Minimalist 4X6L6 100watter

[Bob-I]

Getting back to the minimalist HRM...Here is a clip. It is an amp with the minimalist HRM circuit described earlier in the thread, this time with a cathode bias EL34 output stage (B+ about 470VDC). The amp also a clean channel based on the Bad Cat Hot Cat 30. Each channel feeds one side of the LTPI.

http://www.youtube.com/watch?v=28rkoChtts4

Sounds very good, very different from a traditional Dumble but much better than most hi-gain amps as well. I'd like to hear the Bad Cat channel as well.

The beauty of homebrewing to me, is making the amp into what you want.

[Guitarman18]

I see that on one of your youtube clips that you demonstrate your 'Custom mod switch' which takes it further into HR Marshall territory. Can you elaborate on this? It gives the amp a whole new dimension.

Thanks for sharing.


Cheers, Paul.

[ontariomaximus]

Ontario,

While the playing and tone on your clip are very good for that style, I didn't hear anything there that would have suggested to me that was a Dumble amp. I know Dumbles can shread if pushed, but why copy a Dumble if you're going for an SLO type sound?

Just saying,..

ampdoc1

I wasn't going for a SLO sound, I just did the HRM and how it came was how it came it out. Actually I have done 4 so far, 100W with 4x 6L6, 45W with 2 EL34, 70W with 2 x 6550, and 5w with a single 6V6. It is quite a bit thicker sounding than the SLO imo.

[ontariomaximus]

Getting back to the minimalist HRM...Here is a clip. It is an amp with the minimalist HRM circuit described earlier in the thread, this time with a cathode bias EL34 output stage (B+ about 470VDC). The amp also a clean channel based on the Bad Cat Hot Cat 30. Each channel feeds one side of the LTPI.

http://www.youtube.com/watch?v=28rkoChtts4

Sounds very good, very different from a traditional Dumble but much better than most hi-gain amps as well. I'd like to hear the Bad Cat channel as well.

The beauty of homebrewing to me, is making the amp into what you want.

We did a short clip of the clean channel, I'll get it to youtube in the next day or 2. Did a few clips of a 'wreck express too.

[ontariomaximus]

I see that on one of your youtube clips that you demonstrate your 'Custom mod switch' which takes it further into HR Marshall territory. Can you elaborate on this? It gives the amp a whole new dimension.

Thanks for sharing.


Cheers, Paul.

Sure, I've learned from this site, so here's a 1-switch tweak. IMO, the HRM can be too thick for real percussive/slightly muted playing, e.g. Ain't Talkin' Bout Love.

The OD section is where we want to focus our attention, specifically the size of cathode R's and bypass caps.

What I did is use a 3PDT switch that:
1. changes the 2k7 OD1 rK to 6k (add a 3k3 in series and short across it for stock value)
2. changes the 5.0 uf bpass on OD1 to .22uf (have the .22 fixed, a 4.7 is switched in and out)
3. change the OD2 rK to 820 ohm (switch in a 1k5 r in parallel with the stock 1k8)

So in the modded position, OD1 has a 6k cathode R bypassed with a .22, and the OD2 has an 820 ohm cathode R. And HRM can now stand for Hot Rodded Marshall.

JD preferred the amp in the modded position, as did Bill from Ark Amps. However, the HRM (not modded) excels in neck humbucker leads, as there is quite a bit more fundamental present (as opposed to harmonics and overtones).

[ontariomaximus]

Sounds very good, very different from a traditional Dumble but much better than most hi-gain amps as well. I'd like to hear the Bad Cat channel as well.

The beauty of homebrewing to me, is making the amp into what you want.

Here is a clip of the clean channel:
http://www.youtube.com/watch?v=ey5x6zV9GBM

[guitarsnguns04]

what controls are on the front of the amp for each channel?

[ontariomaximus]

The 2 channel EL34 amp has for the overdrive section: Gain, Master, Treble Bass, Mid and a mod switch on the back that takes it to a more Marshally sound. The PAB is assumed engaged and the overdrive tonestack is whats on the front.
The clean HOT CAT channel just has a volume control. Really, that's all it needs. You have a tone pot on your guitar, and different pickups.

[wicker]

Delete please