[Welcome back….]

1 hour ago, Emile said:

Seriously? TWO or THREE DAYS of downtime? Most organizations shoot for 99.99% uptime, i.e. less than 9 hours of downtime in a year  

Unfortunately it reminds me of unreliable Klipsch subwoofers/etc  

While I missed not being able to access this forum for a few days - its probably worthwhile noting that organizations that achieve the kind of uptime that you mention usually have one or more people who are paid to maintain the infrastructure. I don't think that's the case here.

[Amp Camp Amp]

1 hour ago, wdecho said:

This was posted on the other forum and considering it refers to Klipsch speakers I decided to post this guys results here. The guy possibly could be a member here. 

 

Just finished up an ACA v1.5 - relatively easy build (good thing, since I haven't dusted off the soldering iron in a while) - everything worked fine on power up & bias adjusted nicely (although it took a while).

Did a little listening - replaced a crown pro amp between a Bottlehead Smash preamp & a pair of Klipsch Cornwalls. Very, very nice!! Lots of clarity & good bass response. I think this amp will stay in play.

I think this is clearly a case where simplicity in design can yield great results (if done carefully).

Yup - a member, but I mostly read.  So far, the ACA seems to be a nice match to the Cornwalls.

[Long HDMI cables]

20-25 feet might be pushing the limit for passive cables. Monoprice has some active cables (I think they call them "Redmere" or something like that) - relatively inexpensive & thin. I hooked one up for my son (around 30 feet) and it worked fine (but the cable is directional).

 

Rich

[Cryogenically treated tubes]

As I mentioned, for steel, cryo treatment has a pronounced effect - and a proven, well understood scientific explanation.

 

For other metals such as copper, tungsten, molybdenum - no effect at all. For these materials, there are no low temperature phase transitions and the other changes that some of the advertising points to (like "annealing" or grain growth) slow down exponentially as the temperature is lowered. If you want to affect the grain structure of these metals, heat is needed - not cold.

 

    Rich

[Cryogenically treated tubes]

A short comment on cryo treating cutting tools - steel. There is a clear and explainable effect. Steel undergoes a phase transition (martensitic transition) at very cold temperatures - the crystal structure actually changes, which leads to marked changes in hardness - thus the utility for cutting tools and parts that undergo wear. This transition can also have deleterious effects (liberty ships in WWII, Japanese samurai swords in mainland China in the winter...). If you look at the phase diagram for steel, this transition is very clear.

 

The materials used in tubes do not have phase transitions of this type at cryo temperatures - if anything, the crystal structures are more stable as they get colder due to simple kinetics. The only change in properties that I'd anticipate upon cooling would be simply that they get cold.

 

I'm not going to comment on what differences people say they hear - that leads to discussions that tend to self destruct. People hear what they hear and think what they think - so be it.

 

However, as a former materials engineer (ScD in nuclear materials), I do feel that I understand the materials aspects of this quite well from basic principles and these principles are well understood in the industry.

 

    Rich

[Caution: High Voltage!]

One hand in the pocket is always good advice, as is discharging the power caps via a bleed resistor.

 

Another (which I always follow) is to check that the high voltage is bled off by using a meter to read the actual voltage on the HV side. I don't stick my fingers in there until the meter shows that the voltage is really bled off.

 

I've had enough shocks in the past (in my young & naive days) to pay attention to this.

 

   Rich

[KG 3 Signature Series- $200.00-Lowering to $150.00]

Where in NJ are you located??

 

   Rich