Ani - I am certainly not an expert in these matters, but it's quite common that electronic "boxes" have low output impedance and high input impedance. A box with low input impedance might load down the connected input and change the FR or S/N characteristics. An exception to this generalization is professional gear, that usually uses 600 Ohm balanced inputs and outputs for low level interfaces. Hence the low input impedance of your UCD amps and the balanced inputs.
An input buffer circuit would connect to the signal inputs and provide a high impedance interface while working well with the low(ish) input impedance of your UCDs.
But Chahly - Stahkist don't want speakers that look good, Stahkist wants speakers that sound good!
More like this:
This is the one included in the ucd180 and what google told me hypex recommended to use with your modules.
Now, looking at the UCD180's datasheet, it needs just 1.34V input to go to max power. So it would seem that would hold true if you used that same buffer.
That clean box should drive it with no problem, not sure about the DAC.
The Cleanbox Pro should work fine: it will convert from unbalanced inputs to balanced outputs and also provide the bufferring needed. The balanced output impedance of the Cleanbox is 300 ohms which should easily drive the 1.8 Kohm impedance of the amp. Plus the Cleanbox Pro has a gain control so you can adjust the maximum output of the amp.
@rjj45 said:
But isn't the cleanbox a 2 channel device, and he will need 8 channels of balanced input for the whole project?
yes, the art clean box pro is 2 channel, but this is what i have immediately on hand to try - i can get 3 more. Input buffer might be a solution, but might be a bit much for me to chew on right now, step by step!
Since this would be for active speakers, the miniDSP 4x10HD has balanced out, but I am not sure about the impedance match or if it puts out enough volts to be able to power the UCD32MP. The flyer states 4Vrms (+14 dBu) or 8Vrms (20dBu)
Maximum Output signal Dip switch on motherboard attenuates outputs by 6dB (RCA & Terminal blocks)
Unbalanced outputs (RCA): 2Vrms (+8 dBu) or 0.9Vrms
Balanced outputs (Terminal block): 4Vrms (+14 dBu) or 8Vrms (20dBu)
I don't have a minidsp 4x10HD, so if someone is looking to get rid of one, please let me know!
Another more high end option would be (at double the cost of the miniDSP 4x10HD)
I already have a minidsp nano digi which has 8ch SPDIF out and Toslink/SPDIF input, so everything remains in the digital domain. To this I can connect an 8 ch DAC. The issue is htere isn't many 8ch DAC with balanced out.
I do have 4 small cheap SPDIF DACS, but they are not balanced.
The Okto Dac8Pro is a 8 ch DAC with balanced out. The output are as follows: Main outputs (back side)
o 8 x Neutrik gold-plated XLR connector
o Output level: 4.1 V RMS differential full-scale
o output impedance: 200 Ohms
The Okto Dac8Pro is state of the art, so would be a good investment, but would be overkill for the UCD32MP, but then i have other boards waiting in line to get built into multi-channel amps.
I want to do a bench test and place an order for some basic parts.
What's a good way to do a bench test? I have breadboard jumper wires (short wires with stiff ends). Push the ribbon harness into the j2 connector and on the other end, use the jumpers to connect the pins for amps and amp enable.
I still need to buy balanced xlr cable and cut I half and somehow connect the bare wires to the ribbon for audio in. Any suggestions?
Also for the power, I can go lamp cord plug to fused/ switched surge protector. On the amp end what's a good way to connect? Twist the wires together and electrical tape or some better means of temporary connection capable of handling mains power?
I am going to place an order for a pair of XLR cables, so i can cut and strip them a bit and use aligator to pins cable to connect to the board. And use the level nuts for the mains connections.
This should be good for the bench testing of the amp board. Next to decide on the layout and look for the amp box and the various connectors, wires, etc that would be needed.
Can I use a DMX connector for the XLR cable connection? This would be cleaner and I don't have to cut/splice/destroy an XLR cable. But i don't know how a DMX is different from audio XLR. There seems to be an led/resistor in line, but i will be using only the in portion - so this would be open?
I got a lamp cord for the testing. I was asking about the internal wiring. THNN wire is pretty stiff. But I might stick to it till I find some better alternative.
As far as what's available at home centers, you can get S.O. cord and strip the outer jacket, or like stated above strip the outer jacket from an extension cord, but you don't need much, as it is only for the line voltage connections, so a few feet of S.O. might be your best bet. For the other low voltage connections just grab some hook up wire from a home center or even an auto parts store. If your in no hurry Parts express, Newark, and any other electronics seller will have what you need.
Anyways Menards has only THNN wires. Got a small spool of 14 red, 14 black and a 12 green for now. These seem to be more expensive than speaker cables. I am used to more flexible wires, but I haven't touched any electrical stuff in the US.
Carol direct burial SO cable. FWIW- PE has lower prices than Amazon for it. I tend to go to the local contractor's electrical supply shop and purchase by the foot and get it for about half price.
Comments
Ani - I am certainly not an expert in these matters, but it's quite common that electronic "boxes" have low output impedance and high input impedance. A box with low input impedance might load down the connected input and change the FR or S/N characteristics. An exception to this generalization is professional gear, that usually uses 600 Ohm balanced inputs and outputs for low level interfaces. Hence the low input impedance of your UCD amps and the balanced inputs.
An input buffer circuit would connect to the signal inputs and provide a high impedance interface while working well with the low(ish) input impedance of your UCDs.
More like this:
This is the one included in the ucd180 and what google told me hypex recommended to use with your modules.
Now, looking at the UCD180's datasheet, it needs just 1.34V input to go to max power. So it would seem that would hold true if you used that same buffer.
That clean box should drive it with no problem, not sure about the DAC.
I would just test it with both
Ani -
The Cleanbox Pro should work fine: it will convert from unbalanced inputs to balanced outputs and also provide the bufferring needed. The balanced output impedance of the Cleanbox is 300 ohms which should easily drive the 1.8 Kohm impedance of the amp. Plus the Cleanbox Pro has a gain control so you can adjust the maximum output of the amp.
I concur.
But isn't the cleanbox a 2 channel device, and he will need 8 channels of balanced input for the whole project?
yes, the art clean box pro is 2 channel, but this is what i have immediately on hand to try - i can get 3 more. Input buffer might be a solution, but might be a bit much for me to chew on right now, step by step!
Since this would be for active speakers, the miniDSP 4x10HD has balanced out, but I am not sure about the impedance match or if it puts out enough volts to be able to power the UCD32MP. The flyer states 4Vrms (+14 dBu) or 8Vrms (20dBu)
Maximum Output signal Dip switch on motherboard attenuates outputs by 6dB (RCA & Terminal blocks)
Unbalanced outputs (RCA): 2Vrms (+8 dBu) or 0.9Vrms
Balanced outputs (Terminal block): 4Vrms (+14 dBu) or 8Vrms (20dBu)
I don't have a minidsp 4x10HD, so if someone is looking to get rid of one, please let me know!
Another more high end option would be (at double the cost of the miniDSP 4x10HD)
I already have a minidsp nano digi which has 8ch SPDIF out and Toslink/SPDIF input, so everything remains in the digital domain. To this I can connect an 8 ch DAC. The issue is htere isn't many 8ch DAC with balanced out.
I do have 4 small cheap SPDIF DACS, but they are not balanced.
The Okto Dac8Pro is a 8 ch DAC with balanced out. The output are as follows:
Main outputs (back side)
o 8 x Neutrik gold-plated XLR connector
o Output level: 4.1 V RMS differential full-scale
o output impedance: 200 Ohms
The Okto Dac8Pro is state of the art, so would be a good investment, but would be overkill for the UCD32MP, but then i have other boards waiting in line to get built into multi-channel amps.
I thought there was a minidsp 2x4 with balanced out, but can't seem to find it on Minidsp site.
I want to do a bench test and place an order for some basic parts.
What's a good way to do a bench test? I have breadboard jumper wires (short wires with stiff ends). Push the ribbon harness into the j2 connector and on the other end, use the jumpers to connect the pins for amps and amp enable.
I still need to buy balanced xlr cable and cut I half and somehow connect the bare wires to the ribbon for audio in. Any suggestions?
Also for the power, I can go lamp cord plug to fused/ switched surge protector. On the amp end what's a good way to connect? Twist the wires together and electrical tape or some better means of temporary connection capable of handling mains power?
Wire nuts should do it for mains voltage.
For the input you could cut the ribbon in half and splice. That would take care of the enable pins as well.
I have these knock off wagon lever nuts which I use for XO prototyping ( moving away from my alligator bird's next XO).
It does mention they can be used for building wiring. Any idea if I can use these for mains voltage, anyone use them (or the wagon ones?)
https://smile.amazon.com/dp/B08MPX5JK3/ref=cm_sw_r_cp_apa_fabc_JFA8XGDM38VX9HEVT6M1?_encoding=UTF8&psc=1
I use those Wego nuts all the time. Both for prototyping crossovers as well as mains voltages. They are rated for 600 VDC.
From the amazon link:
Rated voltage: 250V /4KV
Rated current: 32A
That should work.
Great!
I am going to place an order for a pair of XLR cables, so i can cut and strip them a bit and use aligator to pins cable to connect to the board. And use the level nuts for the mains connections.
https://www.amazon.com/gp/product/B001URFZKM/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1
https://www.amazon.com/gp/product/B07FM7GPQN/ref=ox_sc_act_title_2?smid=A19TVI3M6WFVG7&psc=1
This should be good for the bench testing of the amp board. Next to decide on the layout and look for the amp box and the various connectors, wires, etc that would be needed.
The lever nuts I have are rated for 32A 250V, so should be good for the mains.
Though I don't know what 4KV stands for.
Can I use a DMX connector for the XLR cable connection? This would be cleaner and I don't have to cut/splice/destroy an XLR cable. But i don't know how a DMX is different from audio XLR. There seems to be an led/resistor in line, but i will be using only the in portion - so this would be open?
https://www.amazon.com/Terminal-Adapter-Converters-Controller-Decoder/dp/B00Q32V2JC/ref=cm_cr_arp_d_pl_foot_top?ie=UTF8
4kv = 4000 volts, that's the instantaneous voltage before breakdown.
Ani - those connector boards look perfect for you needs!
Thanks for the confirmations - hopefully, i will get this tested in a few days, and then onto to the rest of the build!
Hey Ani - you'll save some $ if you just buy the plugs. And avoid a headache and buy Neutrik brand -
https://www.amazon.com/Neutrik-NC3MX-B-3-Pin-Cable-Contacts/dp/B002AJYW4O/ref=sr_1_5?dchild=1&keywords=neutrik+xlr&qid=1614815644&s=musical-instruments&sr=1-5
stand-offs - brass or nylon what type is preferable? brass or nylon is available in Amazon
Nylon, and I'd check the threaded ends for continuity.
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any other alternative for THNN in 14 / 12 ga?
Cut open a power cord.
I got a lamp cord for the testing. I was asking about the internal wiring. THNN wire is pretty stiff. But I might stick to it till I find some better alternative.
As far as what's available at home centers, you can get S.O. cord and strip the outer jacket, or like stated above strip the outer jacket from an extension cord, but you don't need much, as it is only for the line voltage connections, so a few feet of S.O. might be your best bet. For the other low voltage connections just grab some hook up wire from a home center or even an auto parts store. If your in no hurry Parts express, Newark, and any other electronics seller will have what you need.
Anyways Menards has only THNN wires. Got a small spool of 14 red, 14 black and a 12 green for now. These seem to be more expensive than speaker cables. I am used to more flexible wires, but I haven't touched any electrical stuff in the US.
Menards sells S.O. cable and also small rolls of hook up wire. I believe that you can get SO cable by the foot at Home Depot.
ANI, sO cable is the stuff that is rubbery, with the black outer jacket.
Carol direct burial SO cable. FWIW- PE has lower prices than Amazon for it. I tend to go to the local contractor's electrical supply shop and purchase by the foot and get it for about half price.
InDIYana Event Website