bugera 333xl-212 tone stack mod + more

[harrisxr650]

hey guys. I'm looking for some help- instructions on modding the tone stack of my burgera's clean channel. few months ago i did a full retube and it made a huge improvement on the amps tone but while i liked the results i found out that the clean channel lacks of mids and has to much highs. the preamp tubes i used are the following
V1:Tung-Sol 12AX7 / ECC83 Reissue V1
V2:JJ ECC803 Selected GOLD
V3:JJ 12AX7 / ECC83 Selected GOLD
V4:JJ 12AX7 / ECC83 Selected GOLD

now while i liked the loudness effect v1 has now, i found out the lack of mids is what bothers me most so first of all i'll change the v1 with a spare JJ 12AX7 / ECC83 Selected GOLD i have lying around to see how this will affect the tone and second will try to mess with the amps tone stack and maybe put a presence pot in the back.
If anyone is kind enough to put some info on where and what to change in the tone stack it will be great, i mostly play with stompboxes and thats why i want to do that.
I do have a JSX/XXX schematic ( which seems identical to the 333xl/212 pcb) and i can pm it to anyone kind enough on point me what to change.
And last but not least..i'm getting for Christmas present a pair of Celestions V30's, will these makes any difference? meaning bringing the mids to the front and smooth out the highs? anyone tried them with an 333xl? i'm asking cause i can ask for any other speaker from Santa aka wife..
thanks in advance
Harris

[soundguruman]

hey guys. I'm looking for some help- instructions on modding the tone stack of my burgera's clean channel. few months ago i did a full retube and it made a huge improvement on the amps tone but while i liked the results i found out that the clean channel lacks of mids and has to much highs. the preamp tubes i used are the following
V1:Tung-Sol 12AX7 / ECC83 Reissue V1
V2:JJ ECC803 Selected GOLD
V3:JJ 12AX7 / ECC83 Selected GOLD
V4:JJ 12AX7 / ECC83 Selected GOLD

now while i liked the loudness effect v1 has now, i found out the lack of mids is what bothers me most so first of all i'll change the v1 with a spare JJ 12AX7 / ECC83 Selected GOLD i have lying around to see how this will affect the tone and second will try to mess with the amps tone stack and maybe put a presence pot in the back.
If anyone is kind enough to put some info on where and what to change in the tone stack it will be great, i mostly play with stompboxes and thats why i want to do that.
I do have a JSX/XXX schematic ( which seems identical to the 333xl/212 pcb) and i can pm it to anyone kind enough on point me what to change.
And last but not least..i'm getting for Christmas present a pair of Celestions V30's, will these makes any difference? meaning bringing the mids to the front and smooth out the highs? anyone tried them with an 333xl? i'm asking cause i can ask for any other speaker from Santa aka wife..
thanks in advance
Harris

This is a link to the Tone Stack Calculator:
TSC
This allows you to change the components in the tone stack and see the result in real time. The download has been verified as safe.
You will need to pick the tone circuit which matches the Bugera, to work with... and I don't have a schematic.

No, there are not any mods for Bugeras, except my own, and those are for reliability, not the tone stack.
I'm not sure what that amp has in it yet...
however, PM me the schematic and I will take a look if you want.

[harrisxr650]

JSX/XXX full schematic

Thanks mate, i downloaded TSC but due to work times i dont have much free time to work on it will check though cause it looks very helpfull. bellow you will find the schematic its almost the same with 333xl most of the components have the same value and are according to the schem (was weird when i opened the chassis to bias it after i did a full retube so spend some time comparing the schem with the pcb) . I think the clean channel tone stack is located in the upper left corner but im not sure, my goal is to reduce the highs and sweeten them and increase mids in the circuit in the clean channel and add a bit bass/ mids to the crunch channel ( not sure for that yet) any help will be appreciated
Thanks
Harris
P.S couldn't add an attachment in pm so i uploaded the schem here if i break any of the forum rules i apologies but couldnt find how to pm it.

[soundguruman]

Maybe I'm missing something, but this schematic posted is a Peavey amp.
I thought we were talking about Bugera? Try again posting it?

[harrisxr650]

Yes i know. Bugera doesnt publish schematics but 333xl is an almost 100% copy of peaveys jsx/xxx

[soundguruman]

Does it come from the same factory that copies Mackie and Peavey Mixers,
and calls them "Behringer?"
"designed in Germany" "proprietary designs" Hahahahahahahahahahahahahahahahhhhjh!!!! LMFAO!

Instead of calling a bass amp a: "bass amp"
They call it a: "bass guitar work station." hahahahahahahahahahaahahahahahahahhh! LMFAO! (again.)

[harrisxr650]

so. i played around with TSC and i've notice that the clean channel tone stack is similar to the "fender" tab correct me if im wrong), playing with caps, pots and resistors values i've managed to bring it close to Marshall field with less high freqs, which i guess its what i'm after and since i'm not an expert and its the first time i use TSC or messing up with my amp tone stack any advice should be useful , another question is how accurate is TSC? i mean if i change the components according to the values i've changed will i get the results it showing? Again forgive my silly questions, so far i've build and mod several guitar pedals but its the first time i mess with an amp and i geuss trial and error here could cause a mess.

[Enzo]

How accurate does it need to be? If you change the components to something else, it will perform like the TSC says it will - FOR THE TONE STACK ITSELF. The tone stack is not the sum total of an amp's tone, the amp is a system, the whole system makes the tone. Putting a Fender tone stack in a Marshall head will not make the Marshall head sound like a Fender. The TSC is a model of the tone stack, period, not a model of the amplifier.

[Jazz P Bass]

Bugera 333XL Schematic

Here is the complete schematic set.

[harrisxr650]

Im aware of that Enzo i'm not excpecting by changing 3 caps, 1 resistor and 1 pot in my amp to sound like a marshall i just need to push the mids an soften or reduce the highs a bit . Thanks for the schem Jazz
So, i came up with the following changes based on the schem jazz send and please correct me if i'm wrong.
(in the schem) replace c21 with 470pf, c22 with 22nf, R46 somewhere between 33k and 68k and replace the mid pot with a 50k.
can someone check it and post if these changes will do what i'm looking for?
thanks