prototype building tomorrow

Doc B. · 37239

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Offline Doc B.

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on: May 06, 2010, 09:11:46 AM
PJ, Shawn and I will be building what we hope to be the final prototype before we order chassis and iron for the first production run. If all goes well we should be ready to take pre orders in the next week or two. Pricing is still not determined and won't be until we have everything just the way we want it.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Jim R.

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Reply #1 on: May 08, 2010, 02:46:47 AM
Ok, so how did it go?  Any hum measurements you feel like publishing?

Thanks,

Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)


Offline Doc B.

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Reply #2 on: May 08, 2010, 05:34:56 AM
Not quite finished, so I'll have more info next week.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Doc B.

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Reply #3 on: May 10, 2010, 11:45:58 AM
OK, she's up and running. Output power is right at the expected 3.5W at around 5-10% THD, at 1kHz from the 8 ohm tap into an 8 ohm load. Frequency response looks to be a bit less than 1dB down at 20Hz (that's as low as our quick and dirty sweep setup went) and at the top end it is 3dB down at around 50kHz, again into an 8 ohm load (not sure about the power level for this measurement, we are still learning this new sweep setup). Hum level looks to be a bit less than 1mV RMS into an 8 ohm load. That's with stock Sovtek 2A3s, measuring with a Fluke DMM that seems well calibrated. Our scope seems to give slightly higher RMS readings. It says a bit over 1mV.

Now we are working on the pricing. As you all know prices have been rising steadily on parts and I think the price will be a bit higher than our initial projection a couple years ago, but the price of this kit will still be significantly lower than Paramount.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Jim R.

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Reply #4 on: May 10, 2010, 11:57:57 AM
Coolness!  That hum level is totally acceptable in my book, and everything else looks very nice.

I'm pedalling as fast as I can to get my other two amps sold, and hopefully this will be my next BH project.

Thanks for the update,

Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)


Offline Grainger49

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Reply #5 on: May 10, 2010, 12:12:40 PM
Doc,

I think you have said but I can't find it.  What size chassis is this?  I'm hoping larger than the SEX/FP III/Eros since it needs room for tweaks.



Offline Jim R.

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Reply #6 on: May 10, 2010, 12:25:54 PM
Grainger,

This will be on a 10" x 12" top plate.

HTH,

Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)


Offline Doc B.

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Reply #7 on: May 10, 2010, 12:27:10 PM
OK, price will be $749, just half of the price of the Paramount monoblocks kit. By our standard pricing formula the kit should be priced $100 higher, but we will hold this introductory price as long as we can. I'm charging up my camera and flash batteries to take some pics of the prototype this afternoon. Meantime, here's a quick description:

This is a stereo single ended 2A3 integrated amp, that uses a 12AT7 tube loaded with Camille Cascode Constant Current Sources as the input tube. It has three inputs and a stereo 100K ohm volume control. The chassis plate is 10" wide and 12" deep. It kind of looks like the big brother to the S.E.X. amp, with volume knob front center and power switch at the right front, but with a source selector knob rather than a headphone jack at the left front. The input RCAs, binding posts and IEC power entry are at the back. Power trans and plate chokes are on top behind the tubes, output transformers under the chassis. All iron is custom made for Bottlehead, designed by Paul Joppa. Tubes supplied will be Sovtek 2A3s and EH 12AT7. Power supply will be built on a PC board rather like the Eros kit. As with our other kits the signal caps are easily accessible so you can install the most favored cap of the week. The kit will be very easily converted for operation with a 45 tube, requiring only the reconfiguring of four resistors.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Jim R.

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Reply #8 on: May 10, 2010, 01:19:53 PM
Woo-hoo!  Looks like this will happen sooner than I thought (for me, that is.)

-- Jim

Jim Rebman -- recovering audiophile

Equitech balanced power; uRendu, USB processor -> Musette DAC -> 5670 tube buffer -> Finale Audio F138 FFX -> Cain and Cain Abbys near-field).

s.e.x. 2.1 under construction.  Want list: Stereomour II

All ICs homemade (speaker and power next)


Offline Doc B.

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Reply #9 on: May 11, 2010, 05:53:12 AM
Sorry guys, picture will be delayed a bit. I'm on the second floor flat on my back with a torn up leg and the camera and photoshop are down two flights of stairs.

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Grainger49

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Reply #10 on: May 11, 2010, 07:00:21 AM
Just take care!



Offline Paul Joppa

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Reply #11 on: May 11, 2010, 10:55:38 AM

Paul Joppa


Offline Wardsweb

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Offline Doc B.

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Reply #13 on: May 11, 2010, 12:51:41 PM
When I broke my leg a few years ago I had nine weeks to perfect the art of butt-climbing:
sit on the bottom step (owwww!)
place hands behind self on the next step up (arrrrhhhh)
push with the good leg (uggnh!)
while suspending the injured leg straight out so as not to whap your heel on the stair (&!^@#%$*^!@#%**@#!*&^#@%)
sit on the next step (pant, pant)
repeat, 13 times.

Screw it, I just stayed upstairs all day!

Dan "Doc B." Schmalle
President For Life
Bottlehead Corp.


Offline Dyna Saur

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Reply #14 on: May 19, 2010, 08:01:51 AM
A couple of gin "shadow"  martinis and a good cigar should help ease the pain. 

Get well soon...     (Been there, done that with bad / damaged knees in 1989 and 2001)

A "shadow martini" consists of a glass of one's favorite gin, and then  just let the shadow of the vermouth bottle  fall upon the gin.

/ed B

ed brown