Fender Super Champ XD Make Over (Warning 5E3 content :-)

[ats]

I was given a couple Super Champ XD's that had bad DSP boards a while back. I have been wanting to build a first amp for  a while and have been slowly gathering bits and pieces. I picked up a old 1955 Bell Sound Systems 2122-C  mono HiFi amp  with 6V6 / 6SC7 / 5Y3   over the summer that powered up but did not test beyond that had alot of hum static i'm sure the caps were bad. Hopefully the OT is good. I was going to buy a pre drilled 5e3 chassis and build a cab , but i thought this might be a lil cheaper and kinda fun.

I have been doing a bunch of reading and hopefully can pull this off (deep breath)  I hope you guys don't find if i ask a few questions along the way. I have a few pics of what im working with and were I'm at so far.

[PRR]

If it hums in the speaker, the OT is *probably* working.

The 2212 only needed modest changes to BE a guitar amp. Plus of course all new electrolytics, and whatever has cracked or burned.

Set it in a cabinet, you have an amp like few others, not another post-Silverface.

Those tubes have 50:50 chance of being better than anything you'd buy today.

[ats]

Ahh perhaps i was a bit hasty in gutting it then? I had thought about doing the 5C3 circuit but kinda wanted to get away from the octal 6sc7 tubes that i'm told tend to be microphonic and problematic , i have a bunch of 12ax7 and 12ay7's so i figured the 5e3 made more sense.

[Paul1453]

Yes, that PA probably just needed a couple of new cap cans (or appropriate e-caps installed) and a few minor mods to be a really nice guitar amp head. 
Those little PAs are now high on my watch list after converting a Bogen K10 with mods provided by DummyLoad into a little beast of an amp.   

[ats]

Cool i had a couple  Bogen's way back i was using with my turntable , what type of guitar amp does it resemble?

[Paul1453]

I'm not really an amp name guy.   

The K10 had a 6AU6 & 12AX7 preamp, which happen to be Mullards in mine.

A Bugleboy EZ80 rectifier and a PP 6AQ5 output section.  It rocks hard for a little lunch box!

If you look at almost any of those old tube PAs, I'll bet you will be able to find a guitar amp in the library here that is pretty close to it.   

[ats]

I'm not really an amp name guy.   

The K10 had a 6AU6 & 12AX7 preamp, which happen to be Mullards in mine.

A Bugleboy EZ80 rectifier and a PP 6AQ5 output section.  It rocks hard for a little lunch box!

If you look at almost any of those old tube PAs, I'll bet you will be able to find a guitar amp in the library here that is pretty close to it.   

Thanks that's good to know. I do run across them every so often. Maybe if i can be successful in this build i'll try another :)

[ats]

I managed to get the transformers mounted on the super champ chassis. I'm a little confused by one thing,  on the Bell amp  the two green wires from the transformer were connected to the two filament pins 7 & 2 on the 1st 6V6GT (as pictured above)  But on the Fender Deluxe 5e3 layout it shows one of the one green wire going to the pilot lamp and then on to filament  pin 7 , i get that part, what is confusing me is pin 2 is jumpered to pin 1 and going to ground and the other green wire joins the red yellow wire to ground. Don't both filament pins need to be powered?

Also i noticed the two toggles i want to use are 6 amp @ 125v i noticed that most are 15amp, are 6 amp ok to use?

[Paul1453]

The 12AX7s also have pin 9 Grounded.

This makes me think the PT has a 6.3VAC CT 6.3VAC heater tap with the CT Grounded.
I could be wrong about this.   

[Willabe]

This makes me think the PT has a 6.3VAC CT 6.3VAC heater tap with the CT Grounded.

Look at the Fender layout drawing he posted, what wires do you see coming out of the PT?

[Paul1453]

I see Green and Red/Yellow tied to Ground.

So maybe just a 6.3VAC no CT filament tap? 

That would make more sense.   

I don't know why you send 1 side of your heater tap to Ground, though?
To reduce hum, maybe?

Isn't it more common to use both wires and an artificial CT with 100 ohm resistors?
I prefer this arrangement, if only because I understand it better.

Not fully understanding this type of grounding has caused me to kill at least one PT.   

[Willabe]

I see Green and Red/Yellow tied to Ground. So maybe just a 6.3VAC no CT filament tap?

Right, no heater CT. 

I don't know why you send 1 side of your heater tap to Ground, though?

That's the way they did back then. Look at a bunch of the old Fender tweed series amps schematics and layouts, the 5 _ _ series. 

Isn't it more common to use both wires and an artificial CT with 100 ohm resistors?

Yes, now it is and it's arguably a better, quieter way to run the heater wires.

[ats]

Thanks guys guess i'll just run the two greens to 2 & 7 then. Looks like this transformer has a center tap (green / yellow wire) so i'll ground that to one of the bolts holding the transformer to the chassis.

[PRR]

> why you send 1 side of your heater tap to Ground, though?

Saves a part-foot of wire.

Good enough for AM radio.

Tolerable on older low-gain guitar amps.

Use the modern (late-1950s) plan if you aren't obsessed with penny-savings or you want a modern "quiet" amp.

[ats]

> why you send 1 side of your heater tap to Ground, though?

Saves a part-foot of wire.

Good enough for AM radio.

Tolerable on older low-gain guitar amps.

Use the modern (late-1950s) plan if you aren't obsessed with penny-savings or you want a modern "quiet" amp.

Thank you! . Where would i find the modern late 50's plan?

[sluckey]

Fender just added a center tap to the filament winding and ran two twisted wires to the sockets. Like this...

     http://el34world.com/charts/Schematics/files/fender/Fender_BASSMAN_5F6A.pdf

[ats]

Haven't had tons of time to work on it lately but  have made a lil progress slowly but surely. Here are a few pics of where i am now.

[ats]

Well after many hours & much toil its finally all wired up. I'm too terrified to power it up. If anyone sees anything amiss i'd love your input.

[Paul1453]

Just some comments, here.

I was glad to see you rotate your OT from the earlier pic.
Your cores are still in line though. 
I've read that it can be helpful to not put them on the same plane.   
A slight rotation of the OT would offset their magnetic fields.
It might not be any issue.

None of the inputs have shielded wire on them.
Seems as your power and output wires are well away from them.
Could be another non-issue.

No choke used?  I thought this design suggested one.
I know a resistor can be substituted.
I'm not sure if a choke changes the tone enough to justify the extra cost if you don't have one.

Output jacks.
Hopefully their placement is OK.
Might be a little close to your PI tube.
Maybe not.   

The only way to find out if you have issues is to fire it up.   

[ats]

Just some comments, here.

I was glad to see you rotate your OT from the earlier pic.
Your cores are still in line though. 
I've read that it can be helpful to not put them on the same plane.   
A slight rotation of the OT would offset their magnetic fields.
It might not be any issue.

None of the inputs have shielded wire on them.
Seems as your power and output wires are well away from them.
Could be another non-issue.

No choke used?  I thought this design suggested one.
I know a resistor can be substituted.
I'm not sure if a choke changes the tone enough to justify the extra cost if you don't have one.

Output jacks.
Hopefully their placement is OK.
Might be a little close to your PI tube.
Maybe not.   

The only way to find out if you have issues is to fire it up.   

Thanks for the observations Paul. Yeah the transformers were too close together i did the headphone test method to relocate it for minimum hum , didn't seems to make a difference rotating it as far as the hum was concerned. Defiantly moving it made a huge difference.

I don't recall seeing a 5e3 circuit with a choke none of the schematics i have show one.

I'm a little concerned about the placement of the output jack like you said its kinda close to the PI and also the heater wires run right underneath them... I'm trying to figure out the best way to power this up for the first time got some more reading to do.

[ats]

I have a few questions about first power up. I really don't want to screw this up so i have resisted the temptation to just fire it up.  I have read and re-read the safety precautions that need to be taken ie keeping one hand in your pocket making sure caps are drained ect

 do i need to have a speaker connected for the part of the test with no tubes installed or just when i add tubes?

I have been looking around for a chart of voltages to be checked and where to check them. Most of what i have seen refer to the tubes as v1 , v2 ect ect , on my layout they are just labeled as the type 6V6 12ax7. 

I put together a light bulb limiter, should i use 100 watt bulbs or 60 watt does it make a difference?

Does anyone know of a video that shows how to probe a live amp? I could only find one using an oscilloscope but i don't have one at the moment. i just thought it would be helpful to see it done .

the OT i'm using has taps for 4 ,8 and 16 ohms, i only plan to use the 8 ohm tap. can i just shrink wrap the ends of the unsed taps? , Thanks in advance

[sluckey]

do i need to have a speaker connected for the part of the test with no tubes installed

no

I put together a light bulb limiter, should i use 100 watt bulbs or 60 watt does it make a difference?

I'd use a 60W bulb for a 5E3 size amp. If the bulb does not glow brightly when you first power up with all tubes in and a speaker connected, you are through with the limiter, so remove it.

the OT i'm using has taps for 4 ,8 and 16 ohms, i only plan to use the 8 ohm tap. can i just shrink wrap the ends of the unsed taps?

yes

Here's a pretty good startup procedure...

     http://paulrubyamps.com/info.html#FirstPowerUp

Just be cautiously optimistic. If it's wired correctly it will work.

[ats]

Thanks Sluckey for the info , i'm getting close now , the excitement is starting to build up. I'll report back in a bit

[ats]

I really want to thank you guys for helping me out on my first build. After a few power up tests and some voltage readings i mounted it in the cabinet hooked up the speaker, plugged in my tele and hit a chord. WOW. it sounds amazing even with the cheapo tubes im buring it in with. No hum no weirdness just sweet tweed tone!. Thank you again el34world and its membership is amazing!

Soon i plan to have a custom face plate made and i will make a pine finger jointed tweed cabinet for it to house a 12" speaker , but for now i couldn't be happier.

[birt]

congrats on your build and that is an awesome looking tele you have there 

[ats]

Thanks Birt  I built the tele about 3 years ago. It's my #1

[lucasluan]

you want to sell the DSP card in your Fender Super Champ XD?

[ats]

you want to sell the DSP card in your Fender Super Champ XD?

I do not believe them to be working not 100% sure though , you are welcome to them free of charge if you can do something with them.

[lucasluan]

I do not believe them to be working not 100% sure though , you are welcome to them free of charge if you can do something with them.

Please send me an e-mail to talk in
lucaspontarolo@gmail.com
really need only a DSP component. I pay all the costs .