Caps For BF Amps
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Re: Source for Mallory 150s and opinions
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Posted by DannyMoe on December 01, 1999 at 16:07:05:
In Reply to: Re: Source for Mallory 150s and opinions posted by Jeff
Gehring on November 30, 1999 at 23:13:07:
: : Howdy folks,
: : I’m getting ready to order the parts for the cap job on the showman and
have decided to do my deluxe reverb and one of my supers while I’m ordering
and in there. I’ve read several favorable statements regarding Mallory 150s
(Yellow) for the 25/25 board caps and the 2550 bias supply cap. Can anyone
offer any suggestions whether these are the caps I’m looking for or any
other suggestions. Also a source for these. I couldn’t locate them at
mouser. Thanks, Dave
: Hi! The Mallory 150 series are available from Hoffman Amps
: (and others, I’m sure). The Mallory 150 series is a metallized
: polyester cap, however and isn’t what you want for the cathode
: bypass 25uF/25V and the bias supply filter you mentioned. For
: those, grab some Sprague Atoms from Mouser. The Mallory 150’s
: are pretty much for interstage coupling/tone stack applications.
: Jeff Gehring
About a year ago I tested a whole range of caps in the tone stack of a BF
fender circuit (i.e. not all coupling caps replaced, just tone caps). What
I found was:
1. Old fender brown “cholate drops” — sounded crappy, sort of distorted,
thin and uneven. Burn them.
2. Old fender blue “tootsie roll” caps — sounded great – warm, round,
full. Not harsh or edgy. These are what are in most 64-66 black face
3. Sprage 416 and 419 “Orange drops” — full equ came through, very
accurate, not the high end roll-off you get with a vintage cap, so they may
sound “bright” or a little harsh to some. (Have used these in coupling
situations without sounding too bright…)
4. Mallary 150 “yellow tootsie rolls” — seem to roll off some bass, and
have a nice kind of mid-range hump. A little vintage distortion vibe or
something happening — many say they sound like “tweed” caps, whatever that
means. They are high end eq oriented, but not too bright.
5. Polypropelene caps — pretty warm sounding, cheap and good sound.
Hoffman has these.
6. Cornell Duplier “black cats” — NOS caps. SOund a lot like the blue
fender caps, which may be Cornell Duplier caps?
7. “Oil in foil” high end audiofile caps from Angela — very expensive
($10/cap). Incredible accurate — i.e. when you change the bass pot you get
a very accurate and smooth eq impact. Sounded almost too smooth to my ears
— nice and warm, but technical in their action. If I ever get rich, I’ll
do a whole amp in these. Have not tried them as coupling caps — bet they
would sound great.
Conclusion, one of the reasons old fender amps sound great is their caps,
which are hard to reproduce tonally. The cheap polypropellene caps sound
very good — I think much warmer that Orange drops, which IMHO make fender
amps too harsh and bright when used in the tone stack. NOS Cornell dupliers
are hard to find, but the closest thing around. Mallory 150s a good fit for
that tweed tone.