dumb recapping question

[arkestra]

check this out

http://www.triodeel.com/hf85s.gif

I want to recap one of these and am guessing

mFd=micro=uF?
or is it
mFd=mili=mF?

so is c3 10mfd= 10000uf cap?

[RodC]

mFd=micro=uF? YES
or is it
mFd=mili=mF? NO

so is c3 10mfd= 10000uf cap? No 10 mfd = 10uf, just a different way of expressing it.


Caps are either Micro, Nano, and Pico. (Nano is rare but you see some)

[RodC]

BTW, you should change the input impedance on the front end of that and turn it into a mic pre, or a guitar amp. Maybe even throw in a tranny.

[arkestra]

yeah I was thinking of doing that. I actually hooked up a 1:10 jensen input transformer I had from annother project but it was way too hot. the amp has gain for days even when you go straight into the unbalanced mic input with a mic. use a lower ratio transformer to make it balanced?

[RodC]

That or, put a level control between the tranny and the input. Did you put a shunt resistor across the secondary of the tranny?

[brianroth]

One other thing to be aware of is the now-obsolete "mmF" abbreviation, which stood for micro-micro Farad, or what we now call Picofarads (pF).

Bri

[arkestra]

RodC, tell me more about the shunt resistor. Across the secondary taps on the input? to ground? both? The impedance seems to be ok without the transformer but anyone please expand. .

[RodC]

Take a look at R1 in this schematic:
http://www.jensentransformers.com/as/as020.pdf

There should be a recomended value for your transformer. This affects the freq performance and what impedance is reflected back to the primary side. A transformers impedance is really what is reflected from the secondary to the primary.

[philbo]

On something that old, MFD (mfd) will be uF. And MMFD will be pF.

There are new caps around that have their value stated in millifarads, and also in nanofarads; even some (called supercaps) that are in farads.. So it is a good question. But these are quite new (like less than 10 years or so).
________
Asian Tube

[brianroth]

Nanofarad values are semi-common.

To convert between pF and nF and uF, you jsut slide the decimal points around by 3 or six positions. Example:

1000 pF = 1 nF = .001 uF.

Before anyone nit-picks me, the "u" we've all been using in this thread is actually the Greek letter "mu". I had to look up the code numbers for my PC keyboard, but if you hold down the ALT key and peck 230 into the numeric keypad you get: ?

I don't know how to make a ? on a Mac...or even know if my example will even appear correctly on other types of computers. i just know that I'm seeing a "mu" letter onscreen as I typed this.

Bri

[Roboburger]

but if you hold down the ALT key and peck 230 into the numeric keypad you get: ?
Bri

I gotta try that:

?

Holy cow it worked.

[RefD]

but if you hold down the ALT key and peck 230 into the numeric keypad you get: ?
Bri

I gotta try that:

?

Holy cow it worked.

kickazz.

*puts this info on a post-it note and attaches it to edge of monitor*

[DryCounty]

Mac users:

Option + "m" key = ?

[brianroth]

Cool...I am a PC user, so Mac "ways" are always useful to the rest of us!

Bri