I have to sell my Pyramid-V prototype...

[Wavebourn]

If we can't pay mortgage we can loose our house...

so I am selling everything I can now...

Here is my Pyramid-V prototype on e-pay:

http://cgi.ebay.com/ws/eBayISAPI.dll...m=180327852085

[Jeb-D.]

That's a bummer, sorry to hear

If I come across anyone looking for an amplifier, I'll forward them the link. Do you have any pictures of it with the cage off?

Are you selling any parts?

[Wavebourn]

Originally posted by Jeb-D.
That's a bummer, sorry to hear

If I come across anyone looking for an amplifier, I'll forward them the link. Do you have any pictures of it with the cage off?

Are you selling any parts?

I hope I will not have to sell parts, I am too young yet to retire...

Here is it inside:

[Wavebourn]

They started to bid so early I even did not have a chance to revise the item: I needed to correct some typing errors and grammar mistakes, and to add an information where to see more photos.... I hope somebody will ask questions so I can add more info.

[Trout]

Originally posted by Wavebourn
They started to bid so early I even did not have a chance to revise the item: I needed to correct some typing errors and grammar mistakes, and to add an information where to see more photos.... I hope somebody will ask questions so I can add more info.

You can revise the listing on ebay as well as add more information and pictures. I do it all the time.

[Wavebourn]

Originally posted by Trout



You can revise the listing on ebay as well as add more information and pictures. I do it all the time.

Thank you!

I did that, but after adding pictures I've got a question about more details... Wish I had that question about more details before...

[Zen Mod]

Originally posted by Wavebourn


Thank you!

I did that, but after adding pictures I've got a question about more details... Wish I had that question about more details before...

I know that you had several posts or even thread with greater insight in tech details of that amp .
you can write link to these posts

[Wavebourn]

Originally posted by Zen Mod



I know that you had several posts or even thread with greater insight in tech details of that amp .
you can write link to these posts

Yes, thank you!

First of all, I have to draw the complete schematic diagram and describe it here. I had some drafts, and made some remarks in a notebook when tweaked it... Also, when we used it to listen to nice speakers on Burning Amp festival in San Francisco Jan Didden asked me to write an article about it for Elektor magazine, but I never had a time to sit down and concentrate...

Ok, let's start.

First of all, why Tube Amp Again?

There were so many tube amps designed before solid state devices become available, and engineers and hobbyists still continue to design and build them... Why?

I heard such explanation:

Some people like specific distortions that tubes add to the sound.

I agree with that, when we speak of guitar amps that add dynamic spectrum change that electric guitars need. But when speaking of sound reproduction, I strongly disagree: "specific" tube distortions mean slow rise of low order distortions with power, so if to use designed for electric guitar amps for music listening intermodulation distortions will kill all musical material except plain electric guitars.

This is not true. Nobody likes distortions. Even though vendors of devices that "add tube character" claim that adding such devices in signal path make the sound warmer this is not true. The result is, the mix of solid state specific and tube specific distortions...

I used to add "tube distortions" to guitar sound without any tubes at all, using diodes in feedback path of an operational amplifier. Did they make the sound warmer?

No!

So, why tubes?

[Jeb-D.]

Wavebourn,
How would you compare GU50 to a tube like KT88 or 6550 in your experiences? Both sound quality and electrical performance.

[Wavebourn]

Originally posted by Jeb-D.
Wavebourn,
How would you compare GU50 to a tube like KT88 or 6550 in your experiences? Both sound quality and electrical performance.

Sound quality depends on design, but GU-50 were designed better than KT88. Telefunken designed LS-50 for critical military applications, and don't think GU-50 are cheaper than KT-88 or 6550; they were made with better precision and used more expensive materials, for example nickel to sustain anode power abuse. However they were not used in mass production audio gear that created demand, so go cheaper on ePay.

...but my amp was not designed for FedEx abuse, the power tranny bent the chassis. I'm waiting for pictures from the buyer to figure out what to do next... I expected that the mirror between hot toobs and transformers would act as a hardness rib, but looks it could not help...