59 Bassman ?

[txstrat]

The 10'' Jensen is good enough to find out if they got the chime you're looking for.
Plug the 10'' Jensen into you Bassman (don't play too loud if it's got not enough wattage). It will give you an idea of the high end of Jensen speakers. My Jensens 10s or 12s have almost the same high end and differ a little in the bottom end (the 12s are a little more flabby so to speak).
Make the decision for a C12Q or C12N dependable on the wattage of the amp. With a regular Bassman (40 - 45 watts) I would go with either one C12N (50w) or two C12Q (35w each). Or maybe two C10Q (35w each). I like the 10s a little more.

[chuckb]

Ya, I'm leaning towards the C12N but i may decide to go with the two 10's also. depends on what the results are when I try the 10" I have here. I'll let you know how it (10") sounds and get back to you.

chuck.

[pdf64]

Taking the NFB from the 16ohm tap, using a 27k resistor, is what Marshall did with the JTM45. It makes the Presence control more effective.

[chuckb]

Hey Joe,
I used the exact same circuit for the 5F6A. the same value resistors and caps etc. The OT has only 16 ohm output so what values do you suggest i use here? Any help in doing some changes would be a great.

Chuck.

[JoeM]

Hey Joe,
I used the exact same circuit for the 5F6A. the same value resistors and caps etc. The OT has only 16 ohm output so what values do you suggest i use here? Any help in doing some changes would be a great.

Chuck.

I think there's a sweet spot with the feedback values. In my 5F6A clone I connected a 1M pot (where the 27k is) and adjusted the value by ear/feel. Too much feedback seems sterile, too little gets a bit 'loose', but I'm sure it's a matter of personal taste. I ended up with a 33k, on a 2 ohm tap, not far really from the stock value.

[chuckb]

I could try that and adjust the pot to ear/feel just to find that sweetspot your talking about. I have tried different values on there but always went back to the 27k.

[Enzo]

Maybe it is late to mention, but you do realize that reducing the bass is not the same thing as adding brightness (high end)?

Have you added brightness caps across the volume control for example?

Did you alter the NFB in any way from the original?

[chuckb]

Hey Enzo, Yes i realize that reducing bass is not the same as adding brightness.I haven't tried adding a brightness cap across the volume control,could you suggeat where to start(size of cap etc)? I did alter the NFB and it has helped alot,. I went from 27k and tried several but ended up with 15k that helped out alot in terms of brightness. I also changed out the Cathode bypass cap on v1 to 1uf as well.

[JoeM]

Chuck,

Only a single channel on your 5F6A clone? Take a look at the schematic for a 5F6A, the bright channel has a 100pf (.0001uf) cap across the volume control. (Deluxe Reverb uses a 47pf, the Bright switch on the larger BF amps 120pf). I dont find the 100pf to be too bright on my Bassman clone with humbucker equiped guitars, but you can adjust the values to your tastes/guitars.

[jlatrace]

Put the 5F6A back to stock. THen update the tone stack to a 100K slope resistor (from 56K) and .1UF bass cap (from .02uf). Although this circuit is not on the schematic floating around the internet, it is the tone stack found in most 5F6A's produced beginning very shortly after the 5F6A was introduced. Go to YouTube and search and you will see several examples of tweed bassmans with this tone stack.

The amp is clean and sparkles with highs.

[JoeM]

Put the 5F6A back to stock. THen update the tone stack to a 100K slope resistor (from 56K) and .1UF bass cap (from .02uf). Although this circuit is not on the schematic floating around the internet, it is the tone stack found in most 5F6A's produced beginning very shortly after the 5F6A was introduced. Go to YouTube and search and you will see several examples of tweed bassmans with this tone stack.

The amp is clean and sparkles with highs.

Good point. I researched mine (the Ampage archives have a lot of good info), and used the tone stack you mentioned. Apparently a few may have used a .1uf with a 047.

[jlatrace]

Yeah it is amazing what changing two part values will do to the sound.