Deuce42,
Sorry about that but you will have a much safer and well built amp once you rework it, best in the long run.
Mark
My 5E3 Grounding Scheme - could someone offer some advice?
Moderators: pompeiisneaks, Colossal
Re: My 5E3 Grounding Scheme - could someone offer some advice?
The problem with the old Fender layouts is that they assume you know the basic principles of an amp. They are made more for servicing an existing amp rather than building one from scratch.
Keep your preamp grounds near the input.
Keep the power supply grounds at the other end.
Keep the line earth ground separate.
Keep your preamp grounds near the input.
Keep the power supply grounds at the other end.
Keep the line earth ground separate.
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: My 5E3 Grounding Scheme - could someone offer some advice?
And I appreciate I'm a novice in this area but so eager to learn. I've tried garnering information on the internet but am sort of overloaded with info that seems a bit hit and miss.Structo wrote:The problem with the old Fender layouts is that they assume you know the basic principles of an amp. .
If you were me, where would you start in giving yourself a course for learning about amp designs?
Thanks again for the advice
Re: My 5E3 Grounding Scheme - could someone offer some advice?
If you can find it down under, this book is a good introduction to many practical basics. http://www.amazon.com/How-Service-Your- ... 0962817007
There are always Merlin's books, which are not too technical and very accessible. They assume some very basic knowledge level.
http://www.amazon.com/Designing-Tube-Pr ... n+blencowe
http://www.amazon.com/Designing-Power-S ... n+blencowe
Buy them at lulu.com where you'll get faster delivery (I think.)
Just spend time looking at the classic Fender and Marshall schematics. This are available on the internet, just do a web search.
There is a good theory document posted at AX84.com. You have to sign up.
The resources are endless.
There are always Merlin's books, which are not too technical and very accessible. They assume some very basic knowledge level.
http://www.amazon.com/Designing-Tube-Pr ... n+blencowe
http://www.amazon.com/Designing-Power-S ... n+blencowe
Buy them at lulu.com where you'll get faster delivery (I think.)
Just spend time looking at the classic Fender and Marshall schematics. This are available on the internet, just do a web search.
There is a good theory document posted at AX84.com. You have to sign up.
The resources are endless.
Re: My 5E3 Grounding Scheme - could someone offer some advice?
Thanks for this. I'll start:)Phil_S wrote:If you can find it down under, this book is a good introduction to many practical basics. http://www.amazon.com/How-Service-Your- ... 0962817007
There are always Merlin's books, which are not too technical and very accessible. They assume some very basic knowledge level.
http://www.amazon.com/Designing-Tube-Pr ... n+blencowe
http://www.amazon.com/Designing-Power-S ... n+blencowe
Buy them at lulu.com where you'll get faster delivery (I think.)
Just spend time looking at the classic Fender and Marshall schematics. This are available on the internet, just do a web search.
There is a good theory document posted at AX84.com. You have to sign up.
The resources are endless.
Re: My 5E3 Grounding Scheme - could someone offer some advice?
In the Stickies on the top of this section there is a thread that lists a whole lot of resources.
"Reading Material on Steroids".
This forum is not the best organized forum on the web but in a way it keeps the people that aren't willing to do some work away.
One of the best books I found that explain tube amps at a beginner level is the Dave Hunter- Guitar Amplifier Handbook
http://www.amazon.com/Guitar-Amplifier- ... ave+hunter
"Reading Material on Steroids".
This forum is not the best organized forum on the web but in a way it keeps the people that aren't willing to do some work away.
One of the best books I found that explain tube amps at a beginner level is the Dave Hunter- Guitar Amplifier Handbook
http://www.amazon.com/Guitar-Amplifier- ... ave+hunter
Tom
Don't let that smoke out!
Don't let that smoke out!
Re: My 5E3 Grounding Scheme - could someone offer some advice?
The P1 theory document over on the AX84 site makes for some good reading.
Re: My 5E3 Grounding Scheme - could someone offer some advice?
Just for the heck of it - isolate all the input jacks. Unbolt them and just real quick push them in the chassis so they don't make ground at the chassis holes. I had a 5E3 that would not stop humming until I replaced the Switchcraft input jacks with isolated jacks.
P.S. There is a backer board under that component board - Yes?
P.S. There is a backer board under that component board - Yes?
Re: My 5E3 Grounding Scheme - could someone offer some advice?
The diagram shows the grounding scheme that you find on most Vintage Fender's and Marshall's.
The grounding scheme above runs very quiet if done properly.
* J = Jack, P = Pot, F = Filter cap
* Do not try and solder wires to the chassis itself. A ground that is soldered to a chassis is not as good as a soldered and bolted down ring terminal ground.
* Do not do STAR grounding. I have removed many star grounds in amps to fix grounding problems.
* Do not use the brass Fender style grounding plates. These plates corrode eventually and do not make good contact between the chassis and the brass.
* The power transformer bolt ground wires have a round ring terminal crimped and soldered to them. They can then be bolted down firmly to the metal chassis.
* The Marshall style pot buss wire is shown above. This is a bare wire that is soldered to the back of every pot and is connected to the input jacks ground lugs. I recommend using this buss wire system. You may have to grind, sand or file some of the coating off of the back of the pot so that you can solder the buss wire to it. A 40 watt iron minimum is usually what it takes to solder this buss wire to the pots.
* Make sure all Jacks and pots are bolted down firmly to the metal chassis. If you use plastic jacks, make sure all jacks are grounded to the pot buss wire.
* Your circuit board may have multiple grounds leaving the circuit board. Pre amp grounds are soldered to the pot buss wire. Bias supplies, rectifiers or power tube cathode ground wires all go to the main power transformer bolt.
* All power transformer Center taps get bolted down to the main Power transformer bolt.
* If you use two 100 ohm resistors as your heater center tap, do not use the power transformer heater center tap wire and visa versa.
* If you have a reverb transformer, make sure the reverb jacks are bolted to the chassis and the reverb transformer ground wire is soldered to a ground lug on the reverb jacks. Do not use insulating washers on the reverb jacks.
* Speakers jacks are bolted firmly to the metal chassis. The output transformer ground wire is soldered to a speaker jack ground lug. If you use plastic speakers jacks, solder a ground wire to the jacks and bolt it down to the main power transformer ground bolt where all the other grounds are bolted.
* Your power tube cathode wires may be on the circuit board or leave the tube sockets and go right to the main power transformer ground bolt.
* The power cord green wire can be bolted down to the closest power transformer bolt.
* Filter cap notes: #1 is your main filter cap(s) that are connected to the rectifier. #2 are the power tube screen grid filter cap(s). These two filter cap stages both get bolted to the main power transformer ground bolt.
#3 are all the pre amp and phase inverter filter caps. They are all soldered to the buss wire that runs down the back of the pots.
* If you have a separate rectifier board or a bias circuit board or a Bridge rectifier bolted down somewhere, all these grounds should get bolted down to the main power transformer ground bolt.
The grounding scheme above runs very quiet if done properly.
* J = Jack, P = Pot, F = Filter cap
* Do not try and solder wires to the chassis itself. A ground that is soldered to a chassis is not as good as a soldered and bolted down ring terminal ground.
* Do not do STAR grounding. I have removed many star grounds in amps to fix grounding problems.
* Do not use the brass Fender style grounding plates. These plates corrode eventually and do not make good contact between the chassis and the brass.
* The power transformer bolt ground wires have a round ring terminal crimped and soldered to them. They can then be bolted down firmly to the metal chassis.
* The Marshall style pot buss wire is shown above. This is a bare wire that is soldered to the back of every pot and is connected to the input jacks ground lugs. I recommend using this buss wire system. You may have to grind, sand or file some of the coating off of the back of the pot so that you can solder the buss wire to it. A 40 watt iron minimum is usually what it takes to solder this buss wire to the pots.
* Make sure all Jacks and pots are bolted down firmly to the metal chassis. If you use plastic jacks, make sure all jacks are grounded to the pot buss wire.
* Your circuit board may have multiple grounds leaving the circuit board. Pre amp grounds are soldered to the pot buss wire. Bias supplies, rectifiers or power tube cathode ground wires all go to the main power transformer bolt.
* All power transformer Center taps get bolted down to the main Power transformer bolt.
* If you use two 100 ohm resistors as your heater center tap, do not use the power transformer heater center tap wire and visa versa.
* If you have a reverb transformer, make sure the reverb jacks are bolted to the chassis and the reverb transformer ground wire is soldered to a ground lug on the reverb jacks. Do not use insulating washers on the reverb jacks.
* Speakers jacks are bolted firmly to the metal chassis. The output transformer ground wire is soldered to a speaker jack ground lug. If you use plastic speakers jacks, solder a ground wire to the jacks and bolt it down to the main power transformer ground bolt where all the other grounds are bolted.
* Your power tube cathode wires may be on the circuit board or leave the tube sockets and go right to the main power transformer ground bolt.
* The power cord green wire can be bolted down to the closest power transformer bolt.
* Filter cap notes: #1 is your main filter cap(s) that are connected to the rectifier. #2 are the power tube screen grid filter cap(s). These two filter cap stages both get bolted to the main power transformer ground bolt.
#3 are all the pre amp and phase inverter filter caps. They are all soldered to the buss wire that runs down the back of the pots.
* If you have a separate rectifier board or a bias circuit board or a Bridge rectifier bolted down somewhere, all these grounds should get bolted down to the main power transformer ground bolt.
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Re: My 5E3 Grounding Scheme - could someone offer some advice?
Thats is awesome help. Thanks Davewell!
-
renshen1957
- Posts: 498
- Joined: Fri Feb 20, 2009 8:13 am
- Location: So-Cal
Re: My 5E3 Grounding Scheme - could someone offer some advice?
Hi,deuce42 wrote:Thats is awesome help. Thanks Davewell!
You might want to invest in Kevin O' Connors The Ultimate Tone Vol. 3. available directly from London Power or from Antique electronic supply. www.tubesandmore.com. A bit pricey, but was well worth it in my opinion.
The preliminary chapters discuss proper grounding techniques, wire gauge sizes for signal, heater, etc. with a great deal of practical advice as well as the reasons behind. Plus the different amp projects contain both schematic and layout. Observation, some of the schematics contain an omission or two; always double check the layout against the schematic.
Also if you've been bitten by the amp buidling bug, or if you haven't done so check into safety socket power limiter or some type of limiter when first powering up an amp.
Best Regards,
Steve