trinityamps.com

I was lucky enough to score a Tramp kit from someone who built it, couldn't get it to work and started to disassemble but lost interest. Most of the amp was still together but he'd started to take parts off the board while debugging. Everything was included so now I get to dig in and see if I can find what's going on! I've been running a pedal building business for the past year so know my way around circuits, but this is my first venture into the amp world and the high voltages involved. Wish me luck!

http://www.stuntmonkeypedals.com/pics/tramp/01.jpg
http://www.stuntmonkeypedals.com/pics/tramp/02.jpg
http://www.stuntmonkeypedals.com/pics/tramp/03.jpg
http://www.stuntmonkeypedals.com/pics/tramp/04.jpg
http://www.stuntmonkeypedals.com/pics/tramp/05.jpg

It even came with a funky box
http://www.stuntmonkeypedals.com/pics/tramp/00.jpg

I hope I can figure this out... I've been wanting something fun to test my pedal builds through!

I recognize that amp!
Good luck with it.

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http://pdfelectronics.com

Ditto. There were some layout changes with the latest board so be careful but the design worked.
It was a great looking build and we were unable to make it go in our limited amp camp.

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

I followed the latest layout/schematic so didn't bother with the old stuff. I got it up to speed with the bypass resistors and rewired the missing parts from the board but managed to pull one of the leads off the .01uF capacitor! The closest I had was a 600V .022uF Orange Drop so I stuck it in the spot on the right side of the board.

The only discrepancy I found was the output transformer connection... notice in Pic 2 above that the brown/yellow is capped off. I swapped it for the brown/white and got to examining and resoldering everything else.

Voltages were decent so I tried to fire it up and things got weird. It warmed up and started to make some noise but only at max voltage, then would sputter and die when I started playing too quick, but play okay going slow with single note runs. Changed tubes and the same thing happened, but I noticed Volume/Tude knob didn't affect volume at all. I checked again and found that I'd forgotten to solder up the ground on the pot.... oops!

Straightened out my rookie error and let it warm up again... It's now running perfectly with very little buzz or other unwanted noise. The VRM works perfectly and the sound is fantastic!

http://www.stuntmonkeypedals.com/pics/tramp/06.jpg

http://www.stuntmonkeypedals.com/pics/tramp/07.jpg

http://www.stuntmonkeypedals.com/pics/tramp/08.jpg

http://www.stuntmonkeypedals.com/pics/tramp/09.jpg

I've been playing with it for the past hour ad no issues at all. Can't wait to hit it with some pedals! The rest of the house is asleep so that will have to wait.

That was fast!

_________________
http://pdfelectronics.com

Pretty sure the original owner intended to use the amp with an EL34, that's why the 2K5 (brown/white) OT tap was used.

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http://pdfelectronics.com

Very good. Did you actually find the original problem or just rebuilt and away you go.
Yes, I think EL34 was the plan.

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

He included an EL34 so that makes sense. I basically rebuilt it and added the removed parts + the 220k resistors across the caps. The only other notable things:

1) I reflowed the solder on the entire board and a few of the chassis and socket connections. Most looked fine but a few were suspect.
2) The push/pull pots are dual gang in this kit... on the Vol/Gain/Tude he had the 220k resistor bridging both sets of lugs and I used the forward lug to attach the wire to the board. When I noticed I had missed the ground, I bridged the shield and input forward to both sets of lugs as well..but that shouldn't affect anything??
3) There was one bit of wire overhang on one of the heater wires on the main chassis power ground tag strip that I thought was overly close to shorting out so I bent the wire away just a hair.
4) I pulled the tags on the back of the VRM pot out a bit as those wires looked a bit too close for my tastes.

I'm inclined to thinking the reflow and possibly something on the side of the board the original builder already disassembled was the culprit. All parts tested proper values except the 220k on the Tude switch; it rang it at 160k. I'm going to go back through and trace continuity again to see if anything stands out. It's working fine but I'm a bit paranoid when it comes to working on other people's circuits; most of the wiring remains intact from the previous builder and it looks fantastic, but worth another look anyway

2.
If both sets of lugs are connected together then your putting on "pot" in parallel with the other "pot". Your 500K pot is now 250K. This leads to less drive/gain.

_________________
http://pdfelectronics.com

Hehehe, I should think before I type.

Were these latest layout changes incorporated in the design we built at the amp camp?

It all happened after amp camp John.

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

I went through and cleaned up a few of my own hasty connections and wiring paths, separated the Gain/Tude pot tabs so it's all on the one set of lugs.

Before the Tramp, I was using a Vox Night Train, then moved to a couple Epi Valve Juniors for the simplicity but this thing kicks all their asses! It's amazing how easy it is to dial in great tones; there just doesn't seem to be any bad sounds coming out of this amp. It takes to my pedals in stellar fashion as well, so it's perfect for my needs

I wish I could pinpoint where the original build went south, but the only thing I can surmise without any more details is a bad solder on the board somewhere.


A few quick questions as I'm new to amps; (I just combed through the forum and found a lot of answers)

1) Having replaced the C2 cap with a .022 in place of the .01 uF will change the circuit how? More bass through? Will it be a significant change from the design and intended tone? (Should allow more bass)

2) I built the switching exactly as described in the layout, so just to be sure with the tube selection switch; switch down is 6V6 and switch up is 6L6? This picture shows the switch (kinda). Are there any other mods needed to swap the 6V6 for a 6L6 or does the standard layout do the trick? (Will work as such)

http://www.stuntmonkeypedals.com/pics/tramp/02.jpg

3) When switching to an EL34, is the transformer hookup the only change? (Beautiful link to a cool solution; alternately using a DPDT would work but be less elegant)

4) How do people typically attach the amp chassis to a head? I'm sure there are endless ways to do it but I'd like to have quick access to pull it out, but enough security that it stays put when I'm moving it around or playing with the controls. I'm thinking of maybe a retaining bar screwed in behind the chassis to keep an anchor from backward pressure and maybe some tighter fitting shims on the sides to keep it in place. (my rail idea will work fine in thi head, looks to be a completely individual design thing)

I'll be going through the forum as I'm sure these questions have been asked before. Going to be away for the weekend but will be back to playing with the amp on Monday.

1. Yes with the larger coupling cap you will have more bass. Go back to the 0.01uF that is stock. This amp along with the values were carefully designed.

2. In your pic down is 6V6 and up is 6L6. The 6L6 mode connects both 5W power resistors and the big blue cap in parallel.

3. For EL34 use 2K5 impedance on the OT primary and use the 6L6 bias setting. That thread you linked to details this.

_________________
http://pdfelectronics.com

I went ahead and soldered up the selection switch as per the link for the 4/8/16 with 2k5 and 5k and am trying out the EL34. I think I prefer the 6L6 for general playing but the EL34 seems to have a certain crispness to it when I throw a bunch of distortion at the amp!

Next up I'm planning on getting some KT66/88s and see what they sound like... I also have a bunch of oddity 6V6 tubes from eBay coming soon. I'm loving the Tramp, it's completel replaced my Night Train and Epi Valve Jr. I'd also like to roll a bunch of 12A#7 tubes through the combos to hear what happens. Running my 12AU7 boost pedal (Tone Grenade) into it can give some killer clean boost all the way up to crunchy rock sounds with the tubes I've tried so far, the 6V6 being the least crunchy and the EL34 getting near some of the big hair stuff from my childhood!

I found this quoted in this thread:



Just want to make sure it's correct as per the latest schematic / layout for the KT66/88 tubes? I'm going to print this on sticker stock and put it inside the head.

You got it!! As for mounting a head, there are (or should be) 4 holes in the top deck of the chassis. Drill 4 mtching holes in the cabinet and put 4" long 3/16" bolts through the cabinet and up through the inside of the chassis and put a locknut on the top outside. Sounds harder than it really is.

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

I was looking at those holes... I was mostly afraid they came close to the hi V areas but I shouldn't be touching those bolts unless I'm unplugged anyway!

I also got to my tube rolling and found that the Volume pot is messed up; the wiper lug is not connecting proper on the housing of the pot and when it get a little stress it'll cut in and out. I checked the wire and it's secure and soldered well, the noise and issue is on the lug itself as the whole thing moves when I tug on it a bit. I don't know if it got some solder inside or was overheated and damaged...don't know if it was me or the previous owner and maybe it was even the cause of his issues... I'm going to try the second set of lugs tomorrow to see if it goes away!

I was rolling some tubes through the amp (more on that later) and noticed a really low level crackling/static noise when everything was idle with the 6L6 in place. It sounded like a bad cable so I started there... unplugging the main cable and the sounds persisted; moving the shielded wire caused the amp to buzz loud and die, moving it the other way eliminated the crackling and increased the volume and that's when I noticed the lug issue. I was able to put a bend in the shaft of the lug, enough to keep it from wiggling about and the volume sweep increased immensely! I think I'll have to re-roll my tubes to see if I get the same results.

With things as they are, I found the biggest difference to be in the preamp tube. I tried some Sovtek 12AX7s and found they were a bit tighter than some Made In China tubes, but not overly different... an Electro Harmonix 12AX7 was a world of difference though! Immediately it was smoother and fuller with way better articulation and differentiation from neck to bridge (Les Paul) positions! The Sovtek and Chinese tubes were quite flattening of the entire range in comparison and the sound didn't change all that much when I switched pickup positions. I was only able to try a Sovtek 6V6 with the Vol pot monkey'd together and it was amazing with the EHX and some humbuckers!

Here's a pic of the chassis mounted in my Tramp's head cab as per Stephen's description, you can see the long bolts + nuts at each corner. Underneath the cab they also pass through the rubber amp feet that the cab sits on.




Snowy

Best combination I heard so far was with a 6L6 was a Winged C 6L6 and Tung-Sol 12AX7. Awesome.
Brent @ Sly-Fi Chapel Studio uses that combination.

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

Just a quick update, I moved the wiring to the second set of lugs that were previously unmolested and all the issues have disappeared. She's purring along very, very nicely now. I'm waiting for some interesting tubes to come in to do my next round of tube rolling.

My batch will include various 6V6, 6L6, KT88, EL34.... and a few EL84s!! Can't find any decent priced KT66's yet, but I'm on the hunt.