Preamp mod

brendandwyer

brendandwyer

New member
I've got two Bellari Rp220's and i'm wondering if there are alternate tubes i could use, or simple mods to alter the sound.

I like them, wondering if they can be better :)
 
The easiest would be to replace the output opamps for something decent, like an OP275 or a Burr-brown OPA2604.

A little more expensive and slightly trickier would be to replace the cheap, piece of shit transformer with a Jensen JT-115K-E. This would yield, by far, the greatest improvement.

There are others you could try, but these are the "easier" ones.

.
 
chessrock said:
The easiest would be to replace the output opamps for something decent, like an OP275 or a Burr-brown OPA2604.

A little more expensive and slightly trickier would be to replace the cheap, piece of shit transformer with a Jensen JT-115K-E. This would yield, by far, the greatest improvement.

There are others you could try, but these are the "easier" ones.

.
Click to expand...
thanks man. do you have any leads on where i can buy those components?

thanks
 
chessrock said:
A little more expensive and slightly trickier would be to replace the cheap, piece of shit transformer with a Jensen JT-115K-E.
Click to expand...
Honest question here chess:

What makes replacing the transformer "trickier"? Is it a probelm with physical form factor or is there something else involved?

G.
 
SouthSIDE Glen said:
Honest question here chess:

What makes replacing the transformer "trickier"? Is it a probelm with physical form factor or is there something else involved?

G.
Click to expand...
and how difficult is the opamp mod in general. Can i type in the specified one in the first post and click buy and know that it's correct? Can i then easily locate it in the chassis and replace it?
 
SouthSIDE Glen said:
Honest question here chess:

What makes replacing the transformer "trickier"? Is it a probelm with physical form factor or is there something else involved?
Click to expand...

It's more of a physical form factor. It doesn't fit as tidy as the stock one; you'd have to leave it moreless free-floating, or find another way to mount it to the board manually. Not a really big deal.

Brendan, if I'm not mistaken, I believe the opamps are socketed, so replacing those would be a breeze. Just yank out whatever's in there, and you can try out several different opamps (just pop 'em in) in it's place until you find one that grabs you.

.
 
chessrock said:
It's more of a physical form factor. It doesn't fit as tidy as the stock one; you'd have to leave it moreless free-floating, or find another way to mount it to the board manually. Not a really big deal.

Brendan, if I'm not mistaken, I believe the opamps are socketed, so replacing those would be a breeze. Just yank out whatever's in there, and you can try out several different opamps (just pop 'em in) in it's place until you find one that grabs you.

.
Click to expand...

awesome.

i would imagine the transformer mod involves a bit more? soldering and all that fun stuff?
 
You're not going to damage anything by trying out different chips. Just make sure to touch them, periodically, to see if they overheat. If they get really warm after a few minutes of use, then chances are it's oscillating and you can pretty much disregard it as an option.

I don't know much about the Behringer, but chances are it's surface-mount, which would mean a much trickier mod which should probably be peformed by a more skilled tech. If, by some strange chance, they happen to be socketed, then the chip you'd want to look for is the SSM-2017, I believe. You'd want to swap that out with something along the lines of a Burr-brown INA217 or an Analog Devices SSM-2019 ... or one of the newer THAT chips.

As for the transormers, I can't think of any tutorials or anything. You can pretty much just look at it and tell where everything goes, though. Not really complex stuff ... but if you have a buddy who gets in to electronics it might be a good time to give him a call, just in case.
.
 
chessrock said:
You're not going to damage anything by trying out different chips. Just make sure to touch them, periodically, to see if they overheat. If they get really warm after a few minutes of use, then chances are it's oscillating and you can pretty much disregard it as an option.

I don't know much about the Behringer, but chances are it's surface-mount, which would mean a much trickier mod which should probably be peformed by a more skilled tech. If, by some strange chance, they happen to be socketed, then the chip you'd want to look for is the SSM-2017, I believe. You'd want to swap that out with something along the lines of a Burr-brown INA217 or an Analog Devices SSM-2019 ... or one of the newer THAT chips.

As for the transormers, I can't think of any tutorials or anything. You can pretty much just look at it and tell where everything goes, though. Not really complex stuff ... but if you have a buddy who gets in to electronics it might be a good time to give him a call, just in case.
.
Click to expand...

awesome. thanks a lot for the help
 
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