• 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!

DIY Purifi Amp builds

OP
J

JimB

Addicted to Fun and Learning
Forum Donor
Joined
Sep 19, 2019
Messages
731
Likes
493
Location
California
So, power connections are now in place in my amp.
Only remaining part is the connection from SMPS J4 to Neurochrome buffers J2. From one connection to two connections. Need to build new ribboncable, is it possible to have three connectors on one ribboncable or are the leads cut in the connector?
Similar to pic but with three connectors.
View attachment 94361
You can certainly use more connectors on such a cable, provided the wiring is right. I believe @tomchr has said it is not plug and play (pin to pin). You'll have to confirm pinouts with him, or others who have his board.
 

NTSOS

Member
Joined
Oct 19, 2020
Messages
51
Likes
38
Location
TN

phoenixdogfan

Major Contributor
Forum Donor
Joined
Nov 6, 2018
Messages
3,294
Likes
5,070
Location
Nashville
Well the Eval 1 with Ghent's harnesses are on the way back to Purifi, and the SMPS with my homemade harnesses are at the Post office in the Netherlands awaiting delivery to Hypex tomorrow. Should finally, finally get to the bottom of why the Frankenamp is not working.
 
OP
J

JimB

Addicted to Fun and Learning
Forum Donor
Joined
Sep 19, 2019
Messages
731
Likes
493
Location
California
Well the Eval 1 with Ghent's harnesses are on the way back to Purifi, and the SMPS with my homemade harnesses are at the Post office in the Netherlands awaiting delivery to Hypex tomorrow. Should finally, finally get to the bottom of why the Frankenamp is not working.
I sure hope you like it once all of this is done!

EDIT: I meant, I'm sure you'll like it once all this is done! ;)
 

phoenixdogfan

Major Contributor
Forum Donor
Joined
Nov 6, 2018
Messages
3,294
Likes
5,070
Location
Nashville
I sure hope you like it once all of this is done!

I had better!
Btw, I shared my concerns with Kim of Purifi re the boards being in contact with the back plate. I was told not to worry b/c their model based on the same case touches as well, and it's not problem. So I guess I won't get the back plate modified and save myself a few bucks that way.

All tolled I'm probably around $300-400 over budget what with the shipments of boards back to Hypex including the time customs kicked it back to me, and the custom back end (which ran over $140), and the purchase of the 3m connector, and the purchase of cable from hypex and the purchase of cable from Ghent. Probably closer to $1700 than $1200.

And I still don;t know for certain the root cause. Double checked the aux harness against Ghent's and mine looked perfect and had continuity. It should have worked the first time. I'm really gonna be pist if I find one of the boards was defective to begin with. It will be much better if it turns out to be my own screw up.
 

daniboun

Major Contributor
Joined
May 2, 2020
Messages
1,768
Likes
2,069
Location
France (Lyon)
Hi guys,
I am from TPA325X world, just a question for experts :
Is it possible to use another SMPS LLC PSU other than the SMPS1200A400 to power the Eval. Purifi modules ?
 
OP
J

JimB

Addicted to Fun and Learning
Forum Donor
Joined
Sep 19, 2019
Messages
731
Likes
493
Location
California
Hi guys,
I am from TPA325X world, just a question for experts :
Is it possible to use another SMPS LLC PSU other than the SMPS1200A400 to power the Eval. Purifi modules ?
Sure. Several people have done this and commented on their choices earlier in this topic.
 

daniboun

Major Contributor
Joined
May 2, 2020
Messages
1,768
Likes
2,069
Location
France (Lyon)
Sure. Several people have done this and commented on their choices earlier in this topic.

To avoid reading the 87 pages, can I have a link to a compatible and easy-to-connect alternative power supply?
 

Matias

Master Contributor
Forum Donor
Joined
Jan 1, 2019
Messages
5,029
Likes
10,796
Location
São Paulo, Brazil
D

Deleted member 65

Guest
Backplate holes & cutouts all done, polish & paint next.

Ribboncable question, is it possible to have two ribbons into one connector?

1605878003431.jpeg
 
OP
J

JimB

Addicted to Fun and Learning
Forum Donor
Joined
Sep 19, 2019
Messages
731
Likes
493
Location
California
...
Ribboncable question, is it possible to have two ribbons into one connector?
Why would you need to do this? You can have one long one with a third connector between the ends. Same result, no?
 
D

Deleted member 65

Guest
Why would you need to do this? You can have one long one with a third connector between the ends. Same result, no?

Yes, agree, just investigating if the aesthetics of cable management can be improved in my build ... ;-) not breaking the symmetry ... I know, it’s just me.
 
OP
J

JimB

Addicted to Fun and Learning
Forum Donor
Joined
Sep 19, 2019
Messages
731
Likes
493
Location
California
Yes, agree, just investigating if the aesthetics of cable management can be improved in my build ... ;-) not breaking the symmetry ... I know, it’s just me.
How about the strain relief type? Both ends of the ribbon will come out the same side. I've done this in computers. Neat.
1605908741620.png
1605908812973.png

EDIT: Use it in the middle of your cable.
 
Last edited:

Aardappel

Member
Joined
Nov 19, 2020
Messages
62
Likes
56
Location
Melbourne
Dear audiophiles,

A quick question - given that the stock Purifi EVAL input buffer (as amirm mentioned) reaches max volume at just 1.5V input with the extra gain, how do you guys drive the amp unit? If I am not mistaken, most balanced (XLR) DACs max out around 4V. How do you control the volume?

I am trying to procure a completely new setup from scratch with the Purifi amp, likely a pair of Klipsch RP-8000F speakers and a new balanced DAC that I still need to decide on (currently leaning towards either the Gustard A18 or the SMSL SU-8). My concern is that if the maximum volume is reached at just 36.5% of the max volume of the DAC (1.5/4) that the incremental volume steps are actually quite large. Furthermore, what would happen if the DAC reverts to full output/volume (4V) for example because there was a power reset or something like that, that could mean the end of the speakers. Very keen to find out how to best tackle the volume issue or how you guys drive the amp!

Cheers
 

Aardappel

Member
Joined
Nov 19, 2020
Messages
62
Likes
56
Location
Melbourne
Dear audiophiles,

A quick question - given that the stock Purifi EVAL input buffer (as amirm mentioned) reaches max volume at just 1.5V input with the extra gain, how do you guys drive the amp unit? If I am not mistaken, most balanced (XLR) DACs max out around 4V. How do you control the volume?

I am trying to procure a completely new setup from scratch with the Purifi amp, likely a pair of Klipsch RP-8000F speakers and a new balanced DAC that I still need to decide on (currently leaning towards either the Gustard A18 or the SMSL SU-8). My concern is that if the maximum volume is reached at just 36.5% of the max volume of the DAC (1.5/4) that the incremental volume steps are actually quite large. Furthermore, what would happen if the DAC reverts to full output/volume (4V) for example because there was a power reset or something like that, that could mean the end of the speakers. Very keen to find out how to best tackle the volume issue or how you guys drive the amp!

Cheers

Upon further research I think the best option would be to add an inline attenuator, such as a fixed Rothwell attenuator. Pardon my ignorance, but which gain reduction level should I aim for (-10, -15 or -20 dB), to bring the EVAL1 back into balance with a typical balanced DAC that has a 4V output Voltage?
 
Top Bottom