What is gained by placing a 12AT7 in V5 of a Tremoverb

If you do not use the amps reverb what do you gain.

Just really want to know how to tweak the amp.

Some earlier posts speak to this addition, but unless you use the reverb on the amp I am lost on it's addition or subtraction to the tone.

Please be specific, thanks.

Only half the tube is used as the reverb driver - the other half is in the signal path for the whole amp, after the reverb stage and before the FX loop, in use on both channels/all modes all the time. The reverb recovery is performed by the second half of V1. This is an unusual arrangement - I'm not sure why, possibly for noise reasons in keeping the reverb recovery as far away as possible from the PT end of the amp.

But what it means is that a 12AT7 in V5 also changes the overall gain and tone of the amp, as well as deepening the reverb - it does the usual 12AT7 thing of lowering the gain, increasing the headroom, improving clarity and widening the frequency response. (Less gain and mids, more bass and treble, basically.) I don't always like 12AT7s in 'gain' positions as they can often sound a bit cold, but it seems to work well in this amp/position.

They also work well as a PI if you want to lower the power amp section campared to the preamp. This is more usefull in a non-master volume amp.

Thanks guys.

Just curious, as I am not up on all my lingo...what is the PT end of the amp or what does PT mean, thanks.

PT = Power transformer, OT = Output Transformer

Thanks Brother

PI = Phase Inverter

Ken j said:

They also work well as a PI if you want to lower the power amp section campared to the preamp. This is more usefull in a non-master volume amp.

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Dom

Thanks to you too Brother...that one I knew but there may be other newbies that it helped.

You gurus have no idea how greatly appreciated your helpful information is...a thanks goes out to all of you, and you know who you are.

Great info to know as Im getting ready to replace all the tubes in my 93 head. Looks like its worth it to get all 6.

I actually had a JJ ECC81 (12AT7) that was tested as "balanced for use in phase inverter" from Eurotubes that I just stuck in V5 of my Nomad 45 today. It dropped an easy 2-3 dB off the preamp but definitely seems to have brought out a richer, more detailed character. It also allowed me to crank the power amp up a bit more to compensate for the drop in volume.

I will probably get one of their balanced higain ECC83S models to compare against, but overall, it was an impressive change and much smoother than the Tung-Sol reissue I had in the PI slot previously.