Do Audio Experience Symphonies leak DC current?

I have spke to Katchup privately, but i'll share my responce here as well.

I have the Audio Experience Symphonies preamp and a McCormack DNA-1 power amp. The DNA goes into protection mode a lot...sometimes when I turn on other appliances (vacume, TV), other times it just goes off randomly.

I've been racking my brain trying to figure out why...pehaps this is the cause.
I will email mr. McCormack to see if this leakage would case the protection to kick on.

A search will also turn up Krell amp protection circut problems with BAT pre-amps.

Dave

I emailed YS audio about the potential problem. Hope I get a response.

I have this preamp which by the way is a very nice sounding unit. It appears to put out small amounts of dc. When I measure the dc at the output of my B&K amp it is stable at 4mv. When I hook up the pre to the amp and measure at the amp out the dc measurement walks around the zero point up to about 60mv + and - and does not stabilize at any time. This is still a low total dc out and does not seem to affect the overall sound quality. It would seem the preamp is outputing small and variable dc pulses which I am sure would trigger some amps protection circuitry.

Chui Chi Wai of YS Audio replied to me and requested that i update this thread with the following info.

he said that one output cap needs to be removed which will correct the problem of amps going into protection mode. there are two in parallel, so a simple wire cut is all that's necessary. he sent me a pic, showing where to cut. if anyone's interested i can email it.

he claimed that removing the cap will not degrade sound quality.
if you're thinking about buying a symphonies, he will sell it with one output cap if you request, and he's contemplating doing this on all symphonies now. he noted that after selling the symphonies preamp for 3 years, only two customers have had this problem.

I have similar problem with Symphonies Plus.
I like the sound quality, it is amazing for the price.
Recently, my system produces a humming noise, and this is coming from the Symphonies plus. The reason I can say this is that my cd player (CJ DF-1) has a pair of direct output with a high quality vol. control, and I connected CJ direcly to my Rogue power amp.
They are fine without any noise.

I replaced all 4 tubes of Symphonies plus including the 6x4 rectifier tube, but the same noise is still there.
I am not sure it is due to the DC current leaking or other issues.

I emailed YS to fix this issue and we will see how it goes.

If any others have similar experience, please share here.

Hi all,

I too am considering this preamp. How is the construction of the preamp? is it kinda flimsy casing and so on? This is my first post in this forum. Well, if it's a simple mod of removing a cap, woopy. If it's not built real well, then that is to be considered.

Ray

Hello! Jkimsland.

The humming noise is NOT from DC current leaking.

The cause of the hum noise is 47uf/450v caps at power supply to lost.

you replace the 4 pcs 47uf/ 450V caps at power supply to new item ,that can fix this problem.

If, you need the new 4 pcs 47uf/450v caps.
You can e-mail your address to me.
I will send the caps to you.

Thank you.
Nelson Chui

Hello! Blindman.

Please, you see the News paper at YS-Audio office web site:

http://www.ys-audio.com/news.htm

The problem have solved at August 2003.

Nelson Chui