B+ capacitance confusion

aftec

aftec

Inspired
I guess B+ capacitance is B+ voltage supply capacitance.
It goes from 0-10, if it's capacitance it should be some kind of (i guess micro) farads or is it just a theoretical value for tightness control?
Or is it volts and I get completely confused.
 
xrist04 said:
B+ Capacitance: "Increasing value stiffens response and tightens bass. Decreasing value loosens response. Use in conjunction with Sag control to set response."

source: http://acapella.harmony-central.com/showthread.php?t=2220274
Click to expand...

I'm completely aware of the actual role of the parameter, although I would like to have a better understanding of the meaning and the values. Stiffen response and tighten bass can be achieved by a number of options, like damp, power tube bias, Transformer match etc although all of them does it differently. If the B+ capacitance shapes the sound differently I would like to exploit it or at least understand it and try to exploit it.
 
It has to do with the number/size of capicitors in the virtual power supply. So say you take a stock Marshall and sub the normal 50/50uF LCR cans for 32/32uF, you will get more comprssion, sag, and a looser response. If you beef them up to say 100/100uF cans, you will get a faster, stiffer, tighter feeling amp - it will hold together at high volumes but may be overly stiff at lower volumes. The SLO is a good example of an amp with a lot of filtering in the power section - roughly double what you would see in a normal Marshall circuit. So I would guess that a "5" represents a stock amp which you can increase/decrease from there.
 
JGR said:
It has to do with the number/size of capicitors in the virtual power supply. So say you take a stock Marshall and sub the normal 50/50uF LCR cans for 32/32uF, you will get more comprssion, sag, and a looser response. If you beef them up to say 100/100uF cans, you will get a faster, stiffer, tighter feeling amp - it will hold together at high volumes but may be overly stiff at lower volumes. The SLO is a good example of an amp with a lot of filtering in the power section - roughly double what you would see in a normal Marshall circuit. So I would guess that a "5" represents a stock amp which you can increase/decrease from there.
Click to expand...

Thanks for the explanation!
I would really be interested whether this has anything do with the "virtual choke" if it exists.
My JVM had a big resistor in place and installing a choke did a great deal of difference especially making the amp less stiff and brittle.
 
If it is strictly B+ capacitance, then it is independant of the choke. I would imagine Cliff modeled whatever choke the amp came with. As you mentioned, going from a resistor to a choke, as well as varying the choke size, can have a large effect on the feel of the amp - I guess this could be another advanced parameter someday, though we already have a lot to play with!

aftec said:
JGR said:
It has to do with the number/size of capicitors in the virtual power supply. So say you take a stock Marshall and sub the normal 50/50uF LCR cans for 32/32uF, you will get more comprssion, sag, and a looser response. If you beef them up to say 100/100uF cans, you will get a faster, stiffer, tighter feeling amp - it will hold together at high volumes but may be overly stiff at lower volumes. The SLO is a good example of an amp with a lot of filtering in the power section - roughly double what you would see in a normal Marshall circuit. So I would guess that a "5" represents a stock amp which you can increase/decrease from there.
Click to expand...

Thanks for the explanation!
I would really be interested whether this has anything do with the "virtual choke" if it exists.
My JVM had a big resistor in place and installing a choke did a great deal of difference especially making the amp less stiff and brittle.
Click to expand...
 
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