Solid State Guitar Amp Forum | DIY Guitar Amplifiers

Please login or register.

Login with username, password and session length
Advanced search  

News:

SSGuitar has been upgraded to SMF v2.0.14 and PHP7!

collapse
Pages: [1] 2 3 ... 10
 1 
 on: Today at 11:59:20 AM 
Started by polaris26 - Last post by polaris26
Hello everyone,
I hope this is ok to post here - I am trying to find any information about the solid state music instrument & PA amplifiers made by an obscure company called EMC (Electronic Music Corp?) from Ohio, USA in the late 60's/early 70's.  I have one of their Sagittarius guitar amp heads that I've been slowly restoring/modding, and any information like schematics, layout drawings, etc. would be helpful.  I was able to find a small sales brochure for that product line on eBay but it doesn't have any deep technical data.  Also I am missing some knobs and it seems like a total long shot to try to match them (molded silver plastic type).   Again any and all info would be helpful.
I do know that there are sites selling the info for the later models like the G300, etc but mine is an earlier design and I'm not sure how much overlap there is to pay for a schematic that may not be relevant.

Regards,
Dave 

 2 
 on: Today at 01:59:40 AM 
Started by edjohansson - Last post by DrGonz78
As I am a noob, I want to be sure I'm testing right.....do I put the black end of the multitester to the chassis ground and the red on the metal part?

To add to the great advice just given by Phatt and to answer your question...

Yes you would attach black lead of the meter to the chassis ground and then probe the red secondary connection points. There is the Red w/ Yellow stripe on the secondary and that is what we call the center tap. With amp off do a test to check for continuity from the chassis ground to the center tap connection. Also check resistance from the center tap to each end of the red secondary terminals.

Not saying all this as directive for response in trying to figure anything specific out. Actually just putting it out there so you can spend extra time learning it a bit, as those are thing I did that helped me understand it better too.

 3 
 on: November 20, 2017, 12:52:06 PM 
Started by flester - Last post by Enzo
Safe?  No less safe that any other circuit you build.

Feasible?  Very simple circuit.

Make sense?  Not to me, maybe to other people.  Little plug into the wall chargers are cheap or even free:
https://www.4imprint.com/sampleitem/134168?gclid=EAIaIQobChMIzqD9itrN1wIVGLXACh0C4ACREAQYASABEgLXsfD_BwE&mkid=1pla-s134168&ef_id=Wbo0QgAABcNrZEKB:20171120174403:s

Otherwise, under $2:
https://repairpartsusa.com/dual-usb-home-charger.html?gclid=EAIaIQobChMIzqD9itrN1wIVGLXACh0C4ACREAQYAyABEgIlvPD_BwE

And I can locate those wherever I want, rather than having to go over to my stereo to charge up.

If I needed one in my stereo, and there was no convenience outlet on the unit, I might buy a cheap charger and take the circuit out of it and install that.

 4 
 on: November 20, 2017, 07:17:14 AM 
Started by flester - Last post by flester
Lots of stuff is USB chargeable these days. Is it feasible or safe to build in USB charging to a diy amp or other builds?

Sent from my SM-G935F using Tapatalk


 5 
 on: November 20, 2017, 01:27:17 AM 
Started by edjohansson - Last post by phatt
Power OFF and pull the plug from wall. pull the two red leads,, plug your probes into both ends,, set meter to AC volts,,, turn on the power and you should read around 60 Volts AC between the two Reds. Then test between one Red and the Red with yellow stripe,, you should read half that voltage. (same for other red)
If that all works then reconnect the wires and power up with light limiter and you can  move onto check the DC voltage test points. :tu:
Phil.

 6 
 on: November 19, 2017, 07:51:28 PM 
Started by edjohansson - Last post by edjohansson
I've checked for continuity through the plug/switch/fuse and all is good there. I went to test the first two test points, but I am not getting any ac readings through them. As I am a noob, I want to be sure I'm testing right.....do I put the black end of the multitester to the chassis ground and the red on the metal part? Or do you test on either side? I attached a pic to show what I'm looking at, it's in the middle of the picture.

 7 
 on: November 18, 2017, 10:37:09 PM 
Started by edjohansson - Last post by phatt
Yes just use the low Ohm setting on the meter,, obviously it won't read Zero as there is always a little resistance and a lot of meters are not accurate at very low ohms.
The leads will have some resistance so Self test the meter first by shorting the probes and if it reads 2 Ohms then subtract 2 from your readings.
Most meters come with a diode tester which is also a way to test continuity, often they have a beeper built in which is handy but use the low Ohms setting to be sure.
If you kept the instructions for the meter it will tell you how to use the functions.
Phil.

 8 
 on: November 18, 2017, 10:07:47 AM 
Started by edjohansson - Last post by edjohansson
I will be testing more today, I bought a continuity tester but it was faulty so I have to exchange it. Once I have that I can test for continuity in the plug, switch and fuse. I will have to take the PCB off the chassis to see the solder points underneath as well. My multitester doesn't have continuity testing, but could I test for continuity using the ohms setting (for future reference)?

 9 
 on: November 17, 2017, 12:09:16 AM 
Started by edjohansson - Last post by phatt
Tiss good you built a Limiter but before you can use that you need to establish the primary input path,, which is mains cord > power switch > and fuse. Sometimes the fuse is Before the switch,, sometimes after.

And for Gods sake remember to pull the power cord out of the wall before you go poking inside. Way to easy to to get excited when you finally find the fault and forget to unplug.
Please note the lightbulb limiter won't save your life,, Mains voltage can still kill you.
LEFT hand behind your back when working on live gear.
no watches, no rings, no dangle bracelets or necklaces. :trouble :trouble :trouble
Phil.

 10 
 on: November 16, 2017, 01:42:26 PM 
Started by edjohansson - Last post by edjohansson
Thank you yet again for the advice! I built the light bulb limiter last night, so the fun will begin tonight. All of the tips above should keep me busy for a while  :)

Pages: [1] 2 3 ... 10
* User Controls
 
 
Welcome, Guest. Please login or register.
Did you miss your activation email?
* Recent Posts
EMC "Zodiac" Amplifiers - Seeking Any and All Information by polaris26
[Today at 11:59:20 AM]


Fender 85 Issues - No sound sort of...UPDATE - No Power by DrGonz78
[Today at 01:59:40 AM]


USB charging by Enzo
[November 20, 2017, 12:52:06 PM]


NO soldering wireless guitar amp project. by flester
[November 16, 2017, 05:50:28 AM]


looking for info on the Gallien-Krueger GT2000 amp by smackoj
[November 14, 2017, 08:49:21 AM]

* Sponsors