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GB for DC coupled B1 buffer with shunt PSUs

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#2,387
boards arrived yesterday, they look great!! so pretty in blue. now to decide on a final location for them and budget for errmm non-necessities 😀 think I might go nichicon KG instead of mundorf, much as I love the mundorf in my sigma22 power supplies for my dac, I dont know that I can justify another 100 for caps for this build. i'll be blowing enough on boutique resistors as it is (think letter Z). depends on when it closes, i'm in no hurry and with a 25% off sale at part connection (happens pretty often) i'm not sure I need to. nothing against the GB, its a great service!!

thanks guys for putting this all together!!

edit: I see the mundorf GB has happened already; lucky I wasnt too committed 😉 they do look sexy though, as they do on my dac PSUs
 
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#2,388
qusp said:
boards arrived yesterday, they look great!! so pretty in blue. now to decide on a final location for them and budget for errmm non-necessities 😀 think I might go nichicon KG instead of mundorf, much as I love the mundorf in my sigma22 power supplies for my dac, I dont know that I can justify another 100 for caps for this build. i'll be blowing enough on boutique resistors as it is (think letter Z). depends on when it closes, i'm in no hurry and with a 25% off sale at part connection (happens pretty often) i'm not sure I need to. nothing against the GB, its a great service!!

thanks guys for putting this all together!!

edit: I see the mundorf GB has happened already; lucky I wasnt too committed 😉 they do look sexy though, as they do on my dac PSUs
Click to expand...

qusp,

It might be cheaper for you to go directly to Texas Components Corporation to purchase Z foil resistors. That's where I got mine. They are U.S.$9 there versus $15 at the Parts Connexion. Even with PC's sales, you can't beat $9 for the resistor. I'm using the Vishay TX2575 resistors (Zfoil) for all the series resistance (i.e. 220 ohms) and then using Caddock TFO20 for the rest in the buffer circuit. Adds up pretty quick!

Anand.
 
#2,390
nycavsr2000 said:
qusp,

It might be cheaper for you to go directly to Texas Components Corporation to purchase Z foil resistors. That's where I got mine. They are U.S.$9 there versus $15 at the Parts Connexion. Even with PC's sales, you can't beat $9 for the resistor. I'm using the Vishay TX2575 resistors (Zfoil) for all the series resistance (i.e. 220 ohms) and then using Caddock TFO20 for the rest in the buffer circuit. Adds up pretty quick!

Anand.
Click to expand...
Can we have a picture of your collection of jewels? :bomb:
 
#2,392
Can I substitute the bipolar transistors with different models?

For example the BC550/560 ones with 2n3906/2n3904? Maybe something for the BC-517 as well? Not that they're hard to find or anything, but I've a huge box of transistor soup here - 2n3XX, 2n5XX, A, S, C - all kinds of prefixes basically and if I can use them already, I don't see why not.

I guess finding replacements for the relay drivers isn't a problem, but what about the ones in the regulator itself?
 
#2,393
the FET driver needs medium speed (fT~200MHz) and highish gain (hFE>300).

The relay driver needs medium Ic (>100mA) and good gain at high current (>200 @ 5mA)
hFE>150 @10mA and 20mA saturated @ Ic/Ib>10 for 0.1Vce.

If using a 5V relay, then maybe Ic>150mA, 40mA sat @ Ic/Ib>10 for 0.1Vce.

But, watch all the different pin outs.
 
#2,394
Shall we do another Mes GB?

Salas and I are going to attempt to re-issue some Mesmerizes. We looking for at least 50 units to sell.
Figured that this won't directly interfere with Blue Edition demand, so it's a good time to offer it.
Some people really liked this gadget because of it's relay switched inputs.
We are going to open a potential group buy sheet for a couple of weeks to see if there is real interest. The price would be 14.00 dollars, a single sided board, and would use 2 oz copper instead of 1.

Here is a blurry pic of my original DCB1 Mesmerize.

Here is the sign up sheet.
https://spreadsheets.google.com/ccc?key=0AnAnd3RI56NmdFJPNGVjSzB1T2F6X1MwNlNDeHBDamc&hl=en
 

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#2,395
AndrewT said:
the FET driver needs medium speed (fT~200MHz) and highish gain (hFE>300).
Click to expand...

Right, that would eliminate the 2n39XXs in that case, as they're below those specs. I'll see what else I've got in stock.

AndrewT said:
The relay driver needs medium Ic (>100mA) and good gain at high current (>200 @ 5mA)
hFE>150 @10mA and 20mA saturated @ Ic/Ib>10 for 0.1Vce.

If using a 5V relay, then maybe Ic>150mA, 40mA sat @ Ic/Ib>10 for 0.1Vce.
Click to expand...

Those I'm sure I can find in the "generic transistor" bag.

AndrewT said:
But, watch all the different pin outs.
Click to expand...

This is actually worrying me more than going trough the datasheets for electrical characteristics. I'll end up getting 1 transistor the wrong way, because I forgot it's using a different pinout, sooner or later 🙂

Thanks AndrewT, that's a lot of help, as usual.
 
#2,399
Marra said:
Will the new Mezmerize board have the beefed up power supply of the Blue Hypno?
Click to expand...

No, its not a redesign, just a better quality pcb reissue. There were some voices about missing the Mez full pre, so we thought we can try out and see if there will be some minimum interest in signing up for it. It was something we promised earlier in this thread. That one is not normally being gauged for a reg only heavier use, so its psu is adequate for uF.
 
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