I use the same 130v 300watt bulbs as you and mine do not get brighter or dimmer with volume. Definitely with different drain to ground voltages the brightness changes. I like your build layout. It's sleek and tubey.
What type of transformer are you using? The metal plate holding my 800VA donut in place is nearly as warm as my heat sinks. 58 degrees vs 60ish.
A question about your circuit. Do the tubes in front of the mosfets act as a buffer?
Jeffrey
What type of transformer are you using? The metal plate holding my 800VA donut in place is nearly as warm as my heat sinks. 58 degrees vs 60ish.
A question about your circuit. Do the tubes in front of the mosfets act as a buffer?
Jeffrey
Thanks
The brightness imcreases if I drive it into clipping, and returns to normal afterwards (I'm thinking the coupling cap charges up?- I might try transformer coupling instead)
The transformer is a 572VA toroid, mounted inside the chassis rear middle. It's probably as hot as the heatsink. I have a tube amp with Hammond PT that hits 95c in operation so I'm not overly worried about the temperature
The tubes in front are both a gain stage and buffer to drive the MOSFETs. I'm not sure if they are up to it. I hear a HF roll off that is most likely related to CMiller. I might attempt to buffer the tube with a DN2540 MOSFET or something - not sure how yet though but I assume it'll fit into a typical cathode follower circuit (source follower). Either that, or I'll just boost the HF to compensate LOL
The brightness imcreases if I drive it into clipping, and returns to normal afterwards (I'm thinking the coupling cap charges up?- I might try transformer coupling instead)
The transformer is a 572VA toroid, mounted inside the chassis rear middle. It's probably as hot as the heatsink. I have a tube amp with Hammond PT that hits 95c in operation so I'm not overly worried about the temperature
The tubes in front are both a gain stage and buffer to drive the MOSFETs. I'm not sure if they are up to it. I hear a HF roll off that is most likely related to CMiller. I might attempt to buffer the tube with a DN2540 MOSFET or something - not sure how yet though but I assume it'll fit into a typical cathode follower circuit (source follower). Either that, or I'll just boost the HF to compensate LOL
De-Lite 3.0
Well I'm back to the open/roomy/messy layout and the "De-Lite" is again hum free Now to build a larger family/living room approved chassis. It may just have to rest on the beach a while. Sure it's dangerous but it sounds AMAZING!
@Dennis Hui Aimee Man is now even more soothing.
Jeffrey
Well I'm back to the open/roomy/messy layout and the "De-Lite" is again hum free Now to build a larger family/living room approved chassis. It may just have to rest on the beach a while. Sure it's dangerous but it sounds AMAZING!
@Dennis Hui Aimee Man is now even more soothing.
Jeffrey
I thought I'd post a picture or two of the amp in it's latest state.
Very nice atmosphere.
Thank you. R11 across R16 doesn't give enough adjustment. The 22k is a 5 turn 2W pot, so in theory if I just connect it to ground instead of the light bulb, I'll get enough adjustment?
Like this?
EDIT: As drawn it's working fine! The 6V6 will be reconfigured into a gain stage...
Like this?
EDIT: As drawn it's working fine! The 6V6 will be reconfigured into a gain stage...
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Ok... I put the relay in to short gate to source while the capacitor charges.
All is working now, and I must say the sound is much improved over the grounded source version. I did however change from 16N20D2 to 6N50D2. Not sure how much of that matters...
I left the bias and 1R in place. I figure the 1R provides some degeneration, lowering distortion.
Also the B+ is 72V... It'd be nice to get it higher, but I can't justify spending 200$ on a transformer to gain a few watts, and the heat sink would need a fan.
All is working now, and I must say the sound is much improved over the grounded source version. I did however change from 16N20D2 to 6N50D2. Not sure how much of that matters...
I left the bias and 1R in place. I figure the 1R provides some degeneration, lowering distortion.
Also the B+ is 72V... It'd be nice to get it higher, but I can't justify spending 200$ on a transformer to gain a few watts, and the heat sink would need a fan.
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always spend more on bigger and more sensitive ( not same as efficiency!) speakers, instead on bigger amp hardware ( at least when you're already in big territory)
ok, write something , somewhere, about those EL509/519 amps you have there .......
at least I presume bottles are these
ok, write something , somewhere, about those EL509/519 amps you have there .......
at least I presume bottles are these
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