Bottlehead Forum

Bottlehead Finished Products => Legacy Products => Tube Phono => Topic started by: Doc B. on April 28, 2011, 03:12:29 PM

Title: The latest, RIAA only version
Post by: Doc B. on April 28, 2011, 03:12:29 PM
(http://www.bottlehead.com/sc_images/products/452_large_image.jpg)

Here's a link to more info:

http://www.bottlehead.com/store.php?crn=225&rn=452&action=show_detail (http://www.bottlehead.com/store.php?crn=225&rn=452&action=show_detail)
Title: Re: The latest, RIAA only version
Post by: johnsonad on April 28, 2011, 04:03:26 PM
Congrats team Bottlehead!  This is something I could become interested in.  I'm curious to the lack of adjustablility in input load both resistive and capacitive.  Is it there and I'm just missing it in the description?
Title: Re: The latest, RIAA only version
Post by: Grainger49 on April 29, 2011, 12:50:30 AM
Beautiful build.  But I miss the knobs.
Title: Re: The latest, RIAA only version
Post by: Doc B. on April 29, 2011, 04:46:20 AM
Congrats team Bottlehead!  This is something I could become interested in.  I'm curious to the lack of adjustablility in input load both resistive and capacitive.  Is it there and I'm just missing it in the description?

We can certainly adjust the load for the client when we build the preamp if they are using a cartridge that has a requirement different than the standard 47K ohms. From what I have seen the manufacturer's recommendations for loads often don't apply that well in the typical setup and to find a value that is going to get the response of the cart significantly flatter than the 47K load gives will require measuring the response curve of the cartridge/cable/phono preamp system and "cutting and trying" resistor values until you find one that's better in your particular system. We sometimes install trim pots in the Tube Repro to allow for different playback heads, and the only way to be sure we have it right is to do these response measurements. As for capacitance, the best thing to do seems to be keeping it very low, which we have accomplished with the use of an EF86 pentode at the input. That's probably the best approach, as capacitive loading seems possibly to be a "cure" for issues that should probably be addressed by resistive loading adjustment - or a different cartridge.

All that said, if someone wants to add shunt capacitance to the signal path on top of what their phono cable already adds we could probably accommodate them. These are after all custom built to order.
Title: Re: The latest, RIAA only version
Post by: ssssly on April 29, 2011, 03:05:37 PM
Would that chassis be available for purchase separately? Looks super sexy would love to rebuild my BH gear on it. Looks to be the perfect size for my sr45s, SEX, and Eros with all the extra iron and huge caps I have in them.
Title: Re: The latest, RIAA only version
Post by: Doc B. on April 29, 2011, 06:20:08 PM
Would that chassis be available for purchase separately? Looks super sexy would love to rebuild my BH gear on it. Looks to be the perfect size for my sr45s, SEX, and Eros with all the extra iron and huge caps I have in them.

Call PB at Front Panel Express. He can help you come up with what you need. I think the price for the chassis parts is around $1000, but I may be off there. Not sure what PB would charge to do the CAD design for you.
Title: Re: The latest, RIAA only version
Post by: ssssly on April 30, 2011, 04:12:37 AM
Man! I hope you misplaced the decimal.

I pMed PB, thanks.
Title: Re: The latest, RIAA only version
Post by: Doc B. on April 30, 2011, 05:18:54 AM
Man! I hope you misplaced the decimal.



Nope. Along with that very cool case this preamp has about everything we can throw at it, V-Caps, tantalum resistors, Goldpoint switches, you name it. Quite a few thousands worth of parts go into making that puppy.
Title: Re: The latest, RIAA only version
Post by: keto on May 04, 2011, 06:05:34 AM
It looks amazing and probably sounds... even better :-)
Title: Re: The latest, RIAA only version
Post by: Dobs on May 28, 2011, 06:30:15 PM
Beautiful build.  But I miss the knobs.

I agree
Title: Re: The latest, RIAA only version
Post by: vanofmonks on July 03, 2011, 03:58:20 AM
Can you point us to the power indicator part.  I like the look of that one.

Thanks.
Title: Re: The latest, RIAA only version
Post by: Doc B. on July 03, 2011, 05:32:25 AM
Quote
Can you point us to the power indicator part.

It's a fairly generic indicator jewel for an LED. Comes from Mouser or Digi Key, I can't remember which.