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Bellari RP220 mod - LL1530

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Posted on September 22, 2009 at 17:14:45
electricgoose
Audiophile

Posts: 2
Joined: September 22, 2009
 Dusting off my Bellari RP220 and putting in a LL 1530 input tranny to bring out some life from the tube preamp.

Does anyone know where color codes leads connect to the 1530?

Thanks!!

RE: Bellari RP220 mod - LL1530, posted on September 22, 2009 at 17:57:50
KevinC
Manufacturer

Posts: 1999
Joined: April 19, 2001
Contributor
  Since: October 7, 2002
 Gotta schematic?

Kevin Carter
K&K Audio
www.kandkaudio.com
RE: Bellari RP220 mod - LL1530, posted on September 23, 2009 at 07:23:40
electricgoose
Audiophile

Posts: 2
Joined: September 22, 2009
 I couldn't find a schematic for the RP220. It was a Black Lion Audio modification that was suggested to replace the stock input tranny with a LL1530, but no instructions on hookup. I took my best guess and hooked up the tranny, but I got a low output. I tried to reverse the wiring but same problem.

The four wires going to the PCB for the input tranny are - One to ground. One to (+) XLR in. One to (+) XLR in though a resistor. One to input pad switch.

If you have any hints on where to start, let me know. Otherwise I will keep trying to figure out the schematic by looking at the pcb.

Thanks for your help!

RE: Bellari RP220 mod - LL1530, posted on September 24, 2009 at 05:36:07
KevinC
Manufacturer

Posts: 1999
Joined: April 19, 2001
Contributor
  Since: October 7, 2002
 My first guess would be that the transformer should be wired as 1:7, which is shown in the LL1530 data sheet at the bottom right. The input side (left side in the data sheet diagram) "+" lead should be connected to XLR pin 2 and the other lead to XLR pin 3. The output side "+" lead should be connected to the input pad on the PC board and the other lead to the PC board ground. You can determine which is ground and which is input using an ohmmeter. Connect one ohmmeter lead to an obvious PC board ground point and then test the two input pads. One should read almost no resistance (that would be ground) and the other should be much higher ( that would be the input).

Kevin Carter
K&K Audio
www.kandkaudio.com

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