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August 21, 2019, 04:44:39 AM

Author Topic: ELROG ER300B into BeePre?  (Read 502 times)

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Offline bombay317

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ELROG ER300B into BeePre?
« on: March 20, 2019, 10:57:15 AM »
Background: I have the limited edition BeePre with the BeeQuiet modification and the XLR input modification.

Question: What modifications would be necessary to run ELROG EL300Bs in place of the current 300bs?  I saw some other threads that talked about that, but then in a separate thread advice was to not follow those ones.


ER300B info from https://www.elrog.com/products/

Filament Voltage................................................................5 V

Filament Current ............................................................1.2 A

Amplification Factor ..........................................................3.3

Transconductance ........................................................3.3 mS

Plate Resistance ........................................................950 Ohm

Max. Plate Voltage .........................................................600 V

Max. Plate Dissipation ....................................................40 W
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: ELROG ER300B into BeePre?
« Reply #1 on: March 20, 2019, 11:32:09 AM »
I will take a stab at guessing what PJ would do, but he'll be along shortly I'm sure to weigh in.

If you plug the Elrog into the BeePre, you will probably find that the plate voltage is higher than we'd like, and precariously close to the regulated B+ voltage. 

To address that, you could dial back the plate current by 10mA.  (17.1 ohm R1 instead of 14 ohm R1)  This will leave 10mA extra rolling through the regulator circuit, which will drop the Kreg voltage a little bit, but I can't see real issues with doing that.  If you use the balanced outputs, you will need to replace the 604 ohm resistors with something closer to 1K.

On the filament side, everything should still work just fine with the stock circuit.

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline johnsonad

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Re: ELROG ER300B into BeePre?
« Reply #2 on: March 20, 2019, 12:24:25 PM »
I am on of the few that has tried this and posted on them in the past.  They are very microphonic and IME, where not a good match for the BeePre.  They worked very well in the Parmount/Kaiju's until they died, from poor workmanship and a poor product in general....  They sounded amazing but if I could go back in time, they weren't that great for the price.  My EML Mesh plates have lasted 3 times as long and are going strong still. 
Aaron Johnson

Offline bombay317

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Re: ELROG ER300B into BeePre?
« Reply #3 on: March 25, 2019, 02:38:32 AM »
I was sent the plate curves for the tube.

I'm still thinking about doing this, though not yet sold on it. 
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

Offline m17xr2b

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Re: ELROG ER300B into BeePre?
« Reply #4 on: May 16, 2019, 07:15:22 AM »
I used the elrog 300B for a while in the beePre, no issues on my side.