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Old 15th June 2011, 05:23 PM   #1
diyAudio Member
Join Date: Mar 2010
Default HELP - SMART 845 or 300B SE

Hello All,

I have a monoblocks Unison Research SMART 845 and 2 weeks ago I had here a stereo 300B amplifier " My new 300B Amp " - And my lovely SMART 845 desapear , the 300B was much better in all.
Since than I didn't sleep well thinking about that.
My question is : I try to sell my 845 and look for a good project and buy good elements and build a 300B SE monoblocks or stereo, or open my SMART 845 and change the cables the power supplies ,resistors etc,etc? what is the best .
I know and I'm a little afraid that 845 can kill me, lethal, Iīm newbie ,but before the project I need to buy all and it will be with time and I will learn and I have a friend that is very good in electronics he works with ASR/PAR radares (technician).

thanks in advance for yours replies.

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Old 16th June 2011, 02:56 PM   #2
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azazello's Avatar
Join Date: Aug 2008
Location: Bulgaria
1. 845 is good, but not the best tube /I like 2A3 - RCA and 300B JJ!/.
2. 1000 v. kikes only one more times!....
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Old 16th June 2011, 03:19 PM   #3
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Join Date: Nov 2006
Location: Munich, Bavaria
First question is rather why you like that 300B amp more than your 845 amp.
Either the 300b amp produces more "triodish" sound because of 2. harmonics (no feedback for example) or your 845 amp is badly made (low quality transformers, no clever circuit design etc.)

The ideal starting point would be now when we would have frequency response, distortion spectrum and circuits of both amps :-)
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Old 16th June 2011, 04:01 PM   #4
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Join Date: Mar 2010
I can put here the schematic of the UR smart 845 . It's cheaper change some resistors and wires in smart instead build one 300B . My smart 845 have a good image, focus, but have problems with a lot of information like orchestra, and have 14 dB NFB.
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