Bottlehead Forum
Bottlehead Kits => BeePre => Topic started by: kip.duff on April 14, 2021, 11:42:07 AM
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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.....
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It's not an issue of more powerful amps. It's an issue of power amps with high gain.
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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.
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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......
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A doomed marriage?
Very much so!
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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.