Forums - Pure Audio Project - 1st Watt Desgined Crossover

beowulf

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Posts: 1449

Pure Audio Project - 1st Watt Desgined Crossover
05/26/17 at 07:55:43

Thought this might interest you OB guys, this looks really interesting:

We are proud to announce the release of the PAP-C1, a two way Active Analog Crossover, designed by Nelson Pass and FirstWatt for Open Baffle and PureAudioProject.

The PAP-C1 was specifically designed for speakers with woofers and full range drivers, a popular and raved configuration in PureAudioProject offering.

Based on FirstWatt legendary B5 crossover, the PAP-C1 revised JFet filters allow smooth -12db low and high pass filtering between 100hz to 550hz

In addition, the PAP-C1 features adjustable low-bass boost and a gentle high-mid notch on board, and a continuous gain adjustment of the low frequencies on it's front panel, aka 'loudness'.

PureAudioProject unique modular offering features a variety of full range drivers and their matched passive crossovers integrated with 10" or 15" OB woofers in Open Baffle speakers. With Nelson Pass / FirstWatt revised design, the PAP-C1 offers such flexibility also for bi-amping and active crossovers fans, while keeping the entire audio path pure analog and audiophile.

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Lonely Raven Seasoned Member Jack of all Trades, Master of None Posts: 3567	Re: Pure Audio Project - 1st Watt Desgined Crossover Reply #1 - 05/26/17 at 16:35:17 I bet it sounds great too, knowing how the rest of their stuff sounds. Too bad it costs 10x what I paid for my OB speakers. LOL
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maddog07

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Posts: 590

Re: Pure Audio Project - 1st Watt Desgined Crossover
Reply #2 - 05/26/17 at 20:02:18

Papa Pass is an aficionado of full-range, single driver speakers. If you checkout some of his forum posts, white papers, blogs, etc. you can find specific examples of some of his favs and homebrews. A couple of his FirstWatt amps, while not being designed specifically for the typical impedance/frequency responses of these types of drivers, are quite complimentary to them – current source amps. He has a couple of white papers on CS amps that I can point you to if you’re interested. They are available on the FirstWatt website - http://www.firstwatt.com/pdf/art_cs_amps.pdf They make for quite interesting reading. He believes that CS amps attain higher fidelity when paired with appropriate types of speakers that also have a “current source crossover filter” – these also detailed in one of his white papers.
In an email exchange I had with him not long ago, he stated that he actually voices his amps with Lowther PM6A’s and a pair of big vintage Tannoys. And the most recent FirstWatt amps he recommended to me for driving single driver – full rangers are the J2 and F6. The F1 was also a power trans-conductance amplifier (or power current source, if you like), but is no longer in production. It has been my experience that anything Nelson Pass puts his name on, or is associated with, is very, very good sounding kit – just like Decware. Nelson Pass is also one of the most gracious engineers/designers in all of high-end audio. He will help you trouble shoot your DIY amp as well as sharing his own circuit designs.

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Decware Torii MK3, Theta Digital Miles, RME ADI Dac-2 FS, Aesthetix Calypso, Martin Logan Vista, Audio Nirvana 12's & 15's, Betsy WOW/AMT's, Hawthorne Trio's, PS Audio PW P5, Goertz, Kimber, Nordost, Decware and DIY wires, PSA pwr cords, Cary SLI-80 Sig.

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Donnie Seasoned Member Why does it hurt when I pee? Posts: 2355	Re: Pure Audio Project - 1st Watt Desgined Crossover Reply #3 - 05/26/17 at 22:11:52 I wonder how much better it sounds than my $20 Parts Express el cheapo low pass crossovers?
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beowulf Seasoned Member Posts: 1449	Re: Pure Audio Project - 1st Watt Desgined Crossover Reply #4 - 05/28/17 at 22:58:44 Yes, the price of that unit makes it apprehensive to a lot of us. Considering you can get a miniDSP for under $300 ~ though the 1st Watt keeps it all analog which is pretty cool for us vinyl guys. Like Decware's stuff, the PAP-C1 looks to be of that built like a tank quality as well.
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Donnie Seasoned Member Why does it hurt when I pee? Posts: 2355	Re: Pure Audio Project - 1st Watt Desgined Crossover Reply #5 - 05/29/17 at 02:21:59 I've been looking at some of the First Watt amps. If I have a need to go solid state, they look right up my ally.
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maddog07

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seeker of truth

Posts: 590

Re: Pure Audio Project - 1st Watt Desgined Crossover
Reply #6 - 05/31/17 at 22:51:35

Ashly makes an "analog" electronic xover. Do not discount Ashly Audio, just because they are a "Pro" oriented company. They make some mighty good sounding products and have been in business for decades.
Don't forget fellow "philes" most of the music we listen to passed thru "pro" audio equipment when it was made and recorded before it ever got to us.

I have used the Ashly XR-1001 xover to good effect on many an occasion as a low pass to subs/bass units. If it has any negative effect on the signal passing thru it - it is d...n small !!!!!
You can typically find these brand new in the box for about $199. I had one long ago for many years. Finally after several years of not using it, I sold it. A couple years later, had a need for it again - bought another one. I won't make the mistake of selling this one. I used it most recently to low pass to my Augie amp... before I picked up a Crown XLS (with built-in xover) to drive the Augie's. Ashly has updated the circuitry in this xover over the years, but has not changed the product name/number. The one I have now, is a couple years old, but is a different and better unit than the original one I had. Check it out if you need an electronic xover - especially if you need one for low-passing to subs. I think you might find it more than adequate - and the price is right.

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Decware Torii MK3, Theta Digital Miles, RME ADI Dac-2 FS, Aesthetix Calypso, Martin Logan Vista, Audio Nirvana 12's & 15's, Betsy WOW/AMT's, Hawthorne Trio's, PS Audio PW P5, Goertz, Kimber, Nordost, Decware and DIY wires, PSA pwr cords, Cary SLI-80 Sig.

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Doug

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Posts: 318

Re: Pure Audio Project - 1st Watt Desgined Crossover
Reply #7 - 06/20/25 at 06:26:13

After seven years of constant tinkering with and upgrading all the components in my Pure Audio Project Thrier passive crossovers, I decided to take the advice of Harry Weisfeld, VPI CEO and founder, who, many years ago stated that PAP speakers should not be allowed to be reviewed without the PAP-C1 active crossover being used. I had been very satisfied with the performance of the PAP quintets using PAP's high quality stock crossover components, and even more satisfied after upgrading the capacitors, inductors, and resistors. Everything seemed to be about as good as it could be, but Mr. Weisfeld's words never left the back of my mind.

The PAP C1 has now been in my sytem for a month or so and I will unequivocally state that it is a fantastic crossover. The C1 is basically an upgraded First Watt B5 active crossover, an older FW product that I owned for a few years, but never used with the Quintets. Harry Weisfeld was correct in saying that the C1 crossover is mandatory for getting the best sound from PAP speakers.

I now regret not having made this move years ago. Much was learned changing out all the parts on the passive crossovers, and much money was spent, but unfortunately, even with numerous upgrades, the sound quality with passive components falls far short of what the C1 delivers. The C1 meshes perfectly with the ZR2 and CSP3 in front of it, and the LFD and First Watt amps behind it.

My wife has questioned me many times over the years regarding major upgrades in sound quality, but it has once again happened. The C1 is a great crossover! If you have PAP speakers, the C1 could be a game changer for your system as it has been for mine. Decware, PAP, and First Watt products play extremely well together!

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Jay’s CD2T-Mk3
Denafrips Pontus II
ZROCK2 25th Mods
CSP3 25th & Custom Mods
Speakers:
Lii Song ZF15L
PAP Quintet w/Vox 1.6 or Horn1
Amplifiers:
LFD NCSE, First Watt J2, Cary 300SEI

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Dennis

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Posts: 18

Re: Pure Audio Project - 1st Watt Desgined Crossover
Reply #8 - 06/26/25 at 04:15:43

I’ve had my Quintet 10 for about four years now. Early on Zeev built me a first order point to point XO w Mundorf SGO caps and upgraded resistors. I added some isoacoustic feet too. It did make a huge difference but no upgrade I’ve made had been impactful as adding the BACCH to the chain. My speakers simply disappear and I get ruler flat frequently response with any crosstalk. I’m using a minidsp SHD to manage the high/low pass filters and set the XO points. Sounds deliriously good w my Tori V anniversary amp.

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