2. amps-preamps
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Peachtree Audio Nova125 & sensitive speakers

I wanted to inform any potential buyers of the Peachtree Audio Nova125 (Class D, 2x125W) its inherent incompatibility with high sensitive speakers. I learned this the hard way.

I own a pair of the excellent Klipsch Reference RF7 Mk.ii floorstanding speakers. They are horn loaded and have a very high sensivity (101db); you could practically run them on a clock radio. They used to be powered by a top-of-the-line Rotel pre+power combination. I sold this combo and bought the Nova125 instead because I wanted something simpler and/or more pleasing to the eye.

To my horror I noticed the Klipsch speakers produced a very loud hiss when connected to the beautiful Nova125. I had never heard this before with the Rotel combination. The hissing was clearly noticeable from 8 meter away (30 feet)! When the amp was switched on and nothing was playing, my living room was actually immersed in this horrible noise. The hissing was present and unaltered even when no source was connected and the volume knob was turned down to zero.

I contacted my dealer, who offered a new Nova125 and power conditioners. The hiss remained exactly the same.

I thus contacted Peachtree Audio directly. They simply stated that Class D amplifier tend to have a higher noise floor than typical Class A/B amplifier and that high sensitive speakers should be avoided in combination with an amp like the Nova125.

I am currently selling the Klipsch speakers and will buy the PSB Imagine T2 speakers, which are rated at 90db sensivity. I hope the hiss will not be present with these speakers.

All in all not a very pleasant experience.

I hope this will be helpful to anyone considering Peachtree Audio products (or any other Class D amp).
f_r_e
f_r_e OP
5 posts
 
@Tls49: Yes, I did try tube on or off. No difference.

I also asked Peachtree Audio if the gain could be lowered somehow, but I don't think it can be done. No answer yet.
mlsstl
1,436 posts
 
After reading the other responses, I suspect the noise has nothing to do with the class D amps but is more likely coming from a noisy preamp section. Since you've had 2 different units that sound the same and someone else also has a noisy unit, it appears some hiss is just inherent to this model.

(I looked at the specs and they are a bit odd - Peachtree states the S/N ratio is 96 dB but then claims a dynamic range of 121 dB. Strange.)
zd542
5,339 posts
 
Its a common problem with efficient speakers. There's too much gain. Your old Rotel preamp was acting as a buffer between your amp and your sources. I don't know a lot of technical details regarding your Peachtree but it almost certainly doesn't have a traditional type line stage inside to preform this function. The DAC section probably goes directly into the amp. Given the other post, it doesn't look like you have a global gain setting for your DAC. That would fix the problem. There's nothing wrong with your Peachtree, it just doesn't have that feature. If you still have your Rotel pre, go from the preout on the Peachtree to a line level input on the Rotel and the hiss will go away.
zd542
5,339 posts
 
I should have mentioned in my 1st post. The blame lies with the dealer. As long as you told them what components you had in your system, they should have seen that one coming. Its a pretty easy call (for someone like a dealer that is "supposed" to know what they are doing).
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