add depth/resonance control to Bugera 6262

[Chunkosaurus]

Ok guys I bought a Bugera with the intent to mod it. The one I got was the 5150 II clone. What I want is to add the depth/resonance control to the 2 master sections. Should be pretty simple right?

Also if any one has a schematic for a 100/50/25 power switch (boogie mark series) I want to add that too.

LET THE FRANKENAMP BEGIN!!!!!

[HTH]

check out the 5150 schematic and apply it to your amp - simple.

[Chunkosaurus]

check out the 5150 schematic and apply it to your amp - simple.

Or not... I am just understanding schematics. I can barely make my way through an overdrive schematic. I have been modifying pedals and doing my own wiring on guitars for a while. So I'm no slouch in soldering or elec. basics. I have the 5150 II schematic. I just need someone to explain or draw a diagram of how to add the depth controls. Here's the Schematic.



Also if some one could explain how to do the 3 way power switch (100/50/25%).
I know one does the pen/triode thing and the other cuts out 2 tubes please help.

[tedmich]

where are you gonna shoe horn in 4 extra knobs?

If you have a spot I'd use the smallest pots I can, maybe concentric knobs and only two spots:

2Meg/1 Meg Dual Pot w/Switch (Pkg of 4)-The Electronic Goldmine

these might work, put a 10k resistor across the 2M section and you've got a dual 1M/ 10k audio pot, the switch could be wired to cut out the FDBK, as some like this sound.

I'd get a little PCB from Radio Schack and solder up the components and wire it in!

[defaced]

I would use the values for the caps and pots in from the 5150II schem and use the JSX as a guide how to hook everything up. I think the JSX schematic is easier to understand because it only has one set of presence/resonance controls, (http://www.schematicheaven.com/newam...jsx20_head.pdf). The controls are in the bottom lower left hand side of the first page, and the phase inverter is on page 8. It's really pretty simple to do, all you're adding is a pot and a cap, but I think the 5150II schem is difficult to see what's happening and what goes where.

[Chunkosaurus]

where are you gonna shoe horn in 4 extra knobs?

If you have a spot I'd use the smallest pots I can, maybe concentric knobs and only two spots:

I only have to find room for two extra knobs.


I know I'm only adding a couple pots and resistors and that it's really simple. For some reason I can't figure out where to insert them.

I'm hoping someone can put together an idiot proof diagram that says cut this and solder it here. I really don't get amp schematics yet.

[tedmich]

you first will need a schematic of the Buggy, as it will be needed to find the components that correspond to the 5150II schematic. Or just trace pack the feedback from the 8 ohm speaker output, its usually a shielded wire running to the phase inverter (the last 12ax7 before the power tubes). Find pin #2 on the PI socket and trace it back to the 0.047uF/400v cap and the 4.7k resistor which goes to ground (use a meter with amp off and big PS filter caps bled carefully with a 5k 2W resistor) the feedback wire should connect here (and maybe have its sheild grounded too). Build up the JSX circuit on a little 1x 2 PCB from Radioshack, triple check it and carefully cut the FDBK wire and put it inline. The signal is low voltage but potentially high current, place it carefully away from wires and metal, wrap in saran wrap to be very careful, try knobs.

Adding a switch to remove the fdbk is appreciated by some, but may sound bad for a 5150....

[andyar85]

[tedmich;111503]
can you be a little more specific? I'm trying to do this mod

I found out the 22uF electolithic cap and the schematic there where the control circuit begins. I've made the resonance filter with the pot and cap soldered on it, but don't know exactly where to connect it. it's a bit difficult since I don't have the Bugera schematic, and the relay there switches the presence with the reverb. there is a cap 6n8uF which I think Bugera put in series with the presence control circuit before the feedback and the 39K resistor for the fixed resonance of the amp.

Please correct me if I'm wrong. Any help would be appreciated. I know this shouldn't be very difficult, but since I cant seem to find a schematic it's more on guessing.
Thanks

[tedmich]

its been quite some time since I thought of this, you want to add just a res pot to the Buggy? Then you'd just put the pot (with 6.8uF cap across it) in between the neg (-) terminal of C30 and the feed back from the OT (after the 39k resistor) maybe switched in or out via a DPDT switch. Probably best to switch with vol down or in standby. Many crazy moders at sloclone forums who have undoubtedly done something close to this, check them out they're a nice bunch of guys (unless you steal their stuff and sell it!)

[andyar85]

Thanks for such a quick reply

I was actually thinking of recreating the Peavy schematic for the resonance stage. but there's a thought maybe of using the resonance only for the Lead channel, since I use that the most.
I Identified that the last relay has the role for the clean lead presence and reverb, actually switching the presence for the lead channel and the reverb for it.
I think the relay for the clean channel is somewhere else and it's in a default stage of on.

The presence filter for both channels are there, and the resonance if fixed with a 6n8 and a 39K(there are two resistors) resistor an RC filter, but I need to find the relay terminals to switch between the filters.

Still working on this issue. Sadly I couldn't find a Bugera schematic, but thanks for the one pot ideea
I'm also considering new higher end caps 470uF for the power tubes instead of 330uF

[tedmich]

Good luck! I'd just copy the 5150II(6505+) schematic which is readily available.