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#1
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Anyone have a MOTU MTP-AV, a multimeter, and five minutes?
My MTP-AV ties all the ground pins on both input and output connectors
to the chassis. This violates the MIDI spec, which is specifically designed to prevent ground loops by having devices ground ONLY the output connectors. I sent an e-mail to MOTU, which of course went unanswered. I called today and (after half an hour of busy signals) spoke to a rather obnoxious rep named Steven, who assured me that it was probably just my unit, and if I sent it in they would replace it with another. I asked him to test a unit there, and he said he didn't even have one to test. This seems like a design flaw, not a broken unit, so I don't want to lose the use of my unit for a week while they send me one with the exact same problem. Could someone check out their unit? Ground is pin 2 of the MIDI spec; if pin 2 on an input connector is connected to the chassis, you have the same problem I do. (Tip: It's a lot easier to check the pin of a cable than to try to get a probe into those DIN plugs.) Could someone see if theirs has the same flaw? I'd also be curious to see if the newer MIDI Express XT has the same problem. -- Jay Levitt | Wellesley, MA | Hi! Faster: jay at jay dot eff-em | Where are we going? http://www.jay.fm | Why am I in this handbasket? |
#2
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Anyone have a MOTU MTP-AV, a multimeter, and five minutes?
The front-panel MIDI port (#8) on my MTPAVUSB has Pin 2 grounded on the
MIDI out and NOT grounded on the MIDI in. If you ask them, they will take your credit card number, place a charge hold on it for the amount of a new MTP as a deposit, and send you another unit. When you get it you send your old MTP back and your card never gets charged and you have about 15 minutes downtime. Jay Levitt wrote: My MTP-AV ties all the ground pins on both input and output connectors to the chassis. This violates the MIDI spec, which is specifically designed to prevent ground loops by having devices ground ONLY the output connectors. I sent an e-mail to MOTU, which of course went unanswered. I called today and (after half an hour of busy signals) spoke to a rather obnoxious rep named Steven, who assured me that it was probably just my unit, and if I sent it in they would replace it with another. I asked him to test a unit there, and he said he didn't even have one to test. This seems like a design flaw, not a broken unit, so I don't want to lose the use of my unit for a week while they send me one with the exact same problem. Could someone check out their unit? Ground is pin 2 of the MIDI spec; if pin 2 on an input connector is connected to the chassis, you have the same problem I do. (Tip: It's a lot easier to check the pin of a cable than to try to get a probe into those DIN plugs.) Could someone see if theirs has the same flaw? I'd also be curious to see if the newer MIDI Express XT has the same problem. |
#3
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Anyone have a MOTU MTP-AV, a multimeter, and five minutes?
I just checked a Midi Express XT USB and a parallel/ serial unit and
all of the outputs have pin 2 tied to chassis, pin 2 is floating on all inputs on both models. |