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I built two V6 amps a while back. One is for a buddy of mine. We have been fighting with the sound ever since. I have double checked both amps but I have been unable to find what I have done wrong that would be common on both amps. We never get the nice crunch everyone talks about and you hear on the sound clips. Having volumes on full (even the channels linked together) just makes it loud and kind of farty sounding. It also does not mater if we are using the El84's or the 6v6 outputs. Here are the voltages on one of the amps.

V1 pin 1 150v, pin 3 1v, pin 6 150v
V2 pin 1 180v, pin 3 1.5v, pin 6 262v, pin 8 180v
V3 pin 1 207v, pin 2 53v, pin 6 207v, pin 7 52v, pin 8 75v
V4 pin 3 12v, pin 7 343v, pin 9 330v
V5 pin 3 12v, pin 7 340v, pin 9 330v
V6 pin 4 330v
V7 pin 4 330v

Does anyone have any suggestions?

Voltages look very good.

Can you post a close up pic of the board? and the overall amp build?

Something must have changed since this viewtopic.php?p=6112&highlight=#6112

Could be the Toggle switch ?

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Thanks Coco. Here is a link, I hope, to some pics. Hopefully you can see something that I am missing. I am unsure if I ever got the same distortion levels othes are getting.

You mentioned a toggle switch????

http://s448.photobucket.com/albums/qq20 ... do-photos/

yeah, the one to switch the tubes sets in/out . Is it working OK? Are the contacts good? One builder had a problem with the wires at the toggle switch and it affected his tone.

How are the normal channel sounds?

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Coco, thanks for the response. The output tube switch checks out OK with a meter.

I played a Strat though the high inputs on both channels at various volume and master levels with the tone controls all at 5 and to be honest the sound on both channels never seems to change. Just gets louder when I turn it up. I always seems like a clean channel, although not a very smooth warm clean.

It's almost like the amp is not getting enough signal from the guitar to work properly, but what do I know.

I am not sure if the sound has degraded from the start or not so please don't rule out something I have done wrong from the get go. Also remember there is two amps in question here so again I am leaning toward something wrong with the builds.

Just after I posted this note I did find something wrong. The heater wiring polarity is reversed between V4 and V3-V1. Not sure how important this is but I corrected it but it did not fix the problem.

I am going to go through the amp one more time tonight to try and find what is causing my sound issues but I think I am going to have to start over and re-wire the amp. Is MOJO musical supply a good place to get parts? They don't seem to have the right hookup wire. Who is the best supplier for amp parts?

Also the pics of the Rackmount build sIII V6 are amazing. What workmanship..

Took a quick look athe the board. Looks good. Plus the voltages aregood, so pull the 6V6 and see what happens, if anything, on the EL84 channel.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Thank you so much

Don't panic and start rewiring. It's always something simple

Joe G

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Some assembly required,
Brain sold separately...

About 95% done rebuilding amp. Should be able to test voltages and try it sometime tonight. I did find a possible problem while re-wiring the rectifier area. Pins 4 and 5 on the rectifier tube were reversed. The white was where the yellow should be and visa-versa. I corrected. What do you think, if anything, this would do to the sound of the amp??

Thanks

Reversing those wont make a difference. It's 6.3VAC.

Let's hope there is an improvement!

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Finished the rebuild last night. Checked voltages (the same) and the amp sounds the same. Steve, can I bring the amp to your place for you to listen to it?

Commando (hmmmm)
When you rewired, did you also redo all of the coax cables, the inputs and also the "gain" cable. There is always a potential there for heat gun events...

Joe G

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Brain sold separately...

The coax cables were not replaced but they were cut back a bit and re-stripped with new heatshrink.

You must have tried just about all of the obvious stuff by now, but how about resistor and/or pot values (correct values in all positions), swapping tubes, guitar cables, speakers?

Joe G

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Brain sold separately...

Thanks for response. When I rewired I also took all the components off the board and reinstalled. The resistors I measured with a meter before putting them back in. The pots have also been measured. Tubes are brand new and I even replaced the tube sockets. Tried many cables and two different guitars.

The only section that was not completely overhaulled is the mains power (AC). Although rectifier and heater wires were redone.

Note: Even though I am working on one amp right now we are actually talking about two amps since I build another kit for my buddy around the same time and his is the same.

It must be something I did or not working that is common to both.

All ground busses and board jumper connections still soldered in place (and in the right places) after adding the components to the top of the board? Sometimes they can reflow and drop out of the turrets from the bottom.

You've tried removing one set of output tubes at a time... what else... Are they 12AX7 tubes and not a lower gain tube like 12AY7's??

Have you taken a good close look at the Cliff jack wiring? I work in a small production environment and I'm very good at making things exactly the same. Unfortunately if I make a mistake on the first unit the rest will surely be wrong as well The inputs are really the only "repeated" process in the amp, so some potential there for a repeated mistake.

Sorry we're sort of at a loss out here with only pictures to go by (and I can't even view them from work ). Maybe a visit to the Wizard is in your future

Joe G

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I double checked the ground bus connectons last night. I am sure I also checked the jumper connections but I will check them again tonight.

The removed the 6v6 tubes at one point last night but same result.

Input tubes are 12ax7's.

The Cliff jacks were completly rewired. I agree, this was the area I thought I most likely screwed up. I am pretty sure I have the jacks themselves wired up right. Although I did realize last night that I wired the normal jacks to the sIII input on V1 and the sIII jacks to the normal inputs on V1.

Could an on board capacitor cause a problem like this? Or how about the output transformer?

Agree, I probably have to go see the master and let him listen to the amp and A/B it with a unit he has. I would like to do this soon as this is driving me nuts.

Thanks for you help on this.

Maybe check the output selector switch and make sure that it's "tanged" and oriented the right way. Those can be confusing as well...

Try to think simple

I'll look at your pictures again tonight where I'm allowed to look

Joe G

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The output switch was replaced with a new one. I metered it out before wiring. I will take some new pics as the old ones are outdated.

Well if you do go see the boss, good luck getting through security at Trinity Corporate Headquarters these days with all of the fancy-schmancy secret projects they have going on I just hope that they (sniff sniff) remember us little people

Mr. C... I looked over your pictures last night and couldn't see anything obvious except for maybe some overheated coax cables. Make sure those are checked for possible center conductor to shield shorting, both the amps inputs and also the coax to the gain control. Other than that I'll wait for the new pics.

Try to keep calm, take it slow and observe the precautions while working this out.

Joe G

_________________
Some assembly required,
Brain sold separately...