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Old 22nd October 2013, 08:13 PM   #10241
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Default Grid choke for R1 on the group buy PCB

Not sure if you have used the same nomenclature for all of the variations of the circuit (and too lazy to look back).

First, please forgive my attempts at mixing tube circuit ideas with your FET design.

BUT, could there be something good about using a 47K 2000 H grid choke instead of the 47K resistor?

My curiosity could not be quelled so I had to ask.

Thanks,
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Old 22nd October 2013, 09:22 PM   #10242
Salas is offline Salas  Greece
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Great loop area in the signal's weakest state to no other benefit. Strong hum possibility. Frequency interaction possibility with input JFETs Ciss capacitance.
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Old 23rd October 2013, 04:15 AM   #10243
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Thanks RC and Salas, 103r it is. Bravo gentlemen.

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Originally Posted by RCruz View Post
Sorry I could not answer sooner but a system crash kept me away form the net for a while.

The 103r is really hard to beat for the price... a very musical cart with upgraded high freq response relative to the 103.

Quite forgiving in terms of vta, it responds well to vtf adjustments.

Much better than the lowish cost benz silver mc and sounding much bigger than the stock boboli.

IMO only bettered by expensive carts like the benz ACE red.

The 103r is a very good partner for the simplistic.

The syntec 220 arm is designed for high compliance carts but I have used the 103 with a SME3009 series III improved with splendid results.... just add a small portion of bluetack to the headshell if you need more mass.
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Old 25th October 2013, 06:43 PM   #10244
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Hi guys.
very strange thing happen to my PSU.
I finished it , and measure, everything is fine - 48VDC in each channel when connected directly to the 230V.
when I am trying to build the box with the fuse , I am keep blowing the fuse even with no load. I first thought there is a short somewhere , but there isn't. the led is first on - then the fuse blows , and it slowly got off as the capacitors unloaded.

the fuse is 315mA , 250V - which should be OK.
any ideas ? does anyone used a fuse with similar values.
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Old 25th October 2013, 07:08 PM   #10245
Salas is offline Salas  Greece
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Is it a T (time) slow fuse? How many VA is the transformer(s)?
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Old 25th October 2013, 07:17 PM   #10246
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should be 70 VA (230V main to 2x36VAC , each 30VA).
I think 300mA should be enough .
anyway - 70VA is what written on the supply (It is a custom order E-I core)
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Old 25th October 2013, 07:23 PM   #10247
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BTW - the fuse is not T fuse . it is a plain single thin wire in a bulb.
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Old 25th October 2013, 07:29 PM   #10248
Salas is offline Salas  Greece
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That is why it breaks. Its the transformer's inrush, no wrong doing on your behalf. Either you will keep it closely fused with a 315mA T fuse or you try with progressively higher fast fuse until it cycles on/off with no break incident.
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Old 25th October 2013, 08:01 PM   #10249
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Default Now, I promise to build it as is!

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Great loop area in the signal's weakest state to no other benefit. Strong hum possibility. Frequency interaction possibility with input JFETs Ciss capacitance.
Got my bag of parts and can't wait to hear what you have wrought.

THANKS for your patience with my questions.

Take care,
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Old 25th October 2013, 08:08 PM   #10250
Salas is offline Salas  Greece
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Good luck and keep us posted.
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