5e3 first build _ampro

[ernest]

Hello, may need some help here.  Novice builder and I've gotten myself thus far by figuring it out online.  Hoffman website has been a great asset for most all of this build besides what I could scavenge.  I started out with a Ampro film projector amplifier.

2-6v6, 1-5y3, 1-12ax7

[ernest]

Hi, I moved my thread here by request,  let me know what you think.

thanks, Ernest

[ernest]

Are you putting a 12au7 in the preamp stage just like the fender deluxe calls for?  

From your tube list I thought you might be a tube short, but you picked it up on your sockets.

From what the guys in this forum write, don't forget to a light limiter when you first power up your new amp.  

What are your transformers?

I like your approach.

thanks, I got a 12ay7 electro harmonix from Hoffman.  The tubes listed were just what came in the old projector amp.

From what the guys in this forum write, don't forget to a light limiter when you first power up your new amp.  

What are your transformers?

I'm a bit of a novice here so I'm not sure what you're saying here with the light limiter.  I'm using the PT and OT from the old projector amp.   I had to hunt down a guy on another forum that was using the actul Ampro projector amp as his guitar amp to send me a pic of the label and to help verify what ohm the OT would be.  16 ohm

[Willabe]

Wow, that was fast ernest.

Here's a link to a lamp limiter with instructions on how to use and how to build it. It is a must have/must use tool for amp building/amp repair work.  

Always use this at first start up on new builds and when testing an amp thats not working/dead to check for shorts in the power supply. It very well could save a PT/OT and more.



  http://home.comcast.net/~seluckey/amps/misc/Amp_Scrapbook.pdf


                              Brad      

[ernest]

cool, thanks

[tubenit]

You did a remarkably great job!  Bravo ! 

With respect,  Tubenit

[ernest]

Power on,  guitar turned up, flick standby switch......beautiful vintage tube tone and breaks up oh so nicely,
I'm in bliss right now 

[Willabe]

Power on,  guitar turned up, flick standby switch......beautiful vintage tube tone and breaks up oh so nicely,
I'm in bliss right now 

Nice!


         Brad     

[ernest]

I notice when I'm playing a bit heavy I'm getting some fizzle, pops, like it's overloaded and sounds like shit.  If I back off and play lightly again then it's ok.  I have no extra tubes to swap out so before I go spending money on new tubes, do these symptoms sound like tube problems or did I mess up some wiring?  I plugged my guitar into a solid state amp to check and it's not glitchy pots in the guitar...

[stingray_65]

I plugged my guitar into a solid state amp to check and it's not glitchy pots in the guitar...

"glitchy" pots are seldom "glitchy". What causes the scratchiness generally is DC voltage leaking through the pot.

It looks like you reused the tube sockets.

I had a fizz issue on an early champ build that I tracked down to loose contacts in the power tube socket that I salvaged.

I re-tensioned the contacts with a small pick tool and strong reading glasses. You don't need to move the contacts much at all to get them to tighten up. Then clean the contacts

Deoxit is a must have in my book, especially if you use vintage NOS parts or parts harvested. It seems expensive, but a little goes a LOOOONG way. It's not just for amps, jacks love to be cleaned with it and "glitchy" pots that are dirty clean up nicely too! My local Radio Shack now carries it, so no more paying high shipping for me, the Radio Shack brand "precision electronics cleaner" is good too, but I think the Deoxit is superior.

Ray

[ernest]

thanks, I'll look at the tube sockets first....could be very possible since a broke a few tabs and had to take out the little collar and replace those slots...driving them up into the slot may have widened them.

[ernest]

I've gone through and pinched all the collars inside the tube sockets, sprayed them with DeOxit...fizzle, overloaded breakup to crappy sound still there.....It is more prominent when the Tone control is turned up, I can only think I messed up the way the controls are wired or it's a failing tube.  This is my first experience with tubes so I'm a bit lost right now.  I've got a friend coming over with his working 5e3 and we are going to swap out tubes to see if we narrow it down to a faulty tube.  If you can think of anything else to check please let me know.

[Willabe]

You should wiggle the tube in and out a few times while the sockets female pins are wet. Just spraying them is not enough to clean them.


                  Brad

[ernest]

the problem was 6v6 GTA tube.   I don't know if you can NOT use both a 6v6 GT and GTA together or if this tube was faulty.  I just know that once I put in a 6v6 GT ,the amp sings like it should.  The breakup is so early, I love it.  Again...not sure if it's the old OT, old tubes, or the Hemp cone aluminum coil Celestian G12...or if this unique to the Hoffman board but I'm very much satisfied with this amp.  Sounds like a marshall stack at times but so sensitive the guitars controls.  I'm using a old TTop humbuckers in a vintage MIK plywood Les Paul.

[ernest]

This is how I interpreted the schematic and wired the Pots.  Both a friend and I are confused about the way the Tone control works on this amp compared to his traditional 5e3 board.  It is almost as if my Tone control acts like a Gain control.  Could someone just look over my pots and tell me if they see anything I did wrong.  I marked the center tab as pink and the two leads for Volume go behind the board.  The lead for Tone goes straight to 12ax7.

[ernest]

A pic without the mess...

[Willabe]

I can't quite tell, but it looks like you have one end of the .0047 (.005 on the Fender schemo.) soldered to the wiper of the tone pot (along with the grid wire) instead of the "0" end of the tone pot and you have a black wire going to ground from that far left tab, looking from the back which is the "0" end of the pot.

If so get ride of the black ground wire, leave the grid wire on/at the wiper and move the .0047 caps end over to the "0" end of the tone pot.

I'd also slide a piece of insulation on to that caps leads to keep it from shorting out on the pots case.

If the black wire is not hooked up to the tone pot and goes to a ground star and is also ground at the input jacks ground, you have made a ground loop, unless the input jack is insulated the chassis. If so just snip out one ground or the other.

Also this amps tone control does some what act like a gain boost as you turn it up to get more high end.  


                       Brad    

[ernest]

Thanks Brad,  the pic is misleading but I have the .0047 under the "wiper" and soldered to the ground tab, then a black wire from that to the chassis.  other than the insulation on the caps leads it seems ok, right?

so must just be this design compared to the Fender, It's cool by me I just wanted to make sure. 

Again, I can't stress how early the breakup is on this amp and anything beyond 5 or so on the controls just shreds like a marshall stack.  The friend of mine thinks the speaker I have in it is contributing to this a bit.  It was a bargain buy Celestion G12 from a Line 6 amp that had been reconed with a Hemp cone and the coil is aluminum....perhaps the speaker needs some time to break in aswell.

let me know if I should put up a better pic just to make sure.

thanks again

[Willabe]

the pic is misleading but I have the .0047 under the "wiper" and soldered to the ground tab, then a black wire from that to the chassis.  other than the insulation on the caps leads it seems ok, right?

No.

That's your problem ernest. You have both ends of the .0047 cap grounded. The tone pot only gets (AC) grounded _ through _ the cap.

Get ride of that black wire from/on the "0" (ground end) tab going to ground. It's shorting out the .0047 cap, so the tone control doesn't know it's there. Wont/can't work that way.



                                 Brad      

[ernest]

deeeer.....that was it.

thanks man.

[Willabe]

Everyone makes wiring mistakes, no biggie, your in good company.       It's really only bad if you blow up something from a mis-wiring mistake, at least untill you can find it.

How does she sound now? Is the tone control not acting like a gain boost any more? I think you had it wirerd up kinda like a 2'nd volume control?

Is the breakup a little different now, maybe a little later?

Also the amp might be a little quiter now that you got rid of that ground loop.


                         Brad      

[ernest]

exactly  as you have described.  breakup is a little later and the tone knob effects tone, not gain or volume.   so I just have one ground direct to chassis from the board- the 250 ohm resistor on the very left of the board.  The Ground listed for the right side of the board, noted as a triangle, I have going into the grounds of the input jacks, then over to the pots.   should I ground to the chassis at the right side of the board coming off 1.5k / 22 also? or is already grounded to chassis by the jacks.

[ernest]

couple shots of the etching I made for the back panel.

[Willabe]

First look at this to see what was happing with the way you had it wired. Look at where the wipers are set. Should be easer to understand this way.


                     Brad    

[Willabe]

I have going into the grounds of the input jacks, then over to the pots.   should I ground to the chassis at the right side of the board coming off 1.5k / 22 also? or is already grounded to chassis by the jacks.

It looks like you used Doug's layout, and it looks like 1K5/22uF are already grounded. Besides they must all ready be grounded or the amp wouldn't work.

You've done a great job on your (first?) build, but I think maybe learning a little more about amp grounding (as do all of us sooner or later) is one of the next things that would help you grow as an amp builder?

Look at Doug's layout's in his tube amp library and studie his ground schemes and you'll see he is limiting the chassis ground connections. Look where he grounds what.

Here's another good place for grounding (and much more) info. A lot of the guys here have read this.

http://www.freewebs.com/valvewizard2/Grounding.html

The main ground for the amp leaves through the safety chassis ground (green or green/yellow, 3'rd wire) and any and all other _ chassis _ grounds must find their way over to that chassis ground connection, through the chassis. This is also the noisiest ground point in the whole amp because    _ ALL _ of the amps current leaves the amp from there .

The less the ground to chassis conections, the less problems can arise from ground currents crossing and modulating each other in the chassis and on their way to the main/exit chassis ground. This  _ will _ cause noise in the amps output sound.


                   Brad          

[Willabe]

couple shots of the etching I made for the back panel.

Hey, that's beautiful Ernest! How did you do that?        

It looks like you might have wire brushed out the soft grain of the wood, so that the board is now 3D plus the etching? Or is that the stain bringing out the woods grain?

I like the couple of knots too.


                          Brad      

[ernest]

Hey, that's beautiful Ernest! How did you do that?        

thanks,  I run a laser etcher at work among many other things, but I etch out flexographic foam plates that wrap around a drum on a press and apply glow in the dark to all the Crayola color wonder stuff.

this is just a piece of pine from a pallet.  the laser removed away all the negative area of the design but in doing so followed the densities of the wood grain.....cool effect.

[Willabe]

this is just a piece of pine from a pallet.  the laser removed away all the negative area of the design but in doing so followed the densities of the wood grain.....cool effect.

Yeah, I'll say. Now if I can just get my hands on a lazer etcher.       



                              Brad     

[Willabe]

Here I added color to the drawing to follow the signals by-pass path to input or ground.



                                  Brad    

[ernest]

smelled good in the shop that day.

[Willabe]

So that panel is 3D and not flat.

Man depending on how much your boss will let you use that lazer, you got your self something there.

Why not do a whole amp cab that way?


                                Brad     

[ernest]

still a bit lost here with the GRND.  sorry to beat a dead horse.

This is how I'm Grounded now.



but should I not ground to the chassis at the right also?  or did you already answer this?

[Willabe]

but should I not ground to the chassis at the right also?

As long as the input jacks are not insulated/isolated from the chassis with a flat & shoulder washer or by using a plastic body type jack, then it's already grounded to the chassis, through the jack.

I really think it would help you to get a better understanding of grounding by reading the info at Merlins site.

http://www.freewebs.com/valvewizard2/Grounding.html


                  Brad      

[sluckey]

but should I not ground to the chassis at the right also?

Those switchcraft input jacks usually provide a good ground, especially if you put a toothed washer between the jack body and chassis. But you have a wood faceplate and may not have cranked the jack nuts really tight. In this case I would use a separate dedicated grounding screw and not rely on the jacks for a ground.

[Willabe]

You sound pretty good there ernest. I like it. I never was able to learn how to Travis pick, but i love the sound of it.

And the best part is you made the amp your self.


                      Brad     
                         

[ernest]

You sound pretty good there ernest. I like it. I never was able to learn how to Travis pick, but i love the sound of it.

And the best part is you made the amp your self.


                      Brad     
                       

http://youtu.be/q6Cna7j1PRQ

[plexi50]

Looks and sounds great! Love them 5E3's.