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August 18, 2019, 02:38:17 PM

Author Topic: Remote controlled Smash/SmashUp Build  (Read 250 times)

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Offline Norbert

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Remote controlled Smash/SmashUp Build
« on: October 12, 2018, 10:20:10 AM »
I did a build with remote control which I find quite satisfying. Actually it is my best preamp built so far and I did quite a few.
Apart from the input section and the power supply the amplification circuit itself is not altered in any way. I'm running it with my Seductor power amplifier which I also appreciate very much. These are the things I have changed compared to a stock Smash/SmashUp kit:

1) Replaced cinch input and output jacks with CMC silver ones
2) Replaced input selector with Seiden type
3) Integrated Lite Audio MV-04 remote volume control:
   - Connected as shunt-type attenuator with 50k Audio Note tantal series resistors
   - MV04 voume has a 4 channel volume pot which is wired in 2 parallel pairs
   - 4 wire bridges are necessary to support shunt-mode
   - Relay based input switching of MV04 is not used
   - Remote IR sensor is integrated in left hand mock-up knob
   - AC power supply is connected to 6SN7 heaters
   - MV04 circuit board modifications necessary to divide single ground into 3 different grounds
4) Internal signal cabling is done with HGC silver solid core wire
5) Grounding scheme changed to not switch each inputs ground
6) Screening of input/output cabling with grounded copper foil
7) Output caps changed to Audyn True Copper Max types 1uf / 630V
8) Resistors changed to Audio Note tantal types
9) Power supply:
   - Replaced 1st C with Mundorf Tube Cap Polypropylene 30uF / 600V
   - Replaced 2nd C with Nichicon KX type 470uF / 250V
   - Replaced 270Ohm / 5 W resistor with Hammnod 158M 10H choke
10) Loctal sockets:
   - Remove central locking mechanism completely
   - Installed contact wire from shielding pin #5 to enable proper grounding of the socket's metal parts
   - Mounted O-ring on top between chassis and tube socket for further mechanical decoupling
11) C4S-boards:
   - Replaced stock TL431 shunt regulators on C4S boards with lower noise types LM431
   - 4P1L tubes are so noisy that after all I'm in doubt that this is really necessary

Enjoy and do not hesitate to ask questions!
« Last Edit: October 12, 2018, 10:25:47 AM by Norbert »

Offline Paul Birkeland

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Re: Remote controlled Smash/SmashUp Build
« Reply #1 on: October 12, 2018, 12:44:54 PM »
Cool build!
7) Output caps changed to Audyn True Copper Max types 1uf / 630V
This is quite a bit smaller than the stock parts.  There are lots of 2uF-10uF 250V caps to consider that will be about the same size but won't impose the performance limitations of the 1uF caps.

   - Remove central locking mechanism completely
   - Installed contact wire from shielding pin #5 to enable proper grounding of the socket's metal parts
The center locking mechanism is part of the socket.  You may find that the 4P1L tubes don't stay put so well without it.  Connecting pin 5 to the chassis is part of the stock build...


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man