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Buckeye Amps: Purifi Mono, 2ch, and 3ch Official Thread

BoredErica

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Exciting! Will there be an option to adjust gain like the recently reviewed Vera Audio product?
edit:
Just saw there will be. I hope it can go low! :D
 
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goryu

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I have been planning to buy a VTV purifi stereo amp with the purifi buffer. I understand it has some build issues but I look at it as a diy option. Where else can you get all the parts for less than Purifi and Hypex sells them for? If you could offer say a kit, with all the parts, for DIY people, at less than the cost of the individual parts from Purifi I think you would have a hit.
 

phoenixdogfan

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I currently have the Eval1 that I self assembled from Hypex, Purifi and Ghent parts. It's basically identical to the stereo amp Amir reviewed, and I'm extremely happy with it, but I would have preferred a version which didn't have the connectors directly soldered to the amp board. The Neurochrome would obviously solve that issue.
 

Bachemar

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Would it be possible to do an MCH amp in the XL case mixed in with Hypex for surround/Atmos channels? I would be "very" interested in a 7 channel amp with 3 Purifi and 4 NC252 channels in one box.
 
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Buckeye Amps

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Initial custom buffer design/pricing is done (very happy about the price). Not at all finalized, but would be using TI TPS7A49/30 voltage regulators, OPA1612, toggle switch for either "Norrmal" or "Low" gain (26dB/20dB range), slide switch for "On" "12v Trigger" "Auto Sense", PCB mounted Neutrik XLR connectors (with correct Pin 1 wiring), FastOns for connecting my own speaker binding posts (so can easily allow speakON option), Power LED....among other things.

The Hypex SMPS1200A400 is out of stock until end of April unfortunately. Would make a prototype hopefully in May to undergo testing (including tests similar to what Amir does to verify the input board performance, etc). So, fingers crossed, POSSIBLY June/July availability. Not going to take pre orders until the prototype is done and verified.

For a 2ch Purifi, I am shooting for a price range around $1129.
 
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dwkdnvr

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Hmmm, I was considering the VTV Purifi w/ Neurochrome buffer upgrade, but I may wait to see how this develops.
 
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Buckeye Amps

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A reach out for some thought:

Would a single Hypex SMPS1200A400 for enough for three Purifi modules?
Purifi answered me saying it "should handle nearly all music/movie usage situations"....
 

Ten42

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It may detract some buyers, but the design I am going for is XLR in only. A properly wired RCA to XLR cable will still always be all that is needed for those with RCA.

A properly wired RCA to XLR cable is not all that is needed if one wants to use the full output capabilities of the 1ET400A when using dual single-channel opamps like the OPA1612. According to the 1ET400A's spec sheet, 11.2Vpk-pk (I'm assuming pk-pk even though the spec sheet doesn't specify pk-pk or RMS as 12Vrms input would be ludicrous) referenced from the negative input is the max voltage needed to reach full rated power. That's 11.2V / 4Vrms (XLR line level) / 0.707 (RMS to pk-pk conversion) = 3.96 times XLR line level. In comparison, the single-ended max recommended voltage rating, according to the spec sheet, is 5V. That's 5V / 2Vrms (RCA line level) / 0.707 = 3.54 times RCA line level. That would mean RCA users would never be able to reach the full power rating. It would be trivial to use a differential opamp like the LME49724 (used in the Schiit Magnius, a highly rated amp) instead of the OP1612 which will allow proper differential output with only a single-ended input.
 

Matias

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A reach out for some thought:

Would a single Hypex SMPS1200A400 for enough for three Purifi modules?
Purifi answered me saying it "should handle nearly all music/movie usage situations"....
I think most users would accept to bottleneck say from max 450W to 400W theoretical power on each of the 3 modules in order to get significant savings by using a single SMPS1200A400 and small chassis. Would be the cheapest 3 channel Purifi for sure, and still plenty of power. Sounds great to me!
 

Bachemar

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I think most users would accept to bottleneck say from max 450W to 400W theoretical power on each of the 3 modules in order to get significant savings by using a single SMPS1200A400 and small chassis. Would be the cheapest 3 channel Purifi for sure, and still plenty of power. Sounds great to me!
The specs indicate 1500 max power and 1200W at 20Hz - Considering most HT use (3 channel) will include a subwoofer and would never drive all 3 channels to max power simultaneously. While still retaining full power for 2 channel use, I would happy accept the tradeoff for a small and affordable 3 channel Purifi amp
 

goryu

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Any idea as far as time frame for a purchase?
 
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Buckeye Amps

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Thanks everyone for the website help offers. I am working on one as we speak.
 
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Some more good news:

Because of the approach for this amp, with the custom input board containing nearly everything and wiring being a minimal effort, my hope is that purifi builds would have a lot shorter of a wait time than my Hypex builds.

Purifi customers wouldn't be cutting in line or pushing back the build times of existing Hypex orders but instead be much like a Ghent build where I could slot them in for assembly without affecting timelines.
 
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