John Curl's Blowtorch preamplifier part II

Status
Not open for further replies.
If memory serves, THX assumes the amplifier can deliver a minimum of 100 Wrms into an impedance of 6 Ohms, with THD and IM figures of 0.08% or less. Something like that.

But, as Esperado said, basically it's just a marketing label. Of no real consequence.
 
Last edited:
So you can design an inferior product and then just pay THX to put a sticker on it?

Well, define "inferior".

They have a list of requirements you need to fulfill in order to apply. Then you cross their palms with silver and voila!, you have a THX certified product.

Beisdes, let's be honest - what percentage of products on the market would fulfill the IHF criteria? Rememebr, they stipulate that you run your amp at 1/3 of nominal power for 30 minutes before taking measurements, and I'm willing to bet at least 70% of amps on the market would not endure working for 30 minutes at 1/3 nominal power due to overheating.

Just look at those flimsy aluminium plates with added hair thin "fins" you typically find in the low and even mid sections of the market. I find them most unconvincing.
 
Well, define "inferior".
May-i tell-you a story ?
A friend of mine was in charge to build what was the best movie mixing studio in my country (France).
Imagine: it was in a real big movie theater, with the most impressive 96 tracks automated mixing desk in the middle.
He realized a wall in thick concrete behind the panoramic screen, in order to slot in the speakers enclosures.
When everything was finished, the guy from THX visited the studio to sign the certification and refused, because, on his certifications papers, this wall was specified to be in ... plasterboard.
 
Last edited:
In my country, it's just a slang language to ask for silver and gold. It seems a universal language :scratch:
The thing was stupid. Plasterboard is very resonant and cheap while his wall was totally inert and acoustically damped.
While the studio was prestigious, and the first one to ask for a THX certification in this City, he gave a phone call to the THX company in the state, and said that he don't wanted to be certified anymore by so incompetent people. He got immediately his certification with excuses, and the story had made laugh all the people in the film industry in Paris.
 
Some person in this thread told me that silicone electrical grease was not a good idea for contacts because an electrical spark could carbonize it and ruin the connection. There were no references given.

I was just thinking, we use silicone grease for spark plug boots in cars, and I haven't heard of people having problems with it. Can anyone provide references for this?
 
Administrator
Joined 2007
Paid Member
Some person in this thread told me that silicone electrical grease was not a good idea for contacts because an electrical spark could carbonize it and ruin the connection. There were no references given.

I was just thinking, we use silicone grease for spark plug boots in cars, and I haven't heard of people having problems with it. Can anyone provide references for this?

Silicone based grease is widely used in electronics/electrical engineering. Final anode caps in CRT TV's often had a smear of the stuff applied to prevent the high 25 to 27kV tracking across the glass in humid conditions.

Switches use grease as an aid to assembly. Look up "montage grease"
 
Some person in this thread told me that silicone electrical grease was not a good idea for contacts because an electrical spark could carbonize it and ruin the connection. There were no references given.

I was just thinking, we use silicone grease for spark plug boots in cars, and I haven't heard of people having problems with it. Can anyone provide references for this?

Well WD40 has slivers of silicon carbide in it, that is what helps make it good for gross electrical connectors, but not so suitable for precision electronics and thinly plated stuff, maybe that is the source of dislike?
 
Status
Not open for further replies.