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eBay 6SN7 / 300B Amplifier PCB Kit
http://diyaudioprojects.com/Forum/viewtopic.php?f=9&t=6153
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Author:  Woodo [ 14 Apr 2019, 03:17 ]
Post subject:  Re: eBay 6SN7 / 300B Amplifier PCB Kit

very nice amplifier. you should be proud that it’s out there somewhere playing music for someone’s pleasure. there are certain things i like about my pioneer sc1223 theatre amp such as the convenience of wifi, ethernet, internet radio etc, and the sound is respectable if not a little characterless compared to the tube amp. i’ve never opened it up but i read that it uses the ice power class d module. I’m looking forward to putting the tube amp back into service. I have tried using the preamp out from the theatre amp to drive the tube amp but there must be a mismatch as the sound is not quite right. i just use the iphone. if someone comes up with or knows of a good diy dac that has wifi, usb and ethernet capability and would match the tube amp, that might be worthwhile putting together.

Author:  ILoveHiFi [ 14 Apr 2019, 06:03 ]
Post subject:  Re: eBay 6SN7 / 300B Amplifier PCB Kit

Class d normally have low input impedance of 10k ohms

Author:  Woodo [ 15 Apr 2019, 05:47 ]
Post subject:  Re: eBay 6SN7 / 300B Amplifier PCB Kit

Just can’t find the specs of this amp at the moment but i seem to recall input impedance of 47 k and for the preamp-out impedance was quite low. there is a second preamp-out option with 2k or so impedance. For driving the 6sn7/300b i’m not sure of the significance but the sound isn’t so good.

Author:  Woodo [ 25 May 2019, 22:56 ]
Post subject:  Re: eBay 6SN7 / 300B Amplifier PCB Kit

Completed the re-wire loosely according to the monoblock vision of @suncalc and @mwhouston. Ran into some space issues and suboptimal layout as I stuck to what I had done for the old pcb amp. I will need to move things like the 5v regs around to get a better and neater layout. There's audible hum which sounds like double mains freq which I will keep at. Musically the sound is beautiful though. Early days but sounds like a big improvement compared to the settings used for the pcb amp. Thanks diy friends for the circuit and the diy site.

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