I bought this amp in its assembled form to get familiar with learning to do modifications and better understand tube circuits. Overall, it sounds pretty good to me and I'm surprised how much volume and low end it has compared to a Stage Right 15 watt combo through the same cabinet(closest thing I had to compare it to).
The master volume channel sounds a bit darker and compressed even with the preamp volume reduced to 6-7 and master volume at around 5 compared to the no master channel which has a really nice crunchy well balanced and harmonically sweet tone about it. Any suggestions to the master channel preamp tweaks to help "open" it up a little perhaps a little more along the lines of a Hiwatt DR504. The cabinet is a Marshall 1960A with the G12T-75's. BTW the tubes are Shu guang 12ax7b and EL84 and Electro Harmonix 6CA4 rectifier.
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Ceriatone clone
Moderators: Graydon, CurtissRobin, colossal, zaphod_phil, Daviedawg
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Phrak9
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Ceriatone clone
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Bieworm
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Re: Ceriatone clone
Those G12T75 are pretty mid scooped sounding speakers. A greenback type would work wonders to get a more open tone.
That said, you can change the mid pot to 50k linear to get more of those higher mids in the tone. I can think of no other obvious mods to achieve what you're asking.
That said, you can change the mid pot to 50k linear to get more of those higher mids in the tone. I can think of no other obvious mods to achieve what you're asking.
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"THIS should be played at high volume..preferably in a residential area"
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Bieworm
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Re: Ceriatone clone
Although the TMB is a very commonly built amp, lots of people are disappointed in the tone when it's built. It tends to have a harsh overdrive and sounds anemic. The master volume is not really a master volume, but a gain control (as far as one can call it a control, which it really isn't though)
People think they're getting a lower wattage plexi type amp, but the result is far from plexi territory.
What I'm trying to say is that there are better amps with nicer sounds than the common TMB. I would convert it to a Superlite TMB, which has an organic and nice overdrive. That's one of my top 3 18 watt types.
Most of the ingredients are there in your TMB amp. You would have a spare triode to spend, and this could possibly be a nice opportunity to also change the normal channel to the fat and juicy normal channel of the classic 18 watt. All in all I think this would be my approach. YMMV
People think they're getting a lower wattage plexi type amp, but the result is far from plexi territory.
What I'm trying to say is that there are better amps with nicer sounds than the common TMB. I would convert it to a Superlite TMB, which has an organic and nice overdrive. That's one of my top 3 18 watt types.
Most of the ingredients are there in your TMB amp. You would have a spare triode to spend, and this could possibly be a nice opportunity to also change the normal channel to the fat and juicy normal channel of the classic 18 watt. All in all I think this would be my approach. YMMV
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"THIS should be played at high volume..preferably in a residential area"
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Crabman
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- Location: Sudbury, Ontario
Re: Ceriatone clone
I agree with you on the role of master volume on the TMB. To be honest I just dime it and control output with the gain pot. To my ears it sounds best that way. In other words, it might as well be lifted out of the circuit just like a good ol’ plexi.
However, I would say that the TMB channel can sound very good, but you may need to play around a bit to tighten things up. Mine is clearer than the normal channel when it comes to note definition. Some of the TMB variants out there push too much bass frequency through the system. Those frequencies need to be attenuated early on. My advice to those looking to tweak is to start by reducing the values of the first cathode cap and first coupling cap. Trinity amps have a number of TMB variants, and I have tried most of them through modding. I have found that each has some good and not so good aspects but if you select the best of each you can come up with an excellent TMB channel. I stick with the PI and power amp topology that are common from schematics posted here. That is, the 820ohm/47K combination on the long tail pair and 0.01uF coupling caps from there to the power amp. Using 0.022uF coupling caps between PI and the EL84s and on the first stage of the preamp is a recipe for flubby bass when using humbuckers. I also advocate trying the 2.7K/0.68uF combination on the fist stage cathode.
On some variants, Trinity use a 100K in parallel with the gain pot to attenuate some signal early on. This resistor is wired directly to the pot and I find it to introduce noise. Using a large grid stopper instead (like the original TMB variant) wired directly to the grid on the second stage reduces noise and IMO produces smoother distortion. I see that this approach is used on the superlite TMB together with a voltage divider to reduce signal. I may try converting mine to a divider to attenuate a signal at that point since I find that there is a bit too much signal at a low gain setting .
However, I would say that the TMB channel can sound very good, but you may need to play around a bit to tighten things up. Mine is clearer than the normal channel when it comes to note definition. Some of the TMB variants out there push too much bass frequency through the system. Those frequencies need to be attenuated early on. My advice to those looking to tweak is to start by reducing the values of the first cathode cap and first coupling cap. Trinity amps have a number of TMB variants, and I have tried most of them through modding. I have found that each has some good and not so good aspects but if you select the best of each you can come up with an excellent TMB channel. I stick with the PI and power amp topology that are common from schematics posted here. That is, the 820ohm/47K combination on the long tail pair and 0.01uF coupling caps from there to the power amp. Using 0.022uF coupling caps between PI and the EL84s and on the first stage of the preamp is a recipe for flubby bass when using humbuckers. I also advocate trying the 2.7K/0.68uF combination on the fist stage cathode.
On some variants, Trinity use a 100K in parallel with the gain pot to attenuate some signal early on. This resistor is wired directly to the pot and I find it to introduce noise. Using a large grid stopper instead (like the original TMB variant) wired directly to the grid on the second stage reduces noise and IMO produces smoother distortion. I see that this approach is used on the superlite TMB together with a voltage divider to reduce signal. I may try converting mine to a divider to attenuate a signal at that point since I find that there is a bit too much signal at a low gain setting .
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jmelb
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- Joined: Thu 04/11/24 1:13 am
Re: Ceriatone clone
Some simple things that improved my first tmb build:
-Experiment with some bright caps on the tmb channel volume.
-Add a bypass cap ~500pf across the 470R at the same volume control, leading to the next grid.
-This 470R is an excellent spot to create a voltage divider, which can tame the overdrive and help you voice it to your liking. A bit like how the channel mix resistors and volume controls interact on a bigger dual channel marshall.
-Optional to put another bypass cap on the second stage's cathode of a small value. On the Ceriatone layout this is unbypassed from memory. If you cut some gain using a voltage divider, you can add some more select frequencies back in.
The bright caps will brighten that channel. If you have some push pull pots lying around you can make a switchable one with different values. You can also convert the 'master volume' into a post-phase inverter master with a bit of trickery in the layout.
-Experiment with some bright caps on the tmb channel volume.
-Add a bypass cap ~500pf across the 470R at the same volume control, leading to the next grid.
-This 470R is an excellent spot to create a voltage divider, which can tame the overdrive and help you voice it to your liking. A bit like how the channel mix resistors and volume controls interact on a bigger dual channel marshall.
-Optional to put another bypass cap on the second stage's cathode of a small value. On the Ceriatone layout this is unbypassed from memory. If you cut some gain using a voltage divider, you can add some more select frequencies back in.
The bright caps will brighten that channel. If you have some push pull pots lying around you can make a switchable one with different values. You can also convert the 'master volume' into a post-phase inverter master with a bit of trickery in the layout.
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