Question about the new to my NAD PP2

62sunbeam

Raconteur
I picked up a basically new NAD PP2 in BT and I have a few questions.

First of all when paired with my GAS Sleeping Beauty it sounds really nice and detailed with a nice soundstage even in my odd listening space but it lacks deep bass and I was wondering what factors would help accentuate the lower frequencies. I am using pretty inexpensive interconnects as I am holding out for when I can build the ones I want. ( they aren't the crappy black ones that come with sound equipment from Best buy but they aren't high end either)

In the meantime I was wondering if anyone had recapped their PP2 and what sonic improvements were apparent after doing so? Which caps did you use.
Noise doesn't seem to be an issue so I don't think I will be replacing the power supply unless this too might be considered to the upwardly skewed range of reproduction.

I recapped my B&K Pro 5 with Silmics and I am quite happy so I would imagine these are the caps I would use with the PP2.

Does anyone have a schematic for the PP2?

Thanks

Eric
 
You can find a schematic at DIYAudio.

For the non polarized some Nichicon Muse ES would do the trick for polarized ones you can't beat Panasonic FC's, I would consider putting in op amp sockets and trying some different ones, who knows they may be socketed already, it should improve it all around.
 
G'day all, I believe that upgrades to the power supply, and installing a good 8 pin IC socket and changing the opamp from an NE5532 to an OPA2134 produce good improvement to the bass. Regards, Felix aka catman.
 
I was poking around on the DIY forum and they seem to like a 24 volt 1 amp power supply. Will any supply with these specs do or do I need a special one?

And how do I search for the OPA2134 on Digikey? Do I want one from a particular manufacturer?

Thanks

Eric
 
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G'day mate, regardless of whatever power supply you use, DO NOT exceed split rails voltages of 18 volts per side, or the voltage ratings of the op amps and the other transistor circuitry will be exceeded and severe damage and/or component failure will result. Regards, Felix aka catman.
 
I tried the PP-2 and didn't care for it. A power supply upgrade made it sound more open, but the bass still sounded a bit lean to me. It's overall tonal balance remained unchanged. I think it may be due to the "subsonic" filter feature that cannot be turned off. If that's true and it's in the design, no parts upgrade will help. You'd have to figure out if there's some way to remove the "subsonic" filter without messing up the RIAA EQ. The PP-2 is mostly surface mount micro parts and would be near impossible to mod.

If you don't need moving coil capability, I'd consider selling the PP-2 and replacing it with an ART. You'd probably have enough money left over from selling the PP-2 to buy a new LP and I think you'd be more pleased with the sound.

http://www.amazon.com/ART-Pre-II-Phono-Preamp/dp/B000AJR482/ref=sr_1_2?ie=UTF8&qid=1309013006&sr=8-2
 
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royphil345's comment about the subsonic filter is very likely on the mark; that was the first thing that came to my mind.

This is another one of those situations where one person's apple is another person's orange. A friend of mine traded his ProJect Phono Box for a PP2, and was delighted at how well the bass "tightened up" with the change.

Keep in mind that a properly functioning subsonic filter does not affect the audible bass area of the music-- that is, it only affects signal below 15 to 20 Hz. However, subsonic noise can easily intermodulate with the actual bass content and add a "fullness" that some listeners prefer, even if it's not technically "accurate". Whatever works for you works for you, so I'm not passing any judgement. For myself, I prefer the leaner, tighter bass, but that's just me (and the friend noted above).

I have measured the PP-2 on my bench, and it does have essentially flat response down to 20 Hz, so the SS filter is not kicking in prematurely.
 
What's your favorite?

Also Felix is right on the voltages, 18v per side is the "maximum" for most op amps.

So I'm a bit confused. I read a few threads on the DIY forum that spoke of using a 24Volt 1 amp power supply with the PP2. The original one is 24 volts as well.

How do I make sure the rail voltage doesn't exceed the 18 volts Felix speaks of?

Thanks

Eric
 
I picked up a basically new NAD PP2 in BT and I have a few questions.

First of all when paired with my GAS Sleeping Beauty it sounds really nice and detailed with a nice soundstage even in my odd listening space but it lacks deep bass and I was wondering what factors would help accentuate the lower frequencies. I am using pretty inexpensive interconnects as I am holding out for when I can build the ones I want. ( they aren't the crappy black ones that come with sound equipment from Best buy but they aren't high end either)

In the meantime I was wondering if anyone had recapped their PP2 and what sonic improvements were apparent after doing so? Which caps did you use.
Noise doesn't seem to be an issue so I don't think I will be replacing the power supply unless this too might be considered to the upwardly skewed range of reproduction.

I recapped my B&K Pro 5 with Silmics and I am quite happy so I would imagine these are the caps I would use with the PP2.

Does anyone have a schematic for the PP2?

Thanks

Eric

Hi Eric, I 'modded' my PP2 back in december, new OP2134, and Elna caps, just the OP amp was an audible improvement, as it does have more detail than the NE5532 (at this point the bass still lacked), the caps improved the high end, no doubt there, but the biggest improvement was the PS, the added 900ma is a must, bass is tigher, 'louder' even (just don't expect a huge boost in bass).
But since I was still not happy, so I removed the 56K resistors (I am using the Shure M97Xe, so I did this with that cart in mind, and that boosted the treble, so I wouldn't recommend doing this if you plan on using other cart).
In conclusion, if you don't want to go nuts with it, simply changing the OP amp and adding the 24v 1 amp wallwart is all you really need, I get plenty of bass now, so much so that I haven't used my sub since the PS upgrade.

The PP2 asks for 24volts, but 100ma is just not enough to drive it to full potential IMO.


nad_pp2.gif







John
 
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The ART costs less than you'd spend on mods and a power supply, it sounds better IMO, balanced, open and smooth with no upgrades... and it comes with a beefy 1 amp power supply (9 volts AC, no good for the NAD). It has a switchable subsonic filter (I do prefer it off) and 100pF or 200pF capacitance choices. I don't think anything else under $100.00 can touch it (well... the Bugle kit) and I've heard worse for much more money. Just no moving coil.
 
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G'day all, on the voltages, the voltage regulator configuration used in the power supply will determine the final output voltage, eg 7815 and 7915 regulators will give 15 volt outputs regardless of the power supply feeding them.

On the sub bass (aka subsonic) filters, I am actually a strong advocate of their use. I use these excellent DIY units: http://sound.westhost.com/project99.htm Regards, Felix aka catman.
 
The ART costs less than you'd spend on mods and a power supply, it sounds better IMO, balanced, open and smooth with no upgrades... and it comes with a beefy 1 amp power supply (9 volts AC, no good for the NAD). It has a switchable subsonic filter (I do prefer it off) and 100pF or 200pF capacitance choices. I don't think anything else under $100.00 can touch it (well... the Bugle kit) and I've heard worse for much more money. Just no moving coil.

And there is the rub. I need the MC inputs and I already have the NAD and I am not against modding it for the practice and realize this is just for interim use while I decide on which SUT I plan on building so I can go back to using the phono stage in my Audible Illusions Mod 2C pre.

Thanks

Eric
 
G'day all, the NAD PP2 is an excellent phono stage for modifying (and improving), if one is so disposed. The moving coil stage can be considerably upgraded by using better and lower noise transistors, for example. The BC547/BC557's used aren't particularly 'quiet' and a change to for example BC549/ BC559 transistors (the same lead pinouts) are considerably lower noise.

I like NAD gear as their designs have always been generally excellent, but are little let down by the actual components used (a cost measure, perhaps?)

I repaired a friend's NAD preamp a while back, and improved it considerably, simply by using upgraded components and no circuit changes. Regards, Felix aka catman.
 
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So I put together a tentative order at Digikey and I was able to get Elna Silmic caps for the 470 uF and 47uF cpas but can't find through hole radial caps for the 10uF or 220uF caps I need. Silmic or otherwise.

Should I just go without these?

The 24Volt power supply I found is Digikey part number T1073-P5P-ND
and its 24 volt 1 amp switching energy star compliant. Will this do?

Thanks

Eric
 
So I put together a tentative order at Digikey and I was able to get Elna Silmic caps for the 470 uF and 47uF cpas but can't find through hole radial caps for the 10uF or 220uF caps I need. Silmic or otherwise.

Should I just go without these?

The 24Volt power supply I found is Digikey part number T1073-P5P-ND
and its 24 volt 1 amp switching energy star compliant. Will this do?

Thanks

Eric

Eric,

If you have never ordered components before it seems like a nightmare, you have to take into account not only the correct value, voltage, type but also size and lead spacing. I did this mistake when I first tried to upgrade my 640P, the caps were three times the size and the legs would not even fit through the holes.:D

For BiPolar Caps:

If you need 10uf bipolar from Digikey try these but they are not my favorite bipolar cap:

P1176-ND CAP ALUM 10UF 25V 20% RADIAL

If it were me I would try these 10uf Nichicon Muse ES from Mouser:

647-UES1E100MDM BiPolar - Leaded 25volts 10uF 85c 5x11 2LS

For the 220uf if you need bipolar again these should be fine: 647-UES1V221MHM BiPolar - Leaded 35volts 220uF 85c 12.5x25 5LS

For Polarized caps I like to use either the Elna's like you got if they will fit or Panasonic FC's;

Panasonic FC's at Digikey in 220uf these would be good: P10296-ND CAP ALUM 220UF 35V 20% RADIAL

and 10 uf polarized would be these: P11212-ND CAP ALUM 10UF 25V 20% RADIAL

The wallwart you are looking at should be fine.
 
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Hey Guys,

I can see no further lines on this subject, I hope someone will still read mine ! :D

I tried the mods you're speaking about, I've replaced the OP amp by a OPA2134PA.
But when I looked for the BC547 & BC557 they were not there ! :no:
Instead I found A970 (Q5 & Q6) and C2240 (Q7 & Q8)! :scratch2:

Any ideas why? Is it still worth to replace them by BC549 & BC559?

Thanks
 
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