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

[muslhead]

If you have a ground loop, it will be audible as a hum from the speaker even if no sound/signal is being played.
Such ground loops can be fixed, usually pretty easily.

What I have noticed lately is that when using the Monoprice cables and someone's setup has a ground loop issue, the loop is only ever fixed by using a different RCA to XLR cable.

You will hear it if you have a loop. If you don't hear it, there is nothing to worry about.

thats what i figured, thanks for the reply,
Maybe lucky mine is not audible .... yet. Possibly because mine are only 3ft long

 

[Sammy1358]

They are very similar. The Micro Audio has a higher rail voltage which is needed for the 7040SA to reach its peak output.

Thank you very much for the reply, I am guessing that would be important if you have ultra demanding speakers. I received my amp this morning and have been listening for the past couple of hours and this hands down trounces the class AB amp I was running before. No audio phrasing needed.... Just instant audible gratification. Thank you for your work in bringing these into the market at such a reasonable price Dylan! I am ecstatic with the amp in its current configuration

Noob question for the community, I am running balanced XLRs directly from my DAC which outputs at 4v from the XLRs. I am assuming that I should be using the Medium output settings on the Purifi amp which most closely matches the output of the amp at around 3.89v depending on the impedance demands of the speakers at a given time. Am I understand this correctly?

 

[Buckeye Amps]

Thank you very much for the reply, I am guessing that would be important if you have ultra demanding speakers.

Precisely. It makes the biggest difference for impedance under 4ohms.
And is also more about me trying to offer something others don't (while also being honest about it) without it costing much more (only added $50 overall to the cost of a mono 1ET7040SA)

Edit: price difference corrected 2-18-23

 

[Sammy1358]

Precisely. It makes the biggest difference for impedance under 4ohms.
And is also more about me trying to offer something others don't (while also being honest about it) without it costing much more (only added $30 overall to the cost of a mono 1ET7040SA)

With the success of this amp, when I am ready to move to monoblocks, the extra $100 for the pair will be an easy choice and an appreciated option.

Edit: price to reflect Buckeye's edit
Thanks again,

 

[squared80]

Update:

I am no longer going to advocate/endorse using the Monoprice RCA to XLR cables. Please note, anyone currently using one, there is no issue/distortion/sound degredation.
It is more so that as of late there have been more cases of those specific cables introducing ground loop issues that are resolved by using different RCA to XLR cable brands.

So if you are not hearing an issue, do not worry about it at all.

Not sure if there was a quality issue with production of these cables recently, etc.

Do you have any other suggestions?

 

[Buckeye Amps]

I highly suggest Blue Jeans Cable.
Otherwise there are various brands on Amazon that are wired correctly and people have used without issue before

 

[tmtomh]

I highly suggest Blue Jeans Cable.
Otherwise there are various brands on Amazon that are wired correctly and people have used without issue before

I would echo the recommendation for Blue Jeans. I haven't used their RCA to XLR cables, but I've used their speaker cables and both analogue and digital interconnect cables and have been quite happy with the build quality. I'm sure it is possible to get similarly transparent/properly constructed cables for less money, but I like Blue Jeans because they are pretty much a guaranteed quality/properly built product no matter what you buy, and the price premium you pay over generic/mass-market stuff is very small, especially compared to the prices of "audiophile" cable brands.

I would also note that I've had very good luck with RCA to XLR cables from World's Best Cables, which are one of the main non-Amazon Basics brands sold on Amazon. For those who care, you can choose between Mogami and Canare star-quad variations, and of course different lengths. Prices are reasonable. I had a ground loop, and replacing my RCA to RCA cables with a pair of RCA to XLR cables didn't eliminate it, but it did reduce it significantly. Since RCA to XLR is an imperfect way to address ground loops (XLR to XLR is much more effective), I concluded that these cables must be wired properly or else they probably wouldn't have done anything at all. I think the WBC cables actually don't cost much less than Blue Jeans, but you do get super-fast, free shipping if you're an Amazon Prime member, so they're a good option if you're impatient to try out the cables as a solution.

Oh, one final note: when I reduced, and then later fully eliminated, my ground loop issue, I was shocked to realize that in addition to the hum getting quieter and then going away, the self-hiss of my system also got quieter, and then virtually disappeared, in tandem with the hum. I posted about that here, and learned that ground loops can carry other frequencies as well. The inherent noise floor of my system, it turned out, was far lower than I had thought it was. A great unexpected benefit to addressing the ground loop!

YMMV of course.

 

[Futility]

My 2 and 3 channel amps connect to Yamaha Receiver via Monoprice RCA-to-XLR 3ft cables.

Initially, both front and and rear speakers exhibited buzzing that could be heard from 3ft/1m. Eventually, I tracked the culprit to be Kody media player running on Nvidia Shield connected to AVR. Kodi has a setting that sends "low volume noise" to audio output. I didn't notice it with my previous power amps but it became apparent after switching to Buckeyes. After disabling the "Send noise" and "Keep Audio device alive" settings, the buzz was gone.

After reading today about the possible ground loop issue affecting the MP RCA-XLR cables I re-checked my amps and speakers.
I turned on my receiver and amps and started raising the volume. No buzz or hissing was heard at levels I normally listen at and beyond.

Only after increasing receiver volume to reference -0.0db AND putting my ear to speakers I could identify a faint hum. Moving a few inches away, the sound would become inaudible.

This is my anecdotal evidence that not all Monoprice connectors are faulty. So, don't panic!

 

[Buckeye Amps]

Mark your calendars!

We will be at MWAVE this July. Hope to see some of you there!

Buckeye Amps - Midwest AV Experience

midwestavexperience.com

 

[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.

 

[Futility]

Option 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.

To sway more people take the less costly route, may I recommend posting a visual step-by-step photo guide. It can be as simple as a single photo with inset Step 1-2-3-4 frames.

Also, required tool list would help. Not everyone has a crimping tool but most have pliers. If fix can be done with those, more people will choose to go the DIY route, saving you time and money.

 

[Buckeye Amps]

To sway more people take the less costly route, may I recommend posting a visual step-by-step photo guide. It can be as simple as a single photo with inset Step 1-2-3-4 frames.

Also, required tool list would help. Not everyone has a crimping tool but most have pliers. If fix can be done with those, more people will choose to go the DIY route, saving you time and money.

I am working on that today/tomorrow as well. Will hopefully have something posted by tomorrow night

 

[droid2000]

To sway more people take the less costly route, may I recommend posting a visual step-by-step photo guide. It can be as simple as a single photo with inset Step 1-2-3-4 frames.

Also, required tool list would help. Not everyone has a crimping tool but most have pliers. If fix can be done with those, more people will choose to go the DIY route, saving you time and money.

Great idea. I am having a hard time visualizing what is involved in the two options. I'll go with the cheaper route for Dylan to help a brother out if it looks doable.

 

[Bachemar]

I'm assuming the speaker cable being referenced here, is internal to the amp - From the binding post to the input board, and not the speaker cable that goes from the amp to the speaker end?

 

[ryanosaur]

I'm assuming the speaker cable being referenced here, is internal to the amp - From the binding post to the input board, and not the speaker cable that goes from the amp to the speaker end?

correct

 

[Futility]

The way I understand it. Please, correct me if I'm wrong.

 

[Buckeye Amps]

The way I understand it. Please, correct me if I'm wrong.

View attachment 268304

That is correct (and is an image of a new, fixed build).

I will do a DIY picture guide as asked. Just need a day or two

 

[tmtomh]

Glad the solution has been achieved - and looks like a very simple fix!

 

[Futility]

For those opting for complete cable assembly, could @Buckeye Amps ask them, as a courtesy, to send the old ones back?
After a few weeks you'd have a plenty of cables that only require crimping on one end, free of additional cost.
The best part is, you can still use these returned assemblies in new builds.

While I could probalby do the fix myself, I don't mind waiting a few weeks or even months for the convenience of plug and play fix.

P.S. Are you dreading the idea of crimping 1000s of cables?

 

[bkdc]

Am I understanding that the problem was the material in the tab, nut and quick connectors at binding post???

If this is the case, does the problem exist for people who chose the SpeakOn option?