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The "$250" Amp? - 6LU8 Compactron SE, UL

A friend built me the chasis's and it was his idea of different.

He was going to make me covers for them as well. I'd have been fine mounting them a in a traditional way.

I still need to mount them, its going to be interesting. :)
 
Well I'm usually all for unique, but in this case i'm not sure on the orientation of the toroid transformer. I know you were real concerned about quality because you told me you went through the trouble of acquiring the silver wire for the internals. But in this case i think, not sure, but think, you bit the big one on this because the most interference coming from a toroid comes from the top and the bottom of the tranny which is why everyone mounts them horizontally. In this case its not only in the bottom internals but now on the top and bottom components with that nifty wheel of death configuration. Normally steel is a good shielding material but i doubt you'll benefit from it at all in that orientation. Looks like that paint job turned out very nice though. :)
 
I agree that the worst stray field effect from a torroid transformer will be in an axis that is through the center of the transformer. Horizontal mounting seems to often be the easiest way to mount a torroid, but it also gives the benefit of throwing the stray field away from most of the other circuitry. I also agree that steel shielding helps mitigate stray field effects (hence why steel potting cans are so popular/helpful). Unfortunately the "Price is Right Wheel" mounting scheme defeats any shielding benefit of the chassis. I work in aluminum because it's so much easier to fabricate, when I use steel I like to maximize any potential benefit the material will give me. It must have been non-trivial to have those large holes cut in a steel chassis, and so perfectly. They look like great holes, that's quite an accomplishment.
 
While the interference will be as described by the others, there is a good chance that it won't be an issue. It's not uncommon to stack toroids on top of one another without any sort of issues. To be fair, that is usually with transformer to transformer interference. Not sure how destructive the fields would be when encountering passive parts/wiring.

They do look good. If they suck, you can always quote Happy Gilmore...."The price is wrong, bitch"
 
mashaffer said:
My build is going to part of a tri amp system so tone controls per-se are not needed but it would be kind of nice to have some treble cut available for over bright recordings. Any reason why a simple "tone control" could not be added from the VAS plate to AC ground? Best way to implement?

mike
Click to expand...

Sorry Mike I have no experience with tone controls, but I'd think anything used elsewhere would work here.
 
As to the toroids, from general consensus they don't emit as much stray signals/interference
as standard trannies so as DNewman mentioned it may not be an issue mounting them like that.
 
Thanks for the input on the amount of interference, or lack there of. Its good to know as the tranny's that rage is using on his build are the same ones i'm using on my next build, which is EL84 PP parallel mono blocks. Allthough, i'm guessing the interference will be less on my amp because i'm using some really heavy steel potting cases on my build, they sure do look cool. I have a couple 1 Farad caps from my old car audio days that may still be good, any thoughts about using them in my next build for power filtration?
 
I looked at a bunch of big caps from the car audio guys and all of them were built for very little voltage....so unusable for 110v amps. This might not be the case with what you have, but you should make sure before using them.

Speaker of Toroidal trannies, I have a couple of these left over from my chopper building days. I think they would look bad ass as a Toroidal cover. Cheers.

http://www.badasscovers.com/harleydavidsonaircleanercovers.htm
 
Wheel of fortune, wheel of death... hilarious!

Kenny G fabbed these up for me and it was his idea for being different. They do look cool but are proving to be a bit of a PITA to mount up.

If the interference proves to be an issue I'll build a small plate to bolt on the hole and mount it in a more traditional manner.

When they are actually bolted in they are 1/2-3/4" higher than in the picture. Also he originally planned on making covers for them sort of like a "tomb stone" for the the top.

Thanks for the feedback guys!
 
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djnagle said:
I looked at a bunch of big caps from the car audio guys and all of them were built for very little voltage....so unusable for 110v amps. This might not be the case with what you have, but you should make sure before using them.

Speaker of Toroidal trannies, I have a couple of these left over from my chopper building days. I think they would look bad ass as a Toroidal cover. Cheers.

http://www.badasscovers.com/harleydavidsonaircleanercovers.htm
Click to expand...

Good call Dennis, i bet you're right and they are too low of a voltage tolerance. I'll just have to find some other use for them i guess. As for the covers, those are bad ass!
 
My skills are debatable across the board! (most skilled with the art of destruction by accident)

I'm still using my camera phone. It's romantic mood lighting!
 
Also to everyone, I changed the title of the thread, $250 is a more realistic number to
shoot for here building this thing, and now that Edcor has the larger trannies with the
endbells and better specs for a few bucks more things do add up pretty quick.. :)
 
Toroidal transformers are designed to produce a weak magnetic field in their exterior because of the continuous wire winding around their core, that leaves no piece of the core uncovered by it. Conventional transformers have coils with a finite length and therefore two ends. The magnetic field is created in closed loop lines that cannot touch the wires. The net effect is that a coil has magnetic field lines that escape from the coil through their ends (the coil is like a magnetic dipole). The purpose of the transformer core is to concentrate the field inside it, but a few magnetic field lines eventually are located outside. The design of the toroid transformer tends to avoid this dipole effect by avoiding the ends (i.e., like folding a coil onto itself by joining the ends).
 
Thanks Keg... I'll be calling you in the next few days as I broke one of the 820 resistors in the final RC stage and also broke on of the 510 ohm resistors feeding the triode from the RCA input. :)

This has been one of the most fun DIY projects I've ever done. I can't put into words how cool it is to have scratch built my own amps and speakers. As much as I loved the econo-waveguide speaker project(s) I think I learned a ton more on this one!
 
I made due with a radioshack emergency visit however I don't have the "exact" values I need... Will be in touch! :)
 
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