DINGO PCB and kit BUILD THREAD

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trenchrecordings
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Re: DINGO PCB and kit BUILD THREAD

Postby trenchrecordings » Tue May 21, 2013 11:25 pm

Do I need both op amps in the dingo if I just want to go balanced to unbalanced unity gain ? And the other way around, do i need both op amps in the dingo pcb if I want to go unbalanced to balanced unity gain ? I have an older 8 channel discrete mixer that is unbalanced line in and unbalanced monitor out. I'm hoping the dingos can balance everything and play nice with all my other studio gear. Solve some ground loop problem. Thanks for the reply on the power station thread Joe !

Thanks,
Dave

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Re: DINGO PCB and kit BUILD THREAD

Postby Joe Malone » Wed May 22, 2013 7:28 am

trenchrecordings wrote:Do I need both op amps in the dingo if I just want to go balanced to unbalanced unity gain ? And the other way around, do i need both op amps in the dingo pcb if I want to go unbalanced to balanced unity gain ? I have an older 8 channel discrete mixer that is unbalanced line in and unbalanced monitor out. I'm hoping the dingos can balance everything and play nice with all my other studio gear. Solve some ground loop problem. Thanks for the reply on the power station thread Joe !

Thanks,
Dave


If you are only converting one way you only need one opamp fitted to dingo PUP.

If you need a more compact solution have a look at the regurgitator kit as it can do both type of conversions but only one at a time. So you would need 10 regurgitator kits to do 8 inputs and 2 outputs
Joe :-)
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trenchrecordings
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Re: DINGO PCB and kit BUILD THREAD

Postby trenchrecordings » Tue Jul 16, 2013 12:58 pm

So I can go unbalanced in / balanced out with a gar2520 in the dingo at unity (or plus +6dB is fine)? Do I install RV2 ? I'm not using the vca option

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Re: DINGO PCB and kit BUILD THREAD

Postby Joe Malone » Tue Jul 16, 2013 1:58 pm

trenchrecordings wrote:So I can go unbalanced in / balanced out with a gar2520 in the dingo at unity (or plus +6dB is fine)? Do I install RV2 ? I'm not using the vca option


The GAR2520 is only a single opamp so with it fitted to IC2 you would need a 1:1 output transformer to go fully floating balanced out.
This would give you unity without RV2 fitted or 6dB gain with RV2 fitted and turn down to minimum gain.

You can go quasi Balanced out which will noise cancel into a balanced in with just the GAR2520 fitted and a wire added between pin 1 and pin 3 of the IC2 DIP8 socket.
This references -out to 0v by the same output resistance as the +out with the signal on it so noise canceling works. This is used in lot of mastering equipment and modern Neumann microphones etc

If you fitted a Dual DIP8 opamp to IC2 then you would have electrically balanced output WITHOUT a output transformer.
This would give you 6dB gain without RV2 fitted or 12dB gain with RV2 fitted and turn down to minimum gain.

Hope that makes sense :D

EDIT: Corrected wrong pin numbers linked for quasi balanced out.
Joe :-)

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trenchrecordings
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Re: DINGO PCB and kit BUILD THREAD

Postby trenchrecordings » Tue Jul 16, 2013 11:50 pm

Ok Joe thanks for the info, I will try the quasi balanced out.

How about in the case for an incoming balanced in to unbalanced out with a 2520 in IC1A. Do I need to jumper any pins on the dip8 positon ? Also how would I keep this at unity ?

Thanks,
Dave

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Re: DINGO PCB and kit BUILD THREAD

Postby Joe Malone » Wed Jul 17, 2013 10:28 am

trenchrecordings wrote:Ok Joe thanks for the info, I will try the quasi balanced out.

How about in the case for an incoming balanced in to unbalanced out with a 2520 in IC1A. Do I need to jumper any pins on the dip8 positon ? Also how would I keep this at unity ?

Thanks,
Dave

IC1 is configured to work as a balanced to unbalanced unity buffer with either DIP8 or 2520 etc so no changes needed.

To keep headroom the same when changing from balanced to unbalanced it can be a good idea to set this stage to -6dB by changing R4 and R6 to 10k.
Joe :-)

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trenchrecordings
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Re: DINGO PCB and kit BUILD THREAD

Postby trenchrecordings » Thu Jul 18, 2013 4:38 pm

If I had 10 dingos in a chassis. Would it be ok to daisy chain the power in on them ? It would make for cleaner wiring. Or split 5 and 5, on for each V+ V- rail of the powerplant. Or bus bar the power V+ V- and Ov and run individual sets to each pcb ?

trenchrecordings
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Re: DINGO PCB and kit BUILD THREAD

Postby trenchrecordings » Thu Jul 18, 2013 4:41 pm

And on the same note. Daisy chaining the 48+ 0V in to 8 go betweens will be ok ?

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Re: DINGO PCB and kit BUILD THREAD

Postby Joe Malone » Thu Jul 18, 2013 4:50 pm

trenchrecordings wrote:If I had 10 dingos in a chassis. Would it be ok to daisy chain the power in on them ? It would make for cleaner wiring. Or split 5 and 5, on for each V+ V- rail of the powerplant. Or bus bar the power V+ V- and Ov and run individual sets to each pcb ?


Daisy chain is fine as each dingo has power isolation 10R and 100uF cap filter on each power rail.
Joe :-)

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Re: DINGO PCB and kit BUILD THREAD

Postby Joe Malone » Thu Jul 18, 2013 4:53 pm

trenchrecordings wrote:And on the same note. Daisy chaining the 48+ 0V in to 8 go betweens will be ok ?


Yes Daisy chain is fine as current draw is low and same RC filter idea as above is on the GO between as well.
Joe :-)

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trenchrecordings
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Re: DINGO PCB and kit BUILD THREAD

Postby trenchrecordings » Fri Jul 19, 2013 4:29 am

burnt two dingos, r24 and r23 on both. Two different 2520. Voltages were good +16VDC on +V1 and -16VDC on -V1 from the powerstation. These were the two that i jumpered IC2 dip pin 4 to 7.

At first I had both dingos powered up and I noticed -V1 was only 1.5 Volts. So I disconnected and tested the powerstation. Volt were back to normal. So I connected one dingo, test voltage, it was fine. Seconds later smoke. I tested the other dingo, different 2520, again smoke

Any ideas ?


trenchrecordings
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Re: DINGO PCB and kit BUILD THREAD

Postby trenchrecordings » Fri Jul 19, 2013 5:55 am

Those 2520 are dead as well :) After probing around it seems pin 4 is -16V and pin 7 is out. I probably should have jumpered pin 1 out to pin 3 ?

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Re: DINGO PCB and kit BUILD THREAD

Postby Joe Malone » Fri Jul 19, 2013 7:54 am

trenchrecordings wrote:Those 2520 are dead as well :) After probing around it seems pin 4 is -16V and pin 7 is out. I probably should have jumpered pin 1 out to pin 3 ?


Sorry your completely correct it is 1 to 3 on dingo PCB. I was answering questions about the BA pcb just before answering your question and it is 4 to 7 on the BA PCB. :( :oops:

Send me a email with your address so I can send you a couple of our JLM25HV opamps and some 10R or let me know the cost of replacing the opamps that smoked so I can fix this.

I will go and correct that post so no one else tries to makes smoke escape. The wrong link would have killed the +rail to output transistor and/or the resistor between that.
Joe :-)

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trenchrecordings
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Re: DINGO PCB and kit BUILD THREAD

Postby trenchrecordings » Fri Jul 19, 2013 9:09 am

Nothing like a little smoke show :) Ok Joe ill send you an email tonight

Thanks,
Dave

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