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My bespoke ST70 amp build


Wardsweb

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Thanks for the plug Craig....

 

If there was ever a project that turned out to be something special, it was this one! The Magnequest iron and Craigs tuning turned my VRD's into the most special sounding amps I have heard. My amps feature every other electrical upgrade Craig offers as well using Jupiter Copper coupling capacitors. We even upgraded all the connectors on the amps.

 

Don't get me wrong.... The VRD's in original form are absolutely stunning. The sound difference is kind of tough to describe really, but I'll try...

 

What was once a nice rendition of a piano became a very large resonating instrument. Little things going on in the background of the music become obvious little things, so a great increase in texture. I have never heard backup singers portrayed so transparently. Virtually no confusion in populated ensembles making classical music an absolute thrill ride. Image scale is almost supernatural depending on recording. For example, I have one album, Hugh Masekella "Hope" and it is as if I have superhero's playing in front of me!

 

Put plainly, it is more real sounding. More intimate.

 

This upgrade is not cheap, but like Craig said, my system sounds as good as the best systems I have heard for a fraction of the price. For context, I have heard personally, this system: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwjXvYrb2fzKAhUFwiYKHZp1A34QFggeMAA&url=https%3A%2F%2Fsystems.audiogon.com%2Fsystems%2F5045&usg=AFQjCNEMfh9NSGzKF2nXSsS67QDw2Lh8fg&bvm=bv.114195076,d.eWE

 

The amps in this system showed me what tubes are capable of with regards to imaging and resolution, and my new VRD's are a lighter lower powered sonic equal with even a touch more transparency, due to less tubes in the chain most likely. Craig really made something special here guys.

 

Here is a nice blog about my system:

https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&cad=rja&uact=8&ved=0ahUKEwjf6Zav2PzKAhVB7SYKHTX7B24QFggtMAU&url=http%3A%2F%2Fmagnequest.blogspot.com%2F&usg=AFQjCNG_aY9rzPe3EYVI-_2zCpVAl-l9fQ

 

The speakers then were the Joseph Audio Perspective's. They are now replaced with the Joseph Audio Pearl's. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiErLHj2PzKAhVDSyYKHfA8Ci0QFggcMAA&url=http%3A%2F%2Fwww.josephaudio.com%2Fpearl3%2F&usg=AFQjCNFtNRwBDNeadbg8NK_75TJKoSHFiQ&bvm=bv.114195076,d.eWE

 

Oh, yes... The Sig. VRD's drive them with absolutely NO problem, all by their lonesomes....

Edited by paul79
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Why are you calling me a sloth and xxxjpmxx? Inside joke?

 

You join right after xxxjpmxxx is banned.

Your IP's are close to each others.

You post in the same forums as he did.

You write in the same style.

You have the same technical knowledge

Most people do not believe in coincidence.

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Similarities aside, I see nothing technically wrong with Cindy's posts in this thread. If you think it's baiting or whatever, then you should just ignore it. Otherwise, I read it as someone actually asking a few questions, and others attacking "Cindy" for doing so. Please don't do that, regardless of assumptions you make. Keep things within context here.

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Since nobody helped me to find the answer I dug through some text books and I believe I found what I was looking for. If anyone else is interested here is what I learned.

 

Let's go with the 50% full power that we require for 20kHz. For the 40 watt amp we will use the figure 17v peak for 17.7 watts RMS, close enough to half for me.

 

So for this amplifier we are looking for a slew rate of 2.13 V/us

 

I assume the scope is set for 10us/div in the last photo showing 20kHz squarewaves in post #2. I also assume the vert divisions are 5V/div. 

 

So we want to see no more than a 1/10 a horizontal division (1us) in at least 42% a vertical division (2.13v).

 

We can also deduce the -3db rolloff by looking at the rise time from 10% to 90% of the pulse. I count about 3us which would put the -3db point at around 116kHz.

 

 

This would be a lot easier if the "experts" here would share there information and explain what we are looking at instead of putting down my lack of knowledge in a field I am not an expert in. I am sure all of us could learn form it.

 

 

-Cindy

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Consider this a formal complaint about NOSValves avatar. I find it and him extremely offensive. Forum rules states no profanity.

 

It's kind of hard to fault him for using the same word for an avatar that PWK used to wear on a pin.

 

If you have an issue with a post, use the report button at the bottom of the post in question.  The moderators will deal with it appropriately.

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Under "Terms of Use / Rules"  

 

"You agree, through your use of this service, that you will not use this bulletin board to post any material which is knowingly false and/or defamatory, inaccurate, abusive, vulgar, hateful, harassing, obscene, profane, sexually oriented, racist, threatening, invasive of a person's privacy, or otherwise violative of any law."

 

 

Post #23 NOSValves called me a "smartass" and was not issued anywarning points. He has also called others names like "delusional" in other threads.

 

I on the other hand get a warning point for saying "Your remarks are a good indication of your intellect".      The moderators are clearly discriminating against me for whatever reason and I don't appreciate it.

 

 

-Cindy

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