Fender rhodes peterson vibrato preamp - Page 2 - diyAudio
Go Back   Home > Forums > Live Sound > Instruments and Amps

Instruments and Amps Everything that makes music, Especially including instrument amps.

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 15th May 2013, 12:25 PM   #11
diyAudio Member
 
chrispenycate's Avatar
 
Join Date: Aug 2006
Location: Geneva, Switzerland
Quote:
Originally Posted by cancon View Post
I think the NTE123ap made a modest improvement. Today I noticed that one channel has more hiss and gain than the other. I can get a handful of MPSA18 so perhaps it would be wise to replace the lot?

Chris - I should mention that my preamp is built into a separate enclosure for any input source.
And a very good idea, too, as long as you go straight from the RCA and avoid all the fender passive controls. I was too recently back from touring, and wanted minimum wiring, rather than maximum flexibility.

More gain? What kind of circuit makes the gain dependent on the actives rather than the passives? (I can't access the schematics page from your first post, gives me a frowny face, perhaps because my ip address isn't in the states.
  Reply With Quote
Old 15th May 2013, 01:29 PM   #12
cancon is offline cancon  Canada
diyAudio Member
 
Join Date: Mar 2011
Here's a fresh copy.

Also, I'm not even going straight RCA - that cable is gone and a fresh shielded wire is in its place leading to a 1/4" input. I'll assess the hiss and gain again - I'm not certain if it is present during non-vibrato operation. Definitely uneven during vibrato.
  Reply With Quote
Old 15th May 2013, 04:34 PM   #13
diyAudio Member
 
chrispenycate's Avatar
 
Join Date: Aug 2006
Location: Geneva, Switzerland
The only thing you've got after the volume control is emitter followers; they shouldn't hiss (no gain) and should give same signal in or out. And, when you switch the vibrato in, you're not adding any extra components, and you're not even starting the oscillator up (I'd be ready to accept the astable multivibrator moving the ground a bit, although I'd expect LF noise rather than hiss), and you're reducing the gain of one side or the other, never boosting it. When you switch the vibrato out of circuit all you're doing is turning the little light bulbs on full. I could understand a mismatched photocell, or light bulb for that matter, unbalancing the gain, but generating hiss?
  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
Preamp issue on Fender Blues Jr. Rotus623 Tubes / Valves 15 24th January 2011 03:13 PM
R.I.P. Dicky Peterson of Blue Cheer scott wurcer Everything Else 2 17th October 2009 02:19 AM
Fender Twin Reverb VIBRATO PROBLEM - weak vibrato gibsonripper Tubes / Valves 2 19th January 2008 04:23 AM
Fender Rhodes preamp? Bernardduur Instruments and Amps 2 2nd May 2006 10:43 AM
LDR in Rhodes piano (help!) Magnetmaz Instruments and Amps 1 27th July 2004 06:55 AM


New To Site? Need Help?

All times are GMT. The time now is 10:13 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