OD Level Pot Non HRM

[talbany]

The last several Non Hrm 100w builds I used a 500K OD level pot instead of the stock 250.. I thought the 250k's sweet spot was about 3/4 of the way up.. Didn't matter Audio or Linear...
With the 500 in there the tone was much thicker with more girth especially for single coils.. This stuck the knob at 12:00...you can always of coarse play around with the 150-180k that feeds the pot for the same result.. At first I thought it was that particular amp but am warming up to it on the 3rd one now..Keep in mind this only applies to the 100 watters...Thought I would share my results.. Give it a try...


Tony VVT Amps

[Structo]

Interesting.

The 50 watters have a 100K (Level pot) there. Even the Ceriatone 4 holer uses a 100K.
Although I noticed that the S&M Special has a 250K pot. (50 watt)
My D'Lite uses a 100K.

Do you use the 220K/250pf network on the Send & Return jacks that feeds the PI?

I added a 100K resistor before the .02uf grid cap on my D'Lite (6L6) and it seemed to give it some girth as well.
But I'm told that it may not sound good at gigging volume with that there.
I'm a wood shedder these days so I don't crank it that loud.

[talbany]

Interesting.

The 50 watters have a 100K (Level pot) there. Even the Ceriatone 4 holer uses a 100K.
Although I noticed that the S&M Special has a 250K pot. (50 watt)
My D'Lite uses a 100K.

Do you use the 220K/250pf network on the Send & Return jacks that feeds the PI?

I added a 100K resistor before the .02uf grid cap on my D'Lite (6L6) and it seemed to give it some girth as well.
But I'm told that it may not sound good at gigging volume with that there.
I'm a wood shedder these days so I don't crank it that loud.

Yeah!! what kind of struck me funny about the whole topology of these amps is if you look at the schematic the last gain stage of the OD circuit it consists of a Resistor 150-100k to a 100k pot then to another pot 1m master then to another 220k 250pf cap...so you have a resistor feeding 2 pots and another resistor with a cap across it... To me this kind of stood out as a big tone funnel...Don't get me wrong I am not trying to reinvent the Dumble wheel here just a personal observation..
For those who can get away with opening the amp up and get some of that output tube saturation to help thicken the amp up or a guitar with a fat set of humbuckers the mod may not be needed but I am a Strat player and still like a thick OD tone at not so loud volumes..(Remember Dumble built and designed these amps at least 124 in the 80's when you could go into a club and open an amp up and get away with it)
And yes you are correct about the 100K my mistake... I now remember going to the 250k and noticing the difference but the 500 was the one I settled on... Try Both... Also yes I do use the 220k 270pf cap.. Since this network works for both the clean and OD I left it.. I think it does help to smooth things out a bit and helps with the loading on the PI at high volumes and with a percolator...
For those who are 100k plate fans I highly recommend it to help thicken things in OD... This is not to say that you will settle on the 500k you might like a 250.. I am just saying that whole network between the last gain stage and the master volume is where I would tweak ( if you use the percolator tweak it with it running) and improve the overall tone to better refine the OD to your guitar hands and volume levels you normally would use...Good Luck!!

Tony VVT

[Structo]

For some reason I can't get your schematic to come up.
Looks like it is in the GIF format.
Maybe change it to jpeg.

[Structo]

Argggg, when I saved target to my desktop I got it.

[greiswig]

Tony, was the Plate R on V2b in #124 really 110k?

(We now return you to your regularly scheduled program)

[talbany]

Tony, was the Plate R on V2b in #124 really 110k?

Yeah!!
No that's a 100k plate amp.. I just grabbed that schematic as an example... I think I got it off a post here a while ago so don't hold me to it..


Tony VVT

[talbany]

I recently ran across a post on TGP where Gill states that #124's OD level was a 250k..

-- as opposed to 124 which is a Skyliner with 100K plate load resistors and a couple of tweaks. The specific tweaks were: larger pre OD entrance trimmer -- 350K VS 100K -- and larger than usual "Level" post (250K VS the usual 100K). Both of those changes will contribute to make the overdrive in the amp sound darker and muddier. However, note that the 100K plate load resistors will make the overdrive brighter and harsher right out of the gate, so maybe with new caps and tubes the amp would sound balanced. To me, as already stated, it was more an amp for a Keith Richards kind of sound, with the capability of a liquid overdrive for good measure.

Gil

Gill if your out there and want to verify or resend this post would be cool!! Thanks!!

With the usual pre OD network of 220K + 100K trimmer, I find that with larger than 20K to ground, the OD will just not sound right, and 15K to ground is even better. Of course, dialing that low a gain up front and low gain on the front panel gain control (“Level”) means that one may run out of volume in the overdrive channel, or even if not so, diming the OD master leaves less resistance in series with the output of the OD, which means a brighter and potentially harsher tone. One solution is to go to a higher than 100K master for the overdrive, and I will try that for kicks since it would help by putting a higher series resistance in series with the OD output and by maintaining larger signal level due to lower loading (i.e., more volume on tap). Anyway, with low gain settings as described, the OD can be dialed to be a very natural extension to the clean, but with more hair on tap if so desired. I like that sound a lot, and one can get away with a very fat low-gain OD tone. In contrast, the 200K/150K amp breaks up more quickly (and much more smoothly), so it is harder to dial that type of tone.

I also believe that the 350k entrance pot to V2a helps to thicken the OD tone as well.. What I hear with respect to certain value pots here is a 250K pot set at 100K will yield a thicker darker yet somewhat looser less focused tone than a 100K pot dimmed...Go figure please!!!

If Gill can verify the above post I will go ahead and make the change on the 124 Layout I did!!


Tony VVT Amps