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Cary CAD 805AE 845 300B Tube Question

I have a Raysonic 128 CD Player, Cary SLP-05 Pre and 805 CAD AE amps, and modified Paradigm Studio 100 v2 speakers (replaced caps and resistors in HF crossver and replaced tweeters with Scanspeak D2905/9500). Smooth and no problem with loudness. Can now play without compressing the highs. 28 x 22 room with speakers on long wall with front 5 feet from wall. Zu Varial IC and Wax speaker cables.

I have replaced all the tubes except for the 845 and 300B in the amps. Amperex PQ white label in CD player, Mullard rectifier in the SLP-05 power supply, RCA VT-231 in SLP tubes 1 and 2 for single ended output, and Sylvania 6SNLWGT for the input tubes in the amps.

I have tried the 211 tubes that came with the amps and they sound good but I prefer the more reserved sound of the 845s versus the more forward sound of the 211s.

The question I have is does anyone have experience with how different 845 and 300B output tubes work together. I am looking for the typical things, richer depth of sound, more "attack" or the instrument being right there in the room. I have Herbie's tube dampers but the sounds get too sharp and "un-natural" when I use them on the CD 6922 tubes.

I would be reluctant to spend $1200 on a pair of Aperex 845 tubes or Western Electric 300B. The Shuguang 845M metal plate and Treasure tubes and 300B and other brands are in the $300/Pair range and Sophia Electric are $500/Pair +/- depending. I have read JJ tubes won't fit in the holes in the 805 chassis. I would welcome any combination suggestions of tubes you have used and what sound would be expected from them.
Thank you for your help.

As an aside, is it normal for the the chassis of the 805 to get so hot you can only hold on for about 5 seconds on the 845/211 switch side after two or three hours of playing? I can hold my hand on other parts but still very warm. Good winter is coming up.
Thanks again, Mike.
mberrync
amfibius
282 posts
 
You might want to check this thread out: http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1286194112&&&/Best-845-tube-out-there-

I used to own the 805AE. The amplifier gets hot, but not so hot that I can not hold my hand on the chassis! Make sure you check the bias, if you have over-biased the amp it will run hot and shorten the life of your tubes. Bear in mind that you have to check the bias every time you swap over from the 845's to 211's (even with the switch in place).

My experience was otherwise similar to yours. I preferred the sound of the 845 tube over the 211.
brf
1,715 posts
 
My 805 gets hot but not to point where I cannot keep my hand on any part of the amp (notwithstanding tubes). The 805 is designed to use the chassis as the heat sink.
lewhite
156 posts
 
You are prolly hitting the 300b with too much grid voltage. My 'tube plate ' measures 140F in the resistor side of the 300b and 114F ont other side. FYI the 845 tube is about 400 degrees inside of the plate.
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