Advice on warming up my TC-50 to sound more like my RA100?

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Bottle Rocket
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Joined: Fri Mar 16, 2018 11:13 am

Advice on warming up my TC-50 to sound more like my RA100?

Post by szguitar » Fri Mar 16, 2018 11:26 am

Hey all,

I have two RA100's, 1 combo and 1 head, awesome amps and killer tone. However, I wanted separate gain controls on channel 2 & 3, i also wanted a solo button on each channel, midi control of the amp, and having a rack mount head would make touing much easier. The solution was the TC-50, It does everything i need in an amp and the clean channel is even better then my RA100's. However the dirty tone is a slight bit more of a rectifier vs the JCM800 Marshall tone that i love on my RA100s. it's a slight difference but still is different, EQ changes don't help it's just the amp difference. Any changes via preamp tubes, power tubes or mods anyone has done to warm their TC50 to more of a RA100/Marshall tone?


Triple Recto
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Location: North Carolina

Re: Advice on warming up my TC-50 to sound more like my RA10

Post by bandit2013 » Sat Mar 17, 2018 10:11 am

Hey I am in the same boat as I have both RA100 head and combo. Also have the TC-50 and the TC-100.

The Power supply of the TC-50 is a bit different than that of the RA100 for obvious reasons.... more iron on the RA. I believe the TC-100 also has the same OT as that used on the RA (not exactly sure but looks the same, did not check numbers on them). the TC-100 and the RA-100 are much closer in tone than the TC-50 to the RA-100.

I have experimented with some preamp tubes in the TC-50 (change in V3 and V4 on the 50 which would be the same as the V1 and V2 on the RA). The preamp circuits between the two amps are basically the same but slightly different and did not seem to change much to address the Lo or Hi gain voice with a change in preamp tubes. The effect of preamp tube change in the RA is a bit more notable but that too does not have a dramatic impact on tone of the two channels. V3 might be the best target to focus on for slight change in temper (especially for Hi gain channel). Change in V4 will place more focus on the tone controls as the tone stack is on the last gain stage. This is also true to the RA. They are very much the same preamp, just rearranged the tube positions. Tung Sol in V3 will address the tone for the Hi gain channel but may add some brightness to the Lo gain channel but not as much as you would think. Long plate Mullard 12AX7 will cut some top frequency out just enough but may be too much for the Hi gain channel. A Mullard CV4004 may add some midrange scoop to both channels when used in V4.

You do know that the presence control is not a feedback control? It is a high pass filter so use that as such. Roll back the presence to aid in warming up the tone. Dial in a bit more midrange and roll back the treble. You can also dial out the midrange for a more scooped tone. The relation between the midrange and treble is a bit different than the RA but not by much.

Another way to warm up the overall tone would be to change the Mesa 12AT7 (Chinese) which is very bright tube to a JAN/Phillips 12AT7 which is very warm, RFT 12AT7 is in between the two in tone. I have not tried other 12AT7 in V5 (the cathode follower circuit, The RA has this as V3, which is used as the SEND level for the FX loop, it is always active in the signal path regardless if you have the RA or the TC).

No matter what preamp tubes or power tubes I have used in the TC-50, I could not topple the RA100 head off of its roost. The TC-100 definitely did that. It has some characteristics of the TC-50 but is more closer on tone to the RA100. Hi gain channels are quite similar, thick with a hint of compression. The lo gain or blue channel of the TC-100 is voiced a bit differently than the RA but they are close enough. Even though the TC-100 does not have the power resistor on the outside, the power soak is about the same in design. I believe the TC uses two chokes vs one for the power soak format.

You could opt for an EQ pedal in the FX loop. That would allow you to adjust the tone before it hammers the Phase inverter. Still the smaller iron core OT of the TC-50 may be one thing that would be hard to get around.

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