Post here and let us know you made it home safely

The 5th Annual CarverFest Sep. 9th - 19th
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BillD
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Re: Post here and let us know you made it home safely

Post by BillD » Fri Sep 23, 2011 6:14 pm

Since I published my balanced circuits, there are a couple of new op-amps available that make this task both simple and far more accurate than just using 1% metal film resistors (BTW, if you look inside a Rane box, the first thing they do is to convert to unbalanced using op-amps). This new solution uses a pair of audio line drivers (DRV134) to convert to balanced and a single line receiver (INA2137) to go balanced to unbalanced. All the needed resistors are on the chip and laser trimmed for accuracy. I have put balanced outputs on both a C-11 and a C-2 using the DRV134 chips with great success, and am working on a balanced input for an M-500 using the INA2137.
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Martin1970
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Re: Post here and let us know you made it home safely

Post by Martin1970 » Fri Sep 23, 2011 6:28 pm

BillD wrote:Since I published my balanced circuits, there are a couple of new op-amps available that make this task both simple and far more accurate than just using 1% metal film resistors (BTW, if you look inside a Rane box, the first thing they do is to convert to unbalanced using op-amps). This new solution uses a pair of audio line drivers (DRV134) to convert to balanced and a single line receiver (INA2137) to go balanced to unbalanced. All the needed resistors are on the chip and laser trimmed for accuracy. I have put balanced outputs on both a C-11 and a C-2 using the DRV134 chips with great success, and am working on a balanced input for an M-500 using the INA2137.

I was thinking about 'rolling' some opamps since I already have the thing built and it's zero effort.
Are the BB OPA2604s or the AD712s any better than the ones you originally used? Sorry I'm derailing the crap out of this thread. Hopefully everyone's home by now.
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Chauss
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Re: Post here and let us know you made it home safely

Post by Chauss » Fri Sep 23, 2011 6:42 pm

Martin- play the thing for a while.....I do not see any need to mod the amp IMHO- it is AWESOME as-is!!! :D
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Martin1970
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Re: Post here and let us know you made it home safely

Post by Martin1970 » Fri Sep 23, 2011 6:49 pm

Chauss wrote:Martin- play the thing for a while.....I do not see any need to mod the amp IMHO- it is AWESOME as-is!!! :D
?
I wasn't planning on modding it.
I'm just rambling on about balanced vs. unbalanced.
But you just reminded me that I have to convert back to unbalanced to power these tube amps *sigh*
Maybe I'll just drive them with + and - since the input will be attenuated by the y-split prior to monoblocking anyway.
I wonder which way Gary's planning on doing it.
Carverfest 10: Celebrating the life of our TNRabbit

OconeeOrange
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Re: Post here and let us know you made it home safely

Post by OconeeOrange » Fri Sep 23, 2011 6:59 pm

***
OK

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