Overtone HRM mods

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MTR87
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Overtone HRM mods

Post by MTR87 » Thu Nov 09, 2017 10:05 pm

Hey guys,

Long time lurker, first time poster. I see a lot on this forum about modding the overtone but note much on the hrm model. I find that the HRM has too much high end for my tastes and I feel if I were able to tame it s bit I'd have a wider variety of usable tones. I play anything from blues to rock classic and contemperary. I have plenty of experience with electronics to mod this amp but I'm not knowledgeable on what a particular component change will do.

Any suggestions on mods for the HRM?

Thanks in advance.

Michael

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xtian
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Re: Overtone HRM mods

Post by xtian » Thu Nov 09, 2017 10:26 pm

Hi, Michael!

Please point to a schematic for your amp, and I'll make suggestions.

First target for too bright amps is usually early in the circuit, like bright caps and treble peaking caps, before you even get to the tone stack.
I build and repair tube amps. http://amps.monkeymatic.com

MTR87
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Re: Overtone HRM mods

Post by MTR87 » Thu Nov 09, 2017 10:45 pm

Here's a link to the layout: www.ceriatone.com/ceriatone/wp-content/ ... M-100W.jpg

Unfortunately the schematic is not available.

I really appreciate your insight, thanks!

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xtian
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Re: Overtone HRM mods

Post by xtian » Thu Nov 09, 2017 10:57 pm

The two mods I mentioned are A) clip or lift the 47pF bright cap on the MV. Probably won't make much of a difference, as 47pF is pretty small. B) clip or lift the 470pF treble peaker on V1 pin 7.
I build and repair tube amps. http://amps.monkeymatic.com

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sonicmojo
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Re: Overtone HRM mods

Post by sonicmojo » Fri Nov 10, 2017 2:23 am

What kind of guitar are you typically using? This makes a big difference on these amps. One of the first builds I did was a Ceriatone Bluesmaster HRM. I added a high cut dial with varying capacitor levels near the end of the signal chain. There are old threads on that if you can locate them. It helps a lot with single coils, especially Strats. For Les Paul types with humbuckers I wouldn't typically need any cut, but this is just my experience with my one HRM type amp.
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Bryan

Mark
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Re: Overtone HRM mods

Post by Mark » Tue Nov 14, 2017 8:41 am

What have you done regarding adjusting the HRM tone controls. I find they make quite a bit of difference. I also found it took a lot of time getting the pots adjusted right. I found I had to get the best sound from all the guitars I own.
Yours Sincerely

Mark Abbott

MTR87
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Re: Overtone HRM mods

Post by MTR87 » Thu Nov 16, 2017 10:54 pm

Hi Guys,

After tweaking the amp a bit and playing live, I'm fairly happy with the sound I'm able to achieve without mods.

That being said I think I'd like to change some component values to match an original ods hrm layout as posted on the amp garage to get closer to an original dumble amp.

Sonic mojo- I currently use a heritage Les Paul and a tele w/ 3 p90s. My understanding is that the high cut would only affect the lead channel, is that correct?

Mark - I haven't messed with the internal trim pots yet but my original concern was with the clean and overdrive channels and the internal trim pots only affect the overdrive channel.

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