 
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
|
|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
67.170.179.36
In Reply to: RE: Anyone get their January issue yet ? posted by AbeCollins on December 03, 2024 at 19:53:07
My issue came two days ago, I am wanting to read the Buckeye Purifi review, but the woods, mushrooms, and my camera have argued otherwise...
I have an afternoon appointment tomorrow so I have to stay in town, I'll read it with my morning coffee in the morning.
I love my Purifi amp (first gen VTV) it has been interesting watching Buckeye as a small business. If buying today I would certainly give the company serious consideration.
Follow Ups:
I got a Buckeye 4 channel Hypex NC502MP for my bass panels a couple of months ago -- 1000 watts bridged. Very pleased with it -- no fancy front panel, but I can always have one printed at the drugstore. :-)
I'm thinking of getting the Purifi for my Mini Maggies -- and who knows, if I like it enough, maybe I'll put it on the tweeter, which is currently being driven (absurdly) by an A-21. Hell, after reading Kal's review, maybe I'll put one on the midrange and sell my AHB-2 at a profit.
Let us know if it is a full review or a passing blurb.
TIA
.
2022/03/30 Historical Records CENSORED
In the Stereophile January 2025 issue the review article begins on page 77. It is 5 pages long including measurements by JA and a sidebar by Paul Miller on Class D evolution. I read the entire review (rare for me!) but I skimmed over the music that Kal used as I am unfamiliar with it. That's completely on me and others might find it useful.Buckeye PURIFI EIGENTAKT 1ET9040BA1 monoblocks
$2300/pair sold direct includes free shipping in USAMy take under the heading of Inevitable comparisons :
Kal could hardly discern the sonic differences between the Buckeye PURIFI 1ET9040BA1 monoblocks, NAD M23 Master Series PURIFI stereo amp, and his reference two Benchmark AHB2 stereo amps each bridged for monoblock duty.
He mentioned noticing slight differences in bass or treble between the amps upon A/B switching but those impressions were short lived writing, "However, within minutes, none of those impressions remained apparent; only the characteristics of the music and recording mattered, and I never felt the need to change from one amp to another." Kal still prefers his AHB2 "due mostly to matters of ergonomics and familiarity." Kal did mention that the XLR connector on the Buckeye is not a locking XLR so your XLR cable might slip out if you move the amp around. He suggests powering it OFF before moving the amp.
On the tech side :
I read that the Purifi modules require an input board with gain and Buckeye has their own design but there was no detail on it in the articl. VTV on the other hand makes their own input board that allows the buyer to choose from a variety of op-amps and discrete op-amps.... for a price. Buckeye includes a 12v trigger input. VTV offers it.... for a price.
Worth noting from John Atkinson:
The voltage gain at 1kHz into 8 Ohms was very close to the specified figures, at 25.6dB (High), 20.5dB (Med), and 15.5dB (Low).
Buckeye specs the monoblock input impedance as 51K Ohms. JA measured 8.4K Ohms regardless of gain setting. Why the big discrepancy? I have no idea.
[Edit] I think I found the discrepancy. 51k Ohm is the input impedance of the Purifi modules. According to the Buckeye website their custom input board uses a TI TI OPA1656 OP Amp and I'm guessing that the design around this TI Op Amp resulted in an input impedance of 8.4K Ohm as measured by JA.
Edits: 12/06/24 12/06/24 12/06/24 12/06/24
I don't see anything on the Buckeye website about using the 1656 op amp (what I see is opa1612)....please post a link. The input impedance of the Purifi module is very low...less than 5K.....not 51K. The input of any amp using a Purifi module is set by the input buffer. Why Buckeye lists 51K and it measures 8.4K is weird. I consider anything less than 50K to not be ideal. You get better sound with 50K and above. Just now modding 9 of these new Purifi modules for someone and I am setting the input impedance to 100K per phase. The Purifi eval boards for the mono modules have 5K per phase.....not good.
Ric, I posted the link below to what I believe is the Buckeye page for their Purifi 1ET9040BA based monoblocks. Scroll down to the Custom I/O Board: heading where he lists the TI OPA1656 OP Amp.[EDIT]: Even the Purifi 1ET9040BA PDF data sheet is a bit confusing. It shows the module gain as 14.4 dB so you're left to assume that the overall gain is due to the op-amp input which has 3 settings. The datasheet also shows the module input Z as 1.5kOhm diff & 1.3kOhm single-ended. I have to assume that the higher input Z in some reviews (and your finding) is from the input of the op-amp and I further assume that it will vary depending on what input resistor values the builder chooses to use??? Big question mark. Do you know how they come up with the real input Z because it's not clear to me.
Edits: 12/12/24 12/12/24 12/12/24
