RiStaR

E80cc ?

Not sure I'm helping... just suggesting some stuff Just to be clear, I meant to swap left channel tubes to right channel tubes as a check instead of swapping all of them.

Not sure I understand your question, but those circled headers are the right ones if you don't use the RK27. If you used an RK27 and it's mounted then yes, because they are connected to those headers the mounted attenuator will affect it. Even with the RK27 fully open (max volume) you're still getting channel imbalance? [you should be able to measure the attenuator with a DMM to see if it's bad - at max volume setting especially] I assume you also tried to swap the tubes around to make sure it isn't the tubes?

Very very nice Enrique. Love the color theme!

By attenuator, I meant your volume control (pot or relay-based)... but it's likely your tubes especially if they aren't matched. By lazy and temporary, are you saying you didn't use thermal paste between your transistors and your heatsinks or the ceramic insulators? Probably not a good idea there...

Is there a reason why you're still using the ceramic insulators? The fqpf8n80c are insulated... so they actually reduce thermal conductivity. With regard to your balance issue are your tubes matched? Also check your attenuator (I had an issue once where the relays weren't working properly on my attenuator). Also, how do you like the sound?

I'd really recommend going offboard sinks... with the right size heatsinks for the KGSSHV board, the temps are still a toasty 90C after 15 mins. This had the side effect of "killing" my LT1021s (it always made the voltage to +430V over time until I offboarded the cooling) when cased up. It's been close to a year and the whole setup still runs well. EDIT: just realized I listed the wrong IC and double quoted heh

Nice... so how does your version of the carbon sound JoaMat?

Gorgeous Inu!

Congrats on completing

Thanks Kevin and Joamat for pulling it together for the rest of us mortals

Very cool! Congrats JoaMat!

Had a few requests for this... In terms of a drilling template for the Megatron. I don't have CAD or anything, but this is the jpeg I did out for the drilling of my chassis. I'm not sure if it's useful to the rest of you but it's the closest I have. For the rest who have already built one, if you have something much more accurate, please share it.

Thanks so much for your valuable (unending!) contribution KG. It has afforded the rest of us to just sit back and enjoy great tunes.

Peleus. do follow nopants' figures. Obviously my memory must be shot and added another 0 to the actual figures.

Hi Peleus, What would you be doing for bias voltage for your amp? Just something to think about... If you're sharing it with that 300v line, you may want to be careful with using the right heatsink for the 10m90s. From memory, all my input tubes draw about 20+W. The max for the 10m90s is about 40W i think. Since you haven't started, if you're living in a place that has a high ambient temperature (in the tropics it's normal to be about 30+C), you may also want to consider off-boarding the fqpf8n80c instead of the onboard heatsinks... I was eating through the LT1021s on the + line (they would no longer keep the voltage consistent but drop them an extra +-30v after some random intervals) from the heat when the PSU was closed up with just vent holes at the top. I've since used a larger offboard sink for the fqpf8n80cs and added vents (those used in aircraft cabins for the aircon) to the side of the PS casing to bring the temps way down.

Took a day for mine and it was through email after registering.

Lil Knight has been MIA for a while... I think a few folks have been trying to contact him. I'd suggest trying to PM him instead of just writing into the spreadsheet. If he doesn't respond, you may need to ask Kevin for permission to do a board run yourself unfortunately?

Hi Leonjo, You can use either if you're using the larger version of the PSU board. The insulated version is needed for the smaller board because the distance between the diodes are very close (it's like almost 2mm). If you use the 1210Ds on the newer smaller boards, you'd have to figure a way to insulate them. As to your insulator tubes for the transistor, there isn't any rating so it's hard for anyone to tell you if it'll work. I hope that helps

Hi spritzer, Not disputing the conservative ratings on the mil tubes - I did know that going in. I thank you for caring enough to speak up about it though, even if its abrasive. Best,

Pretty sure he's talking about me not you. Do share your pics when you're done with it

That sounds interesting - just googled the tubes and they look nice too On my megatron I think i found my tubes that work best for me... TS 12ax7; sylvania 12bh7 (it just sounded better than all the au7s i tried); Russian 6P3S-E (they also put out less heat than the EH 6ca7s). Bass is as much as the KGSSHV and the decay sounds perfect for me... now i'm wondering if I should take a gamble and a large box of unmatched ones or pay the premium for the matched quads for backups.

Very interested to see what this is! I'm enjoying my megatron very much

PM Lil Knight (first poster of this thread). Here's the GB spreadsheet.... you may be in luck https://docs.google.com/spreadsheet/ccc?key=0AoNVeoQi85GgdFVrMmtReVpWNVBsQUo2Sl9iSkItM2c#gid=0

Congrats Victor