reverb circuit.


Dave

Title: Re: What to do with a spare triode?
Post by: sluckey on December 14, 2023, 10:35:59 am

Leo believed it was OK to have an unused triode in an amp. So do I.

Title: Re: What to do with a spare triode?
Post by: stratomaster on December 14, 2023, 10:56:08 am

Put a small 3pdt switch in.  Use something like a 12DW7 and now you have two different gain levels at the flip of a switch.  It'll probably pop like mad though.

Title: Re: What to do with a spare triode?
Post by: stratomaster on December 14, 2023, 10:57:14 am

Quote from: stratomaster on December 14, 2023, 10:56:08 am

Put a small 3pdt switch in.  Use something like a 12DW7 and now you have two different gain levels at the flip of a switch.  It'll probably pop like mad though.

Come to think of it, you can parallel the plates and cathodes and just flip the grids. Adjust resistances to keep the operating points consistent with stock. 

You can also give each it's own plate and cathode cap/resistor and have two distinct triode circuits to choose from for stage 1.  Add another switch to "jumper" them like an old Marshall.

Have fun. Think outside the layout/schematic.

Title: Re: What to do with a spare triode?
Post by: Jennings on December 14, 2023, 02:26:33 pm

Thanks folks…some great food for thought on extra gain stages, parallel stages and alternative voicings 👍 Quite tempted by those ideas…it’s made me think I could add a switch for selectable Brilliant/Normal Vox cap voicing a on the input too.


I hear the votes for leaving the vacant stage be…it has been for the last 14yrs. I’m just tempted to have a bit of fun with it.


What about a tremolo perhaps? Any thoughts there?

Title: Re: What to do with a spare triode?
Post by: kagliostro on December 14, 2023, 02:37:46 pm

Give a look to this pdf file after version #7

https://ampgarage.com/forum/files/wreckxpr.pdf (https://ampgarage.com/forum/files/wreckxpr.pdf)


Franco