Mods for a B-52 ST100A (can get one dirt cheap)

[DrGnosis]

Hello All --

I have the opportunity to buy a B-52 ST100A which needs a new transformer for dirt cheap. B-52 amps aren't exactly known for their amazing sound or quality. I'm wondering if this platform would be amenable to (probably extensive) mods that would greatly improve the sound? I do not know all that much about electronics, but I'm hoping someone here does.

Any thoughts or advice would be greatly appreciated.

[J M Fahey]

Hello All --

I have the opportunity to buy a B-52 ST100A which needs a new transformer for dirt cheap. B-52 amps aren't exactly known for their amazing sound or quality. I'm wondering if this platform would be amenable to (probably extensive) mods that would greatly improve the sound? I do not know all that much about electronics, but I'm hoping someone here does.

Any thoughts or advice would be greatly appreciated.

Short answer: IF that dead power transformer is its only problem , you can get one easy and at low cost AND you feel up to the task of repairing it, go ahead: repair it and use as-is. Killer sounding amp.

Slightly longer answer:
Surprise: it has all the goods and is as well made as tons of modern High Gain Metal amplifiers.
How come? .... itīs made by the same factories which make most of the "famous" ones under contract, others apply their own labels and not much more .
Well, besides tons of hype ; when this factory sells them on their own they use their own brand: B52 . I bet there are others too.

Being the same as its famous cousins, it does sound as good; it also shares the same build quality (they all come from the same cradle).

Then why many despise them? (think Harmony Central / the Marshall Forum / My Les Paul and countless other "guitar" forums).
Mainly because of snobbery: "nobody famous uses them so they must be bad".

Funny thing is, many famous DO use them (its cousins made in the same factories), only with different labels glued on.
I have quite a few "american boutique amp" schematics where you can see "designed by" , "modified by" , "drawn by" fields in the schematic sheet are straight written in Chinese characters.
So much for the "Designed in America/UK , assembled/made in China" claims.

The amp is very complex, very complete, already comes with the best Mods and design combinations built in, more than what many imagine and then some.

Yes, I always read posts, typically saying something like "I bought this piece of cr*p at GC for 200 bucks, got a special deal and paid only 150, worst piece of sh*t I ever saw but I modded it (follows long lists of no-schematic-shown replacements such as "pull C23 and place a .001uF Solen cap there, cut track going from x to y , etc.) , now I sound like Cannibal Corpseīs Skull Full of Maggots !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
https://www.youtube.com/watch?v=YQidck9xpX0
Insert your favorite Guitar God name where applicable.

Point is, the unmodded amp already sounds like that if you set it the right way, these "no brand" amps are not tied to a "heritage" sound so can use whatever they want and in fact already incorporate more Mods, straight out of the Factory, than any Forum member can imagine (specially a non Tech Forum member).

I donīt have the ST100A schematic, but as an example of what Iīm saying, hereīs AT100:
b-52_at100_sch.pdf
please open it in a new window and check what I say:

1) it has a full Blackface Fender (Twin Reverb and such) channel, complete with 12AT7 transformer driven reverb for real clean American sound (Rock/Blues/Country/Surf/Pop) if you wish (try that with a high gain Mesa Boogie/Marshall/Peavey/etc.) , check the circuit around: V1-1 , V2-1 , V2-2 plus reverb V10-1 V10-2

2) it has a full high gain channel (around V1-2 V3-1 V3-2 V4-1), with al the tricks built in: bass cut, treble peaking nets, large grid stoppers, cathode follower tone stack drivers , Marshall style tone stack

3) PLUS it already has a Contour circuit for that mid scooped Death Metal sound (V4-2 VR11)

4)Tube driven active send and receive footswitchable Loop, not ICs like on many Famous Amplifiers.
With send and rturn level controls, of course.

5) classic 100W 4 x 5881 power amp, with fixed Presence control and adjustable Resonance (VR16)

6) it has Dual Rectifiers , both SS and 5AR4 .

7) it has a complete switching matrix, uses 2 conventional stereo plugs so you can use many off the shelf footswitches instead of being tied to an expensive proprietary one (which often costs as much as this head)

8) it uses (more expensive) relay switching everywhere (like Peavey or Mesa Boogie)

[rant mode on]if an armchair designer , generally non Tech savvy but with many thousand hours reading generic "guitar" Forums thinks he can turn mud into gold by changing a few caps and resistors here and there, often at random, please be my guest [rant mode off]

Funny side note: this is not exactly news, this is a 2004 design
Donīt think they know less today than 12 years ago

[Steve A.]

Juan: My friend Felix (with the ears of gold) was telling me he really liked the B52 amp he checked out at GC. I did not bother pursuing the tip because "it was just a B52"...

Any high gain amp that includes a BF/SF style preamp for the clean channel gets bonus points in my book.

Thanks for the heads up!

Steve A.

[DrGnosis]

Thank you Juan. That's the best explanation/advice I've gotten. I appreciate it.

[g1]

Also note that the head is only half the equation. The people that are complaining about it could well be complaining about the speaker cabinet they have chosen to use it with. They may even be using great cabinets, just not great in combination with this head.

[DrGnosis]

Also note that the head is only half the equation. The people that are complaining about it could well be complaining about the speaker cabinet they have chosen to use it with. They may even be using great cabinets, just not great in combination with this head.

Very true. I use two home-built 2x12 cabinets loaded with Eminence Private Jacks. They're the best cabs I've ever played through.

[olddawg]

Also note that the head is only half the equation. The people that are complaining about it could well be complaining about the speaker cabinet they have chosen to use it with. They may even be using great cabinets, just not great in combination with this head.

AND... ultimately tone is in the hands! Those of us that have been pro/semipro musicians have had to use "backline" equipment many times. The dirty secret is you pretty much sound like you sound through anything within reason. What did John Lennon say when asked what type/brand of amplifier he ordered for a gig? He replied, "One that works!". Listen to clips of Hendrix live. Doesn't matter if he is playing a Flying V through Dual Showmans or a Strat through Marshals.... Still sounds like Hendrix. I realize that high gain situations may be a slightly different animal. That's why we have pedals. Besides... if you truly don't like the amp, you got it cheap! Sell it for a proffit and buy something else.

[Jazz P Bass]

Hello All --

I have the opportunity to buy a B-52 ST100A which needs a new transformer for dirt cheap. B-52 amps aren't exactly known for their amazing sound or quality. I'm wondering if this platform would be amenable to (probably extensive) mods that would greatly improve the sound? I do not know all that much about electronics, but I'm hoping someone here does.

Any thoughts or advice would be greatly appreciated.

Is that a 'dead' Power transformer or an Output transformer?

[DrGnosis]

Is that a 'dead' Power transformer or an Output transformer?

That's a good question. I don't know. This guy doesn't know anything about amps (not that I'm much better). He's just going by what his electrician relative told him. So, it is kind of risky for me. But, it's SO cheap.

[The Dude]

So, it may not need a transformer at all.

[olddawg]

So, it may not need a transformer at all.

Absolutely... Never trust a second hand diagnosis. Certainly don't order a transformer blind. But... I have heard of these amps eating PTs. I would check the fuses and pull the output and rectifier tubes and fire it up.

[The Dude]

Oh yes! That was my point. As olddawg says, don't just order a transformer or assume someone else diagnosed the amp correctly. Start the work as you would any other repair and follow your own troubleshooting.

By the way, welcome to the place!

[Justin Thomas]

And,

How many of these "users" are playing in their bedroom on 2? Screw that. But it sure looks damn good in your bedroom, right next to your futon ...

Justin

[DrGonz78]

Here is the schematic for ST100A...

[Jazz P Bass]

I have worked on a few of the different B52 100 watters.

They are not a bad amp.

As noted, they need a decent cab configuration to drive.