adding a quickie to a s.e.x.

guf · 4410

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Offline guf

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on: August 16, 2013, 06:46:25 AM
is there any logical reason for it? i built a quickie for my main system but tried it out on my desktop between the sex and the orca's. i'm not sure if it sounded better but it sounded different. my quickie is just in stock for as of now.
thoughts?
« Last Edit: August 16, 2013, 07:12:23 AM by guf »



Offline Doc B.

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Reply #1 on: August 16, 2013, 06:59:44 AM
I think the only technical justification would be to boost the signal from a low output source. But it certainly won't cause any harm and might change the tone or other sonic aspects in a way that you find an improvement.

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Offline corndog71

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Reply #2 on: August 16, 2013, 07:03:03 AM
I've run my sex amp with and without a quickie.  I like the sound both ways.

The world was made for those not cursed with self-awareness.

Rob


Offline denti alligator

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Reply #3 on: August 16, 2013, 11:04:01 AM
I like mine with. Can't put my finger on it, but it's more alive sounding. After much experimenting, however, I've come to use the two as follows: the Quickie at 80% volume fixed; the SEX as volume control. I've found much more microphonics using the SEX as a power amp. Anyway, it sounds quite nice this way. I like th extra boost in gain, and it colors everything nicely.

But maybe I'm just imagining that... :)

- Sam

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Offline adamct

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Reply #4 on: August 16, 2013, 11:13:43 AM
Doc,

I'm curious...I know that you guys recommend using a powered pre-amp with power amps, because it helps to address impedance mismatches between the source and the amp. Why is this less of an issue with headphone amps?

Best regards,
Adam



Offline Paul Birkeland

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Reply #5 on: August 16, 2013, 11:37:24 AM
Why is this less of an issue with headphone amps?

A headphone amp will generally have adequately high input impedance, and very low output impedance.

If you had, say, a Reduction, then 50 feet of cable feeding your headphone amp, then you'd probably want a preamp next to the Reduction to drive the cable.

With most headphone amps, the source gear is pretty close to the amp, so this is not an issue.

Paul "PB" Birkeland

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Offline adamct

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Reply #6 on: August 16, 2013, 12:40:03 PM
Thanks, Paul.

Just to confirm that I'm thinking about this right: although source and amp are usually close together in a speaker system, too, I take it that speaker amps tend to have lower input inpedance than headphone amps, is that right?



Offline Paul Birkeland

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Reply #7 on: August 16, 2013, 01:03:26 PM
They can indeed, even some of the more popular DIY designs can be as low as 10K.

There can also be an increased cable length when you have a few sources cabled to an input selector/attenuator, then more cable feeding to the amplifier.

Paul "PB" Birkeland

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Offline adamct

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Reply #8 on: August 16, 2013, 02:58:38 PM
Got it. Thanks!



Offline boulos

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Reply #9 on: February 13, 2014, 06:15:27 PM
I just finished building the Quickie 1.1 and I'm pairing it with the SEX. It sounds much more musical with it. I set the SEX at highest volume (I get no hum) and use the Quickie for volume control.  The Quickie has PJCCS upgrade and Solen SB270 caps.  I'm not having any issues with microphonics.



Offline Paul Birkeland

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Reply #10 on: February 13, 2014, 06:27:21 PM
Ooo, you got a pearl plate, sweet! 


Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline JamieMcC

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Reply #11 on: February 13, 2014, 10:04:26 PM
That pearl plate looks nice,  I have a large diy store about 2miles away and was looking around the other day they have a massive selection of marble and granite tiles the white marble looked similar. Sold in packs or individually for samples for just a couple of pound. I just thought straight away what a great idea for interesting top plate to place over the alloy one. 

Shoot for the moon if you miss you will still be amongst the stars!


Offline boulos

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Reply #12 on: February 14, 2014, 02:51:17 AM
Ooo, you got a pearl plate, sweet!

yeah :) It was a very nice surprise when I opened the box.  I'm amazed at how quiet the Quickie is. I expected some noise when I raise the volume of the SEX to the max.  When I tried out the BeePre I built for a friend, I could only raise the volume 2/3 the way up. That said, the BeePre+SEX combo was jaw-dropping. 

Thanks so much for the recommendation on the Solen caps.



Offline mcandmar

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Reply #13 on: February 14, 2014, 05:23:04 AM
I see your a fan of Sylvania tubes too ;)

M.McCandless


Offline boulos

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Reply #14 on: February 14, 2014, 06:02:09 AM
I see your a fan of Sylvania tubes too ;)

Totally :) 

I found I really like them on the SEX. Also, on the Quickie, these two Sylvania tubes gave almost identical voltages on both sides (within 0.1V) and don't seem to suffer from microphonics.  However, I did two things that I felt would help: I stuck six thin (~1mm) rubber strips on the groove in the base where the plate sits (four corners and two in the middle of the long edge); and I left a very thin clearance between the tubes and their sockets (they're almost all the way in, but barely resting on the sockets).

The rubber strips I used are the spacers between bumpers (see example image).