The Eagle Supre - Big SE Amp

[mrvfr]

Well - while messing with the chords to "Louie - Louie" today, I missed the UPS truck driving up, but heard the doorbell and found another Eagle S has landed - well packed and mech. pre-assembled. Oh boy - thanks RJ !!
- any more tips appreciated -
I found on some kit site where assembler recommended using a high-liter and highlighting each component and path as one solders each one and when the circuit diag is fully highlighted then you're finished !! - he also recommended having old tubes in the sockets when soldering ? (won't have old ones so will look into that).
Gotta be traveling this weekend so it's gonna sit for a bit - need to finish reading neets on tubes anyway.

[rogb]

I have just fitted the grid/plate changeover switch and it has been working fine for an hour, changing over from el84 to JJ6v6 every now and again. Trannys are running cool and even with 160mA HT and mains fusing, no problems so far. I'm happy with this mod

Sweet! Could you post of pic of it wired up? I'm interesting in seeing it.

Aaron

I could but the switch is right underneath the rear panel switches mounted next to and forward of the el84 socket in a very tight build, heater wires overhead too.
It would be hard to see anything constructive. On this little baby 12" chassis, I have MV, VVR, pre-amp volume, HRM, PAB, mid-boost, to name a few
To say it is crowded is an understatement, it only fitted in because I removed a bias pot and test points that were there unused.
I can describe the wiring exactly for you on the DPDT switch:

Center poles: the wire to the OT and the wire to pin 2 of the el84 from the plate of v1b or v2 via 280K resistor.

EL84 poles: pin 2 and 7
6V6 poles: pin 5 and 3

It's as easy as that, just make sure you have enough juice in your PT for the extra tube's heater etc

Just an update on this mod, in my very cramped 86 Special build, I have been getting quite a few pops and crackles with this power tube switch mod, so I have gone back to 1 tube at a time, and the quietness is back. Seemed like a good idea though and may well work on other circuits, with maybe more space or less gain. Maybe a cap on the switch may help? Any ideas?

[Structo]

Well - while messing with the chords to "Louie - Louie" today, I missed the UPS truck driving up, but heard the doorbell and found another Eagle S has landed - well packed and mech. pre-assembled. Oh boy - thanks RJ !!
- any more tips appreciated -
I found on some kit site where assembler recommended using a high-liter and highlighting each component and path as one solders each one and when the circuit diag is fully highlighted then you're finished !! - he also recommended having old tubes in the sockets when soldering ? (won't have old ones so will look into that).
Gotta be traveling this weekend so it's gonna sit for a bit - need to finish reading neets on tubes anyway.

Yes that can be helpful for the first time builder.
You just need to make a plan and stick with it.

I like to make a poster sized layout of the amp I am building.
Most printers have this option when you look into the properties.
I print the layout on four sheets of paper, then tape them all together to make a larger layout poster.

Like mount all the pots, switches, sockets, hardware, etc. to the chassis.
Build the eyelet boards and install components on them.
Bend the leads on the back of the board to keep the components from falling off.
After you solder them, clip the leads short.
Be sure not to solder any eyelets where wires will go

Solder flying leads of the correct wire to the boards with sufficient length to reach their destinations.

If you install the transformers last you may find it easier to handle the chassis without the awkward balance the transformers create.

The part about plugging in old tubes is to make sure that the pins of the sockets don't get plugged by too much solder that has run down the pin.

If that happens then you can't install the tube.
Just pay attention when soldering the socket pins and don't apply so much solder that it runs down the pin.

Before you install the boards, do all the pot wiring and socket wiring that can be done.

I like to use Teflon insulated wire because it doesn't melt back when soldering.
Same with Teflon shielded cable.

[blues junkie]

Hey guys,

I'm putting all the components on my board and I noticed that the board is almost touching the input jack, which makes it very difficult to run my grounds past the input jack. I was wondering if I should just rout the ground wire under the input jack?

Any help on this would be great.

Thanks.

[angelodp]

Should be ok. You can find some early pics in this thread that address that area.

[RJ Guitars]

Yes Ange is correct, there should be some documentation on that. You can put the wires under the jack in the way you mentioned and it should all work out well. In the next iteration I've moved the board another 1/8th inch further out to make it a little easier. Keep the reports coming. I learn something every time somebody builds one of these things. rj

[blues junkie]

Hey Guys,

I got my board loaded and was wondering if I can get a set of eyes to see if I made any mistakes.

There dry mounted right now. I don't have all my leads on it yet... but that will me next.

Also on the white coupling caps, I don't know if there orientated correctly. I did'nt see any way of telling which side is - & + or does it matter?

Also I still need to bridge the 2 coupling caps together and the 2 100k resistors and the 47uf cap to the diods. I got a piece of buss wire and was wondering if I should use that or just use the leads from the caps and resistors and bridge them from the under side.

Sorry for all the questions.

Thanks.


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[surfsup]

So far so good dude...

[blues junkie]

So far so good dude...

Hey, Thanks alot surf.

[Structo]

Film caps (the white ones) are non polarized, meaing they don't have a + or -

But many of us like to put the foil end of the cap towards the lower impedance side of the circuit.
It is believed to lower the noise floor.

Here is some talk about it and how to detect the foil side.

https://tubeamparchive.com/viewtopic.ph ... light=foil

[M Fowler]

blues junkie,

Your on a good start, take carefully slow and most of all-enjoy the experience.

Mark

[blues junkie]

Hey Guys, thanks for all the input.

Structo, Thanks for the link. I now understand how to position the non polorized caps.

I did the input jack with leads plugged into the amp trick to try to figure out the + & - side of the cap... but I could'nt tell any difference. so I guess I will assmble it as is and hope it is correct.

Anyways again thanks for everyone's help.

[blues junkie]

Hey Guys,

I have another question, I was thinking of using 20AWG solid wire for my grounds instead of the 18AWG stranded I recieved with the kit. I was wondering if that would be ok? I also assume I would need to remove the 18AWG that I soldered in allready or could I leave that in and do the the rest in 20AWG?

Thanks.

Chuck.

[surfsup]

20awg should be fine. You can leave the 18 gauge in where you have it now.

[Zippy]

Hey Guys,

I have another question, I was thinking of using 20AWG solid wire for my grounds instead of the 18AWG stranded I recieved with the kit.

Why? If you have a compelling reason, it might be OK.

I would dissuade you from it because solid copper tends to work harden when you bend it and if you bend it too many times, you may crack it inside the insulation and not know it.