Big upgrade of Neptune 820! Need some advice... - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 1st April 2009, 04:30 AM   #1
diyAudio Member
 
Join Date: Mar 2009
Default Big upgrade of Neptune 820! Need some advice...

Hi all, first post here. I just bought a very inexpensive mixer on ebay - Neptune 820 from the late 70s. Its got built in spring reverb which is totally gnarly, and it works just fine. I thought it would be a fun project to try and soup it up - I've attached the schematic but left out the master section b/c of size restraints. The circuit is based on the RC4136 quad op amp, and my idea was to replace it with OP275s or OPA2406s using BrownDog adapters. I also thought about replacing the PSU caps and all the 10uf electrolytics. EQ caps as well?

My questions are:
1. What do you think the power supply will handle as far as the op-amp current consumption (the 4136 draws <2mA per amp)?
2. Is it worth buying the more expensive caps for this (Black Gates, etc.)?
3. Do you think this is a worthwhile project?
4. What are the "gotchas" I'm not thinking about?

Thanks!!
Attached Images
File Type: jpg neptune 820 channelps.jpg (85.8 KB, 93 views)
  Reply With Quote
Old 2nd April 2009, 12:03 AM   #2
diyAudio Member
 
Join Date: Mar 2009
Here is the rest of that circuit. Anybody want to offer their 2 cents?
Attached Images
File Type: jpg neptune 820 master section2.jpg (49.6 KB, 63 views)
  Reply With Quote
Old 15th October 2012, 03:30 PM   #3
diyAudio Member
 
Join Date: Sep 2007
If you're still around, did you ever do anything with this? How did it turn out?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
LM3886 based Amp -Upgrade advice please. mikesnowdon Chip Amps 3 26th October 2008 01:53 PM
Advice/Help - Cap upgrade dieselpower Tubes / Valves 6 19th June 2007 02:23 AM
Speaker Upgrade Advice Please Friends quasi Multi-Way 2 4th May 2007 04:35 AM
2 way speaker kit upgrade advice mark0311 Multi-Way 3 9th June 2005 11:46 PM
CD upgrade advice ultrachrome Digital Source 3 6th May 2004 06:14 PM


New To Site? Need Help?

All times are GMT. The time now is 02:52 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2