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VDS

Hypex, Purifi clarification

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Hi,

Been reading about Purifi class D amps.  I know several members have them, or Hypex, I’m wondering about the buffer board and op amp chips. Has anyone tried different buffers or op amps? Wondering if they make a meaningful difference?  Looking at Apollon, Nord, March, VTV. Some say the differences are negligible, builders claim a big difference. 
Thanks

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19 hours ago, VDS said:

buffer board and op amp chips.

 

Not sure what a buffer board is in a class D

 

Op Amps are different and have measurable differences in characteristics and performance, I also assume negative feedback in the design.

 

If you think of Tube Rolling, change it to OP Amp rolling. Some may have a very different signature

 

The little inexpensive component may be the most significant determinant to sound quality assuming a competent design.

 

Install sockets and roll away with op amps, they are low cost items.....maybe a cigar and glass of red while you evaluate.....

 

I think it was Pass who did designs to get rid of negative feedback.

 

There are lots of open source Pass designs and  kits, he may have also ejected op amps, or it was someone else....Maybe it is the new Yammies Integrated amps that are differential aka tube like, and ditched op amps.....

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I believe John Warren had done some op amp rolling when configuring a version of the Crown D45. He installed some sockets and tried different ones. Look for a thread on the Crown d45, also check out his site at north Redding engineering. He may have some info there.

Sent from my SM-G986U using Tapatalk

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8 hours ago, The Dude said:

I believe John Warren had done some op amp rolling when configuring a version of the Crown D45. He installed some sockets and tried different ones. Look for a thread on the Crown d45, also check out his site at north Redding engineering. He may have some info there.

 

Few weeks ago I found a video bake off of Caps by a musical instrument repair guy. Understandably his customers were chasing the golden capacitor,

He built a test rig allowing him to rotary switch between caps for his bench and by ear evaluation. All approximately equal.

 

OP Amps on the other hand should have noticeable differences, certainly measurable ones.

 

I suggested it to some of the Yamaha guys on AK, who ran with it. Turns out the "best one" was discontinued and the scramble for the remaining chips began ...........

 

At least one of the AK McIntosh guys socketed his C-34 pre amp and dove in, lost track of his work. Mc factory who also reads the board also dove in and started making noise about better Op amps for old units instead of the older same performance units when you ordered parts or had the factory do work. Significant signal to Noise improvements. Why change amps when you can change op amps for pennies...

 

I'll add it to my ever growing list of projects ............

 

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1 minute ago, Bubo said:

 

Few weeks ago I found a video bake off of Caps by a musical instrument repair guy. Understandably his customers were chasing the golden capacitor,

He built a test rig allowing him to rotary switch between caps for his bench and by ear evaluation. All approximately equal.

 

OP Amps on the other hand should have noticeable differences, certainly measurable ones.

 

I suggested it to some of the Yamaha guys on AK, who ran with it. Turns out the "best one" was discontinued and the scramble for the remaining chips began ...........

 

At least one of the AK McIntosh guys socketed his C-34 pre amp and dove in, lost track of his work. Mc factory who also reads the board also dove in and started making noise about better Op amps for old units instead of the older same performance units when you ordered parts or had the factory do work. Significant signal to Noise improvements. Why change amps when you can change op amps for pennies...

 

I'll add it to my ever growing list of projects ............

 

 

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