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.
128x128ninetynine
If Pass is correct that the INT-150 has the headroom to handle 8mv, it's difficult to imagine a nominal 1mv cartridge inducing overload. That said, preamps can suffer problems beyond simple overload that can distort loud peaks, and the passage you described is ideal for challenging such problems.

Of course it could as simple as VTF being a hair too low for those particular (torturous) passages. Before going crazy, trying bumping VTF up a hair.

It could also be that your tonearm in combination with the JSD resonates internally at certain frequencies. High amplitudes at such frequencies (or multiples thereof) can feed energies back into the cartridge generator... similar to the feedback loop when a microphone's gain is set too high. (Note: I am NOT talking about the generic arm/cartridge resonance test that people use mathematical formulae and test records to bring within the 8-12Hz range. That simplistic test has nothing to do with this problem.) Arm/cart acoustic behaviors can be tested by doing something as simple as sliding a sliver of paper between the cartridge body and headshell. This tends to change a cartridge/tonearm interaction significantly.

Many possible causes. Much experimentation in your future.

Lower the gain on your phono pre. The EMT has twice the output of your AT.
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.
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.
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.
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).
The distortion is with RCA connection too.
The distortion is on the preamp out`s of the Pass too.
Yes, the distortion is generated in the Pass.

Do you read this?
I connect a Focusrite Firewire Interface to the Audia Pre Outputs with XLR cables. This audio interface accepts +16dBu. It clips a little too!

The meter of the Focusrite was red when the trumpet plays.
So the Audia had about 14V at the outputs.
If you go to what you list as chain 1 and swap just the cartridge (Put the AT in place of the EMT), the system should play fine. Even if you don't plan on using your setup this way, it will be a good check to make sure that nothing in the system is damaged.

Going back go chain 1 as you list it. There is one simple thing you can try. I would give it a 50/50 chance of working. Remove the xlr IC's going into your Pass, install the jumpers between pins 1 and 3, and use a pair of single ended rca IC's instead. Going single ended will lower the gain of your source, and may be enough so that you can use your EMT. This is something that you really should try. I think it has a good chance of working.