That's it as measurements go.
Listening tests will follow. Two more AVCs will be made for doing the comparison in stereo.
🙂
George
Listening tests will follow. Two more AVCs will be made for doing the comparison in stereo.
🙂
George
Some days ago, a long time friend came here and we had a comparative listening session.
One AVC pair 7k turns/0.07mm wire over 49% Ni core.
One AVC pair 1k6 turns/0.15mm wire over 49% Ni core.
One AVC pair 1k6 turns/0.15mm wire over 80% Ni core.
An Alps blue 10kOhm potentiometer.
Any of them btn a CD player and a power amplifier to speakers.
Three levels of attenuation. 0dB, 12dB, 29dB.
We were keeping notes and at the end of each section we were discussing our opinion.
One test musical piece. 1st track (Chan Chan) from RY Cooder/ Buena Vista Social Club CD
The consensus was that the 1k6 turns/0.15mm wire over 80% Ni core was a bit ahead of the rest.
Better analysis and instrument definition.
Better control on bass.
His ranking was
1st_1k6 turns/0.15mm wire over 80% Ni core
2nd_7k turns/0.07mm wire over 49% Ni core
3rd_1k6 turns/0.15mm wire over 49% Ni core
4th_Alps blue 10kOhm potentiometer
My ranking was
1st_1k6 turns/0.15mm wire over 80% Ni core
2nd_1k6 turns/0.15mm wire over 49% Ni core
3rd_7k turns/0.07mm wire over 49% Ni core
4th_Alps blue 10kOhm potentiometer
After ending the listening through the speakers and having the discussion, I told him about the measurements I had done.
He said OK and he started to test them, this time CD player-DUT (at 12db attenuation)-headphone amplifier- headphones . He said his opinion hasn't changed.
I did the through headphone testing after he left.
George
One AVC pair 7k turns/0.07mm wire over 49% Ni core.
One AVC pair 1k6 turns/0.15mm wire over 49% Ni core.
One AVC pair 1k6 turns/0.15mm wire over 80% Ni core.
An Alps blue 10kOhm potentiometer.
Any of them btn a CD player and a power amplifier to speakers.
Three levels of attenuation. 0dB, 12dB, 29dB.
We were keeping notes and at the end of each section we were discussing our opinion.
One test musical piece. 1st track (Chan Chan) from RY Cooder/ Buena Vista Social Club CD
The consensus was that the 1k6 turns/0.15mm wire over 80% Ni core was a bit ahead of the rest.
Better analysis and instrument definition.
Better control on bass.
His ranking was
1st_1k6 turns/0.15mm wire over 80% Ni core
2nd_7k turns/0.07mm wire over 49% Ni core
3rd_1k6 turns/0.15mm wire over 49% Ni core
4th_Alps blue 10kOhm potentiometer
My ranking was
1st_1k6 turns/0.15mm wire over 80% Ni core
2nd_1k6 turns/0.15mm wire over 49% Ni core
3rd_7k turns/0.07mm wire over 49% Ni core
4th_Alps blue 10kOhm potentiometer
After ending the listening through the speakers and having the discussion, I told him about the measurements I had done.
He said OK and he started to test them, this time CD player-DUT (at 12db attenuation)-headphone amplifier- headphones . He said his opinion hasn't changed.
I did the through headphone testing after he left.
George
Attachments
Last edited:
All set and working! Conclusions will follow later in the week. I can't believe how are you handling all these thin wires...
So, time for my listening impressions from George's latest AVC with 1k6 turns over 80% Ni core compared to 7k turns over 49% Ni core and to the digital VC. First thing that strikes with the 80% is transparency, clarity if you'd prefer. Almost beats the digital VC on that. A very detailed sound that results to an enhanced soundstage as well. I had to return to the 49% core and the digital VC for a better understanding. The conclusion is that the 80% lacks a tiny bit of grip at the lower frequencies. It's not enough to perceive it as thin bass. Actually, grand pianos sound just fine. What I missed was the body of instruments like guitars and upright bass. And of course, it sounds divine with voices, violins etc. By contrast, the 49% is not that transparent -but not far from the digital control- and it has the right body.
I feel like repeating that I'm not introducing myself as an audiophile expert. I'm just trying to help with my subjective opinions. Also, it has to be mentioned that my speakers are open baffles meaning the bass is the typical dry bass of this type of speakers. What sounds like less body here might be just what a boxy bass needs to shine.
I discussed my findings with George. He seems to have a clear understanding of how the properties of the AVC affect the sound. A final implementation that would combine the best features of all specimens so far seems likely to happen! All this becomes more and more interesting!
I feel like repeating that I'm not introducing myself as an audiophile expert. I'm just trying to help with my subjective opinions. Also, it has to be mentioned that my speakers are open baffles meaning the bass is the typical dry bass of this type of speakers. What sounds like less body here might be just what a boxy bass needs to shine.
I discussed my findings with George. He seems to have a clear understanding of how the properties of the AVC affect the sound. A final implementation that would combine the best features of all specimens so far seems likely to happen! All this becomes more and more interesting!
Thank you Kostas once more for your valuable contribution in this endavour.
I can recall the difficulty of doing critical listening...
Then, you are really good in expressing your listening impressions in a few meaningful words.
Had I had two more bobbins and 80% Ni lams to stuff them, I would already had wound them.
I am thinking of some 2k5-3k turns of 0.1mm wire.
I'll see what I can do in the foreseeable future 🙂
Regards
George
I can recall the difficulty of doing critical listening...
Then, you are really good in expressing your listening impressions in a few meaningful words.
Final. Well, better not bet on it, although I would like to interpret your words as a wish.
Had I had two more bobbins and 80% Ni lams to stuff them, I would already had wound them.
I am thinking of some 2k5-3k turns of 0.1mm wire.
I'll see what I can do in the foreseeable future 🙂
Regards
George
Dear George,
Excellent analysis and set of measures (and listening impression from Kostas as well) for a kind of device that really intrigues me (I like such a kind of hard-core DIY 😉).
But the question is: where do (or Zeta4) source the Nikel cores? Thanks
Guido
Excellent analysis and set of measures (and listening impression from Kostas as well) for a kind of device that really intrigues me (I like such a kind of hard-core DIY 😉).
But the question is: where do (or Zeta4) source the Nikel cores? Thanks
Guido
Thank you Guido. 🙂
I don't know of any source of Ni laminates.
Those I've used were donated by Zeta4. I think he mensioned sourcing them from USA.
George
edit: Here is one source from China
https://www.hongertech.com/ei-type-mu-metal-lamination-for-audio-transformer_p36.html
Data for EI24 core
https://www.hongertech.com/uploadfile/downloads/EI-24.pdf
I don't know of any source of Ni laminates.
Those I've used were donated by Zeta4. I think he mensioned sourcing them from USA.
George
edit: Here is one source from China
https://www.hongertech.com/ei-type-mu-metal-lamination-for-audio-transformer_p36.html
Data for EI24 core
https://www.hongertech.com/uploadfile/downloads/EI-24.pdf
Last edited:
Many thanks George. Unfortunately purchases from China are almost impossible at DIY level (due to minimum quantities, 50 Kg or the like...).
I'm searching on my local market for something similar, if not exactly equal, wish me good luck 😉
I'm searching on my local market for something similar, if not exactly equal, wish me good luck 😉
My Best Wishes Guido 
Needless to say, in case you'll find a source for diy quantities, keep us informed.
George
Needless to say, in case you'll find a source for diy quantities, keep us informed.
George
0.1 mm enamel wire will arrive in a week or so.
In the mean time I thought to do something useful. To build a poor man’s AVC
At the junk area of my shop I found two very small EI-30 power transformers.
0.5mm thick electric steel laminates (ASTM M-27?) Core dimensions: 10mmX12.5mm (~1W power)
I dismantled them, removed the existing windings and wound 6k turns of 0.07mm wire.
Nine coil sections through existing 10 bobbin taps.
George
Attachments
I did the essential electrical parameters measurements.
Then, off to the listening tests 🙂
Haven't done a comparison test, here is just the first impression.
Not bad at all.
Not so airy and detailed as the 80% nickel core but clean mids and a tad reduced treble.
Very good bass and body.
Listening will continue and some electrical test results will be shown later on.
George
Then, off to the listening tests 🙂
Haven't done a comparison test, here is just the first impression.
Not bad at all.
Not so airy and detailed as the 80% nickel core but clean mids and a tad reduced treble.
Very good bass and body.
Listening will continue and some electrical test results will be shown later on.
George
Attachments
