What do you do with the unused triode in a Rocket build?

VintageCharlie · Post by **VintageCharlie** » Tue Sep 29, 2020 6:05 pm

Hey guys,

i am looking for some ideas what to do with the unused triode that you get, if you only build a top boost channel.

I am considering building the normal channel too or turning it into a boost.

What have you tried and what has worked best / was most useful?

Post by **xtian** » Tue Sep 29, 2020 7:39 pm

The Rocket has a lot of gain on tap already!

TAG trivia contest: Whose signature says, "Oh, my God, it has an unused triode!" ?

VintageCharlie · Post by **VintageCharlie** » Wed Sep 30, 2020 4:35 am

You are right about the gain part - there is quite a bit there. It would make sense to turn the triode into a normal channel (sounds really fat with pedals/boosters), but only if it could be jumpered with the Tob boost channel, which it in its natural state cannot. Is there a simple (solid state) way of inverting the phase of the normal channel inside the amp (without using a ABY pedal with phase inverse) so it can be blended with the top boost channel? I guess one would need that part of the circuit, which these ABY pedals use for phase inversion.
Does the AC30CC happen to have something like this, because the channels seem to be linkable internally?

Post by **pompeiisneaks** » Wed Sep 30, 2020 5:14 am

VintageCharlie wrote: ↑Wed Sep 30, 2020 4:35 am You are right about the gain part - there is quite a bit there. It would make sense to turn the triode into a normal channel (sounds really fat with pedals/boosters), but only if it could be jumpered with the Tob boost channel, which it in its natural state cannot. Is there a simple (solid state) way of inverting the phase of the normal channel inside the amp (without using a ABY pedal with phase inverse) so it can be blended with the top boost channel? I guess one would need that part of the circuit, which these ABY pedals use for phase inversion.
Does the AC30CC happen to have something like this, because the channels seem to be linkable internally?

The AC30 I believe sends the signal from the other channel into the other half of the PI instead of to the same side as the top boost channel (I believe this was the tremolo channel). At any rate, if your signal would be out of phase you can just input it into the other side, if the PI is a LTPI. also, though some people have been fond of using LND150's I think that are mosfets that handle the B+ of tube amps just fine and work almost identically to a 12AX7's triode in the amp, but don't need heaters or too much current. Some have used them for the cathode follower side of the cathode follower pair for tone stacks etc.

~Phil

VintageCharlie · Post by **VintageCharlie** » Wed Sep 30, 2020 10:14 am

pompeiisneaks wrote: ↑Wed Sep 30, 2020 5:14 am
VintageCharlie wrote: ↑Wed Sep 30, 2020 4:35 am You are right about the gain part - there is quite a bit there. It would make sense to turn the triode into a normal channel (sounds really fat with pedals/boosters), but only if it could be jumpered with the Tob boost channel, which it in its natural state cannot. Is there a simple (solid state) way of inverting the phase of the normal channel inside the amp (without using a ABY pedal with phase inverse) so it can be blended with the top boost channel? I guess one would need that part of the circuit, which these ABY pedals use for phase inversion.
Does the AC30CC happen to have something like this, because the channels seem to be linkable internally?
The AC30 I believe sends the signal from the other channel into the other half of the PI instead of to the same side as the top boost channel (I believe this was the tremolo channel). At any rate, if your signal would be out of phase you can just input it into the other side, if the PI is a LTPI. also, though some people have been fond of using LND150's I think that are mosfets that handle the B+ of tube amps just fine and work almost identically to a 12AX7's triode in the amp, but don't need heaters or too much current. Some have used them for the cathode follower side of the cathode follower pair for tone stacks etc.

~Phil

Thanks for the input, pompeiisneaks! Would it change the tone / behavior of the normal channel, if it would be fed into the other side of the LTPI? If not, then that sounds like a perfect and easy solution. Would be great to be able to keep the normal channel - sounds massive when pummeled with pedals.

ChopSauce · Post by **ChopSauce** » Wed Sep 30, 2020 10:44 am

I'd say be careful not to collect noise using the left triode. I had to suppress one cold clipper triode on one of my build because it was paired with one triode a few gain stages before, for that reason.

Post by **Colossal** » Wed Sep 30, 2020 10:48 am

VintageCharlie wrote: ↑Wed Sep 30, 2020 10:14 amWould be great to be able to keep the normal channel - sounds massive when pummeled with pedals.

This is what Brian May has always done. Customized Rangemaster slamming just one half triode, no tone stack (+6dB), into the PI.

VintageCharlie · Post by **VintageCharlie** » Wed Sep 30, 2020 10:59 am

Colossal wrote: ↑Wed Sep 30, 2020 10:48 am
VintageCharlie wrote: ↑Wed Sep 30, 2020 10:14 amWould be great to be able to keep the normal channel - sounds massive when pummeled with pedals.
This is what Brian May has always done. Customized Rangemaster slamming just one half triode, no tone stack (+6dB), into the PI.

Yes! I recently tried it on my 63 top boost and the difference compared to the top boost channel was huge. The rangemaster also sounded a lot less honky this way.

VintageCharlie · Post by **VintageCharlie** » Wed Sep 30, 2020 11:02 am

ChopSauce wrote: ↑Wed Sep 30, 2020 10:44 am I'd say be careful not to collect noise using the left triode. I had to suppress one cold clipper triode on one of my build because it was paired with one triode a few gain stages before, for that reason.

Could an alternative to feeding the normal channel to the other side of the PI be something like this?:
http://www.geofex.com/article_folders/p ... verser.htm

From what i understand it was primarily intended for pedals, but could it be easily integrated into a tube amp with the available transformer taps and with the voltages of tube preamps? Looks like its 2 caps, 5 resistors and an opamp.

ChopSauce · Post by **ChopSauce** » Wed Sep 30, 2020 12:15 pm

Sorry, I feel I am not knowledgeable enough to answer. I was just willing to share my experience. Afterwards, I thought maybe if "both of the shared triodes" / both channels are not used at the same time, this is no more an issue...

VintageCharlie · Post by **VintageCharlie** » Wed Sep 30, 2020 12:55 pm

In this case i am interested in using them together - the intention is to blend them.
AS pompeiisneaks said, the vintage AC30 seems to have used one side of the PI input for normal and top boost and the other side for the vibrato channel. And then the AC30CC seems to put the normal channel on the other PI input. So i guess, if it is properly implemented, sounds like the simplest solution.
Only thing that i am wondering about is, if choosing either PI input changes more than just the phase - are there any tonal changes to be expected?

The Amp Garage

What do you do with the unused triode in a Rocket build?

What do you do with the unused triode in a Rocket build?

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Re: What do you do with the unused triode in a Rocket build?

Re: What do you do with the unused triode in a Rocket build?

Re: What do you do with the unused triode in a Rocket build?

Re: What do you do with the unused triode in a Rocket build?

Re: What do you do with the unused triode in a Rocket build?

Re: What do you do with the unused triode in a Rocket build?

Re: What do you do with the unused triode in a Rocket build?