Another cool thing about the Peavey mods

Brad Sarno · Post by **Brad Sarno** » 26 Mar 2004 12:54 pm

It just struck me. One reason that the Peavey mod kits sound so good in the opamp based steel amps is that they use the Burr Brown 604 series opamps. At least that's what was in my Vegas mod kit. The Burr Brown 604 series opamps are FET based. That gives you that warm, sweet, somewhat tubelike sound that FETs are famous for. Evans, Webb, Sho-Bud, and Gretsch amps use FET transistors too. The Burr Browns are pretty famous in the pro and audiophile world for their good sonics. I believe that's also what's in the Hilton pedal.

Brad Sarno

Keith Hilton · Post by **Keith Hilton** » 26 Mar 2004 2:59 pm

Brad, you are correct. Brad,if you will remember,I was using Burr Brown OPA604 chips before Peavey started selling mod kits. I know Hartley Peavey was aware of these chips, because he sent me an article of a headphone circuit that used them. This was long before Peavey offered mod kits. I am certain Hartley Peavey was aware that I was using OPA604 chips in my Digital Sustain, and volume pedal, because I sent him lots of diagrams with that number on the chips. Of course now, Burr Brown is Texas Instruments.
You can still get the OPA604 chip, but you must buy it from Texas Instruments. If you want to experience what Brad is talking about, plug in a 741 chip and then compare it to the sound of a 604 chip. The sound difference will amaze you. A far more exciting chip series to me is the Analog Devices SSM series. They are the absolute CREAM of the crop when it comes to sound quality. Of course they cost $6.75 instead of $.50 cents for a off brand. Proof to me that you sometimes get what you pay for. By the way, Brad, I hear a lot of good things about your Black Box. There are many really good people in our business Brad, and you are one of the really good people.

Blake Hawkins · Post by **Blake Hawkins** » 27 Mar 2004 2:18 am

The chips in my NV400 are OPA2604 is there a difference?

Blake

David L. Donald · Post by **David L. Donald** » 27 Mar 2004 3:32 am

Has anyone seen the schematic for the Transfex Pro 212s amp?
I am curious which chips are there, and especially in the overdrive tube emulator section.
I was quite surprised and pleased with it's sound.
But I would certainly consider upgrading to the TI BB's.

I would guess it is the same chipset for the Transfex unit out of amp.

If memory serves, (an it might not) the 2604 is a pretty standard chip. The gentilmen above will undoubtedly know for sure where it stacks up in the pantheon of chips.

Bill Crook · Post by **Bill Crook** » 27 Mar 2004 6:25 am

Blake..........

The 2604 is 2(two) 604's in a singular case.
A lot of peavey gear has this setup.

Bill

Keith Hilton · Post by **Keith Hilton** » 27 Mar 2004 11:14 am

Bill is correct, it is 2 of the 604's. When I mentioned the Analog Devices SSM series being the cream of the crop in sound, I didn't mean in the pre-amp section. What I meant was in voltage controlled op amps.

Blake Hawkins · Post by **Blake Hawkins** » 27 Mar 2004 2:35 pm

Bill and Keith: Thanks very much.

Blake