John Curl's Blowtorch preamplifier part III

[DPH]

Mogami cable is still around. MOGAMI® - Bulk Cables
Belden as well.

By and large their offerings are no-nonsense, which precludes John's interest. But I do suppose they've introduced some sillier cables which are long on rhetoric and short on performance (or at least short on improvements over other offerings).

 

[wayne]

Gotham audio USA has lots of nice cable and wire, it really holds up for testing very durable.

 

[john curl]

Thanks guys, I might look into Gotham. They are an 'unknown' at the moment.
Of course, I have lots of Mogami, just looking for something new.
Belden and Alpha are pretty good for general wiring I have found. I like a pure copper wire coated with a quality plastic or Teflon.

 

[Max Headroom]

There was an amp featured in Elektor many years ago that used a toroid for the OP transformer.
Use an interwinding screen on a toroid to improve pri-sec HF noise

Torroid output transformers are standard equipment on BGM 100V line PA amplifiers nowadays.
Not sure about screened.


Dan.

 

[Max Headroom]

If you really were a sound engineer, then you would know how to interpret audio measurements which are published all over the internet. You only need to know a few DBT results to be able to correlate the measurements to figure out how DAC, preamp, amp and cables will sound like.
If you don't want to rely on objective test results, you are free not to.

There are behaviours (excess noise is one) that are not revealed by stationary signal excitation ie sine wave excitation, however the ear readily picks up on these errant behaviours.
THD/IMD/N numbers and associated spectral analysis go some way to describing how an item or system sounds but not all the way, CSD plots of excess noise would go further.

Dan.

 

[hitsware]

Torroid output transformers are standard equipment on BGM 100V line PA amplifiers nowadays.

Toroid OPT's are 1 thing ..... Toroid PT's used as OPT's are another ....

 

[Max Headroom]

Thanks guys, I might look into Gotham. They are an 'unknown' at the moment.
Of course, I have lots of Mogami, just looking for something new.
Belden and Alpha are pretty good for general wiring I have found. I like a pure copper wire coated with a quality plastic or Teflon.

Hi John.
Fumed silica filled silicone rubber, specifically Silastic 80 as of Aug 1967 - Silicone Rubber As Cable Insulation with Silastic 167 (Titanium Dioxide pigment/filler) as another useful choice for it's subjective damping properties.
There will be other choices now after 50yrs of course but fumed silica types would be my first choice.
Perhaps there is sleeving available also that would be suitable to fit over bare or enameled wire.


Dan.

 

[wrinkle]

Of course do not forget the protip of ensuring fixing bolt doesn't touch the top of the enclosure. At which point bad things DO happen

Someone I knew used the bolt through the middle for the ground tag...

 

[Max Headroom]

Toroid OPT's are 1 thing ..... Toroid PT's used as OPT's are another ....

They don't look any different.


Dan.

 

[syn08]

There are behaviours (excess noise is one) that are not revealed by stationary signal excitation ie sine wave excitation, however the ear readily picks up on these errant behaviours.
THD/IMD/N numbers and associated spectral analysis go some way to describing how an item or system sounds but not all the way, CSD plots of excess noise would go further.

Dan.

Could you please explain your understanding of “excess noise”? I’m concerned we may have divergent understandings, therefore my difficulties in grasping “CSD plots of excess noise”.

 

[hitsware]

They don't look any different.


Dan.

The interesting part would be the difference in price : )
AND
How well the less expensive 1 worked ...

 

[Tournesol]

Batteries do great things for sound but can be a PITA to keep going..

A second life for exhausted electric car's batteries ?

 

[Max Headroom]

Could you please explain your understanding of “excess noise”? I’m concerned we may have divergent understandings, therefore my difficulties in grasping “CSD plots of excess noise”.

Current noise induced by signal current and having decay and spectral characteristics.


Dan.

 

[Max Headroom]

A second life for exhausted electric car's batteries ?

There are electric car battery wreckers already and selling good cells pretty cheap.


Dan.

 

[john curl]

T, batteries for hi end audio service are just too difficult to maintain. They have to be recharged properly, preferably when the audio is NOT on. The GEL CELL's have the capacity, but do not last as long as normal automotive batteries, because they appear not to be able to shed their contaminants over time. They just go bad, no matter how well you keep them charged. It takes a lot of batteries to match a GOOD AC power supply for a preamp, for example. Power amps, you have to be kidding!
Yet, when I listen to a completely battery powered radio, like I did just today, I always find it to sound 'smoother' than when I power the same radio on a typical AC-DC supply. I have felt this way for the last 50 years, and I still note the difference.
The LAST thing we need is some dangerous Lithium battery packs, especially used ones, to catch fire when they feel like it. There is no free or easy method.

 

[billshurv]

I can think of many reasons not to have that much lithium in my living room. But a bigger problem is that, in many electric cars you don't actually own the battery. in those you do you can't get it out anyway.

 

[chris719]

T, batteries for hi end audio service are just too difficult to maintain. They have to be recharged properly, preferably when the audio is NOT on. The GEL CELL's have the capacity, but do not last as long as normal automotive batteries, because they appear not to be able to shed their contaminants over time. They just go bad, no matter how well you keep them charged. It takes a lot of batteries to match a GOOD AC power supply for a preamp, for example. Power amps, you have to be kidding!
Yet, when I listen to a completely battery powered radio, like I did just today, I always find it to sound 'smoother' than when I power the same radio on a typical AC-DC supply. I have felt this way for the last 50 years, and I still note the difference.
The LAST thing we need is some dangerous Lithium battery packs, especially used ones, to catch fire when they feel like it. There is no free or easy method.

It would be pretty trivial to do a source / preamp with lithium batteries and keep them charged via USB type C PD connection which is disconnected when the batteries reach a certain threshold.

Power amp is another matter. I would not want to be the manufacturer to burn someone's house down because of a bad cell.

 

[Tournesol]

The LAST thing we need is some dangerous Lithium battery packs, especially used ones, to catch fire when they feel like it. There is no free or easy method.

Not so sure, John. One of the most serious proposed solutions to give a second life to Lithium batteries was domestic farms of used batteries recharged with solar cells or wind turbines.

 

[Max Headroom]

......Yet, when I listen to a completely battery powered radio, like I did just today, I always find it to sound 'smoother' than when I power the same radio on a typical AC-DC supply. I have felt this way for the last 50 years, and I still note the difference.

Yes same here, and since I was a kid.
Battery types made a difference too I noticed.

Another thing I noticed as a kid is that the polarity (orientation) of the standard reversible Fig 8 AC power cable makes a further difference.
I have tested this over time with a large range of 'portables' and same result.
Perhaps somebody has theories as to why this is ?.



Dan.

 

[Max Headroom]

I can think of many reasons not to have that much lithium in my living room.

Apart from fire hazard, what reasons ?.


Dan.