Happy so far on amp build project - 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 8th January 2015, 12:08 AM   #1
djcgtr is offline djcgtr  United States
diyAudio Member
 
Join Date: Apr 2006
Location: Northeast Ohio
Default Happy so far on amp build project

I couldn't resist dropping in to share good news on my stereo guitar amp project.
A previous thread I started, was curiosity on some of the members input and their personal experiences regarding heater wiring orientation.

To this point this evening, I have completed the heater wiring, power supply, 5volt and 12 volt regulated circuits for LEDs and dual exhaust fans.
Plus the entire preamp and output circuit on one channel to start out with...

Late last night I fired it up, biasing looks good and B+ tests seemed ok. 494 volts at the plates (EL34 pair). The basic circuit, along with some of my own modifications - is from a Marshall 4140. Yes, the 2x12 combo from around 1980.
I wanted the post P.I. master volume. I currently use a 4140 (slightly modified from original and removed from the combo - made a cabinet for the chassis) but with an old 4x12 cab with 25 watt greenbacks...

This amp build is nominal 50 watt per channel, not 100 watt like a 4140.
Last night when I went for cranking pre and master volumes - the dreaded squeal started at a higher gain setting.
I held off until this evening to check it.

Disconnecting the 100k resistor (feedback circuit) from the 4 ohm output jack stopped the squeal. So I was prepared and proceeded to reverse the plate leads at the octal sockets.
No squeal - awesome. It was 50/50 chance on plate wiring initially...

Plus, I have virtually no hum or noise. Even with the pre and master cranked and all three tone controls maxxed. No oscillations noted. It is a terminal strip - point to point build with star ground scheme. I am very pleased.
I ran a variable output from a stereo I use on my repair bench and this thing cranks. I thought it was interesting that my first "cranked" audio from the radio feed to the amp was "Eruption" by Van Halen.

So, just sharing a happy moment.
Now to build the channel on the other side of the chassis, pretty much a mirror image of the components.

I will borrow a camera when I get this completed for a few photos.

Best of luck on everyone's projects out there.
More to come down the road.

Deric
  Reply With Quote
Old 9th January 2015, 05:27 PM   #2
diyAudio Member
 
funk1980's Avatar
 
Join Date: Sep 2011
Location: Groningen
Ah yes, the satisfaction of a successful build. Tis a great one!
Looking forward to the pics!
  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
Need help with college project - Trying to build a 3 stage amp but I'm lost nxtgenlva Solid State 16 28th March 2014 01:11 PM
First DIY project, which SE tube amp should I build? raver Tubes / Valves 5 14th January 2013 08:39 PM
Pass B1 CLONE build completed and happy omishra Pass Labs 12 30th October 2012 05:23 PM
car amp project to build blakdrag Car Audio 1 18th February 2012 08:45 AM
DJ looking to build an odd project w/ class d amp kearnsentertainment Class D 5 25th January 2011 04:22 PM


New To Site? Need Help?

All times are GMT. The time now is 07:47 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2015 DragonByte Technologies Ltd.
Copyright 1999-2015 diyAudio

Content Relevant URLs by vBSEO 3.3.2