trinityamps.com

Ok now that I have received the missing resistors, I can start my second build. You guessed it. A Tramp!

Specification:

6L6 power tube for now (I only play in my basement. And play is not the right word)
2 Jensen speakers. C10Q + C8R . Was Planning to build a two Stroke but changed my mind for the Tramp.
Slightly oversize cabinet to receive the two speakers.
Front 19.5" wide by 16.25" high
Top side 8"
Bottom side 10"
Will try to shield the heater wire to reduce hum the best I can.
Not decided on the Tolex color yet. Will see later.

Will post the progress here.

Let's get started with the box. Clear Pine of course.



Uploaded with ImageShack.us

Looks like you're off to a great start! Why are you expecting to get hum from the heater wires? That should never happen under normal circumstances, and you make sure to follow the official layout we've developed. In any case you would need to use a magnetic shielding material such as mumetal, if you wanted to shield against 60Hz (or 50Hz) hum being picked up, since it mainly propagates by magnetic induction at those frequencies.

_________________
Great tones come in small glass jars!

I just want to be on the safe side regarding to HUM. I used copper to shield. Same I use on guitar cavity. Hope it can help a little.

The box with the roundover bit used.




Front of the cabinet with the Baltic birch speaker "baffle?"



Back of the cabinet



Tramp logo in 3/16" aluminium i will put on the front Grill. 3.5" wide. Need some cleanup though.

Shielding the heaters will only bring issues to the amp. Co-axial cable is not going to change the fact that the filaments use a 60Hz AC voltage. Shielding is really to protect high impedance signals that are prone to pick up noise. You'd be better off shielding every other connection in the amp before shielding the heaters. If you really want to get anal about the heaters (which I don't think you need to do) you could make them DC type.

That said I would build the amp stock and go from there. It has a very low floor noise level.

_________________
http://pdfelectronics.com

Thank you for correcting me.

As you can see by reading my post, I'm far from an expert. I'm learning. I read everywhere that lead dress is very important, particularly with single ended amp. And that we must make great effort not to induce hum in the signal chain. So it seem to me a good idea to shield the heater wire to eliminate the problem at the source. I wasn't aware of the difference between RF signal or 60 hz, thinking a shield is a shield, my fault.

That said, I don't understand the point that shielding the heater wires could cause problem of his own ? Could you explain the problematic associated with that?

And some correction and addition to my specifications:

6V6 instead of 6L6 (typo)
Turret board instead of eyelet board.

Here some pics of what I did so far.

Shielding the heaters would be messy. Heaters are a pain to wire normally (not so bad in the Tramp though), just imagine how hard it's going to be with that extra conductor from the co-ax. Also most co-ax cable has an inner conductor not suitable for handling the filament current. I wouldnt want to draw the 2+A of current a KT** Tramp would draw with that little 24AWG inner conductor. The RG-174 in the kits is great for signal shielding but is not meant for heaters (or needed).

_________________
http://pdfelectronics.com

I can see what you mean. I builded a 18watts V6 and there were many heaters to route. But in that case (Tramp) do you think that what I made (see previous picture) using copper shielding could cause problem.

Pics of the turret board.

Cant see the pics, they are blocked for me right now.

The Tramp is low noise though. You'll probably be pleasantly surprised when you start it up.

_________________
http://pdfelectronics.com

I can't see any problems with your heater install. The tight twist will reduce most filament noise and the way you routed them would be sufficient. But now they can't move, and will stay where they were put.
Nice job on the turret board. But I don't think turrets are going to work that well for the mosfet.
Pics show good solid workmanship.
But as has been stated before, the noise floor is very low.

Do the pull switch pots outside the chassis and when you connect the flying tag wire makes sure it is long enough to go to its point on the turret board. Don't put a wire at the other end if you wire your board before you install it.
Same with the bias switch and the cliff jack. I do the output jacks before I install them as well.

Nice job on the cab.
What's the tramp logo done from?
Are the speakers selectable or always connected together?

Good luck on the build

_________________
Fantasy Noise is what my shop of dreams is called and was the only way to beat my addiction, like many here I suffer from G.A.S.


Tele's make the best noise

Like I said, the copper foil will provide zero benefit. You use it in guitars to shield against high frequency radiation that carries buzz. At 60Hz (or 50Hz in other parts of the world) it has no effect on hum, which propagates via magnetic induction. The way you have run your heater wires already, tightly against the corners of the chassis, is excellent, and you should expect no problems. However, the copper foil covering you've used looks nice and won't actually hurt anything. So now you've stuck it there you can leave it like that. From what I have seen the number 1 reason inexperienced builders get hum in their amps is from ground loops. In the Tramp layout we have taken a lot of care to ensure you don't get ground loops.


That is incorrect. SE amps are not more prone to hum getting into the signal chain than PP amps. SE amps are more prone to hum from power supply ripple, which in PP amps gets automatically cancelled out in the output transformer. Higher gain amps are more prone to picking up hum in the signal chain than lower gain amps. The Tramp is a lowish gain amp.

_________________
Great tones come in small glass jars!

kurtlives: Hope you can see the pics now. I don't know why sometimes they don't show.

Taz13: Thank you for the info about the build. I take note. The logo is made from 3/16" aluminium sheet. My neighbor is a welder so he have a bin full of leftover. I was thinking to connect the speakers serialy to achieve 16 ohms and use one jack only, leaving the second jack for maybe an external cab.

Zaphod: Thanks for the very clear explanation. Sometime I read text skipping word and exact meaning. Just to write this I must contunally check myself since english is not my first language.

Thank's again guys for supervising my job.

I would try first with each speaker with its own plug. That way you can see which tones you prefer.
I would also put a switch in so I could take the 8" out of circuit to give more flexibilty when plugging in another speaker/cab

looking great so far

_________________
Fantasy Noise is what my shop of dreams is called and was the only way to beat my addiction, like many here I suffer from G.A.S.


Tele's make the best noise

Good Idea!

I will do That. That way I could use the 10", the 8" or both. If I connect them in parallel I must use the 4 ohms positions on the switch. Do you think it will sound similar than using them in serial and using the 16 ohms tap? Silly question. I just have to try both and compare.

Thank's

Just remember always have a load on the amp whenever it is turned on

_________________
Fantasy Noise is what my shop of dreams is called and was the only way to beat my addiction, like many here I suffer from G.A.S.


Tele's make the best noise

Nice Logo, nice cabinet, nice wiring.
The Tramp is very quiiet in it's stock design. The additional shielding is really not required.
On the speakers, put them in Parallel OR use a jack for each speaker and set the impedance to half. (4 ohms).
How did you cut the logo? Scroll saw?
You will need to figure out how to connect up the MOSFET as Taz suggested. Turrets in that position wont help.

Looking Good!

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

You may still be able to shove the MOSFET leads up the turrets, just no visual way to verify that it's soldered correctly.

I've seen a particular 3-pin Molex connector with the correct lead spacing for this MOSFET package. I believe Roland used this approach on their power devices in the JC120. It would be nice to be able to plug/unplug the MOSFET for replacement, etc., easier to locate the MOSFET in certain installs as well.
Stephen, let me look into this and maybe I can offer a small "harness" or "pigtail" for VRM users since it requires a special handtool.

Joe G

_________________
Some assembly required,
Brain sold separately...

Yes a Scroll saw with a blade for non ferrous metal.

I pre adjusted the mosfet visualy and soldered it in place then I put the turret board in place and saw that I only have to enlarge the hole a little and i will use a nut and bolt to secure it to the chassis.

Don't forget to isolate/heatsink the MOSFET.

_________________
http://pdfelectronics.com

Very smart indeed! Yes, be sure the MOSFET is insulated from the Chassis!

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

With the speaker impedances, just remember that the output transformer's highest impedance output tapping has the best high end response. Having said that, if for example you have a speaker that sounds too bright, you may prefer to use a lower impedance secondary tapping, such as the 4 ohm one. Your ears have to decide on that, as well as the speakers you have available.


Your English is fantastic. I wish my French was that good, but over the years it has deteriorated through lack of use.

I really love that Tramp logo you made!

_________________
Great tones come in small glass jars!