Honking Sound?

[vdi_nenna]

Hi Everyone,

Need help or ideas on identifying source of sound. I didn't have a chance to troubleshoot. Looking for some feedback, no pun intended.

Today I got together with a couple guys from the Phila Area Audio Group2 to listen to my F5 and BOSOZ. A test drum track was put on and a strange "honk" or high frequecy squeal was heard just after a floor-tom drum hit. Very powerful. We were listening at fairly high levels, but not obscenely high. The squeal was only heard just after the drum hit and was very brief.

The sound was first heard when lifting the needle of a record. Sounded like the needle was dragged against the groves briefly. We though the tone arm lifting mechnisim was off. Then one of the guys threw in the test cd and we heard it while playing music.

The sounds are similar from the turntable and CD track, but I don't think they are the same thing. During the test track we listened with the volume up high and then lower. In the lower volume position, we did not hear the squeal. We didn't hear the squeal with a tube pre-amp in the chain.

Could this sound be high frequency oscillation? Like to hear your thoughts.

Associated equipment:
High-end turntable (dont remember the brand or cartridge name)
Sony DVD player (tubified tweak)
VTL preamp
Io phono preamp
Bride of Son of Zen unbalanced
Aleph 5
F5
Gallo Neucleus ( dual-sphere with CDT hi-frq driver) I can't find specs on this speaker on the Internet. I know it does not have a crossover from low to hi freq drivers. The CDT uses a transformer to match impedance.

BTW- everyone liked the F5...a lot! Owner liked it over his Aleph 5 in some respects. My F5 is now on loan.

thanks,

Vince

[Zen Mod]

something weird in current limiter area ?

probably because of wackoo spks , if you build F5 by the book .

[Nelson Pass]

Oh yeah. They do that.

Didn't I mention it in the article?

[vdi_nenna]

Only difference between my build and the article is mine is dual-mono to the power cord. It does have current limiting in place like the original.

You think the Gallo's are a weird load for the F5?

Other than that strange "honk", the combo sounds real nice.
Better resolution and air around vocals and instruments than the A5. The silence between the notes is fantastic. I'm really happy with it.

V~

[Zen Mod]

did you use later revision values in current limiting circuit ?

if not - I think that R21,R22 are increased from 10K to 22K , but check these values , that's just from top of my head ...

regarding Gallo's - dunno ...... I'm not familiar with them

[vdi_nenna]

Originally Posted by Zen Mod

did you use later revision values in current limiting circuit ?

if not - I think that R21,R22 are increased from 10K to 22K , but check these values , that's just from top of my head ...

That is news to me. I used the article as printed for the values of the resistors. I keep my schematics at work, let's see... definiately used the 10K values. This is part of the protection circuit. Is there a known issue or does this new value clamp down the output current earlier?

Thanks ZM!

V!

[Zen Mod]

Originally Posted by vdi_nenna

..... does this new value clamp down the output current earlier?
.....

V!

......later

[vdi_nenna]

Ahhh! I see. Will give it a try once I get the amp back. A line has formed.

[Nelson Pass]

I would be very surprised if that was the issue.

If you have an oscilloscope, you should look for oscillation,
as it is a very wideband circuit.

[vdi_nenna]

I would be very surprised if that was the issue.

Nelson, do you mean the the rising of the values R21 & R22 to 22k or being able to drive the speaker properly or both?

We were play some intracate information through the amp and it didn't misbehave at all.
Harry Partch - Wikipedia, the free encyclopedia

Don't understand why that one drum track would be handled any differently.

I have a scope. Don't think I have a clean freq generator. Only a PC based one.

V~