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October 17, 2021, 01:08:58 PM

Author Topic: S.E.X. as preamp feeding Quad II classic MonoBlocks?  (Read 834 times)

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Offline pistachio

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S.E.X. as preamp feeding Quad II classic MonoBlocks?
« on: September 20, 2021, 02:40:05 AM »
Hi all, I'm interested in ordering the SEX 3.0 kit. Primary reasons will be as headphone amp (easy drive Oppo PM-3) and as amp to drive some 92dB speakers in near field home office setup.

However, I have a pair of Quad II that never get used because I lack a preamp for them. I've searched the forum and it seems people have had success with using the S.E.X as a preamp by using the headphone out.

Would this also work with the Quads?
I don't know enough about this to understand possible impedance matching issues etc.
Advice is appreciated, thanks.
Pete.

Offline Paul Birkeland

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Re: S.E.X. as preamp feeding Quad II classic MonoBlocks?
« Reply #1 on: September 20, 2021, 04:14:01 AM »
Yes, you can use the SEX as a preamp.  If you have the super old ones that don't have RCA jacks, you'll need to make some cables or modify the amps a little so you can connect them to the SEX amp. 

You'll also find that vintage power amps have tons and tons of gain, so using a pair of Harrison Labs -12dB attenuators at the input of each amp so they aren't so sensitive.
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man

Offline pistachio

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Re: S.E.X. as preamp feeding Quad II classic MonoBlocks?
« Reply #2 on: September 20, 2021, 12:59:46 PM »
Thanks Paul, that sounds good. Yes, I have the Jones plug to rca adaptors. Also the amps have been checked over and original GEC valves tested well etc. Hence it’s a bit of shame theyve been just sitting on the shelf.
Cheers, pete.

Offline Deluk

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Re: S.E.X. as preamp feeding Quad II classic MonoBlocks?
« Reply #3 on: September 21, 2021, 01:11:25 AM »
As an extra to this, what would be the most suitable BH pre for the Quad II's? Of course the BeePre2 is fine but the big jump in price from a Moreplay has to be considered. A long time ago I asked about using my Crack with my Quad II's and it was agreed that it would be possible if attenuators were used. Would attenuators be needed with a Moreplay?
« Last Edit: September 21, 2021, 10:10:05 AM by Deluk »

Offline Paul Birkeland

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Re: S.E.X. as preamp feeding Quad II classic MonoBlocks?
« Reply #4 on: September 21, 2021, 04:43:09 AM »
The Moreplay and the BeePre have less gain than the Crack and SEX amp do, so the needs for attenuators won't be as significant. 
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man