Ceriatone Forum

So, like a few others here, I have been rockin with my HRM tonestack bypassed for a while now and I do love it ever so much, but there is one downside, the volume jump that occurs from taking the HRM tonestack out of the circuit. It makes it pretty hard to balance between the clean and OD channels, even with a c-lator. For example I normally run my clean master at 12 o clock and with the HRM engaged the OD master also at 12 o clock. With the HRM bypassed, there is so much signal available that I have to run the OD master around 7 or 8 o clock. This doesn't drive the power section as hard and also puts it on the bright cap as well. Any thoughts on how to even out the volume levels? Pot value change like maybe a 500k pot instead of 1ma? Maybe the 100k resistor that feeds the pot can be reduced to 68k or 47k?

Any thoughts or advice would be appreciated.

Thanks!


Gregg

Hi Gregg
Good question, I'm also looking for an answer to this.
Cheers

Instead of unhooking the ground to the HRM board via a 1pdt switch you could use a 3 way switch to switch between the HRm stack, 15-30k (or whatever you prefer) to ground, or the stack lifted completely.

Or use a dpdt Push pull pot on the Drive or OD master pot with the k to ground or HRM tonestack ON

Definitely experiment with how much resistance to ground config you like to even out the Volume difference between channels. Use a 50k trimmer to experiment with how much K you want to ground then replace with said value. 

Thanks, Greg. That actually make alot of sense, due to the fact that by clipping the ground an infinite resistance to ground is theoreticallt introduced. Funny thing is i was thinking of adding a variable PAB system via trimpot or even a full sized one, so the idea shoulda hit me  ;D

Thanks again!

Gregg

So i finally got around to taking Greg Clark's (boldaslove69) advice. I took things one step further, though and installed a 3 way on-off-on switch. Up is HRM Bypass with a 33k resistor, middle is HRM Bypass completely lifted from ground, and down is HRM Engaged. Adding the resistor helps with the volume jump, as promised, and also takes some of the harshness out of being fully bypassed, probably due to being able to turn the level up some an get off of the bright cap.

Since i have a much easier way of a/b'n between HRM and Bypass now, due to the lack of volume jump,  i decided to really sit down and tweak the HRM a bit with the Tung Sol 6L6's in. I installed a Telefunken in the PI spot and reset the voltage swing back to the stock 6 volt setting and got to tweaking. I gotta say, with the Tung Sols in the HRM sounds pretty darn good now. I really like having it on tap without having to reset the volume levels and everything and gives another option for drive on the BM. It's amazing what a simple tube swap and a well placed switch and resistor can do to change your point of view! I can only imagine that when the Weber Cali and Michigan get here it can only get better!

I would highly suggest this simple mod to anyone who has bypassed their HRM or has thought about it, especially on the BM, it may make you look at your amp in a whole new light!

Gregg

With the HRM totally bypassed there is actually LESS drive on tap, but MORE gain. Basically, you have to turn the drive up higher to get the same amount of Overdrive as you would with the HRM engaged. The drive sound is less compressed and more Fender sounding, due to the fact the tonestack is before the OD and not after like a Fender, with the HRM, of course, ideally you would lift the pre OD tonestack (PAB) and utilize the post OD stack, like a Marshall. Remember that HAD called the HRM "Hot Rubber Monkey" but realllt, it was understood that it really stood for Hot Rodded Marshall, and was his way of having a clean Fender sound and an Overdriven Marshall sound in the same amp.

Totally Bypassed, the OD tone will be based completely off of your clean tonestack settings, so it will sound more like your clean sound, just driven. Of course, it is not quite the same since it is a cascading gain type sound, rather than an overdriven PI/Power section sound, and is threfore more compressed, but not as compressed as it is with the HRM engaged. Totally bypassed, it can get quite bassy and a bit harsh, if you have your treble and mids set too high, and is very unbalanced, and really, without a c-lator or attenuator is kinda useless if playing solo, or in a small space. There is that much of a jump. Remember that you are taking an entire tonestack out, just like if you lifted the main tonestack completely (Mega PAB as in the original Bluesmaster).


It is much better with a small resistor bypassing it. The stack is still defeated, but it is much more controlled, less harsh and more balanced and just overall more happy.

Will the BM OD sound like a standard OTS with the HRM bypassed either fully or resistor bypassed? No, not really. It's apples and oranges, really. The BM has a totally different clean tonestack and OD structure than all of the other OTS amps. It is more like a classic BF Fender with a bit of Tweed rolled in there. Its mid frequencies are much more scooped and the overall OD is less compressed and less middy as well. It CAN get those those standard OTS sounds, but with an OD pedal or a compressor in front of the amp, or with the OD trim turned way up to compress the sound, but then you need to run the bass very low and it loses it character IMO.

That being said, i got the Bluesmaster not for its OD, but for its clean tonestack. After talking with Nik and telling him that my fave amp that i no longer have was my old BF Princeton, which had a footswitchable cascading gain circuit, which was similar to HAD's design, but not quite as complex, and that i primarily just cranked the snot out of the amp and ran either a fuzz or distortion plus in front of the thing and rarely used the cascading gain, and that my second fave was my Sovtek Mig 50 that i cranked the snot out of and ran a fuzz in front of, he said that the BM was just what i was looking for. He told me that i may or may not like the OD, even with the HRM bypassed, but that i would love the clean cranked and boosted, and he was right. The OD is cool at times, but mainly i run the clean channel cranked and boosted. I'm starting to like the resistor bypassed HRM, though, and the HRM is even starting to grow on me a bit, but for the most part, for me, it cranked and boosted clean side with fuzz for over the top stuff for me!

Gregg

very nice. i may be leaning towards something different all together. all depends on how the new speakers sound with the BM

Gregg

Ya too Dumbleish. I'm not really into the D-Tones, that's why i got a BM!!

Gregg

Ya. I actually talked to Nik about the possibility of building me an SSS with a BM tonestack and PI. He sails that would be no problem. I think it would be pretty cool. A BM with footswitchable FET to push the front end, and the filter section, and built in reverb, with no OD. I just don't know if I can do 100 watts. Most of the lil gigs I play don't even like my 50 watter and I think the SSS would have to be cranked to sound its best, even with the BM PI in there. At least I know it can be done

Gregg

That sounds pretty cool and sounds like the sort of OD sound I'd be looking for, does anyone know whether Nik would do the on-off-on mod when he (okay his team) builds the amp?

Guess I'll have to ask him!!

I've played both a real 150w Dumble Steel String Singer, and a clone of one (Bludotone High plains), both amps had different circuits but with 150w 6550 equiped pwr sections. The volume was fine, the huge power section just gives the amp more girth, volume is never an issue. You won't have to push the amp to get the goods. With that said, a 100w amp should be just as fine, just not as girthy sounding because of the 6L6's

That's actually very encouraging!! Thanks, Greg!