Buckeye 3 Channel Purifi Amp Review

[Hapo]

That's correct. For people who buy this amp, impeccable measured performance is key. For that reason, I think this is a more significant issue that it otherwise would be.

...thank you for posting this...I was thinking it shouldn't matter if inaudible...

...I remember making fun of youse guys once, but here I am...

...just to keep things in perspective, I was driving Elac Unifi 2.0 UB52's with a Dayton APA 150 amp at one point... (grin)

Elac Uni-Fi 2.0 Review (bookshelf speaker)

This is a review and detailed measurements of the Elac Uni-Fi 2.0 bookshelf speaker. It was kindly sent to me by a member and costs US US $600 a pair on Amazon including Prime shipping. This review will be abbreviated for reasons that will become apparent later. Here is a shot of the speaker...

www.audiosciencereview.com

Review and Measurements of Dayton Audio APA 150 Amp

This is a review and detailed measurements of the Dayton Audio APA 150 power (speaker) amplifier. It is on kind loan from a member. It costs USD $168 from Parts Express including free shipping. If the specs of 75 watts/channel are true, you are getting a stereo amplifier for about $1 per...

www.audiosciencereview.com

...I don't require impeccable measured performance, but I have come to understand that measurements are directly related to sound quality and that most of the other stuff is bullshit...

...I replaced a Dayton APA 150 amp with a Niles SI 2150...this is significant in that a class D amp was chosen over an AB amp based upon Amir's measurements....

...this was a big shift for me...

...I still liked how my Elac Unifi speakers sounded, but traded them in on a pair Elac Carina BS243.4 because the guy @ Crutchfield said they would be less fatiguing w/o giving up definition, and Amire liked them... (grin)

...I still have those, because I kept forgetting I was auditioning them...

...it might be too late to be on point, but the point here is that the measurements have made it easier to find equipment that I really like...

...it is not that I didn't like the APA 150 after I read the review, but it certainly helped to understand the limitations of the amp and explain some of the things I was hearing and blaming on other sources...

...I am slightly ashamed to admit that I really liked the APA 150 and still do, but like the Niles SI 2150 more...I would have never considered it, a class D amp (ug) (shudder) w/o seeing the measurements...

...the Niles amp doesn't really measure all that well, but it is good enough to replace the APA 150 and make a noticeable improvement in my low-ball hi-fi system for very few $$$...

...I only know this because of youse guys...it's youse guys what keep Schitt honest...literally and figuratively...

...now I am looking Class D amps to shade my Adcom GFA 5500, which I deary love like a family member...

 

[Descartes]

I have some builds coming up where the customers choose blue anodized, red anodized, orange anodized, and blue powder coating. Will add those to the gallery as well

Looking forward to seeing the pictures! Especially the blue powder coating and the blue anodized!

 

[Espiritiv]

I have an AC Infinity Aircom sitting on top of my 3ch Purifi set to come on when the inside temperature reaches 86F....it has yet to turn on even when I watch movies near reference (and the 3ch is running my LCR)

Aircom S or T series best for your 3-CH? Seems like S would be fine then if it barely ever comes on.

 

[Buckeye Amps]

I went with the S since it has the smaller footprint (for the 3ch)

 

[Buckeye Amps]

I have begun sending out emails to Purifi owners who previously contacted me about the distortion fix, so now I will post here and the Purifi sales thread as well.

Below are the two options I can send out to any Purifi owner who received their amp BEFORE February 7th (received, not ordered or got tracking). Please email me ([email protected]) and do not PM me here, as your order details are tied to your email so it is easier to pull up shipping information. Also, if your shipping information has changed since the original order, include that in the email.

There are two options:
1) I send out the new tabs and nuts to replace the existing ones, along with new female quick connections to crimp onto your existing speaker wire internally (would just cut off the existing ends, strip the wire, and crimp the new ones on). This route is a little more DIY.
2) I send out the new tabs and nuts, along with a premade speaker cable for each channel, so more of a plug and play replacement. This is a little more costly on my end, so while I will not ask/require any payment for this option, even a small amount is helpful.

PLEASE NOTE: I expect a lot of emails initially, so it may be a day or two until you hear back from me if your email requires a response (you have a question, want to send a small amount of money, need a different option for a fix, etc).
Otherwise, if you email me with your option choice, I will send out the parts necessary within 7-10 days, so just keep an eye out for a USPS package.

 

[Buckeye Amps]

Attached is a quick DIY guide for those who will be replacing the necessary hardware themselves from me

 

[Hapo]

...this level of personal engagement is very impressive and unusual, IMHO...

 

[Espiritiv]

Attached is a quick DIY guide for those who will be replacing the necessary hardware themselves from me

Step 5, do you need a new lock washer as well? I see in Step 3 you take one off.

 

[Buckeye Amps]

Step 5, do you need a new lock washer as well? I see in Step 3 you take one off.

You do not

 

[Calleberg]

Ok, the moment of truth has arrived...

As @Buckeye Amps mentioned, the board designer and I have been going at this diagnosis feverishly. Admittedly, should have found sooner, but I made a critical test error and (as mentioned) the designer had been plagued by a bad dummy load that obscured his measurements until just recently. Since I have been working closely on the troubleshooting, Dylan is allowing me to represent the team to share our finding. In the end, the designer found the cause.

And the culprit is...

View attachment 263237

The binding post connection tab.

Unknown to @Buckeye Amps when he bought the binding posts, the tab is primarily made of steel. Steel is a relatively poor conductor and like a loose or oxidized connection can cause distortion. As with some others, I thought the culprit was the input board, but fortunately it was not. Honorable mention goes to @pma. Within his first few posts in this thread, he mentioned problems with ferrous materials in the signal path. We just had to find it.

@pma is more and more becoming my favorite contributor over here at ASR. Thank you for sharing your knowledge here PMA!

Now that we have established that steel connectors can be problematic in this kind of application. I just can't resist teasing those of you that has a bad case of audiophilia nevrosa with some additional information... Guess what the loudspeaker driver terminals are normaly made of... yes thats right. it's STEEL...

 

[pma]

@pma is more and more becoming my favorite contributor over here at ASR. Thank you for sharing your knowledge here PMA!

Thank you, though I know I am often sharp, harsh and impatient . My goal is to do things technically right and reliable. It is a long path, but I like sharing some gained knowledge, if just at least someone is interested.

Re the steel issue, it is inaudible and occurs only at high current level. It was just good to find it and not to blame electronics of the input buffer.

 

[Rick Sykora]

Now that we have established that steel connectors can be problematic in this kind of application. I just can't resist teasing those of you that has a bad case of audiophilia nevrosa with some additional information... Guess what the loudspeaker driver terminals are normaly made of... yes thats right. it's STEEL...

Correct, am still investigating this but here is what I found from a Sound Stage interview of Lars Risbo of Purifi…

Purifies reliance on speakONs intrigued me, so I asked them about it. Lars Risbo:

Nearly all binding posts and/or banana plugs available we found to be magnetic and added measurable hysteric distortion. The cheapest plastic speakON passed the test. It seems that Benchmark Media Systems came to the same conclusion with their very low distortion AHB2 amplifier.​

 

[Calleberg]

Thank you, though I know I am often sharp, harsh and impatient . My goal is to do things technically right and reliable. It is a long path, but I like sharing some gained knowledge, if just at least someone is interested.

Re the steel issue, it is inaudible and occurs only at high current level. It was just good to find it and not to blame electronics of the input buffer.

I have quoted some of your post for that very reason. Being Technically correct, reliable and also in my experience objectively presented without coloration from personal bias.

And yes, the steel thing is a non issue, obviously at the other end of the speaker cables connected to that Buckeye amp there is going to be a loudspeaker driver of some sort. The material in the terminals of that driver is not going to be even remotely relevant for the performance of said driver because it has so many other shortcomings that dwarfs whatever little impact the terminal material could have

But it is easy to forget sometimes that whatever the equipment and regardless of how good they measure, the real bottle neck are the speakers, and for the most part they are not going to be anywhere near as revealing as an AP analyzer

 

[Head_Unit]

If it had to be returned to be fixed (say the customer doesn't want to or isn't comfortable opening it up) I would obviously cover shipping costs.

I gotta pinch myself that I'm really reading this. Consdering the good service, what's a little rising THD between friends? Heck you can just reprogram the government micronanobots in the COVID and flue and shingles vaccines to allow you to ignore it...

 

[Too Many Notes]

Correct, am still investigating this but here is what I found from a Sound Stage interview of Lars Risbo of Purifi…

Purifies reliance on speakONs intrigued me, so I asked them about it. Lars Risbo:​

​

Nearly all binding posts and/or banana plugs available we found to be magnetic and added measurable hysteric distortion. The cheapest plastic speakON passed the test. It seems that Benchmark Media Systems came to the same conclusion with their very low distortion AHB2 amplifier.​

I have quoted some of your post for that very reason. Being Technically correct, reliable and also in my experience objectively presented without coloration from personal bias.

And yes, the steel thing is a non issue, obviously at the other end of the speaker cables connected to that Buckeye amp there is going to be a loudspeaker driver of some sort. The material in the terminals of that driver is not going to be even remotely relevant for the performance of said driver because it has so many other shortcomings that dwarfs whatever little impact the terminal material could have

But it is easy to forget sometimes that whatever the equipment and regardless of how good they measure, the real bottle neck are the speakers, and for the most part they are not going to be anywhere near as revealing as an AP analyzer

This changes everything. Dylan, please create a guide on how to replace the steel binding posts in our speakers with your brass tabs.

 

[Futility]

Hope this video I found saves someone a few minutes.

Tab/spade connector crimping:

 

[Home Theater Nerd]

I've been using a Buckeye 3-channel Purifi amp for five months now and it has been outstanding. I have very efficient, transparent speakers and the power has been crystal clear without a hint of noise or distortion. As an end user I can attest that the issues detected in this thread have been totally inaudible. Nonetheless, I sent Dylan an email when he announced the fix and he got replacement parts out to me within about a week. Following the posted instructions was a cinch - it took longer to take the amp out of the rack than to pop the cover and swap the tabs and nuts. I got it back up and running last night and it sounds ... exactly the same (crystal clear without a hint of noise or distortion).

I also remember that Dylan's first response to this inaudible issue, before he troubleshot the cause and knew the cost to him, was to promise to make it right at no cost the end user. Even if it meant him replacing the boards - and even if it meant him covering shipping! @Buckeye Amps , thanks for the fantastic customer service, I'll be buying more amps from you!

 

[walt99]

Dylan, enjoying my 8ch 252 and I appreciate what you are doing, keep up the good work!
Now I’m thinking of going to an 8ch Purify, any options there?

 

[Buckeye Amps]

Dylan, enjoying my 8ch 252 and I appreciate what you are doing, keep up the good work!
Now I’m thinking of going to an 8ch Purify, any options there?

Not from me, to be upfront and honest.

In an effort to always be honest and save my customers money I can say that there is almost zero audible gain using something like the Purifi or the new NCx Hypex outside of the front three channels.

MAYBE if someone listens critically to 5ch music using a Purifi for the two surround speakers MIGHT produce a very very subtle improvement. But in 99 out of 100 use cases, I urge customers to save the money and not pay more for Purifi outside of their LCR speakers.

 

[Too Many Notes]

Correct, am still investigating this but here is what I found from a Sound Stage interview of Lars Risbo of Purifi…

Purifies reliance on speakONs intrigued me, so I asked them about it. Lars Risbo:​

​

Nearly all binding posts and/or banana plugs available we found to be magnetic and added measurable hysteric distortion. The cheapest plastic speakON passed the test. It seems that Benchmark Media Systems came to the same conclusion with their very low distortion AHB2 amplifier.​

Previous joking aside, this intrigues me the more I think about it. In theory, could the measurable distortion added by the above components be higher than, say, the extra distortion measured by Amir that was caused by the previously installed steel tabs? In other words, could replacing the tabs in the Buckeye be a complete waste of time if one otherwise uses banana plugs or has speakers with binding posts?