help solve huge feedback when using ARC push-pull 30W power amp

[kip.duff]

Always had intended to try different amps, but now realize the are major compatibility issues.

I had 6A3s in the BeePre- but installed a new set of EH 300B Golds to rule out possible issues- not much change.  The BeePre has IsoNode feet.  Normally using with my Paramount 1.1 monoblocs (Psvane 300B TII or EH 300B) and Altec A7 VOTTs with acceptable hum.  I have an Audio Research Classic 30 30W hybrid push-pull tube amp (6550s) and subbed it for the Paramount 1.1s.  I have attached a spec sheet.  But things got crazy with the ARC amp: kinda like guitar solo feedback and beaucoup hum.  If I put my hand above the tube, hum would go way up more.  Would eventually develop a shriek in one channel.  Though hard to tell, I think the combo of the more snappy power amp behind my BH gear has potential if it can be tamed.  At any rate, I wanna try it- and other amps.

Apparently, I need to make an "L-pad" to reduce gain of the amp- assuming that this combo can work at all.  If someone could give me more details, specs, or photos, I would appreciate it- and any other advice.  If there's room and is feasible, I would like to install whatever I need in either the amp or preamp to avoid extra interconnects and clutter.

Apparently, using more powerful amps is a known issue with the BeePre I- and I noticed that the BeePre II addresses this to some degree.  Before I consider buying a BeePre II kit or another preamp, I want to see what I can do with my current BeePre I (which has Bee Quiet upgrade and nice caps). 

Thanks, Kip.....

[Doc B.]

It's not an issue of more powerful amps. It's an issue of power amps with high gain.

[Paul Birkeland]

The AR has about 31dB of gain, which is a ton.  It's absurdly high for a 30W power amp.  I would use two Harrison labs -24dB attenuators at each input of the ARC, or just not use it.

[kip.duff]

The AR has about 31dB of gain, which is a ton.  It's absurdly high for a 30W power amp.  I would use two Harrison labs -24dB attenuators at each input of the ARC, or just not use it.

Well, I will try this. 

Do you believe this is a bad match?  A doomed marriage?

Thanks for your input...... 

[Paul Birkeland]

A doomed marriage?

Very much so!

[aroide]

Even with my Rogue Atlas Magnum amp, I need an L-pad to reduce noise on my beepre 1.  It was easy for me to solder some nice carbon film resistors in the Rogue Atlas.  But when driving the Bryston I used to have (high gain and DC coupled!), I purchased some -12db RCA pads which worked very well.

With the L-pad, noise is not really audible.