#1
I love to mess around and mod things. How hard would it be to mod the Bugera's. I am thinking about changing the Output Transformer and adding a choke. Is this something that I could do myself? I have exp. with soldering and basic electronics. (10yrs of Custom Car Audio)

I emailed Mercury Magnets and was given this response...

The MMO-100M output ($260.00) and the R103 choke are the two pieces we
suggest as upgrades for that amp.

The MMO-100M is perfect for use with four EL34 or 6L6 tubes. It has 4-8-16
ohm secondary taps.

The R103 choke is only $30.00 and adding this to your amp will be the best
$30.00 you will ever spend on that amp.

Installing these two pieces on your Bugera amp will give you a HUGE tonal
improvement!

Best,

Paul


Any thoughts or links to point in the right direction?

theDogger
#2
Knowing electronics is a good help but if you've never been in a tube amp you want to be very careful. The filter caps store voltage even after amps have been shut off and if you don't drain the correctly it will could kill you.
Short of that, I too tinker with mods and usually I just jump into them and haven't had any bad luck yet. If Mercury is supplying parts that are proper replacements then it theoretically should be as easy as remove a wire - solder a wire. The choke might be a different story since you're adding fresh into the circuit.
#3
Shouldn't be too hard. it's just a matter of transposing the previous OT's wiring to the new one. if you have a schem you can easily find where to put the choke. won't be hard to install oince you find out where.

like inkandlead said, you'll want to bleed the caps or you might get a nasty bite. I've been hit by charged caps countless times and it hurts like hell.

however, in SS amps this is not the case.
#4
Quote by Invader Jim
Shouldn't be too hard. it's just a matter of transposing the previous OT's wiring to the new one. if you have a schem you can easily find where to put the choke. won't be hard to install oince you find out where.

like inkandlead said, you'll want to bleed the caps or you might get a nasty bite. I've been hit by charged caps countless times and it hurts like hell.

however, in SS amps this is not the case.



How do you bleed the caps in am amp? In car audio you use a small light bulb and ground it to drain the 1 farad caps....

As far as a Schematic I have yet to find one. Bugera has not released any. I have google looking but no luck...

theDogger
#5
This is the underside of the 6262 that I found on a forum and I was looking at it and either they installed a MercuryMagnets MAR100-C choke. Where to connect to the board. I can't find any schematics for the Bugera amps...



theDogger
Last edited by theDogger at Sep 22, 2010,
#6
Quote by theDogger
How do you bleed the caps in am amp? In car audio you use a small light bulb and ground it to drain the 1 farad caps.

Same principle, but most amp caps will be much lower capacitance. I don't know what resistance the lightbulbs you use are, but connecting a resistor between the + of the cap and ground is what I do.
#7
You'll "short Out" the Caps with a 1 watt 1Meg resistor. Keep it there for about 30 seconds I think. If you old a voltmeter in series with the resistor you can watch as it bleeds down to a safe level.
#8
^no way. 30 seconds isn't nearly enough time for a 1M resistor to drain hundreds of volts off a cap. 1M is also way too big a value. another thing, you don't put voltmeters in series with anything. always paralell. voltmeters measure a potential difference across the probes. there is no potential difference across a single wire (until voltage drop comes into play, which is negligable in this case). that's like shorting the probes and trying to find a voltage.

dogger: a 220 ohm 10W resistor should work just fine for you. It should bleed a cap in a couple of seconds. I'd also suggest putting a voltmeter across (not in series with) the cap as you drain it to monitor the voltage.

it may be easier on the cap to use a 25k 1W resistor. it'll take quite a bit longer to drain the cap, though.

or you could get several (5 or 6) 120v mini lamps (like the ones with bayonet bases) and hook them in series. it'd be just like the method you used to drain 1F car audio caps.
#9
Thanks for the info. I am going to open the amp up this weekend and take a look.

thanks
theDogger
#10
You might want to look around at other brands of transformers. There are many modders who say the MM are way over priced for what you get. That other brands sound just as good or better and will be cheaper. Ive liked hammond but hayboer(think I spelled it right), even weber are good.
#12
I think a choke comes right after the reservoir cap in the power supply.
Gear:
- Bugera 333
- VJ & VJ cab
- Jackson JS30
- TS9

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#13
Why MM? Their stuff is way overpriced and doesn't sound all that great IMO. I'd recommend Heyboer or Weber instead.
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#16
Ok guys great to know but that still doesn't change the fact that I am not 100% sure where to connect the 2 wire from the choke. Also $30 is not that much to pay. I know that there are cheaper but is was covenant to order everything from the same spot.

So back to the real question....Where to connect the 2 wires???????

theDogger
#17
According to your first post, it is meant to replace R103. So, take out R103 and solder the choke in its place.


A choke is used to offer better filtering in the power supply. R103 should be a big white ceramic resistor.