Modded T-amp dislikes CD player. Why?

[irss]

My system is:

- modded T-amp - audyn 2.2uF caps, fast elna silmic cap on the board, big cap off the board, ALPS 50k pot, quality rca and speaker plugs.

- nad c521bee CD player.

- 88dB sensitivity speakers.

strangely, the T-amp sounds great with any CD player, except my NAD. With NAD it lacks bass, the sound seems to be flat and tiring. However, the same CD player (NAD) sounds good with other solid state amplifiers (technics, rotel) with the same speakers I have. Consequently, it appears that T-amp does not like my NAD.

I still cannot figure out what could be the problem...why t-amp 'hates' my dear NAD CD player

guys, any ideas how could I fix the problem? or should I start looking for other CD player?

I've read that Monica II (NOS DAC) is a good friend of t-amp, but would it solve the problem...

i would really appreciate your help

[GJF]

Which input mod have you performed?

Do the 2.2mf Audyn caps replace the on board surface mount or have you removed some of the other input components?

I have found that the wiring required for installing off-board input caps can help induce noise into the input stage negating some of the benifits of changing, others disagree but the input filter on these amps is there for a purpose.

If it helps any I have an Amp3 thats fine with everything connected to it and an Amp 6 that loaths my Sony Cd player with which it sounds somewhat thin and strident when the same player is smooth and powerfull through the Amp 3!

[irss]

GJF, the mod was done according to the 'stealth mod' on the panomaniac web.

[Pano]

Hmmm....
Sounds like an input impedance problem. As if the NAD doesn't have enough current to drive your modified Sonic. But with the stealth mod you should have a pretty high input impedance. You did remove R01/R02, right? It wouldn't work otherwise.

Do you have an active preamp or line driver that you can put between the NAD and the Sonic? Something to act as a buffer and add a little drive? If it brings back the bass, it's an impedance problem.

[irss]

Pano, yes R01/R02 were removed. I'm not using an active preamp or line driver. Probably I should try one...

Although comparing to other CD players, NAD player plays pretty loud.

[lucpes]

Originally posted by irss
Pano, yes R01/R02 were removed. I'm not using an active preamp or line driver. Probably I should try one...

Although comparing to other CD players, NAD player plays pretty loud.

Try a 47pf cap or so to ground at the input.

[cpemma]

NAD - "The output impedance is very low at 300 ohms, making the NAD C521BEE less sensitive to cables or the ancillary equipment it is partnered with."

My old NAD 5420 works fine with the 5066, that's 120 ohms, 2V RMS @0dB

[Pano]

Originally posted by cpemma
NAD - "The output impedance is very low at 300 ohms

Well, that should be plenty to drive the Sonic. So I don't know what the problem is.
If you do get a chance to put an active preamp or line stage in there, please try it and let us know.

[soongsc]

Output impadance, source impedance, and load impedance capabilities are sometimes mixed in the terminology.