John Curl's Blowtorch preamplifier part II

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#83,443
yes, directionality of the cable -again in the none engineering use of the term... is just about which end of the cable goes to the source and which end to the load.... developed by having cable shield tied to ground at one end only.

Directional fuses I dont know about but might be related to this type of problem:

A couple hundred years ago I had Magnapans when they came out. After a couple years, I heard a slight distortion in one channel and after testing everything, i changed the L and R speakers and the sound moved to the same speaker. I learned there was a fuse inside. I had to cut the grill cloth but there is was... a snap-in fuse holder. I replaced it with a gold flashed contact snap-in fuse holder and the distortion was gone. A think it was a corroded or bad contact with that fuse holder. Might not have needed to use the gold on it but not wanting to have distortion creep up again, was the better long term solution.

All just by listening. (Waly).


THx-RNMarsh
 
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#83,444
scott wurcer said:
I get no action on my ignores, they have all been banned from the pubs.
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That means your Ignore List is a Leading Indicator! You ignore them and right afterwards: they get banned -- Post hoc, ergo propter hoc.

I would like to publicly brag that I predicted Waly would get banned: my prediction date is 05 May 2016 (link). Other DIYA members may have predicted it even sooner but they haven't spoken up yet in this thread.
 
#83,449
I hope that "Lab" is not accredited or even real. Aside from the obvious errors in measurements and the complete lack of details on the measurement process or instruments used, making such broad assumptions about the sonic effects is really questionable for a professional lab. The "directional" effects measured of fuses with a high thermal coefficient without specifying the time to stability each way and checking for repeatability is a complete fail. What was not tested is the fuses fusing characteristics. If it doesn't open correctly you could have a real issue with fire and more on your hands. That lab could get rolled into the lawsuits now that their name is attached.

Its stuff like this that persists for generations in high end audio.

I have seen directionality in cables. Two sources-
1) Which end a seperate shield is attached. it can affect both shield performance and stability in audio stuff.
2) Coax cables where the tension changed as the cable was running through the machinery and the impedance at one end is different from the other. Small but noticeable. Nothing like a small flat on a roller for a coax. Makes an amazing RF filter if the cable is long enough.
 
#83,450
scott wurcer said:
What do you mean Ed? I said like the predictions of the end of the world, which passed uneventfully (you know all the stupid Aztec calendar stuff), Waly was not banned by May 5, 2016.
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That was the date on which Mark made the prediction W would eventually get banned. He did not pick a date just a course of action.

W of course is not really located in Ouagadougou as just a start of his line of camel dung. (He is not yet advanced enough for the modern bovine version.)
 
#83,452
RNMarsh said:
A couple hundred years ago I had Magnapans when they came out. After a couple years, I heard a slight distortion in one channel and after testing everything, i changed the L and R speakers and the sound moved to the same speaker. I learned there was a fuse inside. I had to cut the grill cloth but there is was... a snap-in fuse holder. I replaced it with a gold flashed contact snap-in fuse holder and the distortion was gone. A think it was a corroded or bad contact with that fuse holder. Might not have needed to use the gold on it but not wanting to have distortion creep up again, was the better long term solution.
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Ah, I can explain that one. I recently got a pair of small Magnepans (were being sold on craigslist at an offer I couldn't refulse). The fuses mentioned are in series with the tweeter elements. And they are also shunted by 8 ohm resistors, so when they blow they still leave a resistor in circuit. The tweeter still plays, but it is attentuated and sound like heck (I've read they do that because there were some models of tube amps that could get into trouble of voltage breakdown in their output transformers if their load goes too high impedance at high frequency).

Also, the maggies I got had an intermittent solder connection on the aluminum wires of the tweeter section of one speaker, HF would break in and out, sometime would play for a while seemingly ok then droput out or go weak for a time. The wire was right in a little solder-filled eyelet, held tightly in place, but managed to have many ohms of series resistance in the connection. I heated the solder, pulled out and scraped the outside of the Al wire, reheated the solder and stuck the wire back in. Plays perfectly now. Did the same on the other channel for good measure.

The maggies now sit in my basement taking up space.... wife didn't like even small ones in the living room, particularly 4 foot out from the wall. Anyone in PNW looking for a sweet deal on a pair of SMGAs -- tested and measured good?
 
#83,453
I had the taller model... the highs were not attenuated as the fuse had not blown.... Just bad fuse holder to fuse contact.

But, it is this sort of thing which drives some segments of audio..... next a gold plated fuse ends and fuse holder, suddenly becomes available.


-RNM
 
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#83,457
scott wurcer said:
It's still based on a free open source OS and in general I have found no signal processing algorithms that are not freely available, in fact in the distant past I have contributed (in a small way). For me part of DIY is the learning and I don't need canned ($$$) solutions.

CERN has taken the approach of a grid of thousands of compute nodes spread all over the web more than one way to handle the absurd compute load.

https://en.wikipedia.org/wiki/Worldwide_LHC_Computing_Grid
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Scott, you are welcome, i'll organise personal tour for you, when you arrive in neighborhood ...🙂
Tools
 
#83,458
simon7000 said:
Jan

You are mixing up voltage and current again. Everyone knows the currents are much stronger at a sharp drop. Sometimes you get splashed at electron falls. Very pretty to look at but the spray of stray electrons can make mess for things too close. That is why some folks put their loudspeaker cable up on blocks. It has nothing to do with reducing capacitance or non uniform solenoid effect.

There was a high school teacher who used to be a stickler about the difference. I think he may even have written a paper. His name was Georg Simon Ohm. Interestingly enough he sort of looked like the actor Simon Baker. (Mentalist TV show.)
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I humbly bow to superior knowledge! ��

And yes, the Mentalist is an interesting character. Reminds me of Columbo, but with a better suit.

Jan
 
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