# ZAPCO STUDIO amp mods (pics)



## drumcrusher (May 4, 2008)

for anyone interested, these are some pics of a Studio 100 that i have been working on for a minute. i also have some others that im in the process of modding. they are easier for the most part because i have learned a lot by trial and error on this one. 
im using 2 opa2132 opamps mounted on a brown dog adapter. the 2132 is a dual opamp. the brown dog makes it possible to use two duals in the place of one quad opamp. this opens up a larger selection of "audio grade" opamps, since the list of quads is very limited. i used a silver mica cap across the v+/v- pins of the opamp to control any oscilations in the (unheard) high frequencies. this probably wont be heard, but may cause problems, including the amp running hotter than normal. sometimes it is necessary to use larger caps from those pins to a ground source that is located on the board. unfortunately, on this amp there isnt one located close enough to the opamps location. fortunately the opa2132 isnt as bad as some of the newer super-fast opamps out there. different amps tolerate opamp rolling differently.


----------



## drumcrusher (May 4, 2008)

elna silmic caps were used in the audio sections, panasonics FC and FR caps were used in the power supple. the two input caps were 2.2uf, so i found some evox films that would fit, and bypassed them with some nice EMZ caps that i had. the elnas in the signal path were bypassed with either Vishay 1837's or wimas. im not sure how much they help but i figured i might as well, since im changing everything else. i know doing the film bypasses is very poular in hifi. i also bypassed all of the power supply caps too. and to finnish it up, i parralleled 3 caps for each of the input supply caps, to equal 3600uf, which is probably more than enough. the panasonic FR caps are new, and pretty ugly, but they have great specs and they are very cheap, so i used them.


----------



## drumcrusher (May 4, 2008)

heres a US Amp, and studio 500 that i hope to get finnished soon. ill post soon if anyone gives a f***. haha


----------



## knever3 (Mar 9, 2009)

I cringe when someone wants to modify a Zapco Studio amp. I love them the way they are, but Zapco has done the research and there's better parts out there for pure sonic bliss. It's good to see you are doing your own research. Mad skilz.


----------



## drumcrusher (May 4, 2008)

Yea its pretty unnecessary i guess. It just started as needing to change some old caps out. Then i kept running into that old question, "What does that do?". Ha


----------



## WhippingBoy (Dec 21, 2010)

Keep posting. I know I enjoy the pics.


----------



## drumcrusher (May 4, 2008)

Thanks man. I have an old fosgate pa1 that im just about to Finnish up. The burr browns in that made a bigger difference than on most of the amps. Ill post some pics of that soon.


----------



## HiloDB1 (Feb 25, 2011)

Damn nice work. Wish I new enough to be confident in doing mods like this. If you're ever interested in doing work I got a bunch of Audio System Twister amps sitting around


----------



## drumcrusher (May 4, 2008)

id have to take a look at some of their amps man. ive never had the cover off one of those. want to know what im getting myself into before i make promises. haha ill see if i can dig up some schematics too and get back to you. you can pm me the model numbers if you want me to look into it.


----------



## jasonjordan584 (Apr 27, 2009)

Sell me that studio 500!!!!!


----------



## drumcrusher (May 4, 2008)

Haha. Sorry man i just bought it 2 weeks ago. That puppies stayin with me.


----------



## customtronic (Jul 7, 2007)

I have a pair of gold Studio 150 amps that I'd be willing to sell. Pm me if interested. Thanks!


----------



## goodguyocom (Jan 19, 2011)

what kind of MOD is being done to the studio 500? I have 1 that need to be recap.


----------



## jasonjordan584 (Apr 27, 2009)

Sell it to me lol you have too many amps


----------



## drumcrusher (May 4, 2008)

Right now I'm not sure if im going to mess with the opamps on the studio 500. There are a lot of them. As of now i have replaced caps with silmic ll's, film input caps and some panasonic fms in the power supply. Also i bypassed a bunch with nice films. The opamps are mostly surface mount too which makes them a pita to work on. We'll see though, time will tell. If you need to shout at me about you studio 500 shoot me a pm.


----------



## namesmeanlittle (Nov 20, 2013)

god..... i'm drooling zapco boards are porn i'm sorry but i can look and dream all day.... need money need more


----------



## SkizeR (Apr 19, 2011)

wish i knew how to do this stuff :/


----------

