DINGO PCB and kit BUILD THREAD

[Joe Malone]

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...

Cool Glad you liked the Dingos with the 99v opamps!

We have looked at doing a kit of the super JLM enhanced pultec but we can build the pultec almost as quick as it would take to pack the kit due to the huge amount of cap values that would need to be in the kit.

Lots of new JLM kits and gear coming out this year before we get to look at it again seriously.

[Majestic12]

Hi,

can I use two of these kits to rack up an old SSL stereo EQ module (with unbalanced stereo I/Os)) and have a stereo gain control at the output to compensate for EQ changes ?
I'd like to have only one knob to control both sides at once.

[Joe Malone]

Hi,

can I use two of these kits to rack up an old SSL stereo EQ module (with unbalanced stereo I/Os)) and have a stereo gain control at the output to compensate for EQ changes ?

Yes easy to do with dingo or dingo pup kits with DIL dual opamp output like NE5532AP or OPA2604AP (electrical balanced output like SSL balancing modules use can be done on dINgO PUP kit as well)

or DOA opamp like JLM99v JLM25HV and JLM111DC output transformer (but probably overkill for this application and can only be done on dINgO kit)

I'd like to have only one knob to control both sides at once.

Use a 10k dual log pot wired as a volume control between the output of the SSL modules and the unbalanced into the dingo output amp.

[Majestic12]

Hi,

can I use two of these kits to rack up an old SSL stereo EQ module (with unbalanced stereo I/Os)) and have a stereo gain control at the output to compensate for EQ changes ?

Yes easy to do with dingo or dingo pup kits with DIL dual opamp output like NE5532AP or OPA2604AP (electrical balanced output like SSL balancing modules use can be done on dINgO PUP kit as well)

or DOA opamp like JLM99v JLM25HV and JLM111DC output transformer (but probably overkill for this application and can only be done on dINgO kit)

I'd like to have only one knob to control both sides at once.

Use a 10k dual log pot wired as a volume control between the output of the SSL modules and the unbalanced into the dingo output amp.

But this way I can only attenuate the signal. Can I also have gain boost in a stereo application without adding additional components ?

[Joe Malone]

Hi,

can I use two of these kits to rack up an old SSL stereo EQ module (with unbalanced stereo I/Os)) and have a stereo gain control at the output to compensate for EQ changes ?

Yes easy to do with dingo or dingo pup kits with DIL dual opamp output like NE5532AP or OPA2604AP (electrical balanced output like SSL balancing modules use can be done on dINgO PUP kit as well)

or DOA opamp like JLM99v JLM25HV and JLM111DC output transformer (but probably overkill for this application and can only be done on dINgO kit)

I'd like to have only one knob to control both sides at once.

Use a 10k dual log pot wired as a volume control between the output of the SSL modules and the unbalanced into the dingo output amp.

But this way I can only attenuate the signal. Can I also have gain boost in a stereo application without adding additional components ?

Yes you get gain without adding any parts. The dINgO or dINgO Pup will give 6dB of gain due to the electronic balancing and another 6dB to 34dB of gain with the 20k 25turn trim gain pot fitted. So you can have as much gain as you like.

[rmiller335]

I'm finally getting around to the summing bus I asked about last summer. I've constructed one of the boards, according to the drawings you sent me, and the board measures 11-12 ohms from +vs to 0v and from 0v to -vs, which the PS reads as a short. I am including links to the drawings and a photo of the board in the hopes that you can see what's wrong. I confess to being a bit unclear as to some of the specs so hopefully it's something simple.

http://www.villamilla.com/fileshare/Schematic.jpg
http://www.villamilla.com/fileshare/Drawing.jpg
http://www.villamilla.com/fileshare/Board.JPG

Cheers,
Bob Miller

[rmiller335]

It turns out both zener diodes were shorted. Not sure how that happened, but I replaced them and the voltages are good. Now to wire it up and see what it does with a signal.

Cheers,
Bob Miller

[Joe Malone]

It turns out both zener diodes were shorted. Not sure how that happened, but I replaced them and the voltages are good. Now to wire it up and see what it does with a signal.

Cheers,
Bob Miller

Sorry just got back from being away. Yes the only thing that will put close to a short across the power rails besides a solder short is the zeners diodes gone short or a DIP8 dual opamp in backwards. Both will should make the 2 x 10R smoke.

[rmiller335]

Thanks, Joe. The power supply caught the short and saved the resistors. I've still got something wrong though. I wired everything up today and put the opamps in. When I put the op amps in the voltages went from 20.33v/19.62v to 15.53v/23.9v, and it's just barely passing signal. What do you think?

Cheers,
Bob

[Joe Malone]

Thanks, Joe. The power supply caught the short and saved the resistors. I've still got something wrong though. I wired everything up today and put the opamps in. When I put the op amps in the voltages went from 20.33v/19.62v to 15.53v/23.9v, and it's just barely passing signal. What do you think?

Cheers,
Bob

If the power supply is set to 48v and you are getting those voltages the 10R resistors would be smoking due to a fault.

Is the power supply is set to 48v? And you do have 24v zeners fitted? You should have close to +/-24v at the opamp power pins as the 2 x 10R will not drop more than 0.5v.

Do you get +/-24v without the opamps fitted?

Are you driving the dingo input with series 20k resistors like the summer will do? (or you will destroy the input opamp with the mods done)

Check that you have good audio at the unbalanced out going to the volume pot?

Let em know here what you find.

[rmiller335]

Okay, I had the PS voltage set too low. With that at 48v, all the voltages look okay. The 24v zeners are fitted, and I added 20k resistors in series with my signal (I was using a mic level signal and thought that would be okay). With all that done, I'm getting signal with good gain at the unbalanced out going to the volume pot, but very low signal at the output to the transformer. There's been no smoke or even a warm component so far.

[rmiller335]

By the way, I checked the output pin of the second op amp and that's also very low.

[Joe Malone]

By the way, I checked the output pin of the second op amp and that's also very low.

R19 51R is missing on the dingo PCB so nothing will get to the output transformer at all.

[rmiller335]

I knew there was a stupid mistake in there somewhere. That did it, thanks.

[Joe Malone]

I knew there was a stupid mistake in there somewhere. That did it, thanks.

Cool. Good to hear you have it working.