Starting a Simple SE build...

[Ty_Bower]

I'm not sure what you mean by mounting the MR cap bracket under the chassis. Right now the clamp holds 2 L brackets which are screwed to the top plate.

Cut a hole in the plate big enough for the cap to fit through. Bolt the L brackets underneath the plate, rather than on top.

That's a really nice looking chassis, by the way.

Be sure to stick some rubber washers between the power transformers and the chassis plate, and between the plate and the nut, and underneath the head of the bolt. You want some kind of rubber bushing separating the power transformer from the chassis plate.

 

[nic6paul]

See if this makes sense. The red L's are your brackets. The blue is the band you tighten down to keep it in place. The silver is the top plate. All the mounting hardware is now under the chassis cleaning up the top a bit.

 

[rknize]

i did it similarly:

 

[oldmanStrat]

Very clear Paul... I'm not sure how I would cut that hole, my largest punch is a lot smaller than the MR cap.

RK - very nice! Looks like you are using the nut heads to hold the cap in... That jewel light looks exactly like the one I have - is it a DC light? How did you power it?

 

[rknize]

A cheapo set of hole saws works great on aluminum in a drill press if you go slow with oil.

I'll make some little tabs to grab the cap lip instead of just the nuts. The lamp holder is one of those generic ones. I got some 6.3VAC lamps, so I'll just wire it into the heater winding. More pics are here:

http://www.diyaudio.com/forums/showthread.php?s=&threadid=140978&pagenumber=2

 

[HEADinaJAR]

Hey rknize. What size holes are those for the output tubes? I'm starting with EL34s but I'll want to try other tubes in the future.

 

[rknize]

Input: 1-1/4"
Rectifier: 1-3/4"
Output: 2"

I wanted the output tube holes to clear the biggest 6550/KT88 tubes that I had. But to make it look proportional with smaller tubes, I made the rectifier hole larger than needed. At first I thought I went too far, but I think it came out OK.

Russ

 

[oldmanStrat]

Holy Cow Batman !

Ok, I have spent most of the morning wiring up the amp for basic triode mode with the transendar OPTs...

I powered it on - with sacrificial speakers and a spare iPod (hey it is a test) and nothing blew up. Once I realized that the iPod was totally useless as an audio source (it was wiped clean at work since we are using it as a video preview device) and I was satisfied that it didn't have mega-volts on the input - I brought it into my man cave.

First initial impressions were not exactly stellar. But that soon evaporated...

A little Stevie Ray, some Stones, a bit of Smokey - and a dash of Dire Straights later... Oh my.

This amp drives my Fostex FE166e horns to places its never been before.

Very nice George, thanks for the design work !

pics of the horror show of the initial build to follow... yes a few things that I didn't anticipate came up at the last second... we'll call it a beta test.

 

[HEADinaJAR]

That's great oldmanStrat! I'm starting to get excited! Hurry up Edcore!!!

 

[chrish]

If you mount the PC board so that the tops of the tube sockets are flush with the top of the chassis, you don't have to worry about hole size. Just make the hole the size of the socket and no problem with any tube you may choose.

 

[rknize]

Of course! I happened to like the recessed look, so that is why I did it.

 

[nic6paul]

Are you planning any finish on that aluminum. I assume it is just mill finish and has no chemical finish done to it? Looks fantastic!

 

[oldmanStrat]

here's the underside. I need to do some more cable management - a bag of zip ties should do the trick...

 

[oldmanStrat]

and a right side up pic.

You'll notice the ugly wood screws on the side of the chassis. Once I put the OPT's on the top plate the front part of the box started separating. The weight was just too much for the glue.

None of the switch plates are attached to the case, and it has yet to be varnished.

The damn thing sounds so good, I'm not sure I'll have the heart to take it all apart again.

 

[rknize]

LOL...that's why I purposely didn't wire mine when I test fitted everything.

 

[boywonder]

Not to threadjack, but I'm building a 2 chassis version of this amp with a multi-conductor umbilical cable between them, and my question is would it be better to put the choke and motor run cap in the PS module or in the amp module?

I'm assuming that the choke would be better off in the PS module, since it's seeing AC, but I'm not sure about the motor run cap.

 

[oldmanStrat]

thats fine, it's quiet here anyway... still waiting for the Edcor's to show up before I make more mods.

Looking at the schematics I'd leave the cap & choke with the power supply section - but the cap is so large it probably won't matter where it goes.

But of course, Mr Tubelab's opinion is probably what you were looking for not mine ...

 

[Ty_Bower]

Not to threadjack, but I'm building a 2 chassis version of this amp with a multi-conductor umbilical cable between them...

What are you doing for rectification? I'll assume you're going to forgo the rectifier socket already on the Simple SE board?

Be careful with 450 volts DC in the cable between the two chassis. Make sure whatever insulation you use is properly rated, and has adequate mechanical protection.

 

[oldmanStrat]

So this isn't really a reply to you Ty, but I've been running my amp now for four days... no hiccups - but I have noticed that it runs warm.

So the engineer in me decides to take my infrared thermometer and take some measurements.

All readings after 5 minutes of warm up (deg F) .

Ambient: 65
Power transformer: 112
Top aluminum amp plate: 92
OPT's: 77
EL34 tube heater: 328 !!
5AR4 heater: 254

After an hour:

Ambient: 69
Power transformer: 130
Top aluminum amp plate: 116
OPT's: 91
EL34 tube heater: 384 !!
5AR4 heater: 276

The 12At7 doesn't even glow, so no measurements...

These temps are pretty amazing to me (heater & other tube temps that I didn't list) since I come from the solid state world. Nothing that I can recall exceeds 120C for operating temps, but all of the tubes are running higher than that in a pretty cool environment.

Just thought I would share ... fun with temps.

 

[boywonder]

What are you doing for rectification? I'll assume you're going to forgo the rectifier socket already on the Simple SE board?

Be careful with 450 volts DC in the cable between the two chassis. Make sure whatever insulation you use is properly rated, and has adequate mechanical protection.

The chassis I'm presently building is for the Tubelab SE, followed shortly by the Simple SE, as I have both boards stuffed. I am planning on tube rectification for both. My umbilical cable is rated for 600V. I may end up doing one chassis for the simple SE; I haven't decided yet.

I suppose if I don't put the motor run cap or the choke in the PS chassis, it'll just be a transformer and a power entry module....