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EMT JSD High Output - Charlie Byrd Direct Cut

My JSD has about 1mV ouput. Yesterday i heard the direct cut and the trumpets on the A-side were distorted at the loudest peaks. With my second cartridge, an AT-OC9 there was no problem. My phonopre makes 64dB gain and plays with the EMT clean, because i have connected a headphone amp to it. I think the input of my Pass Labs INT-150 is overloading. Same on RCA-Inputs.... Pass tells me the INT can go until 8V RMS on the symm. Inputs.

It is the first vinyl with this problem, but i am a little bit confused about this.
ninetynine
zd542
5,339 posts
 
Lower the gain on your phono pre. The EMT has twice the output of your AT.
ninetynine's avatar
ninetynine OP
135 posts
 
The Pass is ok and the tonearm cartridge combination too. I tested a headphoneamp at the outputs of the Audia. The Charlie Byrd song is played absolute fine. I connect a Focusrite Firewire Interface to the Audia Pre Outputs with XLR cables. This audio interface accepts +16dBu. It clips a little too!

I cannot lower the gain at the Audia Flight Phono. So i can only buy a quieter cartridge, but i love the EMT.

OK, this record has the only piece of music that maked problems.
zd542
5,339 posts
 
You should list your system and explain how its all connected. It looks like you have quite a few options to work with. Someone may have a solution for you.

"OK, this record has the only piece of music that maked problems."

Once your audio system knows it can get under your skin, it will continue to do so.
ninetynine's avatar
ninetynine OP
135 posts
 
Ok, you`re right.

1. Chain
EMT JSD6 - Reed 3P - Audia Flight Phono (250Ohm) - XLR cable - Pass Labs INT-150 - Dynaudio C1 Signature

2. Chain
AT OC9 - Jelco 750 - same rest

With second chain this trumpet is played without distortion.
dougdeacon
3,338 posts
 
1. This distortion happens when the Audia's output is sent to the Pass. It occurs whether the connection is RCA or firewire/XLR.
2. The distortion does not occur when the Audia's output is sent to a headphone amp.
3. Therefore, this distortion is originating in the Pass (or the speakers, though that's unlikely IMO).

As I posted originally, lack of headroom is unlikely to be the problem. Atmasphere (who builds amplifiers and understands these matters better than I) has frequently posted that preamp circuits with slow slewing rates can exhibit distortions that sound much like mistracking. Slewing distortions are most audible on dynamic peaks with hard blown horns, strong vocals, etc., and they have little to do with a preamp's overall headroom or lack thereof. SS circuits, especially less expensive ones, are more prone to this.

Based on the information provided, this would be my guess. You could confirm by substituting another component for the INT-150 (perhaps higher end separates).
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