hairyandy wrote:For what it's worth, we have had a couple UA's out on the road on the Sheryl Crow gig for a couple years as well as many THD Hot Plates and they worked fine. Last year however we built a few Airbrakes to see how they compare and they killed the others tone-wise. Now there is an Airbrake on every (attenuated) amp on the SC stage...
Andy
Interesting...two questions...
1) Which version of Airbrake did you build...rheostat, or not, or?
2) Please elaborate on how the Airbrakes differed from the UA's.
THANKS.
Well, we've built both--with and without the rheostat. I think the Airbrake just sounds more like the amp's tone unchanged than the UA does. Also, we're not attenuating much, just a couple clicks. IMO any severe attenuation is going to sound different or crappy no matter what you use.
hairyandy wrote:
Well, we've built both--with and without the rheostat. I think the Airbrake just sounds more like the amp's tone unchanged than the UA does. Also, we're not attenuating much, just a couple clicks. IMO any severe attenuation is going to sound different or crappy no matter what you use.
My $.02,
Andy
Thanks Andy. Do you have a preference/recommendation as to which Airbrake version is best? I'm going to build one...only one....
Personally I don't think there's a difference especially if you're not attenuating that much anyway. For the price of the rheostat I'd skip it. I don't plan on building one with a rheostat anymore myself.
hairyandy wrote:Personally I don't think there's a difference especially if you're not attenuating that much anyway. For the price of the rheostat I'd skip it. I don't plan on building one with a rheostat anymore myself.
Andy
Many thanks. You've confirmed what I've suspected...
Truly it seems most of the popular attenuators have their pros and cons.
I remember Ken Fischer himelf saying even though he liked his attenuator design with some amps, he didn't even like it on his own amps.
The Airbrake is quite usuable for a click or two back. Also as many know the resistance points inside can be tweaked a little to vary the attenuation steps.
I think one reason I've prefered the THD in the past over the Airbrake is because of the speakers I use. To me it seems like 25 watt Celestions get a little more soft, compressed and sweet in the highs the more you push them, compared to other higher powered speakers. When you start attenuating it appears this effect is lost somewhat. The THD and UA seem a little darker and sweeter naturally in the high end, which is partially why I prefer them. The THDs seemed more workable for me tonally, but it seems every position has a different feel and EQ to it. I really only like the Airbrake for minimal attenuation and with lower gain tones than I usually go for with my Express.
Another thing with attenuators is how much gain you are cranking the amp up to. My video on Youtube with my Gretsch/Express was done into a THD attenuated WAY down. However I just EQed it in the mix differently and since the amp was almost totally clean anyway there was minimal fizz to worry about. It's the high gain stuff with a cranked Express where to me the UA really seems to work well, along of course with it's nice linear tonal reponse on it's volume knob.
jaysg wrote:I had a Scholz which seemed to prove that purely resistive sucks, but the Airbrake flys in the face of that notion.
Unless you're using "toaster wire" (a la THD), or those expensive new "transistor shaped" power resistors, it's really hard to find a "purely resistive" power resistor. I never saw one, but did the original Scholz use toaster wire too? (By the way, the THD units have added caps and inductors too).
The big wirewound resistors typically used (in the Airbrake, etc.) actually have a small to moderate amount of inbuilt inductance, due to the fact they're basically a long coil of wire wound on a ceramic form.
mhuss wrote:...did the original Scholz use toaster wire too? (By the way, the THD units have added caps and inductors too).
I recall that they were all cement block, radial mount. I've only seen the Altair used once and I have the recollection of glowing wire inside. That was June, 1980....may recall poorly.
[edit]re: question below: I think you want that inductance.
Last edited by jaysg on Fri Nov 28, 2008 11:22 pm, edited 1 time in total.
mhuss wrote:
The big wirewound resistors typically used (in the Airbrake, etc.) actually have a small to moderate amount of inbuilt inductance, due to the fact they're basically a long coil of wire wound on a ceramic form.
--mark
Mark,
IIRC you can for an additional fee order non inductive power resistors from mouser
I measured an 8 ohm 50W Dale metal clad on an LCR meter once and the L was quite small (microhenry range--which I understood to be insignificant at audio) as I remember. That being said I do recall reading something by Dr.Z stating that Ken chose the specific R in the AB for its L. Whether it's one of his flaky sounding thoughts or not I don't know but experimenting with varying an R across the 1mH series L in my Marshall Power Brake, subjectively speaking shorting out the L entirely seemed like the highs were less (as it should be) and less lively sounding as well (don't understand the reason why). Maybe someone could try measuring the L if they've built an AB clone or derivative (which uses the same type power R). 'Course you could just add a series inductor as well if you wanted.
Anyone heard the Faustine? http://www.hugeracksinc.com/forum/viewtopic.php?t=49627
a bunch of guys ab'd it against the UA and said it was no comparison. IT isnt a reamp either.
I had a UA but I popped a power tube twice in a JCM800 on 8ohm that was running into a THD with no problems. I got spooked.
I'll either make an airbake or check out the Faustine. The Faustine is a reactive load.
