Preamp Volume/Balance question

[Face]

Originally Posted by tdelahanty

This issue isnot uncommon with conventional volume controls. Back in the day the resistive elements were carbon and mechanically aligned, allowing a larger margin for error. Today the resistive elements are made of much better materials and are laser trimmmed for a greater level of accuracy. I doubt there is a problem with your volume control unless it is intermittent or noisy.

Unfortunately, it still occurs in modern preamps. The Peachtree Nova was also known for this.

[Labpro]

Hello Cellindo,

Thanks for your advice.
The "humm" really is frustrating.
When you take the time and effort to lower the noise floor, and then have a consistant "humm," it's hard to enjoy the music.
Let me see what my Shindo dealer is able to accomplish. I'll keep the isolation transformer idea in mind also.

Thanks!
Labpro

[Labpro]

Hello tdelahanty,

Thanks for your message.
My Shindo dealer is trying to figure this out.
I think you are right about the iron plates.
I'll keep you posted.

By the way, I was a long time Thiel fan.....had 7.2's. Bought them from Peter McGrath (the famous sound engineer) many moons ago.

Enjoy,

Labpro

[Whart]

Labpro- does the transformer buzz diminish at all after the unit has been on for a while? (not just warm up period for listening but after several hours?)

[cmalak]

Labpro...I may have missed this but have you tried any type of power regenration unit like a PS Audio or a PurePower unit? If it is presence of DC on the line a regenerator could potentially fix the problem. Also, if you have any light dimmers in use on the same circuit that your stereo system is on, that could also be introducing some DC in the line I believe so you can try either having dimmers off completely and see if that helps. Good luck.

[FranklinLG]

So what ultimately happened with this? Did you get the hum resolved? If so, how? What was the cause?

[kev313]

Originally Posted by FranklinLG

So what ultimately happened with this? Did you get the hum resolved? If so, how? What was the cause?

I think he's selling them?

[Labpro]

Thanks for all the feedback and advice on the transformer Humm issue.

It turned out to be a combination of a couple things.

My Shindo dealer placed some vibration absorbing paper on the transformer, and this addressed the mechnaical Humm issue immediately. I like it so much that I want to "paper" my Giscours preamp too.

What I did not consider, is that I switched out my wall plugs, which must have been running "hot" because when I installed the original wall plugs, everything went silent again.

The plugs ended up being the real issue, not the amp. It is amazing how every little change makes a big difference.

Thanks again for everyone's expertise and advice!

Labpro

[omodo]

Labpro, do you have any details of the type of paper used? I have quite bad mechanical hum from my Mr.T transformer which I have not been able to resolve

[kev313]

Originally Posted by omodo

Labpro, do you have any details of the type of paper used? I have quite bad mechanical hum from my Mr.T transformer which I have not been able to resolve

I had the same. Turned out to be my outlet.