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Building and listening to the Edison 60 Amplifier Kit

Go with the glow!

Here I report to you, our reader's, first in the world about a new Amplifier Kit.
Many may think the Day's of Dynakit, Heathkit and building your own Wiliamson Amplifier are long gone.
Not so. With the resurgence of Valve Amplification Kit's have come back. Many Kits. Some of them very expensive, others like Doc "Bottleheads" S.E.X. Amp (Single Ended eXperimenters Kit - 2W SE Power) cheap, for 240 UK Pound ($ 399), but it is not exactly a powerful Amp nor pretty.

The Maplin Millennium 4-20 Amplifier Kit (used to be 170-240 UK Pound) seems to have gone the way of all earthly things. And let's face it, while cheap, it looked pretty dire and the performance was not exactly too good....

One could buy the Audio Note Kit 4; a small Push Pull Amp for 299 UK-Pounds ($ 499) which looks quite decent. But then, you need a Preamp, the power is low and so on.

On the other side of the fence Companies like Jadis and Conrad Johnson have recently introduced "integrated" Valve-Amplifiers, for fairly sensible Money and in the Case of Jadis nice looks. However the Jadis Orchestra costs 1,100 UK Pound ($1,800), as does the Golden Tube Audio SE-40 Single Ended Amp.

Now while quite a few people can afford such an Amplifier, for many it is still a bit too much.

So what if you want a Valve Amp. And you cant afford over onethousand Pound. And you don't like ugly things.

Believe me - you do want a Valve Amp. Listen to a few and then listen to Krell's finest. If you prefer Krell no need to read further. All others might want to have look at Illusion Engines an Article about what a music reproduction system is really doing (or should be doing).

Still I want a Valve-Amp. I want it now, not when I'm old and gray. And no - I'm not going to pay silly prices - what do I do?

Knights in white Armor!


On their white Chargers, in their gleaming Armor and flying Banners, coming to your Aid are Eric "The Viking" Andersson and David Chessell, our Knights in shining Armor.

With them they bring a supply of Amplifier Kit's.

For only 399 UK Pound ($ 660) you get an Amplifier Kit that has it all:

30 Watt per Channel of Ultralinear Push-Pull Power from two Pair of EL-34's, three Line-inputs and a Volume Control.

Or get the 20 Watt per Channel Ultralinear Single Ended Kit with two pairs of EL-34's. How much? 399 UK Pounds.

Or how about a 12-15 Watt Triode Parallel Single Ended Amp. How much? 399 Pound.

You guessed. All these Kit's are exactly the same.

A revolutionary Concept. I know of only one other Amplifier that allows to be used with minimal changes in Either Single Ended Mode or as Push Pull Amplifier. The rather expansive Manley 300B PP/SE Amplifier.

So whatever your taste runs in, whatever works best in your system, the Edison Kit can do it.

Of course, it is a KIT. You MUST assemble the Kit yourself. I think that is half the Fun actually.

While I would not recommend this Kit to "Absolute Beginners" (1) anyone who can solder and has a rudimentary understanding of electronics should be able to assemble the Kit in about a weekend.

The Instructions are concise and pretty easy to follow. Don't take my word for it, have a look - they are on the Web.

Live in the Box?

When I received my Kit, I took time to examine it closely. I noted a few interesting things.
The Casework is of exceptional Quality, using machine screws throughout. The fairly low but deep and standard width Case will fit nicely into almost any system.

The Output Transformers are massive and Air-gapped (required for the SE Operation). They also have Output taps for 8, 4 and 2 Ohm Speakers.

My only area of some concern is the Powersupply. While more than adequate at the Price the kit sells for, I would have liked to see a somewhat larger Transformer and more PSU Capacitance....

The Transformer in the Basic 399 Pound Kit runs hot. Not unsafely so, but hot. Very hot. Okay, it's a Class A Amplifier. It has loads of valves and runs hot. I would like to see a larger Transformer.

However the "realpolitik" means that a cooler running Transformer would cost money. Your Money. So if the price is of concern and your living-room (or listening room) does not get hotter than 30 Degrees Celsius, the Transformer gets a qualified okay from me.

David Chessell must have know my thoughts before I even had time to think them. Packed in the (very professional) Carton for the Kit I found a second Mains-Transformer and PSU Circuit.

I also found additional Powersupply Components and (dig this !) the optional Stainless Steel Top/Front Plate, the wooden Side-cheeks and the good Binding Posts and RCA Jacks.

So okay. My Edison 60 then is not a 399 Pound Kit. Indeed, the Kit with all Options will be more around 650 Pound.

However 499 UK Pound ($820.00) buy you the Kit including the two main Upgrades. The one for better sound and less heat - the second Mains-Transformer and PSU Circuit Board. And the one to placate the Significant Other Half - the Stainless Steel Chassis Top for good looks.

If you ask me, also shell out for the Cherry Wood Side-cheeks. It might be hard for the Hard-core Audiophile to spend 37.50 Pound ($62) on LOOKS (!!?? am I mad) but wait till your Spouse or friends (of whatever gender) see the finished Amp. Believe me, it's worth it.

So whatever your taste and budget will allow, the "basic Black" British looking Kit or the Italian looking Polished Stainless Steel and Wood finish, here you get an Amp with looks as good as any.

I know David will not like me for this, but this Amp is essentially an Audion Amp.

Audion have been for years' purveyors of fine Single-Ended and Push-Pull Amplifiers, mostly powered by the costly 300B Valve. While all Audion Amp's remain fairly reasonably priced, cheap they are not. Each and every of their Amp's has been garnering rave reviews and awards.

The lowest Price Audion Amp is essentially like HALF the Edison 60 (EL 34 SE Amplifier) and will cost you about 600 UK Pound (if memory serves).

The Chassis for the Edison is essentially the same as two of the half-size Audion Amps; many other parts (Transformers for example) clearly are also from the Mother-companies Part's Bin. So in effect, the Edison 60 is really a highly fashionable Audion Amp without the Pricetag.

Even better, if you change some Component Values, use different Sockets and some additional Components; you can convert the Edison 60 to use the fabled 300B Valves, Push-Pull or Single-Ended. The Mains-transformers have suitable windings (two mains Transformers are required to run the 300B) and the Output Transformer will do 300B Duty with ease.

Now I spilled the Secret. Now you know the Secret of Edison.

Remember, we got it to you first....

Building, building - still not finished?

Okay, it took me more than a weekend to build the Amp.

Here is why. I was tempted to just put together an Amp with all the Options fitted. I know better Powersupplies improve the sound. I know so do better Capacitors and so on....

But, I had to restrain myself. I owe it to you our readers to tell you what the basic Kit sounds like. After all, we talk about a 399 Pound Kit. You want to know how this sounds, not like the Super Duper mega Hotrod version comes off.

So, I went ahead AND FITTED ALL OPTIONS. But I fitted them in such a manner that I could start evaluating the Amplifier as if it was the 399 Pound basic Kit and then one by one enable the additional Features.

Doing so meant to drill many more holes into the PCB's, fit many additional PCB Pins and so on. Even so it only took me three evenings to complete the Amp. The instructions are generally clear. What I would like to see is some pictoral Help for wiring up the Power-Valves Sockets. I got by just fine with the Text, but some folks might find it easier if they have a picture to refer to.

Once you have filled all the boards with components, assembled the Chassis and connected it all up and after having double and triple checked every piece of work, just plug the Valves in and switch on. Make sure to connect a Dummy Load across the two Speaker-Outputs ( I used a Pair 20W 8Ohm Resistors available from Tandy/Radioshack).

As all Valves are self-biased, no adjustment is neccesary (or possible).

Check the Voltages and if they are around the Voltages given in the Manual (+/- 10% is perfectly fine) you have a working Amplifier. When checking the Voltages please be careful and keep one hand in your pocket. The 500V DC on the Powersupply can shock yesterdays breakfast out of you and worse. BE SAFE!

Sweet, sweet harmonies

So, the Amp is ready. Fit the covers and whoo, wee; drop the Amp into your system. In my system the Edison 60 really had a though job. Not only are my Speakers are not exactly Lowthers and need a fair deal of Current, the whole Setup is very revealing too.

Dropping a record on my Turntable, cueing the lead-in grove and I settle back for a first listen. And there it is. For me (and a few others so far) my system is always one that makes you say "Wow".

With the Edison my first reaction was "Wavavava-boooom!" There was Space. There was Music.

Eventually I noted that the Magic of the Edison faded somewhat in the lower Frequencies. This is not surprising as it is hard even for many serious Solid State Amp's to control the twin 8" Woofers per Side of my Speakers.

Brief listening with some small stand-mounting Heybrook Speakers confirmed that they worked a lot better with the Edison 60 in its standard configuration. These Speakers had a 6.5" Viva Woofer and a 1" Vifa Softdome Tweeter, simple Cross-overs and a modest Sensitivity. The just loved the Edison. What on my large Speakers turned into some boom and looseness, with these smaller Speakers it was as if half of an Octave of bass was added.

However, I wanted that harmonic richness, that space and all in my big system. So a long time of experimenting started and is still going on. This is really part of what this kit is about. You can make it exactly what suits your taste and your system.

Given the 399 UK Pound Price the basic Kit sounds quite sensational.

The full all out build unit I'm listening now to is something else. Now in single-ended Triode Mode, with improved Powesupplies and many other small and larger "tweaks" this Amp plays in my system better than any Amp in there before. And it does have enough Power (12 Watt) to rock with ZZ-Top after Michael (Schumacher) win's a Grand Prix and for harder stuff to get of the frustration when someone trips his car.

Well, really I cannot tell you how the Amp will sound for you exactly, because it will depend if you want/need Push Pull, Single Ended or whatever connections.... One thing I do know, this Amp will sound great.

So more on the technical side of things, my changes and whatever else another time. For the time being I have to sum up simply: One heck of a sweet Amp which can be made to shine in whatever system you care to put it in.

It looks good. And it will not cost significantly under 700 UK Pound even in the "cost no object" Variant with Foil & Film coupling capacitors and Dual Mono Powersupply.

What more could you want? A Porsche? Get real!

A reasonable CD-Player (like a Marantz CD-67 SE in special order Silver to match the Amp) and a pair decent 2-Way Stand-mounting Speakers (how about the Mordaunt Short MS-20 Pearls) is my suggestion.

Hey, if you buy the basic Amplifier Kit, this leaves you Change from 1,000 Pound.

You can get a better Amp for a lot of Money, or a different one for less Money. I say, time to learn to solder folks....

Enjoy the Music and have a good Time.


(1) Sorry I cannot recommend ANY Valve Amp kit for Absolute Beginners - the many hundreds Volt DC inside can KILL and if you don't know what you are doing, you better let it be. You don't have to take my word for it. Read Doc Bottlehead on Workbench Safety.

© Copyright 1998 Thorsten Loesch for TNT Audio Magazine, http://www.tnt-audio.com

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