I've been in China for over six years now and had a few ideas about opening my own business. Initially I was giving serious thought to opening a training school. Then after a stint at a travel company for a couple of months I had a great idea about a new kind of travel service. For both of these notions I got domain names registered but I subsequently got more interested in other things (not just women I hasten to add).

Well finally, I've found it. The business opportunity that I've been building up to all my life. I announced it at the public English Corner yesterday to a handful of people as I was curious to gauge their response. Overall, very positive and despite being a kind of business they'd not previously encountered they really seemed to get the message quite quickly.

This isn't strictly speaking a business in the traditional sense of being a company. Its more a network of interested and passionate individuals - cells in a super-organism if you...

I built it! It sounds great. The downside is I struggled to find a low cost way to build the box and chassis. If I had simply followed the advice in the kit guide, I would have had an easier time of it, and it might not have cost any more.
The upside is I appreciate the box designs I have seen a lot more.

I'm wondering how many guys and gals out there on diyaudio are interested in sustainable computer audio? Let me unpack what I mean by this phrase for a moment....

Computers on their present course are obviously not a sustainable proposition. I've already posted about the demise of Intel but that's just the tip of the iceberg. Even if all CPUs move over to ARM A9 or A15 tomorrow there's still a huge unsustainable industry supporting the current wave of computers. There's the drive towards smaller feature sizes in memory which is going to hit a brickwall sooner rather than later. Increasing sizes of memory are like a drug that everyone's got addicted to. Remember Bill Gates' original prophesy that '640k will be enough for everybody'? He really meant it at the time. So I can't help but ask 'do we really, really need all this memory?'. My gut tells me not but to prove it requires some innovative thinking.

One of the things that got me thinking along these lines...

TSEC's Passive Ring Modulator In Action At Space Egg.

TSEC's DM1 Soft Distortion Fuzz-Box (The Dirty Muther).

Can High Fidelity include audible distortion?

From the ultimate heights of fidelity we should hear a perfect reproduction of the recorded signal all the way from source to speakers – right? Perhaps that depends on your idea of fidelity. Where does your fidelity lie? What are you being faithful to? To the recorded waveform, or something else? Could your idea of fidelity be that you want the final result to be faithful to the direct sound of the music? Is your goal a faithful reproduction of the music, or of the recorded signal? The two are certainly not mutually exclusive, but can often be at odds.

Low distortion is the second of the two founding pillars of HiFi - frequency response being the first. Any distortion alters the signal, therefore it must be wrong. Or so says conventional thinking. To be highly faithful to the signal, we must alter it as little as possible, granted the possible exception of overall level or volume. But what if our goal...

Inspired by This Thread I decided to build something similar,I've though about it before,and had some parts sitting here,so what the heck!

Amp Schematic

PSU schematic


Here's what I've got at the moment.
25BQ6GTB tubes,(re-)branded DuMont. These are the skinny 6V6-sized bottles.(11W anode rating,and ~200V screen rating)

A pair of those are driving a 3.5K PP output transformer,rated for ~100W. (came from a scrapped Bogen M120 4x PPP 8417 amp.)

Bogen Schematic

B+=457V
Va=455V
B2+/Vg2=224V
Vg1=-43V
Vk (33ohm Rk's) ~1.3V ,About 40ma/tube.
(I saw cathode current peaks of ~80ma per tube,perhaps more? hard to tell with my DMM)

That gives a dissipation of ~18W per tube. Much more current and the plates start to 'blush'.
I did *not* see any screen glow,but the mica's on these particular tubes make it kind of hard to see much inside....

This morning I was waking up the music server to have a listen. I run a Windoze XP box with JRiver Media Center.

JRiver gave me a pop-up error message that there had been an incomplete shutdown, did I want to fix any problems? There had been a power outage for a couple of hours last night that shut down the server. So if course I clicked "OK".

Bam! Screen goes dark. WTF? I look at the crossover and the tube amps - all dark. All dead. Now what I have done?

Well, it wasn't my mouse click that killed everything, the power was out again. Phew. But talk about scary timing. Click OK and everything dies right on the click.

Fortunately for us we have a 12KW generator that kicks in and can run the whole house.

All back to normal now.

You can see how a speaker is made in
Discovery channel how speaker is made
or https://www.youtube.com/watch?v=VN0tmyyC0ak

I have an old Dick Smiths ETI 480 Power Supply. What I don't have ia any information or the Scematic for it.Tthere is plenty of information for the 480 Amp, but that's not what I want. Just the instructions for the Power Supply.

Any help please.