If you're running stock boards, those want a 250k volume pot if I'm not mistaken. Not sure, but other mods may be designed around that same pot value. If you can get a remote rig that has that value, it might be to your advantage.
That’s true, it’s 250K pot. I didn’t find any kits with motorized pots above 100K ( that’s the pot in a kit I’m going to order) or ALPS pots above this value. A 200K Bourns motorized pot exists and was available from Mouser and others (Mouser cat # 652-PRM162K425K204A2); however, it’s on backorder for 13 weeks in Mouser and all other suppliers.
That might be a problem since if you look at PAS3 schematics this 250K is what the first triode of the line amp sees. I can add a 150K resistor in series while removing the 47K grid stopper-like resistor connected to the BS part of the input switch selector but this leads to a gain loss. Any suggestions on solving this pot mismatch?
One thing though, if you can get more inputs, that might also be useful. The stock setup has 6, 3 are effectively phono level, 3 are line-level. You can modify that to be anything you like, but one of the input positions would be occupied by the phono amp. With a 4 position selector, one would have to be occupied by the output of the phono board, leaving you with 3.
Three inputs plus phono should be fine for me: currently I use a CD player, a tape deck and occasionally a tuner. I see a tape monitor in a PAS3 (why it has a 47K resistor in series?); would be a nice thing to add a buffer to it later. Extra inputs are good but I didn’t see a kit with more than four in my price range.
a PAS doesn't have a 6.3 heater winding either really. DC heaters, runs about 22vdc with the heaters on each board in series. The rectifier runs on 12vac.
I will be replacing original PAS power supply with two-transformer one from Audio Nirvana. I hope that I can tap into a filament heater winding before the regulator. The motor takes 100 mA for rotation and 150 mA at the end of the turn so hopefully it’s manageable.
Yet another solution might be to keep the original PAS3 tranny with changing filtering caps and diodes, eliminate the “Power on” bulb that takes 100mA from the heater power supply and instead use this power for remote, adding a resistor to lower voltage to 6V AC . However, I don’t know what is the power consumption by remote controller components other than motor including relays and losses at the voltage regulator/AC to DC converter.
The best solution might be to get a small separate transformer for the remote.
Why is remote so necessary? I am physically challenged, my systems don't have remote. As I lack $6500 to buy new gear of close quality. Dumbed down is lesser. What's a few steps to adjust something? Hate to come across that way. I like my Dynaco original or not too modded. (mine does have better grade passive components, I did that when I built my kits in 1973)
I have to make a confession: I like comfort too much. I hate to do these few steps to adjust something esp. decrease the volume when someone is talking or the phone ringing.
I sold a few very nice pieces of gear including a Pioneer SA-9800 amp that was an outstanding match to my speakers and other system components b/c they didn’t have remotes. PAS-3 is a rare example of a tube preamp that seems to have enough space to install a motorized remote control, its PCB and relays- this was the main reason I purchased it. Sure I’ll replace old components in the PAS-3.
I did this, at least partly. In addition i added cathode followers for both the line output and tape output.
See
http://n.manet.nu/fm1/fm1.html
Nice idea; however, I don’t want to go into this Arduino business since it’s looks to be a an easier solution with this kit.
How are you going to deal with 6 inputs to 4 inputs as far as the front panel labeling goes?
Looking at the PAS3 schematics, I see that the Phono, Tape and Spec inputs go into the phono preamp (or am I wrong? The PAS3 input switch is such a freaking complicated rat’s nest!) If this is so, I’ll eliminate two of them leaving just one relay-controlled phono input. The other 3 inputs, AM, MPX and Spare seem to be linear. Overall, replacement of input selector with relays hopefully will streamline PAS3 inputs.
