Hi Plott,
Great! If you refer to the connection diagram on post #1, the two switches correspond to the main power switch (J149 which goes from standby), and the Tube/SS mode select switch (J140):
The board is basically always on at the +/-15v level from the on board DCDC supply through the 12vdc input. J149 enables the filament heater first then the 90v B+ high voltage for the plates. The opamps always stay on and this prevents turn on pop.
I noticed typo on my notes J109 and J110 for inputs. If using single ended input the -ve pin 3 must be grounded. Not pin 2. If using BTSB lite PCB for inputs this is handled automatically by auto relays.
Great! If you refer to the connection diagram on post #1, the two switches correspond to the main power switch (J149 which goes from standby), and the Tube/SS mode select switch (J140):
The board is basically always on at the +/-15v level from the on board DCDC supply through the 12vdc input. J149 enables the filament heater first then the 90v B+ high voltage for the plates. The opamps always stay on and this prevents turn on pop.
I noticed typo on my notes J109 and J110 for inputs. If using single ended input the -ve pin 3 must be grounded. Not pin 2. If using BTSB lite PCB for inputs this is handled automatically by auto relays.
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I'm listening to the buffer right now and I must say I'm very impressed. It is very transparent, sound as good as with the tube buffer or bypassed. Perfectly silent, no noise. I studied the board in detailled and it is very good enginering, everything is well done, delayed mute at startup done with mosfet, Power-On and Off by a simple switch that activates an enabling circuit for the different sections of the board, tube 6.3V for the Heaters and 90V high Voltage done with dedicated buck converters very well designed. A great and versatile tube preamp front end. I'm very tempted to buy the ICE Power module and build myself an amp. Great work xrk971
Hi Algar_emi,
So glad you got yours working and listening to it! Thanks for the kind words - the design is indeed very comprehensive. It will perfectly orchestrate the turn on and off sequence with a good Class D amp to make it work well.
You can get even a smaller IcePower 200AS2 and the operation should be the same.
So glad you got yours working and listening to it! Thanks for the kind words - the design is indeed very comprehensive. It will perfectly orchestrate the turn on and off sequence with a good Class D amp to make it work well.
You can get even a smaller IcePower 200AS2 and the operation should be the same.
Even the switch between SS buffer or Tube buffer is done without glitches or noise, very impressive. Well done. I have the PCB s/n: 003, one of the first I'm guessing...
Btw what is the switch part number for SW802? I'm guessing it is for local testing, but still would be nice to have. Thanks
SB
Btw what is the switch part number for SW802? I'm guessing it is for local testing, but still would be nice to have. Thanks
SB
I think it is an eSwitch SPST pushbutton part TL1220S2BBGNN
https://www.mouser.com/ProductDetail/E-Switch/TL1220S2BBGNN?qs=NAnG0cOyeN2eMEcrEaXEIw==
https://www.mouser.com/ProductDetail/E-Switch/TL1220S2BBGNN?qs=NAnG0cOyeN2eMEcrEaXEIw==
J118 is a latching DPST switch. Pin 1 is GND and the other two provide N/O or N/C. But both are needed to operate the logic. It’s not a simple make contact to GND. Both sides of switch need to operate in toggle mode. The reason it is like this is for use with latching pushbutton vandalproof type switches in front panel.
Yes that works. I normallly get these. Get the self locking (latching ones). The wire socket that is offered is handy too.
https://a.aliexpress.com/_mLcnRPy
https://a.aliexpress.com/_mLcnRPy
