Crack;Bottlehead OTL
Jun 18, 2020 at 3:01 PM Post #10,126 of 12,335
I notice on the BH page for the power cord assembly it looks like they are using the (quite) stiff PVC coated wire. Does it matter if you use silicone coated wire of the same AWG? I know it would be less inclined to stay as tightly twisted but in terms of sound?
IMO unless you get a major power cable change/difference, there will be no difference. This is not a Bottlehead specific comment, but a universal amp comment.
 
Jun 18, 2020 at 3:17 PM Post #10,127 of 12,335
IMO unless you get a major power cable change/difference, there will be no difference. This is not a Bottlehead specific comment, but a universal amp comment.

Fun to make though and am currently using a cheap cable that came from an LED strip's power adaptor. Either that one or a spare kettle lead I have. Also it isn't really too expensive to make your own. Not using a hospital grade one but a better made tighter MK plug. The right angle IEC is also quite cool.

My point being that whether it makes any audible difference (true or false or placebo) with this amp the power cable is on view, it isn't in the back and unseen.

As a reference I am in the UK so we always hear about 240V but when measuring during the build it varied between 221V and 232V. Pretty regular rather than big swings.

The wire question was more to do with the PVC vs silicon coating. PVC holds a twist better but (for those that hear a difference) is PVC more desirable due to any "sonic" benefit or is it just because of the twisting ability or because it's the old trick that the dog remembers?
 
Last edited:
Jun 19, 2020 at 12:04 AM Post #10,128 of 12,335
I notice on the BH page for the power cord assembly it looks like they are using the (quite) stiff PVC coated wire. Does it matter if you use silicone coated wire of the same AWG? I know it would be less inclined to stay as tightly twisted but in terms of sound?
Bottlehead mentions in the instructions that it's OK if the cables unwind a bit after twisting them up with the screwdriver. You might just make the initial winding of the cables a bit tighter to compensate for additional unwinding occurring due to the cables being less stiff. I think a proper braid also has a lot to do with it, and a silicone wire might braid easier.
As to the sound benefits, as I posted before, I can hear it. If it is placebo....give me some more placebo, please.
 
Jun 19, 2020 at 10:21 AM Post #10,129 of 12,335
As to the sound benefits, as I posted before, I can hear it. If it is placebo....give me some more placebo, please.

That reminds me of a guy who made a similar comment on a different forum. He was in an argument with others about whether he was wasting money on his $10k speaker cables. His position was, what does it matter whether the difference he heard was real or not? If he hears it, his outlay was justified even if it's just placebo effect.

I myself have never believed that any type of cables make a difference, and thus I've never heard a difference. To hear it, you must first believe it. Hearing occurs in the brain, not in the ears.
 
Last edited:
Jun 19, 2020 at 11:19 AM Post #10,130 of 12,335
Fun to make though and am currently using a cheap cable that came from an LED strip's power adaptor. Either that one or a spare kettle lead I have. Also it isn't really to expensive to make your own. Not using a hospital grade one but a better made tighter MK plug. The right angle IEC is also quite cool.

My point being that whether it makes any audible difference (true or false or placebo) with this amp the power cable is on view, it isn't in the back and unseen.

As a reference I am in the UK so we always hear about 240V but when measuring during the build it varied between 221V and 232V. Pretty regular rather than big swings.

The wire question was more to do with the PVC vs silicon coating. PVC holds a twist better but (for those that hear a difference) is PVC more desirable due to any "sonic" benefit or is it just because of the twisting ability or because it's the old trick that the dog remembers?
I am in the UK too. I have very variable power. I needed to get voltage regulation to get my main amp to be quiet in fact. I also built a reasonably posh power cable using Neotech UPOCC Copper & MS HD Power Parts. IMO it makes an audible difference, but it will set you back as much as a Crack.
 
Jun 19, 2020 at 3:09 PM Post #10,131 of 12,335
That reminds me of a guy who made a similar comment on a different forum. He was in an argument with others about whether he was wasting money on his $10k speaker cables. His position was, what does it matter whether the difference he heard was real or not? If he hears it, his outlay was justified even if it's just placebo effect.

I myself have never believed that any type of cables make a difference, and thus I've never heard a difference. To hear it, you must first believe it. Hearing occurs in the brain, not in the ears.
That reminds me of a guy who made a similar comment on a different forum. He was in an argument with others about whether he was wasting money on his $10k speaker cables. His position was, what does it matter whether the difference he heard was real or not? If he hears it, his outlay was justified even if it's just placebo effect.

I myself have never believed that any type of cables make a difference, and thus I've never heard a difference. To hear it, you must first believe it. Hearing occurs in the brain, not in the ears.
I was being sarcastic about the placebo, I really can hear a difference and I do think it would be clear if A/B testing.
It doesn't seem to be a stretch to think that the clean delivery of power could have a material impact on a device relying on that power for its functions.
Anecdotally, when I purchased a power conditioner, my gaming monitor's image got better. Prior to the power conditioner, I had horizontal faint lines that would make their way up the screen. Now, that is not an issue. It's a 3440x1440p high refresh IPS monitor with G-Sync if that matters. That example showed me that dirty power can hurt performance of a piece of electronics.
The power conditioner also helped to clean up some of the noise that I was hearing in my BHC.

I've never been one to believe in cables and always thought it was BS, but after so many positive reviews of the power cord, I can say that it does make a material difference. I'd imagine an electrical engineer somewhere could probably elaborate on why superior power delivery to an electronic device may improve performance.
 
Last edited:
Jun 19, 2020 at 7:00 PM Post #10,132 of 12,335
I'm not that good with cables. But i do try tube rolling.

Meet the grandparents of 12AU7, the first indirectly heated medium mu triodes, type 27.

Shown here is a mesh plate version -227- labeled Sonatron (a 1920's company).

IMG_5554.jpg

Based on build/labeling/date code; this pair was made by Sylvania.
This makes it no surprise that these sound close to their Sylvania type 37 brothers i've tried before (similar, but with more Crack friendly 6.3V heaters).
The sound is open and airy, clear, detailed but with a touch of floppy bass. Not as good a soundstage as the 37 version but I do like them!
I have to investigate deeper to find out if AC vs DC heaters influence the soundstage in any way (this could explain the difference i'm hearing).

Don't use these in a standard Crack. With a 2.5V heater voltage (and 1A current), they won't work.
I'm using them with an external power supply.
To get most out of this, i've added a switch in my existing @Deyan adapter.
This makes it possible to switch from the internal to external heater supply and back.
 
Jun 23, 2020 at 2:10 PM Post #10,134 of 12,335
... glow test passed. Part way through my 1st Crack build ...

Whenever I get time in the next few days, phase 1 should wrap up. Then, onto speedball..

Fun build project.

20200616_191223.jpg
Well, it works. I have plugged in my cheap "sacrificial headphones" and they are good to go. I had to tidy up one solder-point at the point of voltage testing, but all well otherwise. Eventually I'll get the courage to plug in more expensive headphones (Eikons will start). I have plenty of nice tubes. I have no illusion that the Crack will be able to coexist with my Glenn amp, but it was a very fun project. Perhaps I'll take it to my office? Not sure yet!
20200623_183355.jpg

Inside
bhin.jpg
 
Jun 23, 2020 at 5:44 PM Post #10,135 of 12,335
Well, it works. I have plugged in my cheap "sacrificial headphones" and they are good to go. I had to tidy up one solder-point at the point of voltage testing, but all well otherwise. Eventually I'll get the courage to plug in more expensive headphones (Eikons will start). I have plenty of nice tubes. I have no illusion that the Crack will be able to coexist with my Glenn amp, but it was a very fun project. Perhaps I'll take it to my office? Not sure yet!
20200623_183355.jpg
Inside
bhin.jpg
Congrats. And yes! Take it to the office! I'm going to build a Mainline or Crack for my office, too!

Love the paint color, too.
 
Jun 25, 2020 at 7:12 AM Post #10,136 of 12,335
Which SS amp made you smile as much as the BHC?
Are they really comparable? According to one of the first matches in Google:
In the end, its all about your investment. Tubes are hotter, and the power they make watt for watt is more expensive.

If the closest you can get to real music is your goal, tubes are the way to go. If its anything else (sound pressure, low heat), probably solid state.

The reason is simple: the ear perceives sound pressure via the presence of higher ordered harmonics- the 5th and above. It does **not** gauge the fundamental tones! This is probably due to the fact that pure fundamental tones are very rare in nature.

Tubes might seem to make more distortion when you look at amp specs on paper, but the harmonic distortion they make tends to be the lower orders- the 2nd - 4th, to which the ear is far less sensitive!

So a simple way to put it is that tubes more closely obey the most important rule of human hearing which is how we sense sound pressure. So it is much easier to build an amplifier that sounds natural to the human ear with tubes.

Another way to look at this is that the ear hears volume on a logarithmic scale. In a way, it comes quite close to sensing harmonics on a log scale too- being so sensitive to the higher harmonics that they can easily be detected by the ear even when the THD is only 0.005%.

We don't weight the harmonic distortions electronics make under our current measurement regime. The 2nd order (which contributes to 'richness') is given the same importance as the 7th! This is quite odd, because we've known since the 1930s that the ear is more sensitive to higher orders (see the Radiotron Designer's Handbook, 3rd edition). In the 1960s, General Electric did a study confirming this, that showed that humans don't care if up to 30% of 2nd order is present, but object quite a lot of 0.1% of the 7th order is present. Yet despite having this knowledge, we continue to ignore the implications (probably because of the money; transistor amps are simply less expensive to make and often have higher profit margins).

This is why there is a solid state/tubes debate; its why tubes are still around after being declared 'obsolete' in the 1960s; and the debate won't be going away any time soon. When our testing systems continue to ignore some of the most important aspects of human hearing/perceptual rules, you can count on the spec sheet not telling you how the equipment sounds (or doesn't) just as spec sheets have done for the last 60 years.
 
Last edited:
Jun 26, 2020 at 12:56 PM Post #10,137 of 12,335
Which SS amp made you smile as much as the BHC?
Are they really comparable? According to one of the first matches in Google:
I recently found a great deal on the HDVA 600 from Sennheiser that I'm waiting on. I will let you know how it acts with the HD650 and HD800 once I've tried it!!!
I'm in love with my BHC and great tubes. The HDVA will have a long road to climb to beat out the world of tubes...
 
Jun 26, 2020 at 3:25 PM Post #10,138 of 12,335
Well, it works. I have plugged in my cheap "sacrificial headphones" and they are good to go. I had to tidy up one solder-point at the point of voltage testing, but all well otherwise. Eventually I'll get the courage to plug in more expensive headphones (Eikons will start). I have plenty of nice tubes. I have no illusion that the Crack will be able to coexist with my Glenn amp, but it was a very fun project. Perhaps I'll take it to my office? Not sure yet!
20200623_183355.jpg
Inside
bhin.jpg

Congrats!! Nothing like that first listen feeling to confirm it works!

I'm very interested in hearing how your Glenn OTL compares to the BHC. I built my BHC at the same time I put a deposit down for a Glenn amp and I can't imagine any amp sounding better than the BHC :) Are you planning on installing the Speedball at some point?
 
Jun 26, 2020 at 3:44 PM Post #10,139 of 12,335
Well, it works. I have plugged in my cheap "sacrificial headphones" and they are good to go. I had to tidy up one solder-point at the point of voltage testing, but all well otherwise. Eventually I'll get the courage to plug in more expensive headphones (Eikons will start). I have plenty of nice tubes. I have no illusion that the Crack will be able to coexist with my Glenn amp, but it was a very fun project. Perhaps I'll take it to my office? Not sure yet!
20200623_183355.jpg
Inside
bhin.jpg

Nice work! Around the office I refer to myself as a "software guy" and really admire those of you who are handy with a soldering iron and can turn out such classy work.
 
Jun 26, 2020 at 10:14 PM Post #10,140 of 12,335
Well, it works. I have plugged in my cheap "sacrificial headphones" and they are good to go. I had to tidy up one solder-point at the point of voltage testing, but all well otherwise. Eventually I'll get the courage to plug in more expensive headphones (Eikons will start). I have plenty of nice tubes. I have no illusion that the Crack will be able to coexist with my Glenn amp, but it was a very fun project. Perhaps I'll take it to my office? Not sure yet!
20200623_183355.jpg
Inside
bhin.jpg
Glad to learn you have a Crack too. :)

I haven't turned on my Crack for more than a year. But I have no plan to get rid of it. :)
 

Users who are viewing this thread

Back
Top