OD Trimmer----where's yours set-?

butwhatif · Post by **butwhatif** » Tue Feb 04, 2014 7:03 pm

This has been discussed many times, but maybe we can get a comparison survey? Non-HRM, HRM, Real thing values welcome. Be sure to identify the build. DC resistance to ground from the trimmer slider--to--ground. Preferably w/the amp OFF.

wjdunham · Post by **wjdunham** » Tue Feb 04, 2014 7:27 pm

butwhatif wrote:This has been discussed many times, but maybe we can get a comparison survey? Non-HRM, HRM, Real thing values welcome. Be sure to identify the build. DC resistance to ground from the trimmer slider--to--ground. Preferably w/the amp OFF.

I set them all with the amp on and the OD channel selected, 26.5K for the non-HRM builds (100K Drive and OD Level pots). Spent an afternoon with Terry Haitt making some adjustments to his #102 and we spent a bit of time on this adjustment and settled on that value as the best sounding. Here's what it sounds like:

https://soundcloud.com/bill-18-1/shake- ... eli-albert

Bill

www.sebagosound.com

pedro · Post by **pedro** » Tue Feb 04, 2014 8:41 pm

Hi,

Non HRM 102 circuits ( 50 watt builds ) both set to 23.5K to ground. (Front panel mounted with a set screw on one of the amps. )
I know this is the "ford" measured setting from 102, but seems to work well for me settings with mid boost on.

Cheers
Pete

talbany · Post by **talbany** » Wed Feb 05, 2014 12:59 am

If you guy's would look at the layout I did for the 102 amp I wrote it right next to the trimmer (with the amp on!!) 25.53K....

http://ampgarage.com/forum/download/file.php?id=20659

Same with 183..22k

http://ampgarage.com/forum/download/file.php?id=16846

I have seen and heard about various trigger settings on different ODS amps (generally starting around 25k up to 53k)..He put that trigger on there for a reason to compensate for guitars output,gain factor of V1 and V2 and overall general character of clean channel & OD..I think Dumble knew all of these factors would be different on every amp so he added an adjustable control (on all but 1 that I know of)there to find the sweet spot on that particular amp with those tubes (121 even had an external trigger)...So my point here is use the values on the layouts as a starting point don't worry about what he set it at on a totally different amp than yours..Just adjust it to match your taste and style for the guitars YOU own and play...BTW Dumble doesn't tell you how to set your drive and level controls.. Same thing with the OD Trigger..It's just he 1st one
Have fun and USE YOUR EARS!!

Tony

llemtt · Post by **llemtt** » Wed Feb 05, 2014 1:56 pm

I just set it where I like it...

(in my amps it's accessible directly from under chassis)

have fun

ayan · Post by **ayan** » Wed Feb 05, 2014 7:00 pm

Agreed 100%. One thing that has always happened to me, though, is that I like the sound of the overdrive when the preamp volume is set pretty high -- pretty much independently of where the trimmer and the subsequent "drive" control are set. The problem with that is that the clean sound can get a little grindy, which I don't caref or, and that if you want not too much overdrive and have the preamp volume high, it'll be hard to balance the volume of clean and overdrive channels -- the clean will always be louder in non HRM amp. That, IMHO, a weak point in the ODS architecture.

G.

talbany wrote:If you guy's would look at the layout I did for the 102 amp I wrote it right next to the trimmer (with the amp on!!) 25.53K....

http://ampgarage.com/forum/download/file.php?id=20659

Same with 183..22k

http://ampgarage.com/forum/download/file.php?id=16846

I have seen and heard about various trigger settings on different ODS amps (generally starting around 25k up to 53k)..He put that trigger on there for a reason to compensate for guitars output,gain factor of V1 and V2 and overall general character of clean channel & OD..I think Dumble knew all of these factors would be different on every amp so he added an adjustable control (on all but 1 that I know of)there to find the sweet spot on that particular amp with those tubes (121 even had an external trigger)...So my point here is use the values on the layouts as a starting point don't worry about what he set it at on a totally different amp than yours..Just adjust it to match your taste and style for the guitars YOU own and play...BTW Dumble doesn't tell you how to set your drive and level controls.. Same thing with the OD Trigger..It's just he 1st one
Have fun and USE YOUR EARS!!

Tony

talbany · Post by **talbany** » Wed Feb 05, 2014 7:51 pm

Gil
Yeah I have that happen as well..ODS flaw.. I always thought a great mod to that would be to add another relay and attach it to a 50K tweaker pot inside so you can lift the input vol pot to taste when you go to OD..I have just never had the time to do it.. If you want to try this at some point (I doubt I'll get to it) let me know and I'll be glad to send you a PCB relay board and pot to try it..

All The Best!!

Tony

Structo · Post by **Structo** » Wed Feb 05, 2014 8:01 pm

I also agree.
It seems to be a balancing act to get the clean and OD to balance out. (not an issue that I have had)

I should clarify that I use a Dumbleator tube effects loop, so things are happening there too.

I also run my preamp gain high (around 1:00) and the master volume about (1:00-2:00).
So with these settings, I control the actual volume of the amp with the output pot on the Dumbleator which acts as a Master/Master volume for the entire setup.

I think I have the OD trimmer pot around 25K with amp on.

I am not truthfully after a crystal clean sound but most of the time I am not turned up enough to really change that.

On my D'lite 44 amp (50 watts or so) I modded the OD channel with an external OR trim pot.
Even with that, it was a kind subtle dynamic that really didn't reveal itself until that amp was really cranking.

butwhatif · Post by **butwhatif** » Wed Feb 05, 2014 8:56 pm

Agreed Gil, it's always a juggling act-depending on the gig, venue, etc. Right now i use 23.5k and think i like it. I do not like to mess with it as doing that is confusing even more. I like to set it and play a couple months to see how it works out.

glasman · Post by **glasman** » Wed Feb 05, 2014 9:14 pm

For me, I personally adjust the trimmer so that I measure about 7db of gain from the input to the OD trimmer section and the junction of the drive pot and the series resistor. It is a nice starting spot for non-HRM amps.

For HRM style, usually I set the pot to about 13K or so off of ground. Depends on what the customer wants.

ayan · Post by **ayan** » Wed Feb 05, 2014 9:26 pm

Thanks, I probably have a PCB for the relay, but I am too lazy to do anything anymore. Lifting the preamp volume pot on OD would be ideal, and it would renderd the bright switch off on OD, which is also something that would make sense to me. Clearly, H.A. Dumble didn't have the imagination to come up with the good stuff!

G.

talbany wrote:Gil
Yeah I have that happen as well..ODS flaw.. I always thought a great mod to that would be to add another relay and attach it to a 50K tweaker pot inside so you can lift the input vol pot to taste when you go to OD..I have just never had the time to do it.. If you want to try this at some point (I doubt I'll get to it) let me know and I'll be glad to send you a PCB relay board and pot to try it..

All The Best!!

Tony

The Amp Garage

OD Trimmer----where's yours set-?

OD Trimmer----where's yours set-?

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Re: OD Trimmer----where's yours set-?

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