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Old 17th January 2002, 06:09 PM   #1
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Default tape loop buffer for Zen Preamp

I'm in the process of building the balanced zen preamp. I built the BOZ preamp a few years ago and love it!!! With the new preamp I would greatly appreciate any suggestions on a buffer circuit to add tape loop/processor capabilities.

Thanks!!!!
Tom
trq10180@flash.net
tquinn@redback.com
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Old 17th January 2002, 09:56 PM   #2
jam is offline jam  United States
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Tom,

How about a simple current sourced mosfet buffer. Idleing the mosfet at about 10ma. should be enough. Input impedence should be very high and a bias of 10ma. should be high enough to drive the input of most tape decks.

Jam

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Old 17th January 2002, 11:03 PM   #3
mlloyd1 is offline mlloyd1  United States
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This buffer works very well for me:


Michael
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Old 17th January 2002, 11:58 PM   #4
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Slightly off the subject, but can I ask: Where do you find those higher- Idss parts in the US? I have looked while preparing to build a Pearl, and can only find the parts at Consolidated Electronics and MCM so far; and those are apparently the -GR (low) ones. Do you know where can I find the -BL or -V parts without going to Europe or Asia?

There was a previous thread that contained this discussion, but all sources mentioned were overseas relative to the US.

Thanks-
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Old 17th January 2002, 11:59 PM   #5
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By the way... I'm talking about 2SK389BL and 2SK170BL.
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Old 18th January 2002, 12:10 AM   #6
mlloyd1 is offline mlloyd1  United States
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Default source for BL JFETs - good question; no idea!

I'd like to know myself. I've only been able to find the GR in the US. I was actually looking for some V, the highest Idss group. Toshiba hasn't been willing to give me samples

I have a few 2SK170BL and 2SJ74BL that I got from an old (but REALLY good - before the transport irreparably died) casette deck.

Michael
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Old 18th January 2002, 12:24 AM   #7
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If you're looking for GR, you've found him...I'm right here.
I would like to hear of a good source for those devices, as it seems that the majority of the places selling them keeping popping up in Counterfeit? discussions. I would like to buy with a bit more confidence.
Jam,
I'd say 10mA should do an admirable job. Actually, you could probably get by with less, but it never hurts to have more drive than you need. The converse, however, is a bummer.

Grey
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Old 18th January 2002, 08:05 AM   #8
ergo is offline ergo  Estonia
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Everyone, check out

http://www.borbelyaudio.com/

Pricing information -> components

I think it is also much safer to order from Mr. Borbely even if it's a bit more expensive. He uses these transistors in his own projects so they should be the "real" ones : )

Ergo
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Old 18th January 2002, 01:14 PM   #9
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Default 2SK369BL at Consolidated

I got a few pcs. of 2SK369BL (*BL*, not *GR*)from Consolidated just a few days ago, so they might still have them.

Andrej Deticek
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