The Eagle Supre - Big SE Amp

[RJ Guitars]

Thanks guys for the great insights, schematics, and general info. I love it when these threads take off and some great info is shared.

The grounds are setup in zones - I am not sure if I learned that from Randall Aiken or Jason Cox (Boozhound Labs) but this has been extremely effective in the Push/Pull amps. I had three zones (transformer center taps, preamp - Power supply filter. Now I moved the power tube cathode to it's own zone (should have been that way all along) and I also ran the wires from the filter caps back to a lug directly on the chassis. I also ran the Heater supply center tap to the output tube cathode.

Finally, I pulled the output transformer off and did the headphone trick with it... yes I know I should have done that before I mounted it. Eventually I decided to eat some crow and move the OPT... I know, I know, some of you had mentioned this earlier and previous success doesn't mean it was going to work this time. Crow tastes awful but I spose it could be worse!

I managed to do a reasonable job of making it all look good considering there were a lot of holes in the wrong place and it actually forced me to move the voltage switch to the front panel which cleaned up the internal wiring way perfect.

While I had the amp on the bench, I pulled off the V1a resistor and bypass capacitor and replaced it with a diode and .1uF filter cap. I know everybody is probably tired of hearing about Merlin, but it is another trick in his book that he mentions is a good tool to eliminate hum in the first gain stage. Somehow I was surprised it worked, didn't seem to make any difference in the sound of things, and at the point I couldn't tell if it reduced the hum any further or not.

All of the standard anti-hum technology tricks have been done and I've moved around wires and I think the search for tone can begin.

rj

[Structo]

Looks good RJ.

Funny (odd) about the transformers.

Hum can be very frustrating to track down.

[RJ Guitars]

Playing the Les Paul through this amp yielded a nice surprise. It was quieter for one thing, but the available tones were quite nice and this might just turn out to be a good amp for humbucker guitars. It sounded good enough that I was inspired to make a quick and dirty AV clip so you can hear rather than just get my description of things.

http://rjguitars.net/Eagle_Supre--Quick_n_Dirty.MOV

This is not pretty and I obviously need some audio equipment. I used the camera Mic which has some funky background noise and is slightly overdriven, but the character of the amp seemed to stay intact.

rj

[Zippy]

All of the standard anti-hum technology tricks have been done and I've moved around wires and I think the search for tone can begin.

Plug in the ASAT Jr.

How hot does that EL34 cathode resistor get? I'm thinkin' you might want to give it some more space and get it away from the bypass cap.

Looks cool. Looking forward to hearing some output tube taste tests.

[angelodp]

rj, have you got an updated BOM please.

Ange

[ChrisM]

Interesting indeed.

I see you have your IEC ground point sharing with some other grounds though.

[Zippy]

rj, have you got an updated BOM please.

Ange

Ange,

I tried responding to your PM but I keep getting the same error message.

If you'll PM me your e-mail address, we can chat.

Bottom line is that I don't have the "current" BoM nor do I know whether "current" = "final". RJ and I were on the phone yesterday and today I got an e-mail that the amp is growing a personality as it gets closer to sonic bliss. Best to be patient and let RJ get settled in with the amp.

Or... Work with the original schematic as there aren't that many parts in this lil' guy and be prepared to sub a few parts when you learn of RJ's final tweaks.

Or...

Be well,

George

[angelodp]

I have a question on the on/off switch. It looks like the PT wires that are meant to connect to the rectifier diodes are first attached to the on/off switch. ?

Is that switch for a on/standby/off setup? cannot make out exactly what that switch is?

A

[surfsup]

The PT RJ used has two options for the HT voltage from the PT. I don't remember the values but you have the option to use the secondary leads for a 300-0-300 PT or a 260-0-260 PT, I think.

So RJ put them on a switch so the user can just toggle between the two.

[angelodp]

Thanks for that. Now I recall the conversation about momentary issues when switching between the two leads.

[Zippy]

Thanks for that. Now I recall the conversation about momentary issues when switching between the two leads.

Just to be sure we're not confusing someone: There are two switches - a power ON switch and a PT secondary voltage selection switch.

[angelodp]

Of course, silly me I have that type switch in my Dlite. Thanks Zip for clearing things up

[RJ Guitars]

Interesting indeed.

I see you have your IEC ground point sharing with some other grounds though.

Chris, I was going to move the system grounds to another lug, but once the amp got quiet I really didn't want to make changes. I know that we refer to the IEC ground is the safety ground for obvious reasons. Is there a technical reason like system noise or other technical strategy to isolate the IEC socket all to itself?

rj

[HTH]

sounds really nice, love SE amps.

btw, that switch on the Dr.Z is likely to be a split-load plate switch on the second stage since it's a 'wreck-inspired amp (like the switch on the Komet)

[Zippy]

btw, that switch on the Dr.Z is likely to be a split-load plate switch on the second stage since it's a 'wreck-inspired amp (like the switch on the Komet)

To what post are you responding???