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Donald
11-03-2004, 07:49 PM
Just got a used Carver amp that has the 3 pin Cannon plug input or 1/4" 3 conductor phone plug.

What is best way to connect a pre-amp with RCA jack to this amp? Use 2 conductor shielded with red going from RCA center pin to Cannon + and RCA shield to Cannon -. What about the ground pin on the Cannon and the sheild in the cable? Same question for 3 conductor phone jack.

Oldmics
11-03-2004, 08:08 PM
Might be a Pin 3 hot amp (+).

Whereas you would want to keep your signal polarity correct thruout.

Oldmics

Zilch
11-03-2004, 08:17 PM
I just go buy Hosa cables at the pro audio store. The generally recommended scheme is to connect the RCA pin to the XLR "hot" pin 2 or TRS "tip," and the RCA shield to both the XLR "cold" pin 3 and "shield" pin 1 or TRS "ring" and "sleeve." Make sure which pin is "hot" (+) at Carver input, i.e., pin 2 or 3. AES standard is pin 2.

If ground loop problems occur, try leaving the input ground (shield or sleeve) connection disconnected.

Many balanced input amps (check Carver to be sure) are set up so that the unbalanced-to-balanced conection has been anticipated in the wiring of the input jacks, and a 1/4" TS inserted into a 1/4" TRS balanced input automatically unbalances the input and makes all the right connections. In this case, just wire RCA pin to TS tip, and RCA shield to TS sleeve and hope there's no ground loop problem....

boputnam
11-03-2004, 08:22 PM
Donald:

Oldmics makes an important point on the inconsistency of "old" balanced gear - there was a time when much of it was Pin3 = +. Now, we here have adopted Pin2 = +, but you might need the Carver manual to be certain.

If/when you get it, and determine proper wiring, you should in any case consider dripping Pin1 (shield) at the inputs to the Carver. This will physically break the ground loop possible between the unbalanced pre-amp and balanced amp.

But you gotta figure-out which is Pin hot, first...

Donald
11-03-2004, 08:36 PM
Got to hit RS for parts tomorrow. :-)

It is a Carver TFM-22. 350w/ch into 8 ohms.

Oldmics
11-03-2004, 10:11 PM
I don"t have the schematic for the TFM 22,however I do have schematics for the TFM 15,TFM 25, and theTFM 35 .According to the schematics that I have, ALL of these units are Pin 3 hot.

Its a safe bet that the TFM 22 is a Pin 3 Hot device.Bob wouldnt change his design philosiphy on an amp of similiar series.

Flip em if ya got em!!!!!

Oldmics

Mr. Widget
11-03-2004, 11:44 PM
Originally posted by Donald
Got to hit RS for parts tomorrow. :-)


Go to RS if you absolutely can't wait to hear your new amp, but I would strongly recommend you order some Neutrik connectors and use the shielded cable of your choice. I have had more RS connectors fail on me over the years than I care to recount. Occasionally they will carry Switchcraft which is OK but usually they carry real crap in their little blister packs.

Widget

jblnut
11-04-2004, 08:01 AM
I have several pro amps in the house including a Carver PM175 and I use Monster Studio 1/4" to RCA cables to connect them to home audio gear. I 've never had any noise or gounding issues using these cables. Perhaps using the XLR inputs and their more expensive cables is overkill, especially when you're not really using the ground capability converting to RCA on the other side ?

jblnut

Donald
11-04-2004, 01:18 PM
So 1/4" mono phone jacks are OK? Meaning barrel and tip. Or do I need stereo 1/4" meaning barrel, ring and tip?

If the latter, which 2 of the 3 are using for hot and ground?

Mr. Widget
11-04-2004, 01:32 PM
You should be able to pop the lid and discern that rather easily. Other than the possibility of inverting phase, I would expect mono 1/4" phono plug adapters would work with standard RCA cables.

Widget

Donald
11-04-2004, 05:37 PM
Sorry, I have so many Carvers showing up I had the wrong model. The one in question is a PM 1.5. Not a TFM-22. That just arrived and it has plain RCA inputs.

Oldmics
11-04-2004, 06:13 PM
Pin 3 Hot-Definitely

Enjoy the Fan Noise

Oldmics

boputnam
11-05-2004, 10:26 AM
Originally posted by Oldmics
Enjoy the Fan Noise :rotfl: Or, stuff your racks in the pantry... :hmm:

MJC
11-22-2004, 07:46 AM
You should be able to pop the lid and discern that rather easily. Other than the possibility of inverting phase, I would expect mono 1/4" phono plug adapters would work with standard RCA cables.

Widget
I'm using a Monster Z Bass 100 connecting the sub out on a Marantz 880 receiver to the 1/4" phono input on a K2. At the K2 I'm using a mono 1/4 to rca adapter.
I don't have a hum problem, but when I change tv channels, either with c-band sat receiver or the OTA HD receiver, I get a thump. If the Crown is turned off then the thump dosen't occur. What is the best way to get rid of the thump?

dieterj
11-22-2004, 08:41 AM
What is best way to connect a pre-amp with RCA jack to this amp? Use 2 conductor shielded with red going from RCA center pin to Cannon + and RCA shield to Cannon -. What about the ground pin on the Cannon and the sheild in the cable? Same question for 3 conductor phone jack.
Hello Donald, this a Schematic from my Crown Amp,

boputnam
11-22-2004, 12:47 PM
Hello Donald, this a Schematic from my Crown Amp, Nice. Here's a .pdf I created from it...

Donald
11-22-2004, 06:09 PM
Well, the Carver had the pins usage silk screened on the back of the unit. :-)Pin 3 is +, 2 is - and 1 is ground. My RCA center goes to +, RCA shield to 2. 1 is not connected.

I have no hum I can hear.

Donald
11-22-2004, 06:12 PM
Bo,

Thanks for the diagram.