Toasty for a tranny, but not surprising for a Hammond/Allied.
The cathode resistors dissipate 2-3W and I see you have them under the top plate (along with the other power resistors). Seems like your top plate could benefit from some ventilation.
Probably sinking heat from the top plate.
Yeah well, they're heaters!
Looking good!
Russ
I just received my Edcore GXSE-15-8-5k OPTs, and I have a question about wiring them up to my Simple SE.
The GSXE has 5 pins:
IN: pin 1 = plate, pin 3 = screen, pin 5 = B+
OUT: pin 7 = 8 Ohms, pin 9 = Common
On the Simple SE wiring diagram http://tubelab.com/SimpleSE_wiring.htm it shows 4 coloured wires for triode and 5 for UL and CFB.
Could someone tell me which pin is which colour?
The GSXE has 5 pins:
IN: pin 1 = plate, pin 3 = screen, pin 5 = B+
OUT: pin 7 = 8 Ohms, pin 9 = Common
On the Simple SE wiring diagram http://tubelab.com/SimpleSE_wiring.htm it shows 4 coloured wires for triode and 5 for UL and CFB.
Could someone tell me which pin is which colour?
some observations:
First, always - always follow directions! I have my EL34's wired in ultralinear mode once I got the big Edcor OPTs. First thing I noticed was that I now developed a 60hz hum. Small but noticeable. Last night It was worse than usual... doing the usual debug - with a meter at first - probing around looking for AC on ground points or anything exposed. Nothing. Now that I was sure I hadn't done something really dumb like put AC onto the chassis, I touched various ground points on the chassis to see if I could make it worse (feet off the floor sitting on a cloth chair - yeah, it was a sight). Turns out the volume pot made things hum the worst.
It's an oak chassis, and the Radio Shack pot doesn't have a ground lug... made a piece of bare wire to stretch from the pot shaft to the input jack... poof. Nice and quiet. It's a temporary hack, and I'll fix it right this weekend (along with the other fixes - see below)
Another thing: my winged C EL34's glow blue! I researched this pretty well following rk's adventures and even though it's really only one tube - I don't think there is much of a problem here.
Lastly, today I received some EH Kt88's. I was really looking forward to listening to them all evening - I used 3/4" spacers on the PCB to top plate. The base of the Kt88's are a LOT bigger than the holes I've cut, so they barely made contact. Powered them up anyway. Everything worked, but one channel was definitely quieter than the other. Powered down and put the El34's back in.
Back to the volume pot. When I was assembling the box I measured the resistance of each leg of the volume pot and surprisingly one channel was different then the other by 6-7K ohms. Must be a 10% pot... but I swear I can hear the difference between the two channels.
So I'll need a new pot. And new standoff's. Might as well put in the nice AC light in while I'm at it...
The bright side is that the BIG BLUE Edcor's ROCK! I can't detect any loss of high end with these, and the bass response has definitely improved.
George - I owe you a beer. Make that a six pack!
PS - wondering if the Tubelab SE is even better... can anyone say 300B's?
First, always - always follow directions! I have my EL34's wired in ultralinear mode once I got the big Edcor OPTs. First thing I noticed was that I now developed a 60hz hum. Small but noticeable. Last night It was worse than usual... doing the usual debug - with a meter at first - probing around looking for AC on ground points or anything exposed. Nothing. Now that I was sure I hadn't done something really dumb like put AC onto the chassis, I touched various ground points on the chassis to see if I could make it worse (feet off the floor sitting on a cloth chair - yeah, it was a sight). Turns out the volume pot made things hum the worst.
It's an oak chassis, and the Radio Shack pot doesn't have a ground lug... made a piece of bare wire to stretch from the pot shaft to the input jack... poof. Nice and quiet. It's a temporary hack, and I'll fix it right this weekend (along with the other fixes - see below)
Another thing: my winged C EL34's glow blue! I researched this pretty well following rk's adventures and even though it's really only one tube - I don't think there is much of a problem here.
Lastly, today I received some EH Kt88's. I was really looking forward to listening to them all evening - I used 3/4" spacers on the PCB to top plate. The base of the Kt88's are a LOT bigger than the holes I've cut, so they barely made contact. Powered them up anyway. Everything worked, but one channel was definitely quieter than the other. Powered down and put the El34's back in.
Back to the volume pot. When I was assembling the box I measured the resistance of each leg of the volume pot and surprisingly one channel was different then the other by 6-7K ohms. Must be a 10% pot... but I swear I can hear the difference between the two channels.
So I'll need a new pot. And new standoff's. Might as well put in the nice AC light in while I'm at it...
The bright side is that the BIG BLUE Edcor's ROCK! I can't detect any loss of high end with these, and the bass response has definitely improved.
George - I owe you a beer. Make that a six pack!
PS - wondering if the Tubelab SE is even better... can anyone say 300B's?
oldmanStrat said:
Mine also glow, but it is confined to inside the cage. It looks like the glow surrounds the screen wires. Based on what i have read about carbon-coated screen wires, this seems plausible.
I honestly didn't spend that much time with the Simple SE, but the Tubelab SE has been running on a breadboard for well over a month now. Even though I has SSE setup in triode mode with no feedback, TSE is just different somehow. I only had two nights of listening with SSE and I happened to get my new speakers on one of those nights. The speakers' horns were a little offensive with the Dynaco but were better with the SSE. I wanted to see if TSE was any better and I felt that it was. More even harmonics maybe...I dunno. I haven't hooked either to a scope. I've had the 300Bs in there for a week or two, but I may be going back to 45s here at some point....
The SSE chassis has been painted. I'm giving the panels some time under the heat lamp, plus I'm waiting for a few parts from AES before final assembly....
Russ
Beautiful photo, Russ.
I've got some of that lighter shade of blue on the insides of my plates too. I've also got some blue on the inside of the glass where a few electrons manage to sneak past the plate.
I've got some of that lighter shade of blue on the insides of my plates too. I've also got some blue on the inside of the glass where a few electrons manage to sneak past the plate.
An externally hosted image should be here but it was not working when we last tested it.
Thanks. Nice pic too. It's cool how every type of tube is a little different. The Sylvania 6V6GTs in my first amp glowed strongly and I always assumed this was typical. The JAN Sylvania 6L6GCs I have no glass glow, but the micas glow brightly. Weird.
Back to the SED EL34s...they are great tubes. That pic was taken of the Dynaco. As far as modern production tubes go, I have to tip my hat to SED. I have some of their KT88s too and they are also great sounding tubes.
Back to the SED EL34s...they are great tubes. That pic was taken of the Dynaco. As far as modern production tubes go, I have to tip my hat to SED. I have some of their KT88s too and they are also great sounding tubes.
I believe I may get a bit of that as well. If it is only on one tube (even after swapping them) and especially if it is only in one large spot, the usually means there is a slight misalignment in the mica that is allowing electrons to escape the cage and hit the glass right there. Many tubes, like Ty's, always do it and they will generally all look the same.
It's nothing to worry about unless the difference in the one tube is quite pronounced. Your's looks typical. My SEDs probably have had a bit of what you have, I can't remember. I've had some tubes, JJ's in particular, that have assembly issues and one of the symptoms other than internal shorts is a very large, bright blue glow in one spot that none of the other tubes have. Looking carefully at the micas, I could usually spot the problem.
Russ
It's nothing to worry about unless the difference in the one tube is quite pronounced. Your's looks typical. My SEDs probably have had a bit of what you have, I can't remember. I've had some tubes, JJ's in particular, that have assembly issues and one of the symptoms other than internal shorts is a very large, bright blue glow in one spot that none of the other tubes have. Looking carefully at the micas, I could usually spot the problem.
Russ
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.