• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

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Amps: 2X125W 833 single ended
DAC: 8XTDA1541A Parallel I2s connected non oversampling dac
Transport: Marantz CD80 I2s connected, non oversampling modified
Loudspeakers: Tannoy Saturn S10

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An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.

Is that module out in front on the floor a proximity sensor to crowbar the B+ if a pet, child or adult animal approaches these exposed anode electric chair amplifiers?
 
Nice job Tony,

I like it! Great use for a re-purposed electrical cabinet. Looks like it was just about big enough for all the parts. I have three 810's in parallel in a tabletop tesla coil. They throw a lot of heat. You should put clear plexy sides on the top tier to show the glow.

Are you cathode direct coupled from your drivers or using an I.T.? What output iron did you use on the 810? Plate voltage? This tube is like a mighty 805 with considerably more balls.
Hi Bob
Thank you my out-put is from Electric Print audio CT3KB 200ma, I used IT also from Electric Print in Shisido style, using positive bias +16v for 810 Vp 760v Ip 125ma, bias current is around 12ma, driver's Ip is 50ma, make this two currents flow in opposite direction then the IT has 50ma in pri will be good enough for the job, the sides also free stuffs no choice ! heat and the cooling fan made the two sides bend in, so I had drilled holes in the 810's close area of the plexy to solve the problem.
regard Tony
 
whaw, did you build these?!?!?

Amps: 2X125W 833 single ended
DAC: 8XTDA1541A Parallel I2s connected non oversampling dac
Transport: Marantz CD80 I2s connected, non oversampling modified
Loudspeakers: Tannoy Saturn S10

An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
 
6eb8 surplus amp

Built this amp from surplus components I bought locally. All surplus components except the bamboo case that if found for 9.99 at target. The top is a piece of aluminum sheet that I cut and sanded with my orbital sander. It gave it a really nice brushed look. It puts out 3.5 watts per channel without distortion and it goes decently to 5. I have hooked it up to my very efficient full range speakers and it sounds great, obviously i only reach the first watt or so before it becomes to loud. Its actually a gift for my father, I am now building him a pair of 91d db speakers with surplus radio shack full range drivers.
 

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Hi,
Unfortunately i don't have the phono preamp yet. I am going to build a tube preamp, then i can listen vinyl records.
HI Noyan
I met 833 amp first time at WAVAC room in CES Las Vegas 5 years ago , it gave me no surprise in sound quality because it only showed with CD, I believe source is the most important. if you don't mind I give you some suggestions for your phono amp to match to your 833's level in quality, better with low out-put MC cart, silver step-up transformer, LCR for RIAA net-work, transformer coupling,no feedback DHT in out-put, with arm and table to-getter will cost a lot, or in other way you can tast the differrent between analogue and digital is to find a Revox A77 (in picture 4 tracks) B77 or PR99 (2 tracks) even Pro machine Studer A810(in picture), price on ebay is real bargain compare to their time before. source also can find from ebay pre record tape or highest quality from Tape Project copy. you don't have to build pre amp now just plug in then you can find the emotion different between with CD, although those machine come with transistor amp, still much better than CD,or you can build a all tube re-pro amp later
Tony Ma
 

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hi there, nice amps you said you was getting low level humming from the amp ,would you know what the cause was as i am getting humming from my preamp,although it seems to be getting louder.but dies down when i have my hand over the 2 left tubes.hope i do not have to throw this thing off a bridge or i might follow it .thanks.
 
It being virtually impossible to retain the beautiful brushed finish during panel fabrication, I would guess you brushed the panel after the holes were punched/drilled.

How did you get this finish on the panel, and

What is the panel made of? -It looks a bit like nickel-plated steel...?

Beautiful job- wonderful craftsmanship- Congratulations!!
 
Here is how I made the topplate

Thanks guys :)
The top plate is of 4mm thick 6061-T6 hardened aluminium (fligth quality)
All holes, countersinks and treads where made first, and after that, the "brushed" surface finnish.
I have used a handhold beltsander with 80 grid paper, which cause a rather rough surface
After that, using the same beltsander and a blank grid paper (and some wheatstone oil) which smoothed the surface down a bit.
The blank paper with oil treatment gave a bit of shiny surface
Messy, yes you bet...
After cleaning I used Sonax car wax to close the open surface pores to prevent finger prints.

Regards
Pix
Sweden
 
Pix-

Nice choice of material! -For some reason, I've been stuck on using 5052 H32 or else steel -but 6061 T6 is a GREAT idea- the best of both worlds!

Thanks also for the idea of using coarse grit to make the texture and finer grit to remove the rouch edge- this is no doubt a big improvement over using a medium or fine abrasive only. I also like the idea of using hard wax to finish the top- I'll have to try that. I wonder if you've ever tried clear acrylic and if so, I wonder about its durability and resistance to yellowing from the heat of tube-type electronics.

Your chassis turned out beautifully, both the top panel and the wooden base- really great craftsmanship!

I'm searching for a finishing technique- I've painted my first project and although that turns out OK, it's not as fine as I'd like. I've considered anodizing, but that leaves a hard insulating surface over the aluminum- rather difficult to get a good ground when you need it, and is difficult to do well. I've also seen aluminum panels dipped in a caustic solution- very, very fine-looking, but also very subject to scratching and also to absorbing oils from fingerprints.

Your technique is beautiful. Congratulations on your excellent craftsmanship.
 
"I've considered anodizing, but that leaves a hard insulating surface over the aluminum- rather difficult to get a good ground when you need it".

The hard surface is much more durable than paint and I just hit the surface with a dremel when I need to make an electrical connection.

You really need to do that anyway, be it paint, wax, clear, or whatever, because aluminum oxidizes so rapidly.

There are two types of anodizing surfaces. Type II is a thing coat that is typically what everyone uses. Type III, or Hard Coat, is much thicker (up to 5 mills) and very, very durable. I used Type II black anodizing on mine after brushing the aluminum by hand.
 
My simple 2A3 SE mono block

Simple 2A3 SE Mono block .....

7F7 Paralell as input/driver ................

6X5 * 2 as tube rectifier .................

0_2A3_SEMono_RightAngleBoth_3.jpg


You can see detail of the amp. I built .............. <a href="http://www.thaidiyaudio.net/index.php/topic,3339.0.html" target="_blank"> here .</a>




and welcome any suggestion..........