How hot is too hot?

[Jim R.]

Adam,

I agree that especially for the 800s a better amp than the crack is going to be very hard to find.  Given what PB said though, I could see going to a 2-chassis crack with a fully shunt regulated, all film cap power supply in one chassis (and SR DC filaments too) and the amp guts and speedball in the other, and maybe the extra inputs and upgraded attenuator as well.  But for an all-out amp, a second chassis is no big deal.

-- Jim

[adamct]

I like that idea....

[Paul Birkeland]

I agree that especially for the 800s a better amp than the crack is going to be very hard to find.  Given what PB said though, I could see going to a 2-chassis crack with a fully shunt regulated, all film cap power supply in one chassis (and SR DC filaments too) and the amp guts and speedball in the other, and maybe the extra inputs and upgraded attenuator as well.  But for an all-out amp, a second chassis is no big deal.

I'm not sure there's a market for an $8000-$12000 Crack...

[adamct]

Putting aside the film caps, would it really cost that much? What is the expensive part? I'm sure that sounds like the dumbest question ever, but I don't even know what shunt-regulated means yet (still working my way through The Art of Electronics) let alone what parts are needed and what they cost. The second chassis can't cost that much. The stepped attenuator is expensive, but it adds less than $300 to the price, not $3,000. What are SR DC filaments?

[Paul Birkeland]

A product like this would seem to be unsuitable as a kit. 

As far as parts go, this would be on a similar level to the BeePre, but with more stages.  Two large custom aluminum chassis would run ~$1200 each, then add the parts, then add the labor to construct, and the price has gone sky high.  Yes, film caps are expensive, try pricing six 220uF 250V film caps (ICW's are $90 each, AVX's are $82), not to mention what we'd put on the output (Duelunds could chew up the better part of $10,000 for four 40uF capacitors).

For that matter, to be nice to the shunt regulators, I'd probably want to separate out the driver supply and give itself its own pair of shunt regulators, so you'd be looking at one 6080, maybe two EL84's or another 6080, and two dual triode driver tubes (5687 perhaps).  This is a lot to build, I would expect to spend 3-4 full days constructing such a monster.

[adamct]

Where's the problem? Sounds good to me...

Just kidding. But more seriously, why would the chassis need to be aluminum, rather than wood, like the other kits? And I was serious about putting aside the film caps. I think your approach of putting good electrolytics in the kit, and then letting people choose whether to install film caps (and if so, which ones) is the right way to go and keeps the cost down.

As for the build time...this is a hobby. Putting in a couple of days is but a drop in the bucket compared to the time I have invested in this hobby. 

[Jim R.]

Hey Paul,

You have to realize that when I put forth ideas like this it is not meant as a product suggestion, just a what-if for somebody with the design chops (definitely not me at this point) and the motivation (and of course the wherewithal.)

BH amps are just great as they are though of course they have also inspired many an over-the-top modifications as well.
 I really love the crack as is with a couple of the common mods and really don't have any motivation to build an all-out version -- I'm just not that fanatical about my headphone listening, but I do like what I have and with the 800s, it is to my ears, as good as I'll ever need.

No, you guys just keep doing what you're doing -- it's already the best thing going.

[Paul Birkeland]

Just kidding. But more seriously, why would the chassis need to be aluminum, rather than wood, like the other kits?

Presuming it's a finished product, an aluminum chassis travels much, much better on the big brown truck.

[4krow]

Yah, I got a 'what if' gene too. When I start thinking about something, it starts to spiral into space. But that is a really good thing because I can bring back towards earth until it starts to make sense again. This actually is one reason I read in this forum. The ideas are great(and usually rational). It gives something to toss around in my head.

[VoltSecond]

After 2 hours of self heating:

Transformers / inductors / Resistors (except sand cast) should be cool enough you can touch them (watch high voltages!) for 3 seconds and not cuss. (< 60 C )

Caps should be barely warm. You could hold them or if they were baked potatoes, you could eat them slowly.  ( < 40 C)

Sand cast resistors can run slightly hotter than transformers. The problem is, they heat up parts next to them.  (<70 C)

[Grainger49]

V-S, I like the unit of measure, and not cuss!