question on dumble od section experimentation

[ACDCG400]

hey guys, im building a dumbleish amp for myself...finally, and wanted to ask if theres was a way i could get much more gain out of the od section, like with another tube. wanted to voice it alla guns and roses if i could, but just getting in the GNR range of gain is what is the tricky part. thoughts?

Thanks for your time guys!
Donato

[jerrydyer]

you can get a lot of gain out of it as is. just some minor tweaks. which schem are you going to use. ? The reason I am chiming in is in the past month or so Ive had three overtone HMR's come to me to be hot rodded a little.

I like to get rid of the second tone stack, plate resistor gets changed back to the original spec. the internal trim pot 100k gets dumped, put a different one on the chassis outside so you can get at it. 220k before it goes to 100k with a cap over the top with a switch. 1000 pf is a good starting point but that really rocks it. I think I changed the 5ufs to 1 but not sure. lots of little things in the overdrive area to play with.

[JayB]

I do the same as Jerry except I still like the second tone stack, I like to put that on the chassis too. Putting that internal trimmer on the chassis lets you get any thing from dumble tones to higher gains.

I'm starting to think that the feedback on the tonestack recovery has a lot to do with the feel of that amp when it comes to those dumble tones.

[jerrydyer]

I was curious as to why, on the local feedback circuit some have a 22meg on both sides of the 056. cap. Im running that circuit in a kt66 based amp and I lowered that 22meg to half that and this thing sustains for days. I call it the Classic Squared.. there is a good clip of it on youtube. interesting thing that local feedback loop. I think with some tweaking you can have that santana type feedback even at lower volume levels. that would be cool. Like the live Europa thing?

[JayB]

I have no idea the reasoning behind it. I've gone down as low as 10meg and liked it a lot. Much lower than that just started to effect the gain. Very touch responsive. Kind of wish I didn't sell that amp. It just had a nice feel to it.

[tubenit]

Im running that circuit in a kt66 based amp and I lowered that 22meg to half that and this thing sustains for days. I call it the Classic Squared.. there is a good clip of it on youtube. interesting thing that local feedback loop.

&feature=related

&feature=related

[jerrydyer]

You put my crummy playing on the metro site..... I kill you now.

I just lowered a brown note dumble clone to just the 22meg and it improved greatly. man this thing is cool .. It sounds like a high quality comp just barely on. its perfect. Gott incopr that perfection into a lead distorted lead tone.

[tubenit]

You put my crummy playing on the metro site..... I kill you now.

Hey man, you've got nice amps!  And your playing is alot better than mine is.
 

With respect, Tubenit

[jerrydyer]

why did I say metro... I meant hoffman and thanks bro.

Im losing it. turning into an old dude.

[ACDCG400]

im thinking of using this schematic, if i was to do the HRM. tho im not sure if i should do something different, like have 2 seperate channels.

[jerrydyer]

the ceriatone site has some cool layouts too. build the original overtone special youll love it. its got two channels   

also one of these guys here posted a really cool dumble clone schem.  just be sure to include that cool local feedback loop if your going for that dumble ish tone.

[ACDCG400]

Which overdrive special do u mean Jerry? and i think ill put it on a switch! =D

[jerrydyer]

Ceriatone Overtone Special 50... his first one.

[Tone Junkie]

Jerry does the ceriatone overtone special have the feedback loop.
Thanks Bill

[G._Hoffman]

Jerry does the ceriatone overtone special have the feedback loop.
Thanks Bill

Well, judging from their layouts, yes, but even if they didn't it's a 1 cap and 1 resistor - it's pretty easy to add to any amp where you want it.  Oh, and a SPST switch, if you want.


Gabriel

[foghornleghorn]

In my Bluesmaster HRM there is no local feedback. It has plenty of gain, all high plates. If I wanted to play with the gain all the time I'd move the OD entrance trimpot to the chassis rear apron and crank it to suit.

In an FET equipped Dumble, I have two, a '70s 50W and a #124 100W, I set up the OD entrance to a normal level for flexibility and crank the FET trimpot up so the FET input is considerably hotter than the normal input. Works for me.

+1 on putting the HRM tonestack out to the front faceplate, would not do it any other way. I also reeelly like separate masters for clean and od, makes balancing volume soooo much easier.

Footswitching both PAB and MB and running both together in OD is awesome on the #124, the Bluesmaster only needs MB as it's naturally bassier, at least mine is.

[jerrydyer]

yeah the BM is heavier on the bass and the lead when cranked is a little more old school like old cranked fender . the overtone special is a little more defined, if Im using that correctly, it will do more of a rock thing. I built a BM for Brendon of Shakkah. They're a Christian band here in orange county CA.

to the other quastion above the overtone yeah has the local feedback circuit but it is as the other guy said just one extra res and cap. depending on which way or how much comp you like or need. This brown note dumble clone had the two 22meg in series. I got rid of one. the bloom factor just shot up considerably. (Wonder if he will sell this one? )

[Tone Junkie]

Jerry because Im not really as up on these things as I would like could you explain exactly wetre in the circuit this is sorry to be a pain but Im trying to learn something on these today and Imj still a little lost as to were in the circuit its at. Man its sucks being a newbie Im learning quick but Im so far behind .
Thanks Bill

[jerrydyer]

its bridging the input grid and the plate on the second gain stage. check out ceriatones site and their layouts. Overtone Special 50

[Tone Junkie]

Thanks Jerry will do.
Bill

[overtone]

Jerry because Im not really as up on these things as I would like could you explain exactly wetre in the circuit this is sorry to be a pain but Im trying to learn something on these today and Imj still a little lost as to were in the circuit its at. Man its sucks being a newbie Im learning quick but Im so far behind .
Thanks Bill

I am new to the circuit too, it took me a while to understand where on earth this is all going on, so here's a schematic of the first two stages for you,
have a good Easter, tony

[Tone Junkie]

Thanks Tony I could not for the life of me figure were they were going i could see were they came from but it was vague.  Bill

[ACDCG400]

is there a way to make the hrm switchable? like when u are on the clean channel its out of the picture, but when u engage overdrive, or a boost of some sort, the hrm will come into play.  is that even possible? haha

[G._Hoffman]

is there a way to make the hrm switchable? like when u are on the clean channel its out of the picture, but when u engage overdrive, or a boost of some sort, the hrm will come into play.  is that even possible? haha

You can put a switch anywhere on the grid side of the cap.  You don't want the DC from the plate across the switch.  If you want it to be switched with the channel switching, you can use a second relay.


Gabriel

[Tone Junkie]

So was the local feedback what they call the hrm in that circuit.
Thanks

[ACDCG400]

Thanks guys/G. Hoffman!

[Tone Junkie]

What does the HRM stand for.
Thanks Bill

[tubenit]

Hot Rubber Monkey        Yeah, it sounds like a joke, but do a search on AmpGarage and see what you come up with.

http://ampgarage.com/forum/viewtopic.php?p=143333&highlight=hot+rubber+monkey#143333

with respect, Tubenit