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Audiotrak Prodigy HD2 opamp configurations list
Apr 2, 2010 at 3:07 AM Post #257 of 492
Quote:

Originally Posted by m4a1rifle /img/forum/go_quote.gif
I have read this whole thread, they only mentioned the model name like "OPA2604" but if you could click this link to farnell you can see that there are 2 version of "OPA2604" namely OPA2604AP. (with a dot) and OPA2604AP, wideband and low noise type... both are also "OPA2604", but which one should i get? i know the "A" is the quality as in S>B>A, and "P" is package type MDIP-8, but the "." (dot), and wideband/low noise no one mentioned about it before...


If you are unsure just ask a person in the thread.
 
Apr 5, 2010 at 5:18 AM Post #259 of 492
Quote:

Originally Posted by majkel /img/forum/go_quote.gif
You'll get the same OPA2604AP in each case.


I see, but the price is different
OPA2604AP. costs RM14.63
OPA2604AP costs RM20.50

I wonder if the higher price is worth the quality gained?
 
Apr 5, 2010 at 7:11 PM Post #260 of 492
Hello can get a HD2 with 3x OPA2604.

Like to replace them for 2x LT1028 + AD797 as buffer.

Because found great eBay items :ready to plug in!
ad797 $34(item 220493729673)
and 2x LT1028 $20 (item 300405500796)

No gain adjustment in this configuration nessasary?
 
Apr 6, 2010 at 11:33 PM Post #261 of 492
hey have any of you guys compared the optical out from this card to like the optical out from a macbook pro or something like the trends ud10 or teralink usb to sdif converters

I've personally compared the optical out from a trends ud10 and a macbook pro and the ud10s optical out sounded better, I'm just wondering if hd2s optical out may sound even better
 
Apr 8, 2010 at 7:13 AM Post #262 of 492
Quote:

Originally Posted by Space2012 /img/forum/go_quote.gif
Hello can get a HD2 with 3x OPA2604.

Like to replace them for 2x LT1028 + AD797 as buffer.

Because found great eBay items :ready to plug in!
ad797 $34(item 220493729673)
and 2x LT1028 $20 (item 300405500796)

No gain adjustment in this configuration nessasary?


You will need the simple mod from ear fanatic posted a few pages ago for the LT1028, simply 4 resistors to solder, easy

LT1028ANC8 are claimed to be better than the CS8 you plan to order.

As for 797, version BRZ is claimed to be the best.
see this one
Dual to Mono Op amp module 4558 NE5532 TL072 to AD797BR - eBay (item 350336041861 end time May-02-10 05:48:20 PDT)
 
Apr 9, 2010 at 8:09 AM Post #263 of 492
Quote:

Originally Posted by Space2012 /img/forum/go_quote.gif
Hello can get a HD2 with 3x OPA2604.

Like to replace them for 2x LT1028 + AD797 as buffer.

Because found great eBay items :ready to plug in!
ad797 $34(item 220493729673)
and 2x LT1028 $20 (item 300405500796)

No gain adjustment in this configuration nessasary?


Actually Im not sure... The configuration what I used was 2x AD797 + LT1028 as buffer.

Never tried backwards....

Leeperry: Did You try LT1028's as DAC output?

You have to find out 2 things:
-is the AD797 unity gain or not (I know the LT1028 is not)
-what is the gain on the differential opamps on the DAC output

I never looked at that one.

To be honest, the function of these opamps is not amplifiing the signal. The DAC output is differential.
To make the signal single ended, there is a differential amplifier stage on the DAC output, but there is a need for a buffer after this... the rest You know.
So there is no really need of 2x gain that would make an LT1028 generally stable on either stage.
 
Apr 9, 2010 at 12:03 PM Post #264 of 492
Quote:

Originally Posted by earfanatic /img/forum/go_quote.gif
Leeperry: Did You try LT1028's as DAC output?


I did, yes, they were sounding very thin and really nothing to write home about.

IME the 1028AC needs to be at the very last stage to deliver, and tbh its incredible low end bass response is quite something
ph34r.gif
 
Apr 18, 2010 at 10:13 AM Post #268 of 492
Hi there,

Soon I'll post the better HD2 buffer gain mod.
For those who is not up to date this mod is made to make possible to use the LT1028 opamp on the HD2 buffer stage, which is the magic ingredients to complete the most incredible sound paired with AD797BRZ-s on the DAC output.

The original mod can be found here: HD2 mod by Earfanatic
DSC00012.JPG

I want to improve it and lower the signal to be able to leave the volume of the DAC 100% - thus keeping up the SNR ratio. With this there is no need to lower the volume on the computer to prevent distortion. The signal must be lowered because the buffer opamp has a volume limit caused by the supplied voltage to it, this causes the distortion after 78% level on the previous mod.

This mod need SMD resistor soldering too... but if I can I will post an easyer (but more ugly) solution too.

The aim is to lower the signal to half before the Buffer and set the buffer gain to double (2x) or a bit more thus after this any non unity gain buffer can be used safely on the Prodigy HD2.
 
Apr 19, 2010 at 10:35 AM Post #269 of 492
Quote:

Originally Posted by earfanatic /img/forum/go_quote.gif
Hi there,

Soon I'll post the better HD2 buffer gain mod.


Hi. I've seen you made a serious mod on your HD2. I'm also interested to get more out of my card. I use 2*LT1364 + LM4562 ATM.

Also seen you'd buy RCAs from kácsa. Are you from hungary? That'd be awesome.
eek3smile.gif
 
Apr 19, 2010 at 11:51 AM Post #270 of 492
Quote:

Originally Posted by earfanatic /img/forum/go_quote.gif
Hi there,

Soon I'll post the better HD2 buffer gain mod.
For those who is not up to date this mod is made to make possible to use the LT1028 opamp on the HD2 buffer stage, which is the magic ingredients to complete the most incredible sound paired with AD797BRZ-s on the DAC output.

The original mod can be found here: HD2 mod by Earfanatic
DSC00012.JPG

I want to improve it and lower the signal to be able to leave the volume of the DAC 100% - thus keeping up the SNR ratio. With this there is no need to lower the volume on the computer to prevent distortion. The signal must be lowered because the buffer opamp has a volume limit caused by the supplied voltage to it, this causes the distortion after 78% level on the previous mod.

This mod need SMD resistor soldering too... but if I can I will post an easyer (but more ugly) solution too.

The aim is to lower the signal to half before the Buffer and set the buffer gain to double (2x) or a bit more thus after this any non unity gain buffer can be used safely on the Prodigy HD2.


Great stuff.
 
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