MAC RACK KIT with Green MAC & DINGO PCBs Build Thread

[Andreas]

Has it been covered somewhere how to connect the transformers?
I need help with it, please

[Joe Malone]

Has it been covered somewhere how to connect the transformers?
I need help with it, please

In first post of this thread

Dingo to JLM111DC wiring
P- to -1
P+ to +1
S+ to +2
S- to -3
Link +3 to -2 on JLM111DC

[Andreas]

Ooops, I must have been blind…Thanks for your help

[Andreas]

Aaargh…killed some 24V Zeners because I didn´t connect the meter correct.
Is there a picture or something how do connect the meter?

[Andreas]

According to this page, the meter doesn't show all connections. There are connections for the led and the coil. Which is which?
http://www.jlmaudio.com/shop/index.php?_a=viewProd&productId=20

Ok. got it to work. The inner connections are for the coil.

I suggest a PDF with all the relevant data

[goldstache]

Hello Joe! I ordered a dingo pup and mac about 2 years ago and am finally getting around to assembly. I have an old opamp labs bipolar power transformer, current rated up to 100ma. Will this be enough for both units? I'm thinking probably not, as I've seen mentioned the pup itself draws about that under use. Thanks!

[Joe Malone]

Hello Joe! I ordered a dingo pup and mac about 2 years ago and am finally getting around to assembly. I have an old opamp labs bipolar power transformer, current rated up to 100ma. Will this be enough for both units? I'm thinking probably not, as I've seen mentioned the pup itself draws about that under use. Thanks!

Maybe enough. I would certainly try it and see if the +/- rails stay regulated at the correct voltages.

[frans]

Sometimes I like the action of the MAC compressor better than me continously adapting the gain of the preamp to softer and louder parts.

[Joe Malone]

Sometimes I like the action of the MAC compressor better than me continously adapting the gain of the preamp to softer and louder parts.

[giampi]

hi joe
I am interested in this MAC compressor ..
I have some questions:
I saw from the photos mounted optocoupler Vartec or SILONEX NSL32 .... as provided in your MAC RACK kits?

Instead of DINGO kit, I would put my Tube buffer (for similar to LA2A ..)
is this possible? It must have the special features to be integrated with the MAC ???
Thanks for your answer
giampiero

[Joe Malone]

hi joe
I am interested in this MAC compressor ..
I have some questions:
I saw from the photos mounted optocoupler Vartec or SILONEX NSL32 .... as provided in your MAC RACK kits?

Instead of DINGO kit, I would put my Tube buffer (for similar to LA2A ..)
is this possible? It must have the special features to be integrated with the MAC ???
Thanks for your answer
giampiero

Yes it is possible. MAC pcb kit and MAC rack kits come with match optos. A pair for single channel or a quad of optos for stereo use.

You could use a 1:1 input transformer and 100k input impedance tube make up amp which could just be a 100k log pot feeding tube input amp for for makeup.

The dingo also has a hard bypass relay circuit which is controlled by the GR / OFF / VU switch on the MAC which should be added to your tube setup.

The feed from the unbalanced output of the tube makeup amp before the step down output transformer would need to be attenuated for the VU meter cal to work properly. Adding a series resistor between JLMIO pin 7 & unbalanced tube amp output before the output transformer would work. So If using 4:1 output transformer which would give 12dB attenuation use 150k series resistor to match balanced output level so VU meter pot on MAC will cal properly. VU buffer input impedance is 47k.

If you look at the dingo schematic on here you will see how to wire everything to the JLMIO connector to make this work.

[nkay24]

Hey Joe,

Having some trouble with my Mac kit still, i emailed you about some different problems a couple months ago. Anyway i've got it up and working on my bench, calibrated and compressing fine, all the voltages check out and ground points to the chassis. But i'm having trouble when i put it in my rack, when the chassis grounds with the other gear in my rack it goes into its safety mode (lights flashing) and pops a zener on the dingo. Im using an aftermarket 48V - 65W power supply from jaycar as the guy i got the kit off couldn't find the original power supply. Has me baffled as to what is going on. Hope you can help.

Cheers,
Rohan

[Joe Malone]

Hey Joe,

Having some trouble with my Mac kit still, i emailed you about some different problems a couple months ago. Anyway i've got it up and working on my bench, calibrated and compressing fine, all the voltages check out and ground points to the chassis. But i'm having trouble when i put it in my rack, when the chassis grounds with the other gear in my rack it goes into its safety mode (lights flashing) and pops a zener on the dingo. Im using an aftermarket 48V - 65W power supply from jaycar as the guy i got the kit off couldn't find the original power supply. Has me baffled as to what is going on. Hope you can help.

Cheers,
Rohan

HI Rohan
The 48v is split into +/-24v by the 24 zeners on each dingo pcb and the 0v on the dingo should be connected to the case. Make sure the -V -24v rails is not shorted to the case instead by a rack screw under the dingo pcb or by any wiring as then the problem you describe could happen.

Attach here or email me a few large clear well lit photos of the MAC build and wiring if you cannot find the short so I can check it over.

Or you can ship it us to do the repair.

[frans]

Hello Joe, the meter light of my MAC has gone dead and i wondered if there's voltage on or if it's the light in the meter. Took the multimeter to it and got +30 volts ... So there's additional wondering if something on the board crapped out. 30 volts seem a bit high and maybe that blew out the light in the meter? Could it be R14?

[Joe Malone]

Hello Joe, the meter light of my MAC has gone dead and i wondered if there's voltage on or if it's the light in the meter. Took the multimeter to it and got +30 volts ... So there's additional wondering if something on the board crapped out. 30 volts seem a bit high and maybe that blew out the light in the meter? Could it be R14?

If the led is working you will get about 2v but if it goes open circuit you will read about 30v. This is feed via a resistor and relay coil and is normal.

To test link the outside terminals of the meter with a wire to short them together and the comp should work perfectly but have no meter light.

We have the 5mm clear leds listed on the webshop under VU meters. Or use a clear white 5mm led around 800 to 1000Mcd.