Distortion with GC with some records

[reins]

Hi,

I build my GC with BrianGTs kit and I'm not so happy with it. First it seems a bit bright in combination with my DAC and second I get clearly audible distortions with some CDs. It is especially audible with solo piano records and seems to depend on high dynamics.

I exchanged my amps to exclude distortion from active XO and drivers. The distortions were gone, but the GC produces boomy and unstructured bass.

Does anyone has a hint what could be wrong with my GC?

Regards
stephan

[Nuuk]

Full system details are required here, particularly details of any pre amp or buffer.

Also what sort of PSU have you used?

[Upupa Epops]

Many CD's have big distortion , which you can see on scope ( hard clipping ), don't make any ilusions yourself.

[carlosfm]

Originally posted by reins
I exchanged my amps to exclude distortion from active XO and drivers. The distortions were gone, but the GC produces boomy and unstructured bass.

Does anyone has a hint what could be wrong with my GC?

Regards
stephan

Read below:

Originally posted by Nuuk
Also what sort of PSU have you used?

I insist: or people start regulating or using high capacitance with some tricks , or the unregulated-low-capacitance PSU will not be anyway nearly enough to drive most speakers.

[DIAR]

yes, many cd's have huge distortion. Try for example india arie - acoustic soul or alicia keys - songs in a minor. When I heard these records for the first time, I thought my speakers were broken.

[carlosfm]

I have a Focal/JmLab CD that is a festival of untight and resonant bass with the typical unregulated GC.
Get it right, and you get a tight punch in the chest.

[carlosfm]

Originally posted by DIAR
yes, many cd's have huge distortion. Try for example india arie - acoustic soul or alicia keys - songs in a minor. When I heard these records for the first time, I thought my speakers were broken.

Are you sure it's the recordings?
I advise you to go to a local distributor and listen to those recordings on a serious system.
You will maby find out that something else is wrong.

[jackinnj]

some LP's have enormous dynamic range -- it could be that there isn't enough headroom -- go back to the national semi "overture" design tool and see that you aren't bumping into this constraint with your power supply.

[reins]

Originally posted by Nuuk
Full system details are required here, particularly details of any pre amp or buffer.

System:

DAC----input buffer--volume control--bass boost (dipole)--

----- 4th order low pass-- subsonic -- solid state amp ----woofer
--|
----- 4th order high pass-- low pass-- GC --------full range

With this configuration I get the distortion, if I exchange the solid state with the GC amp, the distortions in the treble path are gone.

Originally posted by Nuuk
Also what sort of PSU have you used?

It's the unregulated PSU from BrianGT kit.

Originally posted by Upupa Epops
Many CD's have big distortion , which you can see on scope ( hard clipping ), don't make any ilusions yourself.

I don't think its the CD because if I change the GC to solid state, the distortions are gone.

Regards
Stephan

[Raka]

Have I heard dipoles?

It happened to me that due to the equalization of the dipoles, I was clipping. You can check if the input signal maximum level is ok, or if the total gain is high enough to saturate some lines.