ok - how it sounds with those spks?
and what these spks are ?
ZM Drooooooollllllllll ........ I'm sucker for speakers ......
and what these spks are ?
ZM Drooooooollllllllll ........ I'm sucker for speakers ......
Sounds good, better than I expected. They need to break in for a while.
The speakers are DIY, altec 515 in my the base horn and a TAD2001 on top with a Charles Hanson designed quadratic throat wave guide.
The speakers are DIY, altec 515 in my the base horn and a TAD2001 on top with a Charles Hanson designed quadratic throat wave guide.
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man, those spks are beauty 
have more pics somewhere posted?
if not, feel free to make some fun in , say, Da Pub
have more pics somewhere posted?
if not, feel free to make some fun in , say, Da Pub
I was thinking they would sound more like the original zen amps. They are much more open and transparent. I will be interested to see the measurements tomorrow.
Definitely! I think my drooooooollllllllll puddle is slightly out of frame in the lower right. 😀
I'm not prone to drooling over speakers but those speakers are Beautiful!! And the wiring on the crossovers is top notch!
Jeffrey
Jeffrey
Thanks for the accolades
I did some testing today. What I found is that I could increase-decrease the THD by varying the Vds of the THF-51. I started at 35 volts and had about .59% THD by increasing the Vds to 37 I could get it down to .44%. I could go even lower but then you are cutting the voltage across the ccs. The nice thing is I could set the distortion of each mono block to the same distortion.
So you will see that they look very similar but one is at 37v the other is at 37.44v.
They sound great big and open. They do sound “loud” as you push them and the distortion goes up. Luckily with 100dB speakers I don’t need much.
I did some testing today. What I found is that I could increase-decrease the THD by varying the Vds of the THF-51. I started at 35 volts and had about .59% THD by increasing the Vds to 37 I could get it down to .44%. I could go even lower but then you are cutting the voltage across the ccs. The nice thing is I could set the distortion of each mono block to the same distortion.
So you will see that they look very similar but one is at 37v the other is at 37.44v.
They sound great big and open. They do sound “loud” as you push them and the distortion goes up. Luckily with 100dB speakers I don’t need much.
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I had convinced myself the Sissy was enough, perhaps a trip up north one day will be enough of a fix 🙂 . Beautifully orchestrated - both amp and speakers..dB
I have done some further investigations. I see that the gain of the amp changes quite a bit with the load impedance. I confirmed this on the bench with different loads.
Some of the “loud” I was hearing was from impedance variations in my horn speakers. The 515 is 16ohms and the horn is set at 10ohm shunt before the autoformer.
I placed a 15ohm 10w in parallel with the speaker and the sound stabilized.
The amps are sounding great with this change and time to break them in.
🙂
Some of the “loud” I was hearing was from impedance variations in my horn speakers. The 515 is 16ohms and the horn is set at 10ohm shunt before the autoformer.
I placed a 15ohm 10w in parallel with the speaker and the sound stabilized.
The amps are sounding great with this change and time to break them in.
🙂
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interesting, parts for impedance linearization just arrived, will check out soon. (with sissy s., not b. bush)
tnx for sharing,
st
(why this? ; )
tnx for sharing,
st
(why this? ; )