HD83 World Audio Design - Anyone Got Experience?
Aug 9, 2001 at 12:51 AM Thread Starter Post #1 of 7

eeyssjr

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OK. I am this close to orderig this head amp kit, from worldaudiodesign.co.uk

First of all, i was owndering if anyone has built this, and could just give me general feedback about it, what i can expect etc etc. Anything really.

Then there is something specific. The amp is on this page:

World Audio Design UK

The amp uses Mullard ECL83 valves. Now i checked online at the tube store to see if i could get replacements for these valves, if and when i needed them. Turns out they dont sell them anymore - not in manufacture or something.

Is this correct? What could i do if they go pop - replacements? Is it worth building an amp with just one set of tubes?

Any help really appreciated.
 
Aug 9, 2001 at 2:25 AM Post #2 of 7
I don't know if anybody is still making ecl83 but some are still avaliable. I found some for about $9.00 each. You could buy a few and they should keep you going long enough. You could also look at a MG Head or similar that use readily avaliable tubes. I would e-mail your concerns to World Audio and see what they have to say, also.
 
Aug 9, 2001 at 1:41 PM Post #3 of 7
Thanks Budgie

I considered the Earmax and the MG Head, but have the DIY itch, and this HD83 seems a pretty sorted, simple design. A no frills circuit that should sound good. The output trannies are also good quality.

Anyway, the tube store says the following:

As far as I know, you should be able to use a 6BM8 tube. We have them here: http://store.yahoo.com/thetubestore/svetlana6bm8.html.
According to the substitution handbook, the ECL83 is the same as the
ECL82/6BM8. This may be only for certain designs that more flexible, but I
don't have any other info for you to really confirm.


This sheds light on things a little, but i will contact WAD and see if their design is robust enough to make a direct ECL83 ---> ECL82/6BM8 swap. If so, i have the go ahead.
 
Oct 9, 2001 at 11:06 PM Post #5 of 7
Hello,

I know numerous people who tried 6BM8. Its pentode is pretty low noise and they say they can use these for headphones. (They say for speakers, these are sure thing.)

Note the capacitor coupling between two stages (cascode). You can improve this amp by putting higher quality capacitor. This upgrade should be very simple yet difference should be clearly audible.

Tomo

P.S. I hear some people are using 6AS12 (2 triodes and 1 pentode) for headphones.
 
Sep 7, 2009 at 3:08 PM Post #6 of 7
In case you're still interested there is a direct equivalent phillips valve (can't remember what it is off-hand, but I think it's now supplied with the modern HD83 equivalent (Headphone3??) so check the World Designs page). They look and sound exactly like the mullards so I suspect the only difference is the logo on the glass.
 

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