Mid Control for a Traynor YGM?

[SamBooka]

I was thinking a mid control would be nice on my YGM4.
Looking at the schematic, it doesnt look familiar enough for me to guess where to put a pot (r10?)

Any suggestions?

Thanks.

 

[doctord02]

The Traynor YGM amps of old use a Baxendall tone stack (or a James, I dont remember which...), which is a considerably different circuit from the standard Fender/Marshall/Vox stack that uses a mid control... You have to replace or heavily mod the entire tone stack to accomplish this...

It's not gonna be as easy as just swapping a pot for a resistor...

 

[schmidlin]

Check out the Cheiftan:
http://schematicheaven.com/newamps/matchless_chieftan.pdf
The mid cut is an old Gibson trick, and can go many places in the in the pre-PI preamp. Break the volume wiper or post R9 at the grid. But know that it removes mids only: on 10 you pretty much get stock.

I use it all the time in designs, sucks more mids than any standard tone stack.

 

[SamBooka]

Thanks Doc. At least my confusion is understandable this time.
Schmidlin, I will take a look at the circuit tonight. Actually want more of a mid boost, maybe I will try EQin the signal before it hits the amp.

Thanks all.

 

[phsyconoodler]

Try cranking the bass and treble all the way up.That simulates a mid boost with the baxandall tone stack.

 

[schmidlin]

Never seen a stack like that and it is catching my interest. Not a Baxandall, notice how with Treble and Bass on zero you get NO signal. Baxandall's leave you with all Mids that way. Curious how it reacts/sounds.

 

[LowellH]

Nope, not a Baxandall/James type stack. I've never seen it anywhere else either. Depending on the control settings these tend to be mid-heavy amps (in my opinion) so schmidlins mid-cut idea might be the best to go.

Or maybe try a small cap in series with a 500k-1M pot across the treble cap C4?

 

[SamBooka]

I am actually looking for a mid boost for this amp. I am currently running bass and treble around 4 so diming them might be an idea.

 

[LowellH]

A small cap in series with a large pot across C4 will let you dial in more mids. Increasing the value of C4 will turn the treble pot into more of a midrange control.

 

[schmidlin]

Lowell, wouldn't C5 block any added mids? I know it's not a standard RC relationship at that point...

Mids should be easy to get. *Should* First thought was a .68 substitution cap on one or two of the cathodes. Plenty of mid-heavy speakers out there, too.

 

[LowellH]

It shouldn't, but after looking at it more closely I think altering the value of R5 might be a better way to go. Or replace it with a pot. Higher values should drop the rolloff freq of the treble control.

 

[parkhead]

Its a great tone stack

for a mid boost

replace c6 .01 with .0056
this boosts the lower mids as well as reducing the amount of mids than can get pulled out of the bottom of the tone stack
this pushes the mid frequency peak down

if that is too bass mid heavy try .02 this strips out some bottom and cleans up better
this pushes the mid frequency peak up

the bass control determines the boost or cut of that peak

Otherwise the resistors are what you need to play with
R5 can be increased considerably resulting in both a gain and mid boost
when you look at the circuit in the amp R5 looks like its in paralell with the tone stack and loads the whole thing down ... I've tried values as high as 470k here

R9 and r10 determine how much mid and bass are pulled out of the circuit
I went with 27k in some cases to tidy up the bottom

Further If you are looking for a lead guitar sound you can decrease r4 from
1800k to 820k this will add gain and mids before you even get to the tone stack

you probably want to DIME the treble and bass controls to get the mids up
when dialing in the amp
throw it on the bench make sure the family is out
and play with the tone stack values till you get what you want

I always play the amp Dimed when doing this,
if I can dial the amp in dimed and have a tone that holds together I can always turn down the amp
and back it off

I listen for the general midrange complexity of the EQ and look to remove
bass or treble frequencies that splatter or flubber
if you can dial these out dimed the general eq should be fairly articulate
and cut decently at lower settings




p

 

[schmidlin]

Nice info. Another reason I come here.

 

[SamBooka]

Amazing Park! I hope to try it next weekend.
Last night I tried getting a usable tone by doing the opposite (something I discovered with these amps this spring).
Turn the Vol to 4
Turn the bass to 0
Turn the treble to 0
Start bringin up the bass and treble. Bright switch to taste.

I should mention that I am using this amp for jazz. My Es165 with a classic 57. It just seems to be missing some mid umph.

When I play jazz with my Tele and a 71 Gibson HB in the neck.. ooooooh... ahhhhh... very very nice. Almost sounds good regardless of how the amp is set.
Weird huh?