Zodia
Super Member
Please bear with me, I tried to write this with my limited vocabulary, as English is my second language.
I am back again with yet another thread about the NAD PP2, and the M97xe.
I find this little pre amp, interesting and a great little pre box.
So i set myself (with the help of Felix) to try and "MOD" this little box, and get it M97xe ready, here is what i found.
Tests were done using an upgraded Technics Sl1200 MK2/M97xe, Nad PP2, Onkyo TX-SR602, Modded Fisher speakers Original Woofer with KLH mid and tweeter, and Dire Straits "Brothers In Arm".
First off, the PP2 is quite capable out of the box, (with one exception, it could do better as far as bass is concerned) but i wanted more from it, so the first order of business was to upgrade the OPamp, so an OPA2134 was put in it, and almost instantly the difference was noticeable, bass, midrange and treble more defined, but not by much (sorry but i don't have any equipment to measure the increase in frequency response, i rely on my ears alone), so i figured, "why not try this, cartridge loading mumbo jumbo i keep hearing about".
After hours of trying to figure out where the darn resistors that i need to replace were, i was about to just give up and leave it be, but then it dawned on me..."Wait a minute, i am looking for a 4 band resistor, but they are all 5 band...DUH!", a victory dance and a pat on the back later, i installed the required resistor needed to get 62K (in this case i didn't have the required 77K resistor, but had a 22K resistor which i soldered in series with the existing 56K to get a close enough value of 63K).
My findings are, there was No change in bass, mids got slightly "brighter" and highs (treble) improved to a level that is audible not only through the headphones but also the speakers, the difference is that noticeable, but not to a point that is not tolerable, it is quite pleasant to the hear.
Then I had a brain storm, why not try without any resistor in place, so i removed both the 22k and 56k resistor, hooked it up and spun the same record.
WOW, that is all i could say.
Now keep in mind that i am not an expert DIY'er, I just like to play around with stuff like this and some times i get the occasional puff of smoke and Bang, But this time all went well, but what happened next got me puzzled, the treble increased tremendously, yet not to a point where it was unbearable, i rather liked it, the only draw back, was that the midrange now was almost gone, vocals, seemed muffled and drowned by the instruments, even some instruments sounded BLAH, the midrange simply got rolled off, I reported this to Felix and he sent me this link, http://www.tnt-audio.com/sorgenti/load_the_magnets_e.html , and that made me go "AHA", so that is the draw back on the M97xe with anything more than 62K, sure, you get the exceptional treble increase, but you do loose the midrange, so back to 62K+- it went.
My conclusion, it is not so much about the phono stage (as far as the M97xe is concerned) but loading the M97xe at 62k, and that is anything but mumbo jumbo, it really works, at 62K the bass, midrange and treble response sound right, the frequency response is even, you get the right amount of mid and treble,
My next quest is to, bypass the electrolytic caps, and try to bypass the subsonic filtering on the PP2 ( that would be the "true" mod on the PP2), I know i can squeeze more bass out of it, maybe even improve the midrange some more :scratch2:.
Other than that, i don't think there is much that can be done to the PP2 that will improve more, but i am going to continue to test it and improve things as i go along (or destroy it trying).
Thank you for reading.
I know most of it doesn't make sense , but hey, I gave it a shot.
I am back again with yet another thread about the NAD PP2, and the M97xe.
I find this little pre amp, interesting and a great little pre box.
So i set myself (with the help of Felix) to try and "MOD" this little box, and get it M97xe ready, here is what i found.
Tests were done using an upgraded Technics Sl1200 MK2/M97xe, Nad PP2, Onkyo TX-SR602, Modded Fisher speakers Original Woofer with KLH mid and tweeter, and Dire Straits "Brothers In Arm".
First off, the PP2 is quite capable out of the box, (with one exception, it could do better as far as bass is concerned) but i wanted more from it, so the first order of business was to upgrade the OPamp, so an OPA2134 was put in it, and almost instantly the difference was noticeable, bass, midrange and treble more defined, but not by much (sorry but i don't have any equipment to measure the increase in frequency response, i rely on my ears alone), so i figured, "why not try this, cartridge loading mumbo jumbo i keep hearing about".
After hours of trying to figure out where the darn resistors that i need to replace were, i was about to just give up and leave it be, but then it dawned on me..."Wait a minute, i am looking for a 4 band resistor, but they are all 5 band...DUH!", a victory dance and a pat on the back later, i installed the required resistor needed to get 62K (in this case i didn't have the required 77K resistor, but had a 22K resistor which i soldered in series with the existing 56K to get a close enough value of 63K).
My findings are, there was No change in bass, mids got slightly "brighter" and highs (treble) improved to a level that is audible not only through the headphones but also the speakers, the difference is that noticeable, but not to a point that is not tolerable, it is quite pleasant to the hear.
Then I had a brain storm, why not try without any resistor in place, so i removed both the 22k and 56k resistor, hooked it up and spun the same record.
WOW, that is all i could say.
Now keep in mind that i am not an expert DIY'er, I just like to play around with stuff like this and some times i get the occasional puff of smoke and Bang, But this time all went well, but what happened next got me puzzled, the treble increased tremendously, yet not to a point where it was unbearable, i rather liked it, the only draw back, was that the midrange now was almost gone, vocals, seemed muffled and drowned by the instruments, even some instruments sounded BLAH, the midrange simply got rolled off, I reported this to Felix and he sent me this link, http://www.tnt-audio.com/sorgenti/load_the_magnets_e.html , and that made me go "AHA", so that is the draw back on the M97xe with anything more than 62K, sure, you get the exceptional treble increase, but you do loose the midrange, so back to 62K+- it went.
My conclusion, it is not so much about the phono stage (as far as the M97xe is concerned) but loading the M97xe at 62k, and that is anything but mumbo jumbo, it really works, at 62K the bass, midrange and treble response sound right, the frequency response is even, you get the right amount of mid and treble,
My next quest is to, bypass the electrolytic caps, and try to bypass the subsonic filtering on the PP2 ( that would be the "true" mod on the PP2), I know i can squeeze more bass out of it, maybe even improve the midrange some more :scratch2:.
Other than that, i don't think there is much that can be done to the PP2 that will improve more, but i am going to continue to test it and improve things as i go along (or destroy it trying).
Thank you for reading.
I know most of it doesn't make sense , but hey, I gave it a shot.
.
Regards, Felix aka catman.