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Cavalli EHHA Embedded Hybrid Headphone Amp - Page 5

post #61 of 1816
I wonder if they are 6GM8/ECC86's. They are not that easy to find anymore.
post #62 of 1816
The glassjar kits ship with 6GM8 ( until Jeff's stash runs out at least) and he is selling them at incredibly reasonable prices considering how rare they are lately.

my hat goes off to the man

..dB

ps smeggyman - looking good me lad
post #63 of 1816
Quote:
Originally Posted by sachu View Post
yeah...mine!! 20$ for the 3 of them ought to cover eh?

Sachu knows - I paid $12.00 each for those! (need one more for my fully balanced build) I have 4 Philco 6GM8s.

There are also the 6922 and 6H30 options...

Jeff is indeed offering a good deal...
post #64 of 1816
Thread Starter 
Cool, so the stock tubes are pretty well regarded? However, rare doesnt sound good, I may need to find a spare set.. just in case

I wish I didn't feel like such crap, it's hard to get going when you're in bed most of the day
post #65 of 1816
The design center tube is the 6gm8. But I knew that they would start to get rare because of other designs and so I also worked this out for 6922s and 6H30s. If fact the original design used the 6H30 because it is a good low voltage tube for being a high voltage tube.

However, this amp is not like the CTH or the SOHA II. It is not made for tube rolling. Just want you guys to know that you should not expect to roll tubes in this amp except for a very limited set of tube types. Tubes like the 12xxx series will simply not perform well.

You'll have to have fun with the other features of this amp.
post #66 of 1816
Quote:
Originally Posted by runeight View Post
...You'll have to have fun with the other features of this amp.
Like it's stellar performance? Or so I hear...

6GM8/ECC86s are around, tubeworld has some, as does upscaleaudio. The 6922 (or even 7922) would be an economical sub.

I have a line on some 6GM8s locally, depending on qty, condition and price, I'd be happy to group buy if there is interest. Communication has been slow, I'll update when I hear something...
post #67 of 1816
Thread Starter 
I was gonna ask, if the 2W resistor = 18wpc, what will the 1/2 W resistor output? Ideally I'd like enough juice to run stax transfo boxes, K1000, super inefficient orthodynamics etc. Ideally around 5wpc or over. Also, does that output pwer get fed through the phone jack or is there some other wiring setup to allow that output level?
post #68 of 1816
Quote:
Originally Posted by smeggy View Post
I was gonna ask, if the 2W resistor = 18wpc, what will the 1/2 W resistor output? Ideally I'd like enough juice to run stax transfo boxes, K1000, super inefficient orthodynamics etc. Ideally around 5wpc or over. Also, does that output pwer get fed through the phone jack or is there some other wiring setup to allow that output level?
Actually, looking at your board pics they look like small 2W resistors to me. Are they really 1/2W?

In any case, you can run multiple watts with 1/2W.
post #69 of 1816
It's called a volume control

The ideal way for you to do this would be to set a rotary switcher that changes the gain of the closed loop - that way you can still have fine control with the conventional pot and adjust the overall gain for the headphone of your choice ..dB
post #70 of 1816
Thread Starter 
Quote:
Originally Posted by runeight View Post
Actually, looking at your board pics they look like small 2W resistors to me. Are they really 1/2W?

In any case, you can run multiple watts with 1/2W.
Awesome, sounds ideal then. I dunno the actual wattage of the resistor but it's listed as 1/2w in the BoM so..

BTW, did you look at that delay circuit on ebay? If that would work should I feed it into the Sigma22 after the heater supply. Power >heater >delay >sigma.

Quote:
Originally Posted by dBel84 View Post
It's called a volume control

The ideal way for you to do this would be to set a rotary switcher that changes the gain of the closed loop - that way you can still have fine control with the conventional pot and adjust the overall gain for the headphone of your choice ..dB
I have no idea how to do that, but if it can feed multiple watts through the normal output I'll rig something
post #71 of 1816
Does anyone have a schematic for that delay circuit? Or the specs on the relay contacts?
post #72 of 1816
How about using a couple of damper tubes instead? Or would the transformer required for the heater circuit be too great?
post #73 of 1816
Thread Starter 
Not that I'm aware of. Hopefully somebody will buy one to see. Going off the blurb it looked like it would be suitable, ac and supposedly strong enough for big tube amps but who knows.

I'm so new at all this DIY I have little real clue. This is only my second build so I'm in the dark on a lot of the technicalities and rely on the knowledge of others until more of this stuff sinks in
post #74 of 1816
Here is a sneak peek at my progress...

Its a one chassis solution..everything (heater supply, S22 supply, included) is going to be on that chassis.




Just testing to see my chassis work was ok...

Going to bring up the S22 board later tonight and then the heater supply.

If all goes well with the supplies, tomorrow its going to be mounting the heater supply to the chassis and the S22 toroid needs to be bolted down as well ( i have a piece of acrylic cut out to secure it on.)

Also tomorrow, will try to design the end panels which will be made out of wood. However, this might come a few weeks down the line as I am trying to cajole my boss to do it for me
post #75 of 1816
I just love these type of recycled chassis - going to be one very unique amp.

good luck with the testing phase ..dB
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