Hi Mark, I don't own a Neotek (hopefully someday!) but i have been doing some opamp swapping on my soundcraft 400b. i have been replacing the TL072's with Burr Brown OPA2134's and have had good success. you need to be careful regarding oscillation and you really should have an oscilloscope for testing. I haven't dippped into any of the crazy fast new opamps, but I have had positive, audible results with the OPA2134's. things are a little clearer and there is less noise.
from what I recall, the Series I has some TL074's, you might want to try out some OPA4134's as well. if you want to try those faster opamps, you will probably need some 0.1uf's on the power rails of each opamp and possibly a bandwidth limiting cap across the feedback resistor. not sure if you have recapped the board, but i noticed amuch bigger difference from replacing all the electrolytics than I did from the opamps. On 1/4/09, Ike Zimbel <[email protected]> wrote: > > Hi Mark, > I just checked the data sheet for those chips, and they spec a max ps > voltage of +/-17 volts. The Neoteks run on +/-18 volts. If you really like > the National chips, you will have to trim your power supply voltage down to > +/-17 volts to accommodate them. This shouldn't affect the performance of > the other chips very much...Soundcraft consoles use many of the same > original chips and they run on +/-17v. Otherwise you need to use other > chips. > best, > Ike > > > Mark Little wrote: > Have any of you successfully used the quad LME49740 in the Series 1e? > > At the advice of my tech I swapped the chips in a couple channels to test > and they sounded GREAT for a while. Big, clear, extended soundstage... I > also replaced the 5534 with the LME49710. After a little while I started > having noise issues on power up and the PSU (ps-4) was having problems. > > The tech fixed a blown cap in the psu and I put all the old chips back in > the desk to get it all up and running again. > > After hearing how great the channels were with the better chips I was > hoping there was a way to get them working without causing other problems. > Perhaps there are certain chips that work better in different parts of the > circuit. I would appreciate any advice. As you can tell, I am not much of a > tech. Thanks! > > Mark > > > > > > Sent from my iPod > ------ > > You can unsubscribe at anytime by sending an email to > mailto:[email protected] with "unsubscribe neotek" in the message > body. If you have any difficulties, or questions --please send an email to > [email protected]. > > The Neotek list is lovingly hosted by Catapult Web Development. Remember > that any message or reply sent to the list will be automatically forwarded > to all subscribers. > Vive Le Neotek ! > > Thanks. > > > -- > Ike Zimbel > Zimbel Audio Productions Ltd. > Toronto > 416-720-0887 > "Studio House Calls" - Repairs and upgrades to analog audio equipment > including: Amek, Allen & Heath, Neve, Neotek, MCI, Soundcraft and more. > > > ------ You can unsubscribe at anytime by sending an email to > mailto:[email protected] with "unsubscribe neotek" in the message > body. If you have any difficulties, or questions --please send an email to > [email protected]. The Neotek list is lovingly hosted by Catapult Web > Development. Remember that any message or reply sent to the list will be > automatically forwarded to all subscribers. Vive Le Neotek ! Thanks. ------ You can unsubscribe at anytime by sending an email to mailto:[email protected] with "unsubscribe neotek" in the message body. If you have any difficulties, or questions --please send an email to [email protected]. The Neotek list is lovingly hosted by Catapult Web Development. Remember that any message or reply sent to the list will be automatically forwarded to all subscribers. Vive Le Neotek ! Thanks.
