grounded grid

[kevin gilmore]

kgsshv-carbon with the sic-fets turned into 6ca7

was going to be next year  

 

[nopants]

bh modern? how's the prototype (assuming you've built one)

I thought the main issues around this were the fets needed to drive the el34 inputs

[kevin gilmore]

have not built one yet.  may change the drive transistors to ksc2690A

been thinking about this a while, saw no reason not to do the board.

 

5.6 x 4.7 inches

Edited December 26, 2015 by kevin gilmore

[mwl168]

Kevin, you are killing me!

[kevin gilmore]

board file posted 

I can do the same thing with the nanotube, for the ultimate in gigantic.

fets, triodes... its all the same thing...

 

[nopants]

maybe the tube circlotron will be similar sized if you've got tubes instead of heatsink

fun projects are getting more fun though, no parts headaches ATM

[spritzer]

This will form the basis of the new Blue Hawaii I'll build next year.  Good thing here is that tube failure is far less catastrophic plus it should sound better. 

[nopants]

I have some original bh boards here maybe I should case it so they can use the same power supply

[spritzer]

No problem running this at +/-400V but it can go up +/-450V.  We could even do something like the T2 CCS and push it even further. 

[Laowei]

Thanks for the belated Christmas present Kevin.

What is the intended current thru each tube? 

[kevin gilmore]

updated file

current thru the tube designed to be 20ma, so a bit more than previous

driver transistor is ksc2690a only, dissipates a little less than 1W, needs very small heatsink

you loose about 45 volts across the tube, so +/-450 is ideal

 

 

Edited December 27, 2015 by kevin gilmore

[sorenb]

What does the tube socket pin numbering refer to?
 

Edited December 27, 2015 by sorenb

[kevin gilmore]

ignore the tube pin numbers, they do not show up anyway. its how that socket was made when I did the t2

picture above updated

Edited December 27, 2015 by kevin gilmore

[sorenb]

would cascoding the 6S4A with  KSC2690 be possible as well?

apart from the j79 being obsolete would that be a suitable replacement for 2690?

[Kerry]

Very cool Kevin.  I've modeled this as well and definitely want to build it.  Thanks again for pushing us along

[Laowei]

2 hours ago, sorenb said:

would cascoding the 6S4A with  KSC2690 be possible as well?

In a KGST?

I don't believe it would work with a CCS on the tail as well as on each plate. That's a different circuit topology with a grounded cathode,  rather than the BH, Carbon, and Kevin's latest grounded grid variants. 

 

 

 

[kevin gilmore]

in the original kgbh, the 2sj79 can be replaced with a ksa1220A and the 2sk216 can be replaced with a ksc2690a. Not the same pinout.

someone would have to test, but synthesis shows it would definitely work. in fact the ksa1220a and ksc2690a are faster and lower capacitance parts than the originals.

Edited December 27, 2015 by kevin gilmore

[nopants]

im up for testing them in the original boards, need to get that thing finished anyway. does that make them similarly applicable in other designs like the t2, or the 6c33c amplifier?

[kevin gilmore]

the 2sj79 and 2sk216 are 200v parts, the ksa1220a/ksc2690a parts are 160 volts.

would probably work if you are careful.

[joehpj]

How about PSU? Same as carbon? or the KGSShv PS?

[kevin gilmore]

same as carbon makes it easy to fit in the box

 

[wokstarr26]

A very dumb question.

How large is the heatsinks req for the 10M90S.

Looking at the holes a L aluminum bracket is required to mount the board to an external heatsink.

Or I am missing something here

[kevin gilmore]

16 watts per channel for the 10m90s plus another 10 watts for each power supply

Edited December 29, 2015 by kevin gilmore

[xianghao]

AWSOME!

it seems that can use the KGSSHV-PSU( 450v ver) , carbon-PSU and BH-PSU.

i can`t wait to be the first one to build it.

[Inu]

How about 2SC5171 / 2SA1930?

180V, Lower Cob(16PF), Flat hfe-Ic

In Japan, popular than 2SC2690(A).