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Greetings!
I bought a SF Princeton NR here about a month ago and that one is awesome. I put a Ragin' Cajun in there and it's fabulous. Exactly the tone I was looking for.
Back in the day I used to run a SF Bassman and 2x12 cab and a '65 modified Bandmaster and 2x12 as a stereo rig. Very L O U D. So, now the kids are old enough, I'm thinking of some light gigging, but really don't think I'll need the huge amp thing - even then I'd run those big amps at around 4-5 on a gig. Some gigs maybe between 5-6.
So, I'm thinking now I want to run a pair of Princetons, so soon after I got the first one mentioned above, I saw #2 on Ebay for a great price, advertised as Torres modded, so I knew I could be in for a treat. And that is definitely true. Here is the pair...
And from the back...
So let's take a closer look at the Torres modded Princeton (here after referred to, more appropriately now IMHO, as #2). The detail pictures are large so I'll just attach them.
So, I have no idea what the hell that dude did to this thing. Added a transformer so I guess he changed the PI around. The trem is gone, the trem depth is a dual-ganged pot, same as the "presence" pot on the back. There's a pot underneath labeled "hum" which is connected directly to the extra transformer. Doesn't sound terrible, but it buzzes and hums.
I'm ripping all of that crap out of there and making it stock. I was considering either the Stokes or Paul C mods, and was leaning quite heavily toward the Stokes - but it seems there's mixed opinion about whether the OT can handle the mod. I like the idea of the Stokes mod alone because all I want is to squeeze a teeny extra juice from the thing so it's giving me about 15 watts out. I don't want to change the sound characteristics. But all of this is for way later.
My experience in this realm is with vintage synths. I have restored many vintage analog and hybrid synths. I usually do LOTS of research before I jump into a project and this Princeton is no exception. The mere fact that I'm typing this post means that I have heeded the "high voltage" warnings and have adopted the procedures for draining, then measuring the caps before starting to poke and prod in there.
My questions:
1. I'm using the AA964 schematic and layout. The only difference I can see other than the differences how the wires are supposed to go under the tagboard, is the rectifier. Does the AA964 circuit manage a 5u4gb rectifier without changes? If not what changes need I make?
2. What kind of diode is that in the bias circuit?
3. The cap can in Princeton #2 is a 20 20 20 20 475v. The schematic seems to indicate this is to spec - yes? I've seen lots of people suggest a 20 40 40 20 or something like that cap can in lots of other threads.
4. If you look at the layout HERE, where B from the cap can attaches to B on the tagboard - that's "290 v.", right, not "290 k" - my printout makes it look almost like "290 k" as if a resistor is supposed to be there. The GIF here looks like a "v."
5. Torres installed a 15.5k bias pot (it reads 17.5 k, but something is adding 2k even at zero, so I'm assuming 15.5k) with 12k resistor. Is this an okay combo for an adjustable bias instead of the 22k fixed? I've seen all sorts of values but they tend to ball-park this combined value.
Anything else you want to add, or ask, by all means do! Wish me luck!
I bought a SF Princeton NR here about a month ago and that one is awesome. I put a Ragin' Cajun in there and it's fabulous. Exactly the tone I was looking for.
Back in the day I used to run a SF Bassman and 2x12 cab and a '65 modified Bandmaster and 2x12 as a stereo rig. Very L O U D. So, now the kids are old enough, I'm thinking of some light gigging, but really don't think I'll need the huge amp thing - even then I'd run those big amps at around 4-5 on a gig. Some gigs maybe between 5-6.
So, I'm thinking now I want to run a pair of Princetons, so soon after I got the first one mentioned above, I saw #2 on Ebay for a great price, advertised as Torres modded, so I knew I could be in for a treat. And that is definitely true. Here is the pair...
And from the back...
So let's take a closer look at the Torres modded Princeton (here after referred to, more appropriately now IMHO, as #2). The detail pictures are large so I'll just attach them.
So, I have no idea what the hell that dude did to this thing. Added a transformer so I guess he changed the PI around. The trem is gone, the trem depth is a dual-ganged pot, same as the "presence" pot on the back. There's a pot underneath labeled "hum" which is connected directly to the extra transformer. Doesn't sound terrible, but it buzzes and hums.
I'm ripping all of that crap out of there and making it stock. I was considering either the Stokes or Paul C mods, and was leaning quite heavily toward the Stokes - but it seems there's mixed opinion about whether the OT can handle the mod. I like the idea of the Stokes mod alone because all I want is to squeeze a teeny extra juice from the thing so it's giving me about 15 watts out. I don't want to change the sound characteristics. But all of this is for way later.
My experience in this realm is with vintage synths. I have restored many vintage analog and hybrid synths. I usually do LOTS of research before I jump into a project and this Princeton is no exception. The mere fact that I'm typing this post means that I have heeded the "high voltage" warnings and have adopted the procedures for draining, then measuring the caps before starting to poke and prod in there.
My questions:
1. I'm using the AA964 schematic and layout. The only difference I can see other than the differences how the wires are supposed to go under the tagboard, is the rectifier. Does the AA964 circuit manage a 5u4gb rectifier without changes? If not what changes need I make?
2. What kind of diode is that in the bias circuit?
3. The cap can in Princeton #2 is a 20 20 20 20 475v. The schematic seems to indicate this is to spec - yes? I've seen lots of people suggest a 20 40 40 20 or something like that cap can in lots of other threads.
4. If you look at the layout HERE, where B from the cap can attaches to B on the tagboard - that's "290 v.", right, not "290 k" - my printout makes it look almost like "290 k" as if a resistor is supposed to be there. The GIF here looks like a "v."
5. Torres installed a 15.5k bias pot (it reads 17.5 k, but something is adding 2k even at zero, so I'm assuming 15.5k) with 12k resistor. Is this an okay combo for an adjustable bias instead of the 22k fixed? I've seen all sorts of values but they tend to ball-park this combined value.
Anything else you want to add, or ask, by all means do! Wish me luck!
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