Raining on My Parade...

Could those of you well-versed in analog provide some theories for this problem? After several years of being out of analog, I recently took the plunge and got some new gear.

I just received and set up my Nottingham Spacedeck/OL Rega Modified 250 arm/Dynavector 20XH cartridge. My phono stage is an Audio Research PH3, and my preamp is a First Sound Presence Deluxe MK2. All the connections appear to be correct, but when I tried to play a record, there was an immediate loud popping sound--or to be more precise, a double pop, which occurs about once per revolution. At first, I thought the record was scratched, even though I cleaned it thoroughly before putting it on. So I tried the other side and experienced the same loud double pop.

Now here's the really weird part. When I removed the stylus from the record and moved the arm back away from the platter, the popping sound continued with each revolution. Even weirder, when I stopped the platter from rotating, the popping sound STILL continued at the same interval. The only way to stop it is to mute the preamp. I could hear the music underneath the popping sound, but the pop is so loud it overwhelms the music. And it seems very strange that it continues with the turntable COMPLETELY still. Muting will stop the popping, but then when I take the pre back off of mute, the popping does not start again until I try to play another record. Very perplexing.

So, does anyone have any theories on this problem? Is the output on the cartridge (2.6 mv) too high? The AR PH3 came with a kit which would lower the gain if I replace the resistors, but I thought I would be fine as long as the output wasn't 5 or 6 mv. Before I perform surgery on this unit, I want to understand the problem. Maybe it's something else.

Has anyone ever experienced anything like this before? I would be very grateful for any advice or suggestions you might have. My happy reunion with vinyl hangs in the balance.

Weird - maybe an exorcism - actually are the tubes in the phono preamp good or set in properly?
Sounds like , and I can't be sure without hearing it, a bad capacitor, or at least a short in the capacitor, I am not familiar enough with the table. If there is another table available to you, and it would not have to be much of one, I would hook it up and see if I still have the problem, if I had another pre amp close by I would insert it into the system and see if I still had the problem. Not always easy I know,but at leat you could narrow it down as to which it is. but If your close to Nashville your welcome to borrow one of mine. I kinda in a way doubt it has anything to do with the actual revolution of the platter as it is not a dd table, just appears that way. Double check yout ground, also run tt direct into the pre amp without the phono stage, wont be much gain, but should be able to hear enough to detect popping. Also check cartridge and check your grounding, bad ground could do that. Probably telling you all you have tried already, but maybe you have missed something in your frustration as I do sometimes.
That's really odd. Is the motor plugged into the same line conditioner/outlet as the pre?
Ultimately, I don't have an answer for you, but if you go to AudioAsylum.com and post in the VINYL forum, I'm sure someone can answer it for you...
TTs are supposed to pop, like Model A Fords backfire aren't they? Sorry, couldn't help it-- just slipped out. I'll leave you guys alone;>) Cheers. Craig

Thanks for the suggestions, folks, and the humor. In this hobby, you have to smile sometimes when things go from bad to weird. I have tried a few different things, including inserting an old JVC turntable and Audio Technica cartridge into the system just to see if the popping would continue. It did. Now I am convinced the problem is in the phono stage. There is a kit included with the PH3 which, when installed, will lower the gain for higher output cartridges. I'll also call Audio Research for advice.

Of course, if anyone around here as any other ideas, I'll try most anything at this point, including an exorcism.
i would guess a bad cap as well.
I believe you are on the right track. The problem is definitely with the Phono stage. Since you verified all your connections and the popping stops when the preamp is muted, I would lean towards a defective component in your phono stage.

This is where I would start unit you discover further evidence that points to another source.