5e3 build project-need some help pls

[IBTom]

I've just completed a 5E3 kit. The kit is from Triode. It's my first build and I'm definately not a tech, by any means.

All initial tests were good, no smoke, no blown fuse, all tubes lit up nicely, very light hum. I gave it a solid 5+ minutes warm up time and tried out my guitar. No sound. I did some poking around with a bright light and magnifying glass and id'd a wire on one of the 6v6s had broke. I soldered it back on, still no sound.

I'm not sure where to begin in trouble shooting this. I've traced every wire from turret to final point to ensure I've matched the schematic. I've tested resistors on the board, and they all test to, or very close to thier intended value. I haven't began to test actual voltages yet, since my thoughts are that if voltages were not up to par, there would be other problems noted.

Any suggestions?

Thanks,
Tom

[ked]

The first thing I would do is check voltages to make sure you at least have voltage where it is should be. Check you input wiring, make sure it is correct and not grounding out the signal. Look at the solder joints, reflow anything that seems iffy. Make sure your tubes and speaker are good. You said you tested all the resistors so I assume they are correct and in the right location. Also, check the output jack, make sure it is wired correctly and grounded. If you touch the grid of V1 with a probe you should get a pop through the speaker. HTH.

Ken

[hasserl]

Yeah, make sure the speaker jack is wired correctly, as well as the speaker you're running it out to. I would do that first, before you spend a lot of time running the amp troubleshooting it with no load applied, if it is a mis-wired output. If you're certain all is right there, than start the voltage checks. If all voltages look correct I would follow the signal path looking for where you loose it at. You can start at the input jack and follow it through the amp, checking all connections, or start at the output tubes and work your way backward. As you probe the connections/components in the signal path there should be static noise out of the speaker each time you touch a connection. This is where a signal generator comes in so handy, inject a signal into the front and trace it through the amp step by step looking for the source of trouble.

If you have no signal generator and scope, you can make some cheap troubleshooting tools with info listed here: http://www.el34world.com/Hoffman/tools.htm BEfore I got a signal generator and scope I fixed a lot of amps just getting creative about how you go about it. Think it through, step by step; take your time and don't panic. When I'm having trouble with a particular project I find it helpful to just get away from it for awhile and stop thinking about it, then when I come back to it later often times I find the culprit right away. Funny how many times that happens.

[IBTom]

Thanks for the tips guys. I'm a mechanic by trade so trouble shooting for me typically takes a methodical approach, just not sure where to start applying my efforts in this new realm. Venturing into the world of electronics is my attempt to demystify some of that "magic" and get a cool sounding amp that I built myself. I'll press on with your help and let you know what I find out.

I'm going to ask a question that will seem real simple and perhaps stupid to some, but here it goes:

Since you guys mentioned checking my speaker jacks to ensure they're wired correctly...... My diagram indicates one point on the output jack as a G and the other as a T. In my mind, the G is the ground and the T is the tang.

The input jacks have a G, T and an S. Applying my logic above, I can , or think I can, figure out the S position.

Am I correct in my assumptions? If not, that could explain my entire problem.

Tom

[hasserl]

Sounds right to me, but typically I see these labeled as Sleeve and Tip, the S should be for Switch. Doesn't your output jack have the switch? It doesn't have to to function, but Fender's usually do, the switch being connected to ground so that if nothing is plugged in the circuit is completed to ground, which is preferable to being open.

[drgonzoguitar]

Thanks for the tips guys. I'm a mechanic by trade so trouble shooting for me typically takes a methodical approach, just not sure where to start applying my efforts in this new realm. Venturing into the world of electronics is my attempt to demystify some of that "magic" and get a cool sounding amp that I built myself. I'll press on with your help and let you know what I find out.

I'm going to ask a question that will seem real simple and perhaps stupid to some, but here it goes:

Since you guys mentioned checking my speaker jacks to ensure they're wired correctly...... My diagram indicates one point on the output jack as a G and the other as a T. In my mind, the G is the ground and the T is the tang.

The input jacks have a G, T and an S. Applying my logic above, I can , or think I can, figure out the S position.

Am I correct in my assumptions? If not, that could explain my entire problem.

Tom


G = Ground
T = Tip (of the jack)
S = Sleeve

It sounds like when you insert a 1/4" male jack, it should break the short between the sleeve and tip. Once this is opened, your input should work. In this picture "Ring" and "sleeve" are interchangeable terms.
http://www.smallbearelec.com/stores/sbe/catalog/12A.jpg

The "half-split" method of troubleshooting works for electronics too!


Take a few pics and post them on the jack if this doesnt help.

[IBTom]

Improvement, however so slight still constitutes progress, right? So what I"m understanding based on all your imput is that per drgonzo's pic, the NC position is a normally closed switch. I examined my input jacks and found that I had wired my ground to the switch and then the switch to the next inputs switch, rather than ground. I de-soldered all four inputs and re-ran them and attempted a test. My achieved results are I now can hear crackling from the speaker when I slide the cord tip into the jack. Didn't have this before. I get a very slight click when I toggle my pup selector switch. My hum is slightly louder than before, though still low. It does increase though when I turn the tone control up to 10.

Tomorrow night I'll begin reading out the tubes, unless you have any more suggestions.

Thanks guys!

Tom

[phsyconoodler]

If you made that mistake on the output jack,you made it on the input jacks too.

[sdgvintage]

Send me some pics, I help people troubleshoot their 5e3 kits all the time.
Get my email from my website.

[IBTom]

My amp is rockin! :RoCkInThanks for the help guys! I started checking continuity in each lead and found what was supposed to be an input to preamp V1 point 7 was actually soldered to the output point on the back of the board. Yep, I reversed them while building.

Amp sounds good. Hum is a little louder now than I'd like and there is a high pitched squeal when any of the controls are turned past 9. When I hit 10 the amp goes silent. Any thoughts on this one?

I'll play with it a bit, then re-run some of the leads to clean it up a bit and tighten up the twists to see if I can reduce the hum.

My first amp build! There's certain to be more in the future.

Tom

[Trout]

Amp sounds good. Hum is a little louder now than I'd like and there is a high pitched squeal when any of the controls are turned past 9. When I hit 10 the amp goes silent. Any thoughts on this one?


That is commonly associated with reversed primarly leads on the output transformer, try flipping them.

[phsyconoodler]

No.An amp with no negative feedback doesn't care where the leads are.
You still have some grounding issues.

[Trout]

No.An amp with no negative feedback doesn't care where the leads are.
You still have some grounding issues.

Actually,,

I have on several occasions had that problem come across my bench. High frequency oscillation caused by reversed primary. In fact, I have seen it happen on a couple SE amps as well.
And yes they were non-negative feedback amps.
It is generally a result of poor quality transformer inductance issues.

One unit I worked on that comes to mind instantly was a 5E3 that used the same OT from Triode Electronics.
I suspect it was due to the fact that the color coded wires were reversed internally. Simply reversing the blue and brown wires cured it of squeel. Also, when it was wired wrong, the amp would go into cutoff when the knobs were above 9.


The no negative feedback thing would apply if the negative secondary lead was lifted.

edit, by his description I do agree he also has a grounding scheme issue as well.

[IBTom]

I've scrubbed through the entire unit. Re-ran my wires to the preamp tubes to clean it up a bit and ensure that I didn't have any obvious areas for the hum to be generated from. Also relocated my power supply cord to get it out of the chassis immediately and away from the rest of the wires.

No change except the hum is now louder. I'm not finding any areas where there are ground issues.

I tried the reversing of the brown and blue leads. Bingo. Squeal stopped. Loud hum remained. I can run the volume all the way to 10 now, except that my tone control doesn't work. When I dial it above 2, the amp quiets. Hit 5 and it begins to break and crackle, and that's without playing a chord.

You guys have been a huge help. Any more thoughts?

Tom

[Trout]

I've scrubbed through the entire unit. Re-ran my wires to the preamp tubes to clean it up a bit and ensure that I didn't have any obvious areas for the hum to be generated from. Also relocated my power supply cord to get it out of the chassis immediately and away from the rest of the wires.

No change except the hum is now louder. I'm not finding any areas where there are ground issues.

I tried the reversing of the brown and blue leads. Bingo. Squeal stopped. Loud hum remained. I can run the volume all the way to 10 now, except that my tone control doesn't work. When I dial it above 2, the amp quiets. Hit 5 and it begins to break and crackle, and that's without playing a chord.

You guys have been a huge help. Any more thoughts?

Tom


Hey Tom, Glad we cured the Squeel,

Is there any possibility you can post a few pictures? Generally on a 5E3 build a couple photos and the guys here can spot the problem fairly easy.

[IBTom]

After looking at some other wiring jobs online, I see where I'll need to unwind and re-run that mess coming out of the power transformer and the two green lines from the pilot to the filaments will need to be twisted up good too.

What else can you recommend based on the loss of tone mentioned in my last post?
I couldn't get the photo's to post directly into the reply, so here's links to them in photobucket.

http://i406.photobucket.com/albums/pp145/tandt99/DSC_0005_edited-1.jpg
http://i406.photobucket.com/albums/pp145/tandt99/DSC_0006_edited-1.jpg
http://i406.photobucket.com/albums/pp145/tandt99/DSC_0008_edited-1.jpg

Tom

[tybone]

You might want to feed your information back to the triode folks for future reference.

[IBTom]

My two sets of 68k resistors on the turret board, input side, after the jacks and feeding to the V1 preamp tube positions 2 and 7 are both reading 34-35k. All other resisters read what they should. The color codes are correct. Could this be part of my problem??

Thanks,
Tom

[hasserl]

Did you use the brass grounding plate for your grounds?

Does your power transformer have a center tap for the filament circuit? How is it grounded?

[phsyconoodler]

No.When two 68k resistors are in parallel like that they read half the resistance.That reading is normal.
I can't tell by the pictures if you have a grounded heater centre tap or a pair of 100 ohm resistors.
I find the biggest area of grounding that causes 5E3 problems is at the filter caps.The original wiring layout is correct and guys often not do it that way for convienience.Well it ain't convienient if it hums.
Your filament wires need to be in sync with each other too.Pin 2 to pin 2,pin 7 to pin 7 on the power tubes and the same on the preamp tubes.Pins 4 & 5 to the same on the next tube.
Also running wires so they lay on the chassis is better than up in the air,except for heater wires.They can be either way.
The input jack wiring is the most confusing thing about 5E3's and if they are wrong the amp hums or may not even work.
Go to www.hoffmanamps.com (http://www.hoffmanamps.com) and look in his libray of information on how to wire up hi/lo jacks.
And finally,cheap jacks go a long way to making problems.Use switchcraft only if you want good performance.Weber of offshore stuff is just plain useless.
In the second picture I see a green wire with a white stripe.Is that grounded?

[Trout]

Here is the wiring layout that Triode uses for their 5E3 Component kit.

As you can see, well sort of see, the OP followed it pretty much as shown.
The kit/drawing shows a crude attempt at star gounding. The biggest problem I see would be the long gound leads.
The PT has a center tap, so the 100 ohm resistors are not needed on the 6.3V supply.

He might do well to use a ground buss simply due to the lack of a brass grounding plate.
I would use a shielded wire from the volume pot to pin 3 of V2, that lead tends to pick up noise easily.

http://site.triodestore.com/5E3_Layout_Diagram.bmp

[Trout]

My two sets of 68k resistors on the turret board, input side, after the jacks and feeding to the V1 preamp tube positions 2 and 7 are both reading 34-35k. All other resisters read what they should. The color codes are correct. Could this be part of my problem??

Thanks,
Tom


Hey Tom,

The layout that came with the triode 5E3 kit does not follow the original especially well. There is a lot of un-needed complication which IMO is adding to the problem.

If you are up for the challenge, I editted the layout to eliminate the extra wire, and generally speaking cleaned up the grounding.
It would however require removing the board and essentially start over because some of the wire under the board is removed.

Let me know, and I will email you the file.

Ed

[IBTom]

A buddy of mine recommended this site to me quite some time ago. You guys are incredible. I'm very amazed at the amount of patience and help you've provided. Thank you!!

All jacks in my rig are switchcraft and the pots are CTS. There's not a brass grounding plate or bar, but there's going to be. Trout has offered up some re-wire guidance and I'll give that a shot and see how it plays out. Will probably be a few days before I get it done though.

I'll let you know how it works out.

Tom

[hasserl]

Yeah, I've found out the hard way that the brass grounding plate is the way to go. I had to undo a star ground system and use the brass plate and my hum issue went away. It may be counter intuitive, but in those Fender style amps it just plain works.

[skipm45]

I've scrubbed through the entire unit. Re-ran my wires to the preamp tubes to clean it up a bit and ensure that I didn't have any obvious areas for the hum to be generated from. Also relocated my power supply cord to get it out of the chassis immediately and away from the rest of the wires.

No change except the hum is now louder. I'm not finding any areas where there are ground issues.

I tried the reversing of the brown and blue leads. Bingo. Squeal stopped. Loud hum remained. I can run the volume all the way to 10 now, except that my tone control doesn't work. When I dial it above 2, the amp quiets. Hit 5 and it begins to break and crackle, and that's without playing a chord.

You guys have been a huge help. Any more thoughts?

Tom


As far as hum, what kind of grounding scheme did you use?
and, yes, some pictures would be helpful.
I like using a modified star ground system in a 5E3 style amp
Many paths to the same end

Skip
www.skipzcircuits.com (http://www.skipzcircuits.com)

[Trout]

As far as hum, what kind of grounding scheme did you use?
and, yes, some pictures would be helpful.
I like using a modified star ground system in a 5E3 style amp
Many paths to the same end

Skip
www.skipzcircuits.com (http://www.skipzcircuits.com)

The OP used the triode electronics layout I posted above, It uses a star ground type scheme, just not an idea arrangement. I suspect he has a couple other possible problems** due to the tone pot not working.

** I have on 3 occasions had to replace the silver mica cap on tone pots which gave the same symptom.

I sent him a bunch of front/top/bottom photo's of a quality board loaded and ready to install as well as links to other pictures detailing better filament wiring.
Give him a couple days to re-wire and he should have a real tone monster.

Hey Skip, I checked out your site, that is a pretty nice looking VVR module you have there. How is the fixed bias version coming?

[Curly]

I'm not a tech ... but I'd check the wiring on the input jacks and the volume & tone controls.

when wired correctly, the volumes are interactive, even if not "jumped" ... that is, the secondary volume will affect the volume of the channel you're plugged into

[IBTom]

Yesterday afternoon, around 4:30 I suppose, I broke out my gear and set up for surgery. I removed the chassis, cut all the wires and pulled the board free. Following Trout's guidance, piece by piece, wire by wire, I rebuilt my amp. At midnight thirty I was ready for my first test run. Since I was rewiring this monster, I put the blue and brown wires back to their original location to see if that problem was caused by me or the OT. Ever so carefully, in a determined attempt not to wake the Mrs, I begain playing with the knobs. Holy crap, when I turned the tone knob, it squealed so loud I'm surprised the whole neighborhood didn't jump out of bed. Quickly, I removed and swapped the blue and brown wires again. One more time for a quick test. All sounded good enough to clean up and get some rest at 1am.

AFter about an hour of playing around this evening I must say, I'm happy. Pretty freakin' happy indeed. No annoying hum. My tone control works. My volume controls will go all the way up and not cut out.
And I've learned a lot.

Thank you. Thank you. Thank you. I'm heading back out to play some more.

Tom

[Trout]

WAY TO GO TOM!!
:AOK:AOK


Just wait my friend, Now your hooked!!

Do not avoid the temptation, start saving pennies for the next one.

Hmmm Bandmaster? Or Maybe a 18W 1974X? Or Hey I know,

A HIWATT!!:bow

[hasserl]

Congrats Tom!

[skipm45]

.

Hey Skip, I checked out your site, that is a pretty nice looking VVR module you have there. How is the fixed bias version coming?

Hey Trout,
Thanks for the kind words.
I have a proto of the fixed bias version running on the bench. Bias tracks the B+ very smoothly. Currently it's a "frankenboard" with the bias regulator wired into an existing VVRX board and a new bias supply bugged onto the whole mess.
Here are a few *action* photos running a Weber 6M45. It's pretty ugly (don't say I didn't warn you:)) but it works well.
http://i246.photobucket.com/albums/gg106/skipm45/VVRFX/DSCN1382.jpg
http://i246.photobucket.com/albums/gg106/skipm45/VVRFX/DSCN1391.jpg
http://i246.photobucket.com/albums/gg106/skipm45/VVRFX/DSCN1392.jpg
http://i246.photobucket.com/albums/gg106/skipm45/VVRFX/DSCN1393.jpg
http://i246.photobucket.com/albums/gg106/skipm45/VVRFX/DSCN1395.jpg

The tiny amount of non-linearity is not audibly discernable.
I'm about a month out (give or take a week) from offering it as a product.


Sorry about hijacking the thread

Skip
www.skipzcircuits.com (http://www.skipzcircuits.com)

[bmcmusic]

Two things come to mind. Regarding the tone control post #3 goes through a .005 cap to ground. If you have also grounded it to your volume or star ground, it will no longer behave like a tone control.

Did you use sheilded cable from the inputs and the volume? They only get grounded on one side. Did you use a star ground system? I usually star ground the the filter caps to the preamp side and all input and volume grounds ect. to a point farthest away from the transformer and the filter caps to the power and the cathode to a point on one of the transformer bolts.
You might check hoffmanamps.com I believe they have something regarding star grounding your amp.

Good luck. I am sure you will get to the bottom of it. We all here to help.

If you are really having trouble, email me and I'll give you my number and you can call and I'll see if I can walk you through it.

Bob
www.mcmusicsound.com (http://www.mcmusicsound.com)