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I ordered 2 Quickies, one for a headphone amp and the one discussed here to boost and control volume for a low pass filter to run my bass amps. I would like to run the Excites without a high pass filter directly to the lowthers.
Do I need any more caps or resistors in this circuit to avoid any evil interactions, with an interstage tranny feeding the Quickie and the Excite?
Thanks in advance.
Triamp... Take a load off!
Follow Ups:
A couple of questions:
Is the output impedance of your preamp selectable between 600 or 150 ohms?
You want a LP filter at what frequency?
The Quickie has a preamp output impedance of roughly 4k, so running it into a 500 ohm resistor is probably not the best use. If your preamp really had ouput impedance that low, you might consider driving an RC filter that is hooked up before the 100K pot. This would let your low output impedance preamp do a lot of the work, and use the Quickie more as a buffer than anything else.
Thanks CB.So... If I just ran the preamp to both the Quickie and the Excite II in parallel, would I have any problems of one circuit affecting the other?
In answer to your questions: Yes, that schematic shows the signal coming directly from the phono stage, which has an selectable OT of 150/600 ohm. In parallel with that is a TVC (autoformer type) and I forget its output impedance.
I'm looking for a LP filter at about 100-120hz (this one is 12 dB/octave at about 127 Hz). I was originally trying to keep caps out of the signal path. I realize the Quickie probably has at least one cap in the signal path that I won't be able to remove, so maybe a good RC filter would work.
And thanks for the info about the pot being 100K. My Alps Black Beauty will work if I can find room for it.
Triamp... Take a load off!
Edits: 09/15/09
You seem to be off in a good direction. You might also try using the Quickie right after the TVC.
I would just throw an RC filter in at the input of the Quickie to get your LP filter at 100 hz.
That would seem to be a good application -- buffering passive
line-level crossover filters. I couldn't find mention of the
output impedance and gain of the Quickie in a quick (possibly
too quick) search. Numbers available?
Skip
Thanks for the reply.
Theoretical attenuation in the xover is only 3.5dB, so I figure all I need is about 6dB max and attenuate from there. I have to assume the Quickie will have more than that.
I was also wondering about the output Z, since I plan to use my Paramour upgrade trannies for the headphone Quickie and not this one. The original Paramour OT's probably are not the best fit to drive bass amps, so I would probably go stock or with 10K:600 stepdowns (so I would then need another 4X gain).
So yeah, knowing the output Z would be nice. I was hoping to get it from the schematic. Also to find out what pot is being used, since I have an Alps Black Beauty 100K log that's been hopping from project to project. But if this stuff is all in the parts list/schematic, I can wait.
There seem to be quite a few nice applications for this product. Nice and quiet DHT is always in demand.
Triamp... Take a load off!
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