Balanced B1 Buffer

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I thought the PIN1 problem required the XLR PIN1 to be connected to chassis right next to the XLR socket.

Correct! I failed to mentioned I chose a point on the chassis very close to all 4 XLR's. Maybe I should have made 4 holes each closer to every single, XLR, however It would have required more drilling and tapping and I had enough of it by then! I also used a larger wire to this ground than the signal wire. This was to ensure a lower resistance path to ground. I referred to Mr. Neil A. Muncy paper (Noise Susceptibility in Analog and Digital Signal Processing Systems) as my reference.
Cheers,
Eric
 
I now have a perfectly working balanced B1 bufferamp.
I used shielded input<>output wiring; no hum no noise, just music.
For a noob, not bad, I think, like my knob?
Ruudjoo
 

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Bought it in Denmark cheap; is overstock from Thule Audio, that was high end audio equipment that existed only for a few years. These were sold then to replace the standard boring grey knob. Came by post from Denmark to The Netherlands for 7 Euro.
(sidekick-audio.com : Thule spare parts)
Ruudjoo
 
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Balanced B1

hi ,:)
I have my B1 boards running a balanced in ( XLR + to in - to ground and pin 1 floats no connection got that from Nelson's amps,THANKS NELSON,so far no hum,noise or other wise ,I am feeding signal from a computer or shingaclone, to minidac wm8741 to deq2496 to dcx2496 4 way config ,to the B1's to The amp's ( chipamps,swtp tiger.01 nelsons F5) to nelsons slot loaded speaker for bass, 12 speakers per slot,4 inline mids and 2 ribbons with 2 silk domes with 2 ribbons for the highs,,,,,,not done yet I have a HOMEWRECKER with a peavey 18" low rider with a 550 watt fet amp I have almost got it all going but I'm OLD and Slow so I'm not done yet,I would like to use F5's for all the amps except the sub ,got to test that fet amp first.....to be continued:D
 
Did you consider using the B1 with bipolar supplies and in bridge mode? It would have a balanced output as well. The input transformer may not be required if you have a balanced source. Output here is 970mV into 10k. Bandwidth is very nice with no weird things. The advantage of using a bipolar supply is obviously that no coupling cap is required.
 

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hi ,:)
I have my B1 boards running a balanced in ( XLR + to in - to ground and pin 1 floats no connection got that from Nelson's amps,THANKS NELSON,so far no hum,noise or other wise ,I am feeding signal from a computer or shingaclone, to minidac wm8741 to deq2496 to dcx2496 4 way config ,to the B1's to The amp's ( chipamps,swtp tiger.01 nelsons F5) to nelsons slot loaded speaker for bass, 12 speakers per slot,4 inline mids and 2 ribbons with 2 silk domes with 2 ribbons for the highs,,,,,,not done yet I have a HOMEWRECKER with a peavey 18" low rider with a 550 watt fet amp I have almost got it all going but I'm OLD and Slow so I'm not done yet,I would like to use F5's for all the amps except the sub ,got to test that fet amp first.....to be continued:D

What's the shield in the cable connected to? What kind of cable are you using?
 
hi,
The cable I use is low loss microphone cable,The ground or pin 1 floats not connected to anything,One thing normal (Unbalanced signal) is approx. 15 db below balanced in other words you got more signal than you need, I use a pot or a pad to get the signal lower ,but only if it's a problem to my amps input,I use a 50 K pot usually does the trick,I have also sean the cinch circuit ,it uses a resistor in the + side and a cap on the - side back to gnd ,this circuit was comming off a dac chip ,I think it's there to trap the HF off from the dac outputs.I haven't had to use that yet! here's some pics of my setup! Thanks MR.Nelson Pass for all you do for us!:):):):):):):):):):)
 

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hi,
The cable I use is low loss microphone cable,The ground or pin 1 floats not connected to anything,One thing normal (Unbalanced signal) is approx. 15 db below balanced in other words you got more signal than you need, I use a pot or a pad to get the signal lower ,but only if it's a problem to my amps input,I use a 50 K pot usually does the trick,I have also sean the cinch circuit ,it uses a resistor in the + side and a cap on the - side back to gnd ,this circuit was comming off a dac chip ,I think it's there to trap the HF off from the dac outputs.I haven't had to use that yet! here's some pics of my setup! Thanks MR.Nelson Pass for all you do for us!:):):):):):):):):):)

OK, so your source is not balanced. The shield should be connected to chassis ground at one end in that case, otherwise it's not doing anything for you.
 
Did you consider using the B1 with bipolar supplies and in bridge mode? It would have a balanced output as well. The input transformer may not be required if you have a balanced source. Output here is 970mV into 10k. Bandwidth is very nice with no weird things. The advantage of using a bipolar supply is obviously that no coupling cap is required.

Of course, with this arrangement, neither output can be grounded in the attached equipment, meaning that anything that is connected to this has to have balanced inputs with DC blocking. It will not work with single ended equipment unless you use something like a transformer to convert it.
 
If doing a linear PSU for a balanced preamp, would there be benefit in doing a separate winding, diodes, and regs to each board (crosstalk or other)? Or is that a waste of time, and I should just take the DC output of a single rail and split it to the two boards? Or is there benefit but the main issue then getting matched input to each board, even with LM317 implementation?
 
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