No not the green stuff some people smoke :D
The ones mounted on the PCB, I am thinking of dumping those and wiring in some chassis mount pots. I am thinking of mounting them on a divider in the chassis I ordered from Par-Metal.
Question is on how to wire them to the PCB?
Pot question
4 posts
• Page 1 of 1
by EWBrown » Tue Oct 05, 2004 12:45 pm
The PCB has three pads for each of the pots in a little triangle, and two of the pads are wired together (wiper and one end). Just wire the pot the same way, tie the wiper (center) and one end together, connect that to either one of the "joined" PCB pads, and connect the other "free" end of the pot to the remaining pad on the PCB. If you want clockwise rotation of the pot to increase the bias current (reduce the resistance value) then connect the center and right hand side pot lugs together (pot shaft pointed towards you, the three connectiions on top. Small guage, twisted pair (22) wire should be fine for this application.
Conversely, the original trimpots could just be top mounted, and access holes can be drilled to match up with them, and test points from the top of the 10 ohm resistor(s) can be brought out to "pin" jacks wherever it is convenient, so that the Par-Metal chassis doesn't have to be opened whenever the bias has to checked or adjusted.
One hint: Turn the Par Metal chassis "upside down" so that the vent holes are on the bottom, the unpunched plate is somewhat thicker (0.090 inch) and stronger. this will better support the three transformers and makes for a much neater appearance. I use Radio Shack "stick-on" rubber feet to allow for airflow underneath. The removable front panel is 1/8 inch thick, so some insulated RCA jacks might not mount properly.
On the Rev B unit in my "gallery", I used isolated BNC jacks, and RCA to BNC adapters. For some applications, I use BNC cables rather than RCAs, just an old RF geek's habits, I guess...
/ed B in NH.
Conversely, the original trimpots could just be top mounted, and access holes can be drilled to match up with them, and test points from the top of the 10 ohm resistor(s) can be brought out to "pin" jacks wherever it is convenient, so that the Par-Metal chassis doesn't have to be opened whenever the bias has to checked or adjusted.
One hint: Turn the Par Metal chassis "upside down" so that the vent holes are on the bottom, the unpunched plate is somewhat thicker (0.090 inch) and stronger. this will better support the three transformers and makes for a much neater appearance. I use Radio Shack "stick-on" rubber feet to allow for airflow underneath. The removable front panel is 1/8 inch thick, so some insulated RCA jacks might not mount properly.
On the Rev B unit in my "gallery", I used isolated BNC jacks, and RCA to BNC adapters. For some applications, I use BNC cables rather than RCAs, just an old RF geek's habits, I guess...
/ed B in NH.
Real Radios Glow in the Dark
-
EWBrown - Insulator & Iron Magnate
- Posts: 6389
- Joined: Wed Mar 19, 2003 6:03 am
- Location: Now located in Clay County, NC !
by DortoH » Tue Oct 05, 2004 1:10 pm
Cool, I gues if I waited until I got home i would have seen they are tied together :)
Got any pics of you Rev B in the Par-Metal case? I'd love to see them. Thanks for the tip on turning it over! I have some rubber feet from an old turntable, they are about 1" high so that should allow for plenty of air to get under there. I will most likely be adding some fans as well.
Got any pics of you Rev B in the Par-Metal case? I'd love to see them. Thanks for the tip on turning it over! I have some rubber feet from an old turntable, they are about 1" high so that should allow for plenty of air to get under there. I will most likely be adding some fans as well.
- DortoH
- Posts: 100
- Joined: Mon Aug 30, 2004 1:00 pm
- Location: Great White North aka Canada
this is it
by EWBrown » Wed Oct 06, 2004 5:21 am
THis one:
http://www.diytube.com/jalbum/ed/slides ... T%20a.html
and the next three are the Rev B in the Par-Metal 16X8X3 chassis, BNC connectors instead of RCAs, 325-0-325 power trannie, Hammond 1650Fs.
I didn't do anything to bring out the bias adjustment pots or measuring points, I have to remove the bottom to do so, at this point in time.
/ed B
http://www.diytube.com/jalbum/ed/slides ... T%20a.html
and the next three are the Rev B in the Par-Metal 16X8X3 chassis, BNC connectors instead of RCAs, 325-0-325 power trannie, Hammond 1650Fs.
I didn't do anything to bring out the bias adjustment pots or measuring points, I have to remove the bottom to do so, at this point in time.
/ed B
Real Radios Glow in the Dark
-
EWBrown - Insulator & Iron Magnate
- Posts: 6389
- Joined: Wed Mar 19, 2003 6:03 am
- Location: Now located in Clay County, NC !
4 posts
• Page 1 of 1
Who is online
Users browsing this forum: No registered users and 74 guests