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January 29, 2020, 04:44:52 AM

Author Topic: BeePre Input Transformer Modification  (Read 4506 times)

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Offline fullheadofnothing

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BeePre Input Transformer Modification
« on: July 28, 2014, 10:34:48 AM »
Well, a while ago PB and I did a photoshoot for the input transformers to give a balanced input to the BeePre. The plan always was to get it up on the website, rather than as a pdf manual. A few things came up here and there (like a full replacement of the website), and now it's finally up. It's in the blog section of the website, or here is the link.

http://bottlehead.com/bee-pre-input-transformer-modification/
Joshua Harris

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Offline Demsy

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Re: BeePre Input Transformer Modification
« Reply #1 on: August 31, 2014, 03:10:39 AM »
Hi Josh,

It says 404 Page Not Found. Is it removed?

Offline fullheadofnothing

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Re: BeePre Input Transformer Modification
« Reply #2 on: September 01, 2014, 07:42:05 AM »
It got lost in the recent website shuffle. I've put it back now.
Joshua Harris

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Offline Demsy

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Re: BeePre Input Transformer Modification
« Reply #3 on: September 04, 2014, 01:48:10 PM »
Thanks Josh!

Offline bombay317

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Re: BeePre Input Transformer Modification
« Reply #4 on: December 15, 2017, 04:08:14 AM »
I am going to be following your instructions. 

I contacted Cinemag, and they have 4 week lead times on the transformers (if anyone was interested to know that).  I opted for the double shielded ones. 

Mouser ships immediately, but they always do that.  Another option would be Digikey or Jameco, but all of that stuff is usually in stock by the 1,000s.
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Offline bombay317

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Re: BeePre Input Transformer Modification
« Reply #5 on: February 12, 2018, 06:04:39 AM »
When I went through this I noticed a difference between the BeePre mod and the BeePre XLR procedure.

https://bottlehead.com/bee-pre-input-transformer-modification/ in this there is no step to tie Pin 1 of the XLR input to the chassis ground. 

There is a step covered in the BeePre manual at the first step of "Output Wiring" that ties Pin 1 of the XLR input to the chassis ground.

Should this be done for this input?
Niagara 7000
Benchmark DAC3L (XBOX1 and TV)
CA Performance w/ Satisfy Turntable
Talismann V2 CA Cartridge
Tavish Designs Adagio Vacuum Tube Phono
BHSE Amp
Stax SR-009
BeePre 300B w/ BeeQuiet and Cinemag Transformers
Kaiju 300B w/ DC Filament
Jäger Speakers
Transparent and Benchmark Cables

Online Paul Birkeland

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Re: BeePre Input Transformer Modification
« Reply #6 on: February 12, 2018, 06:39:47 AM »
It's not unreasonable to put a switch into the BeePre to make this connection.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline bombay317

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Re: BeePre Input Transformer Modification
« Reply #7 on: February 12, 2018, 10:10:27 AM »
Paul,

I am not sure I follow your comment.  Are you saying you should put a switch in between Pin 1 and the XLR shield?  I'm trying to understand what you mean.

In the data sheet http://cinemag.biz/line_input/PDF/CMLI-15-15B.pdf for the CMLI-15/15B2 under the "TYPICAL APPLICATION" section, there is a switch installed from Pin 1 to ground, but it is also in parallel to a R and C.  Not sure if that is what you meant?

I really just followed the "BeePre Input Transformer Modification" by Joshua Harris.  These XLR inputs take the place of R3 and L3 and do use the green and brown pairs that go to the input switch.
Niagara 7000
Benchmark DAC3L (XBOX1 and TV)
CA Performance w/ Satisfy Turntable
Talismann V2 CA Cartridge
Tavish Designs Adagio Vacuum Tube Phono
BHSE Amp
Stax SR-009
BeePre 300B w/ BeeQuiet and Cinemag Transformers
Kaiju 300B w/ DC Filament
Jäger Speakers
Transparent and Benchmark Cables

Online Paul Birkeland

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Re: BeePre Input Transformer Modification
« Reply #8 on: February 12, 2018, 11:25:05 AM »
Sure, you can follow Cinemag's documentation.  One position gives a hard ground to the load end of the shield, while the other position looks to provide a convenient path to ground for high frequency noise.

The BeePre we used for those photos is mine, and I haven't noticed any noise on the balanced input, but I use my BeePre in a pretty quiet environment with short cables.

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline grufti

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Re: BeePre Input Transformer Modification
« Reply #9 on: July 27, 2019, 10:05:42 PM »
The link to the page describing the input transformer modification is dead again. I would like to take a look at it. Is it still possible to revive that page one more time?

Offline Deke609

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Derek
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Roon Intel NUC ->  Yggdrasil DAC -> BeePre (w/ BeeQuiet and EML 300B)  -> Kaiju (w/ DCFil and EML 300B) or Stereomour II (2A3 [EML Mesh] and 45 Conversion [EML 45B])  -> Audeze LCD4