Rock Amp (70's SS guitar amp) - 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 14th June 2009, 01:48 PM   #1
diyAudio Member
 
pigsnoot's Avatar
 
Join Date: Jun 2009
Default Rock Amp (70's SS guitar amp)

I've got this great little guitar amp, It goes way too loud for It's size and it gives a biting harsh fuzz sound when cranked wich I like a lot!I think It's solid state, but there are also opamps on the board...

Now like a lot of the old amps It's a 2 prong plug, not grounded
(I think that's the reason of the hum it's producing....)

I want to relocate the plug and use standard 3 core plug so there's no power cord attached anymore...

I'd like grounding to the chassis,but there's already stuff connected to the chassis, one wire from the transformer wich is also connected to a cap.....

So is it safe to just ground the chassis to my 3 way power plug I like to install?

I'm no engineer, so I hope this question isn't too silly for you guys...

I just don' want to blow this cute amp, and ofcourse don't want to risk any shocks!!!!
Click the image to open in full size.
  Reply With Quote
Old 14th June 2009, 02:26 PM   #2
diyAudio Member
 
pigsnoot's Avatar
 
Join Date: Jun 2009
Another version I found on he web...
These seem to be quite rare, but not very expensive ...
Click the image to open in full size.
  Reply With Quote
Old 14th June 2009, 02:32 PM   #3
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
In one of your pictures the line cord is shown and is clearly 3 core.

It's more likely someone just fitted a 2 prong plug.
  Reply With Quote
Old 14th June 2009, 05:56 PM   #4
diyAudio Member
 
pigsnoot's Avatar
 
Join Date: Jun 2009
Quote:
Originally posted by jaycee
In one of your pictures the line cord is shown and is clearly 3 core.

It's more likely someone just fitted a 2 prong plug.
No no I've put that cord in there, ready to be soldered!
The original Is already gone....
I'm just waiting for a go on soldering chassis to earth ground....
  Reply With Quote
Old 14th June 2009, 08:51 PM   #5
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
Hm, it looks like it's a single ended supply amp, so the case will be attached to the transformers 0V tap. Earthing it will probably cause more problems than it will solve.

My guess is that the humming is caused by that 2200uF 50V capacitor, which is most likely the power supply filter capacitor, now being old and worn out. Another source of hum could simply be the transformer field being picked up by the fact that it's mounted right on top of the chassis with the circuitry in!

AS you don't have much electronics experience I'm not sure how to advise you further, but I wouldn't advise connecting an earth. You COULD however, still add an IEC socket, this is easy enough to do.
  Reply With Quote
Old 14th June 2009, 10:37 PM   #6
diyAudio Member
 
pigsnoot's Avatar
 
Join Date: Jun 2009
Thnx...I hope replacing the cap will solve the issue....
So the earth pin of he IEC socket will remain unused?
Isn' there any risk of recieving shocks when plugging in your guitar and singing in a Microphone?
  Reply With Quote
Old 14th June 2009, 11:40 PM   #7
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
To get a shock the transformer's insulation would have to break down and the primary short to the secondary.

Without examining the amp in greater detail it's hard to say how to correctly apply earthing to this unit. The power supply will most likely require some revision to make this work correctly.

I'm wondering where that ceramic cap that's been hot glued down is going. If the other end of it is connected to the Neutral wire of the power cord - take it out!
  Reply With Quote
Old 15th June 2009, 12:15 PM   #8
diyAudio Member
 
unclejed613's Avatar
 
Join Date: Dec 2006
brown to the power switch, blue to the other termimal that the power cord went to (most likely to the other power transformer wire), and the green/yellow to the ground lug. leave the ceramic cap where it is. replace the power supply cap. the unit probably needs other caps replaced, but one step at a time.

so the cable should connect:
brown to the power switch, power switch then goes to the fuse, fuse to the transformer.

blue wire then goes to the other wire from the transformer, and possibly the ceramic cap.

G/Y wire to the ground lug. leave a couple extra inches of wire on the ground.
__________________
Vintage Audio and Pro-Audio repair ampz(removethis)@sohonet.net
spammer trap: spammers must die
  Reply With Quote
Old 23rd July 2009, 11:37 PM   #9
chiliD is offline chiliD  United States
diyAudio Member
 
Join Date: Jul 2009
Sorry I'm late to the party.

I found this site when doing a search for Rock Amps.

I had one of the original ones from back in the '70s...if my recollection is accurate, I had serial #18.

I took mine on tour with me to Canada in '81 and got the greatest tone from it (at the time, anyway).

Seeing photos of them again really makes me miss my old one (I'd sold mine when I got back from the tour in '81...regret ever getting rid of it!)

Sorry for the thread hijack.
  Reply With Quote
Old 24th July 2009, 03:07 PM   #10
diyAudio Member
 
gain wire's Avatar
 
Join Date: Nov 2004
Location: NCR
Holy Cow! I never thought I'd see someone post a picture of a rock amp! Is that a ten inch speaker?


"Gadzooks, what a tone!"

gimme a day, I'll explain...
__________________
Trans-directional-servo-logamp non-zerocrossing autogain compressing thingamajig
  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
Rock - Progressive Rock ->>> Rixsta Music 118 10th December 2012 09:00 PM
OLD Stoner Rock renfrow Music 193 24th July 2012 09:49 PM
F3's rock coils Pass Labs 7 1st October 2008 09:39 PM
rock music and SE? jarthel Tubes / Valves 16 25th June 2007 11:20 PM


New To Site? Need Help?

All times are GMT. The time now is 07:53 AM.


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