Location: Liverpool
Posts: 766
I'm Sandro.
Only thing that one should wear when working on a late is underpants and or Brasserie all rest is optional extra
Note Underpants or Brasserie will exclude one or the other unless you are like one Fitter I use to know that went on holiday to Brasill and came back whit a pair of bubbies
Do we need to be politically correct one the Brexit is over ?
Any way Martin and I decided not to post more about the BOX
I have been working on the finishing touches
This is the temperature controller
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Temperature controller
Prerequisite:
The amplifier must reach working temperature quickly
When the temperature is reached 2 cooling fans turn on andkeep the temperature at a set value
Component used are when possible are the same as used troughout on other part of the amplifier
Bling whenever possible 😊
How it works
From the positive supply rail, a Mossfet switches on and supplya variable voltage to the fans
The speed of the fans is controlled by 2 thermistors placedon the heat sink
As the temperature increase the thermistor resistance dropthose are in series whit a variable resistor VR 1 that set a voltage that throughthe gate resistor eventually turn on the Mossfet as the voltage increase
Around 3 volts are required by the Mossfet to startconducting
As the Mossfet output voltage is low the 2 fans’1s ,2 X 12volts units will stall also as the amplifier must reach a working temperature quicklythe supply to the Mossfet is switched on and off
The operation of the relay will also switch on 2 Led oneindicating low temperature the other cooking temperature
The relay part of the circuit is the same as the one used onthe speaker protection board
The point at which the relay turns on is set by Vr 2
A third Led switches on if the temperature ever goes to hiand is set by Vr3
Led 4 is the Speaker protection Led and is on this sameboard
The board control circuit is supply by a 7812-voltageregulator as 12 volts are required by the Vu meter boards that I will notdiscuss at present
Q1 Q3 KSC945 Q2 MPSA06
R1 1K R2 100K
Vr1 100 K thermistors 4.7K
RL 1 12 V relay
Vr2 Vr3 and all other to be assessed
Location: Liverpool
Posts: 766
I'm Sandro.
Sorry for crappy photos + copy and paste make same words stick togheterer
Comments especialy as resistor values are most velcome as I am building a couple of protos (see circuit boards) to start whit
Location: Liverpool
Posts: 766
I'm Sandro.
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Fan controller now completed
I had to change the previous design as the relay was chattering a bit
Location: Liverpool
Posts: 766
I'm Sandro.
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Another view of the fan controller board (Silver plated of course)
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One off the 4 VU meter Bling
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All drilling is done now is time for assembly
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Location: Liverpool
Posts: 766
I'm Sandro.
Location: Liverpool
Posts: 766
I'm Sandro.
Location: Liverpool
Posts: 766
I'm Sandro.
First listen happen last week
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Left channel finished there is same minor work to do left
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right channel is going back on bench today to get boxed in
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Location: Liverpool
Posts: 18
I'm Martin.
Here some pictures of the amps in the final position/system.20190530_114649.jpg20190530_114809.jpg20190530_114906.jpg20190530_114649.jpg20190530_114809.jpg20190530_114906.jpg
Wow, they look amazing!
Alex
Main System: Digital: HP Laptop/M2Tech Hiface/Logitech Media Server/FLAC; Marantz SA7001 KI Signature SACD Player and other digital stuff into Gatorised Beresford Caiman DAC Vinyl: Garrard 401/SME 3009 SII Improved/Sumiko HS/Nagaoka MP-30
Amplifier: Rega Brio R. Speakers: Spendor SP1. Cables: Various, mainly Mark Grant. Please see "about me" for the rest of my cr@p! Gallery
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There is only one way to avoid criticism: do nothing, say nothing and be nothing Aristotle