Pro Audio Design Forum

mediatechnology wrote:I thought the only justification for an active MC preamp module at this point might be cost.

It looks like the LL1678 is about $105 each? It might be comparable cost-wise too if it takes as many as 3-4X 1512/channel.

That's right, from K&K Audio. The Jensen's are also about the same price.

The one item we haven't added in this investigation is the effect of the optimum load capacitance. I was looking at the Jensen MC transformers last night. It surprised me to see that their test circuit loaded the secondary with a C as well as an R. That's the first time I've seen that for an MC car...

What was the overall preamp/EQ gain with the LL1678 and DL-103 to get to +4 dBu? I don't have an exact number because I tweaked the termination resistor by hand. Every time the value went up so did the level. The basic idea was to have 7cm/sec lateral produce -2dBu at the output of the preamp. Then...

Here is a shot of the final build. There were some issues with bringing the A/B gain switch to the front panel so that was undone. I also did a bit of rewiring. I've never gotten the phono playback so close to sounding like the source before. I have the Denon DL103 almost unloaded. It's a 221kΩ in p...

mediatechnology wrote:
Glad it was worthy of replacing the vintage Shure SE22.

It was no contest. This is not only quieter but sounds better.

I removed the old Shure SE22 phono pre I was using today. I'm all in. I'm going to build a "demo unit" and pass it around. I'm very curious to get feedback from others (mostly cutters). First I need to finish restoring the lathe I'm supposed to deliver in six weeks...At least I got this bu...

Paul - You might want to cut the wire ties bundling the left channel gain switch to the right channel input leads and re-route the left gain switch separately. That might be introducing a capacitive imbalance in either the right channel input or left channel front-end. The imbalance was there befor...

I did some more work on the gain switching I want. I set it up with the gain range I wanted and the fine trim. http://www.saltmastering.com/PTS/PTS-gain-1.jpg +/- 6dB wasn't a fine enough resolution for me so I tried +/- 3dB. Still no good. I am using this primarily for reference listening so I want...

Thanks. It's going to be very flexible. I realized that with a 1:32 step up the Denon 103 wants to see a 100k load which is already there. I was using 1:16 before. I was going to use a second set of transformers for the SPU. Now all I have to do to change over to the SPU is put the right value paral...

Wayne was kind enough to send me assembled and tested PCB's to build a Phono Transfer System. This is like a dream come true for me. I've always wanted something like this. My needs are different than Wayne's so I built it up a bit different. My primary use is to interface with a lathe for playback....