• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

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

goryu

Addicted to Fun and Learning
Joined
Oct 4, 2019
Messages
530
Likes
275
Ah, ok, thought they were going to be a standard feature. Thanks.
 

Rottmannash

Major Contributor
Forum Donor
Joined
Nov 11, 2020
Messages
2,968
Likes
2,604
Location
Nashville
Are you gonna send one to @amirm for review and measurements?
 

Rottmannash

Major Contributor
Forum Donor
Joined
Nov 11, 2020
Messages
2,968
Likes
2,604
Location
Nashville
If it measures as I suspect, I will order a 3 channel Purifi and relegate my VTV Purifi to a secondary system. Love the added features you're offering, including gain and clipping indicators. Great work!
 

bkdc

Active Member
Forum Donor
Joined
Feb 28, 2022
Messages
274
Likes
269
I'm looking for Stereo Purifi amps. No need for heat sinks. The Purifi design runs amazingly cool. My P452 never gets warm in it's aluminum case. The NC502MP generates quite a bit more heat so I can see the value heat sinks might add there with long hours of use. But if Buckeye is trying to keep cost down on the Purifi build - heat sinks will increase prices and may not make much of a difference with a stereo Purifi design.

If Buckeye decides to build 1ET7040SA amplifiers, I think heat sinks will be required for anyone that dares to need 500+ watts. Power output at 2 ohms load on the 1ET400a and the 1ET7040sa is essentially thermally limited. The new Apollon PET 950 1ET7040SA module amps are designed properly with heat sinks on the power supplies and the Purifi amplifier modules attached to heat sink fins on the side of the chassis. I know a custom chassis takes investment and the wiring is impeccable but the price/markup is incredible. I would love to see a budget option with well-designed heatsinks for the Purifis.
 
Last edited:

Billy Budapest

Major Contributor
Forum Donor
Joined
Oct 11, 2019
Messages
1,810
Likes
2,674
Suggestion for special edition case color—champagne faceplate, like Conrad-Johnson, Accuphase, and some Sony ES gear.
 

Matias

Master Contributor
Forum Donor
Joined
Jan 1, 2019
Messages
5,029
Likes
10,794
Location
São Paulo, Brazil

Billy Budapest

Major Contributor
Forum Donor
Joined
Oct 11, 2019
Messages
1,810
Likes
2,674

dragonist2

New Member
Joined
May 3, 2022
Messages
1
Likes
0
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.
Would something like the March Audio p262 that has both XLR and RCA inputs but still uses the OP1612 be a solution for the issue you describe? Or does it come down to the opamp itself and not implementation?

Sidebar: Sorry to derail, I am not suggesting any changes to the current product. Just curious as to the engineering behind this post.
 
Last edited:

kgt

Member
Joined
Jan 26, 2022
Messages
8
Likes
2
The debugging/testing on the 2ch Purifi Input Buffer Board is complete and a prototype build is being sent out for measurements (not to Amir but a 3rd party to diagnose any issues before a final production unit).

I can confirm the Purifi board allows both clipping indication and error state indication, which from what I have been told is something most other Purifi builds out there do not offer.
@Buckeye Amps
So, I assume the 3rd party measurements are done and now final production unit is being built? And next step is to send the final production unit to Amir to review?
 

Keened

Senior Member
Forum Donor
Joined
Nov 2, 2021
Messages
329
Likes
219
Would something like the March Audio p262 that has both XLR and RCA inputs but still uses the OP1612 be a solution for the issue you describe? Or does it come down to the opamp itself and not implementation?

Sidebar: Sorry to derail, I am not suggesting any changes to the current product. Just curious as to the engineering behind this post.
Either in this thread or their HyperX thread the go through the reasoning. IIRC it comes down to they are getting a custom input buffer designed by a fellow board member at a very reasonable rate and trying to add RCA would add costs both in terms of parts and design.

They did confirm that a properly terminated RCA -> XLR will work and they have multiple gain settings to compensate.
 
OP
Buckeye Amps

Buckeye Amps

Major Contributor
Audio Company
Forum Donor
Joined
May 28, 2020
Messages
1,653
Likes
6,506
@Buckeye Amps
So, I assume the 3rd party measurements are done and now final production unit is being built? And next step is to send the final production unit to Amir to review?
A revision had to be made to the prototype board, so as soon as the new one is in my hands it will be sent out for 3rd party measurements
 

goryu

Addicted to Fun and Learning
Joined
Oct 4, 2019
Messages
530
Likes
275
A revision had to be made to the prototype board, so as soon as the new one is in my hands it will be sent out for 3rd party measurements

Weren't you going to use Neurochrome buffer boards at one point? What happened to that?
 
OP
Buckeye Amps

Buckeye Amps

Major Contributor
Audio Company
Forum Donor
Joined
May 28, 2020
Messages
1,653
Likes
6,506
Weren't you going to use Neurochrome buffer boards at one point? What happened to that?
A member here reached out as they do microelectronics design/fabrication and helped me make all the new boards I am using for my Purifi and Hypex lineup.
It has allowed me to offer some features on the Purifi not many have.
 

goryu

Addicted to Fun and Learning
Joined
Oct 4, 2019
Messages
530
Likes
275
A member here reached out as they do microelectronics design/fabrication and helped me make all the new boards I am using for my Purifi and Hypex lineup.
It has allowed me to offer some features on the Purifi not many have.

have you tested the buffer boards to see how they spec out?
 
Top Bottom