DINGO PCB and kit BUILD THREAD

[Gold]

But I am not sure what the unbalanced device is that the dingo is connected too?
But if it is passive then that is usually fine.

The unbalanced out feeds a 5k T pad rotary switch. I would like to have as much headroom as possible on the output. A +21dBu clip point at the unbalanced input would be ideal. I also changed R25 to 5k for correct termination of the pad.

[Joe Malone]

But I am not sure what the unbalanced device is that the dingo is connected too?
But if it is passive then that is usually fine.

The unbalanced out feeds a 5k T pad rotary switch. I would like to have as much headroom as possible on the output. A +21dBu clip point at the unbalanced input would be ideal. I also changed R25 to 5k for correct termination of the pad.

For +/-24v opamps

Clip points in your setup
bal in +20.5dBu / unbal out +20.5dbu / unbal in +15.5dBu / bal out +26.5dBu

Clip points with R4 and R6 changed to 10k and 17db GAIN from output amp and balancing
bal in +26.5dBu / unbal out +20.5dbu / unbal in +9.5dBu / bal out +26.5dBu

[Gold]

Thanks Joe. Very helpful!

[martthie_08]

I would like to build a Pultec'ish EQ with the DINGO, using my own filter circuit and have some questions:

For debalancing / input impedance matching I would like to use the Hybrid or 99V opamp. Does the first opamp contribute noticably to the sound as it has gain = 1?

For gain makeup, is it possible to use an API 2520 with the JLM111DC output transformer for balancing?

Any other suggestions for maximum sonic bliss?

thanks and best regards, Marten

[Joe Malone]

I would like to build a Pultec'ish EQ with the DINGO, using my own filter circuit and have some questions:

For debalancing / input impedance matching I would like to use the Hybrid or 99V opamp. Does the first opamp contribute noticably to the sound as it has gain = 1?

Only slightly

For gain makeup, is it possible to use an API 2520 with the JLM111DC output transformer for balancing?

Yes but best to use our JLM25HV version of the 2520 so you can run +/-24v rails for best headroom.

Any other suggestions for maximum sonic bliss?

For fat sounding EQ and best headroom use +/-24v rails with JLM25HV or Hybrid for input and JLM99v with JLM111DC on output. You can then swap the opamps to make a tighter sounding EQ. Gives you the best of both worlds.

[martthie_08]

Joe, thanks for the reply, that is exactly what I wanted to know!

[rmiller335]

An EE I'm not, although I've built several guitar amps, preamps and have a BA4 in my rack. I am thinking that I can use a diyrecordingequipment.com endless summer with a couple of Dingos with 99v's and JLM111DC's to make a line level in & out summing amp. Does that sound reasonable, and is there anything I should know before I order everything?

Thanks,
Bob

[Joe Malone]

An EE I'm not, although I've built several guitar amps, preamps and have a BA4 in my rack. I am thinking that I can use a diyrecordingequipment.com endless summer with a couple of Dingos with 99v's and JLM111DC's to make a line level in & out summing amp. Does that sound reasonable, and is there anything I should know before I order everything?

Thanks,
Bob

Yes basically that is how we made the SUMO summing mixer. Uses the first balanced in opamp stage for summing all channels and then allows of master level control followed by second opamp and output transformer. Just change R3 & R5 from 20k to zero ohm links on dingo PCB and feed resistive balanced summing into dingo balanced input. I can do a simple drawing for you when you order if you remind me in the comments box of the order.

[frans]

I have been at my Dingo over the holidays and came up with a few questions.

C 1+2 no strip on the side to mark "minus" - but legs different, the shorter
should be "minus", right?

C 5+7 / C 12+13 = are 16 volts, but 25 volts rating on the schematic.. (with my +/-24 v PSU) I guess that's okay because Joe knows what he does. No strip = shorter leg: minus

C6 and ZD1- not in the bag - located right near where the VCA goes - seems I just need those if I build something with the VCA.

ZD2+3: I don't need them, because I got +/- 24 volts

C9, R14: I don't need them, because I don't do an active EQ

R11: No VCA, no R11 needed

R12: another for the VCA

C8: without a value on the schematic - duh! Huh? I got no clue. Perhaps if stuff oscillates?

[Joe Malone]

I have been at my Dingo over the holidays and came up with a few questions.

C 1+2 no strip on the side to mark "minus" - but legs different, the shorter
should be "minus", right?

C1 and C2 in the kit are 10uF Non Polar so can go around.

C 5+7 / C 12+13 = are 16 volts, but 25 volts rating on the schematic.. (with my +/-24 v PSU) I guess that's okay because Joe knows what he does. No strip = shorter leg: minus

All 470uF are now 16v Non Polar types so can go in either way around. Voltage type could be as low as 10v as they are only blocking from a few millivolts with normal opamps to a couple of volts with JLM99v.

C6 and ZD1- not in the bag - located right near where the VCA goes - seems I just need those if I build something with the VCA.

Correct. Only used on VCA compressor so not included.

ZD2+3: I don't need them, because I got +/- 24 volts

Correct. Do not fit when providing +/-24v. Only use when running from 48v single rail like our 48v SMPS.

C9, R14: I don't need them, because I don't do an active EQ

Correct. Only used on EQ so not included.

R11: No VCA, no R11 needed

Correct. Only used on VCA compressor so not included.

R12: another for the VCA

Correct. Only used on VCA compressor so not included.

C8: without a value on the schematic - duh! Huh? I got no clue. Perhaps if stuff oscillates?

Correct some opamps may oscillate if the circuit impedance driving there +in pin goes to high. If so a C8 of 47pF to 100pF will usually stop the oscillation.

[frans]

Joe, you make me feel smart!!!

[Joe Malone]

Joe, you make me feel smart!!!

[frans]

My slow build... (better slow than faulty) I hooked the Dingo (without the 99vs in their place) up to my +/-24v AC/DC and measured
at the opamp socket pins with my DMM. Plus and minus 24 volts are +24.4 /- 24.0, 0 volts is 0 volts, fine. (just made a note to revisit
the trimmer on the AC/DC to get the +24.4 closer to +24.0)
At the -input and output pin there's (debalancing side) +0.9 volts, same on the output/balancing side but with -1.4 volts on -input and output pins.
Is that okay?

I plan to build a MacOpto later this year and I've got an empty 19" that has been measuring equipment in it's former life, there's a nice PSU
in there with +/-15 volts and 5 volts. Which JLM opamps would fit that? I guess the debalancing side could take a OPA2604AP, but for the
output transformer I want something with more muscle, would the +/16v 99v be good or rather a JLM25HV or JLM25HVFET?
The 5 volts could supply the LEDs and maybe the relay on the Dingo?

[Joe Malone]

My slow build... (better slow than faulty) I hooked the Dingo (without the 99vs in their place) up to my +/-24v AC/DC and measured
at the opamp socket pins with my DMM. Plus and minus 24 volts are +24.4 /- 24.0, 0 volts is 0 volts, fine. (just made a note to revisit
the trimmer on the AC/DC to get the +24.4 closer to +24.0)
At the -input and output pin there's (debalancing side) +0.9 volts, same on the output/balancing side but with -1.4 volts on -input and output pins.
Is that okay?

That all sounds fine.

I plan to build a MacOpto later this year and I've got an empty 19" that has been measuring equipment in it's former life, there's a nice PSU
in there with +/-15 volts and 5 volts. Which JLM opamps would fit that? I guess the debalancing side could take a OPA2604AP, but for the
output transformer I want something with more muscle, would the +/16v 99v be good or rather a JLM25HV or JLM25HVFET?
The 5 volts could supply the LEDs and maybe the relay on the Dingo?

On +/-15v with 1:2 output transformer you can use JLM99v LV, JLM25HV or FET, V8 etc.

[frans]

Another successful JLM build! I did the Pultec clone from the NRG forum with a Dingo and two 99v
http://www.nrgrecording.de/nrg/viewtopi ... sc&start=0
and even if there's a rat's nest of 36 wires from the board to the pots and switches (thank god for multi-pin connectors) I got everything to work at first attempt. Thanks to Joe, the patron saint of DIY and his very, very well thought-out multifunctional kits. I drooled over the pics of his Pultec and would prefer a JLM board where the switches and pots solder right on the board without wires - but I assume Joe got his reasons for not selling this board... and his finished Pultec is simply too much for my wallet but surely 101% worth it. Soooo... now on with the show: another two channels of 99v preamps are waiting in the basement...