Edison Kit Range
The Edison kits are an excellent entry point into the world of valve amplification. Since it’s launch the Edison 60 kit has been a best seller creating a world wide following with all who have purchased it.
Now, we are currently working on two new kits - The Edison Triode and the Edison E1!
The Edison Triode is a 300B based kit, operating in pure Class-A with no feedback to produce 10W of pure listening pleasure. It is now in pre-production stage just awaiting the writing of a user manual.
The Edison E1 will be our first Preamp kit, and is ideal for many systems with multiple sources, as well as complimenting any of our Edison or Audion power amplifiers.
The joy of self-assembly can be a very satisfying experience, but part builds are available for those less willing to dive straight in!
As a core product the Edison 60 can perform many roles in a broad system, and has enough power for today’s varied sources not only for hi-fi but to be a part of any home entertainment system.
To top that, it can be configured in either Push-Pull or Single-Ended mode with enough power for any purist with speakers of 88dB efficiency and higher.
The entry model is competitively priced to help you along. Although technically complete, it can be upgraded with additional components to improve the product inevitably outperforming retail products costing many times more! The kit is complete, having everything you need to build it right down to the last nut.
All kits are supplied with the latest user manual and circuit diagram and online email support where needed. If you are not overly confident with a soldering iron we can even factory build some or all of your kit for you.
Mr. Thorsten-Loesch of TNT-Audio.com has fun with an Edison 60 kit amplifier!
My impression of the quality of the major parts is quite favourable. Most importantly, the output transformers are serious hunks of Iron.
The output transformer has output tapings for 4 and 8 Ohm and the primary is made up from four identical Windings, which allows for a wide range of connection options. I have seen similar output transformers priced at $150 US Dollars each, so the output transformers supplied account probably for almost half the cost of the kit.
As Self-Biased Push-Pull Ultra-Linear connected amplifier an output of 30Watt is claimed, for PSE Ultra-Linear 18/20W. An option is available to use a fixed bias Class-AB circuit delivering about 50 Watt Ultra-Linear, however I do not think this a very advisable option, still if you need the Watt's....
The mains transformer in the Standard Kit is a little on the small side, however still sufficient. It is a 100mm diameter Toroidal affair, larger than what most Japanese 2 X 100VA mid hi-fi amplifiers sport. A second transformer can be purchased for about $110 USD and fitted with obvious benefits. (Much improved New Transformer supplied now!)
The ‘Star’ of the show is actually the casework. Anyone who has seen the Maplin 4-20 Kit (it has just the right looks for the "Honey look what followed me home" Crowd”) will know what one does not want sitting in ones equipment rack. The chassis is actually of exactly the same style as used by Audion (the company behind Edison) in the renowned "Audion" range of SE amplifiers. Even without the optional polished stainless steel front/top plate and without the optional wooden side-cheeks the Edison will look rather nice.
In line with many other Audion amplifiers the Edison is actually an "integrated amp." with three inputs and a volume control. An Alps Blue Velvet Volume Control is offered as optional Extra (approx. $16 USD) over the part provided as standard and I for one would recommend this upgrade highly....
The socketry provided as standard is pretty basic, better RCA sockets and binding posts can be purchased from Audion or at your nearest electronic store. For the record, I received the optional sockets and binding posts, and the binding posts are a lot better than what I normally fit, the RCA Jacks of the usual "Tiffany Style" design with PTFE Insulation.
The quality of the remaining parts (capacitors, resistors and so on) is what I usually call "Industrial", meaning no fancy boutique cap's or Black Gate electrolytic's, but then what do you expect for a Kit price of about $700 USD?
The supplied valves are four Sovtek EL34G and four Sovtek 6922 input/driver valves. Considering the price as 30 Watt Class-A Push-Pull Kit, the $650 USD may seem not such huge bargain, until one considers the Range of possible options....
The basic Kit can be a 30 Watt Ultra-Linear Push-Pull or 20 Watt Ultra-Linear Single-Ended amplifier (competition for the GTA SE-40 brewing here maybe?). Triode Connection is of course possible and the amp. features the (IMHO) completely indispensable output tapping to accommodate a wide range of speakers
It is quite possible to start with the basic Kit and at a later stage (when funds allow) to upgrade the unit to dual-mono power supplies for example. Lastly, if I’m not mistaken, the two 3.7V 4A heater-windings per mains transformer (not used in the kit) make a nice rectified and filtered 5V for a 300B filament, and the output transformer certainly looks beefy enough to make (a slightly marginal) but competent output transformer for a 300B PSE amplifier.
Well, the Instructions are clear and concise. Everything went together fairly simple and fairly uneventful.
It took me a lot longer than it should take normally, as I received every option possible under the sun and decided to fit them all.
However, in order to get a handle on how the UK £449 GBP basic kit sounds I had to make sure that I had all options fitted BUT NOT ENABLED....
This required a large quantity of additional PCB pins to be fitted. As a result I am able to very quickly switch between the various configurations. This was done because it is fairly difficult to remove the PCB's and work on the solder side once fitted.
As a result of this it is also vital TO VERY CAREFULLY CHECK YOU WORK prior to fitting the PCB's in the chassis. Correcting mistakes later will take much time....
Fitting two mains transformers proved a little challenging at first. After discussing this with Dave Chessell from Audion, he noted that future batches of chassis would come suitably pre-drilled to accommodate either one or two mains transformers, so you should not have the problems....(This has now been done ..ed..)
As noted I was also supplied with the (optional) better RCA sockets and binding-posts. Considering the substantial difficulty of re-fitting these later I built the Kit with the better connection hardware.
I also added a "direct" input bypassing the passive line-stage, as my system is primarily vinyl oriented and hence has got a superb preamp.
The volume control in the kit is made by Alps and the same (sans Motor) as found for example in the well-respected Marantz PM-66 KI Signature Amplifier (£500 GBP). It is however not the last word in transparency. The channel-tracking on these controls is very good BTW if my own experiences are anything to go by.
I also decided to use my favourite wire for wiring the Amp. Again once fitted the wire is hard to upgrade or replace. I think such small changes are within the scope of what any individual constructor may do.
Indeed, I cannot really cite Audion/Edison for packing fairly nondescript wire with the kit. Such a wide variety of options and preferences exist that certainly whatever would be packed with the Kit would be the wrong stuff for someone....
Only one more note on connectors and wires. The loudspeaker connectors supplied in the Basic Kit are perfectly serviceable, but in true British tradition Banana-plug ONLY. You cannot use speaker cables with spades directly.
At only £2.50 GBP each, about $4.00 USD (as per the pricelist on the Edison web site) the optional binding posts will accept any form of connection up to the most monstrous spades. They give little in design, sound and quality to the WBT ones that cost real money.... They are highly recommended for anyone in need of something other than Banana connectors.
For the whole amp, it is probably a good Idea to lay out the major parts in front of you on the empty workbench. Then read the assembly manual (again) and think through in which sequence it would be best to assemble what.
The manual is quite good on that, however it is still only in "Beta" as it has been only recently translated from Swedish into English... (now completely rewritten .. ed)
I feel for example that it is advantageous to first wire up all the RCA sockets in the bottom chassis assembly and to then wire the loudspeaker connectors before finally fitting and wiring the output transformers.
Both RCA sockets and speaker connectors are otherwise hidden behind the output transformers and hence fairly difficult to get at. This is not specifically mentioned in the manual.
So applying a little forethought (just as with any large project) will speed up things no end and also make the assembly a much more enjoyable experience.
I am sure subsequent revisions of the manual will address such minor issues.
The assembly of the PCB's is straightforward and simple. As I had only the downloaded manual published on the web, I do not know if the final printed items includes photographs of the finished boards or (better) an enlarged stuffing guide. I personally at least find such things useful.
Lastly, PLEASE MAKE SURE TO TAKE THE SAFETY NOTES SERIOUS. Also make sure electrolytic capacitors go in the right way.
If you are not particularly experienced in electronics it might be a good Idea to have the boards checked by an experienced friend before fitting them.
If you do it all by yourself, leave the assembled boards for a night and look at them fresh the next day.
In the end, after two day's work (well not all day long - it's Summer so I go out as well ;-) ) I was ready to power the unit up. Do not do this without a load attached to the output. Tandy/Radio Shack sells very nice 20W 8-Ohm resistors, which is what I use for such purposes.
Also do NOT switch the amp on without the valves fitted.
All valves lit up. All voltages measured okay (a bit high, but that is the 252V AC delivered to my flat). So, I connected a CD-player and headphone up - and got (almost) no sound!
What had happened was that I had wired the front-end for Push-Pull operation and the output transformer for SE operation. Hence the signals cancelled out in the output transformer and thus no sound.... Given how little leakage was there the AC symmetry of the Edison amp. seems impressive.
I was less impressed with the amount of hum produced by the SE wired output stage (headphones do exaggerate this somewhat), so I rewired the output as Push-Pull. The hum went away totally, proving that it is just a PSU issue in SE mode.
A (optional) set of capacitors for the audio PCB is available and works as far as reducing the hum is concerned.
This is not part of the basic Kit however, so the SE mode of amp. may give you some problems with hum without the additional components fitted. Much will depend on your specific speakers.
After correcting the wiring and closing the chassis I took the amp. into the living room and connected it to the system....
Even before I got the amp. connected up, I noted just how pretty an amplifier this is. While the wooden side-cheeks and the stainless-steel top/front plate set you back quite a bit of money (about £70.00 GBP together - $115.00 USD), they make for a look not all that removed from what you would expect on expensive Italian valve esoterica.
Just a little bit less obviously sensuous (the styling ‘Unison Research’ uses is out rightly obscene I would call it naughty - but nice). It is like a slightly reserved British variant of the styling ‘Unison Research’ is so fond of.
I love the styling. So did my friends who where around on Tuesday for a long pre-scheduled listening test on interconnects and mains cables.
If you always have a problem sneaking these black boxes past your spouse or girlfriend, she will love this amp. for its looks, with the optional bits fitted. She will probably allow you to leave the amp. out in the open (best high up on the rack as no valve cage is provided). Which is just as well, as this amp is pure Class-A, it runs hot. Real hot. So you do want to keep the amp. out in the open, well “aired".
Having checked the mains-transformer temperature; I do note that (like Gustaf mentioned) that the transformer is VERY hot. Not hotter than some other transformers I know about. Not hotter than at least the one of another inexpensive valve amp. kit I know of. (Much improved New Transformer supplied now!)
Nevertheless a little hotter than I like. However speaking strictly as engineer it is perfectly safe and not as hot as to endanger the lifespan of the electrolytic capacitors. Specifying a more powerful (and cooler running) part would have probably driven up the price quite a bit. So unless your listening room has regularly temperatures in excess of 30 Degrees Celsius the Edison 60 with one mains transformer only is just fine if hot...(Much improved New Transformer supplied now!).
But we were on about listening. And sound.
I dropped the Edison 60 straight in at the deep end.
Not broken in it replaced my (tweaked to the hilt and then some) rather good Marantz power amp. This amp. is quite amazing, transparent, without harshness and tremendous bass control. It’s only fault is that it is a very “literal" amplifier....
It recounts the recording, but a bit soul-less. Still it manages to impress the heck out of a lot audio-buddies, specifically the 2A3 and 300B crowd....
In addition my speakers are any small valve amplifiers worst nightmare. Very similar to the Wilson Audio Watt/Puppy combination they are usefully efficient, but need an amp. that can control the woofers....
Why am I explaining all of this? Because I think my criticism of the basic Kit's sound should be seen in context. I have taken a nice small and inexpensive valve-amplifier kit and dropped it into a “serious High-End System". This is not the most likely company for the Edison in its basic guise.
Now for the “meat". Immediately after cueing up some music it became clear to me that my system had just obtained a very notable improvement throughout the mid-range and in it's spatial presentation....
Everything was more natural, free flowing. Well pretty much what one does expect from good valve amp.
The three dimensionality given to the music was specifically startling. I have always thought of my own system as being rather good on sound staging and imaging, with (within the constraints of the living/listening room) very good depth and lateral spread.
Seems I was wrong about that. The way the Edison made the walls of my living room disappear was positively amazing. While listening to more music, slowly some small shortfalls presented themselves.
During our listening session on Tuesday this became somewhat more evident. With the aid of my friends we came to similar conclusion about the sound of the Edison 60 connected up as the basic kit.
The Edison 60 is a very entertaining amplifier. It makes listening to music very enjoyable; it does however lack a certain degree of low-frequency control and transparency. This really is hardly surprising and in no way gets in the way of enjoying the music.
However, larger orchestral climaxes showed that there was too much too loose bass while for example cymbals where slightly smeared. At the same time the mid-range is absolutely glorious and hint's that the Edison 60 has “more than just an arm up its sleeve".
Considering the price of the kit we all were quite impressed. In the end however, my solid state Marantz amp. went back into the system for the rest of the afternoon and evening. Simply the superior bass control and transparency of it allowed us to more clearly and easily distinguish between the different interconnects and mains cables we tried to rate.
The Edison 60 BTW is a “connoisseur" of mains cables, refusing to give the best it had with either normal cables or Kimber mains cables. Using my own “UBYTE-M" mains cable (very similar to Synergistic Researches AC-Master Coupler) provided a surprisingly large improvement.
I could stop here, simply state that the Edison 60 is indeed a fine amplifier and a good buy for the £459 GBP asking price (that is about $700 USD).
I would probably recommend a nice and not too expensive 2-Way speaker and moderate CD-player for a very nice stereo system at a fairly sensible price. I would probably suggest something like the Mordaunt Short MS-25 speaker and the Marantz CD-67 MKII CD-player to form a system for a little over £1000 GBP.
I would recommend the gold Fronted Marantz player as this would compliment the (optional) stainless steel top of the amplifier nicely.
Well here you go. I just could leave it there.
But I can't.
Slightly dissatisfied with the performance I decided to pull out all stops with the Edison 60. I enabled the second set of PSU and mains transformer, enabled the additional capacitors on the PCB. Not in hum reducing mode but to bolster PSU capacitance and introduced a smattering of 2.2uF 630V Foil & Film bypass capacitors across the coupling capacitors.
I then eliminated the negative-feedback and the cathode bypass capacitors on the input, in order to reduce the now excessive gain. As the output stage was already wired as Push-Pull Triode I left it at that.
I dropped the amp. back into my system and was knocked out. While a tiny hint of overhang persists in the bass, the amp. now has a more solid bass performance on the 8-Ohm output tap than prior to the changes on the 4-Ohm tap.
Pacing and speed took a major step forward. With the negative-feedback eliminated the treble opened up and has become way more natural. The decay on cymbals is unbelievable. Where before sound staging was wide and deep but slightly fuzzy, now it is acoustic holography.
Without any reservation, this fully loaded Triode Push-Pull version of the Edison 60 is the best Amp I have had in my system so far. And I had quite a few. It is highly recommended.
Having just looked at the most recent price list I noticed that Graeme Holland (Audion’s CEO) has introduced the Edison Plus special. For a list price of £549 GBP (about $850 USD). This includes the stainless steel top/front plate, the second mains transformer and PSU board.
If you can find a few nice small bypass cap's or the money to buy the foil & film capacitors sold as upgrade, you could be listening to pretty much the same amplifier I do now for that. And believe me, you will be amazed.
End of Rave.
I will play around with the SE mode soon, but at the moment, I just want to listen to some more music, let the components break in further and quite frankly enjoy the music.
More from Thorsten with the Edison 60 kit with 300B’s this time:
Converting the Edison 60 Amp to 300B Output Valves by Thorsten Loesch
This 300B Parallel Single Ended (PSE) Amplifier is based upon the Edison 60 Amplifier Kit which is made by Audion. This modified Version uses the PCB's from the Edison Kit with only minor changes. The biggest changes are in the PSU. The driver stage is similar to that of the Audio-Note P4 and the Audion Silver Night. The input valves found to sound best were old production Tesla E88CC (goldpin) (supplied by us) and General Electric 6CG7 (think of it as a 6SN7 in a 9-pin bottle). In general there is nothing unusual about this circuit
The rectification is solid state with extensive filtering.
A pair of Svetlana SV300B valves per channel produce about 18 watts per channel. Heaters are all AC, the noise on the Output is around 2mV. The sound of the Edison Amplifier with 300B Output Valves in PSE zero feedback operation is more alive, more vibrant and dynamic than when using the EL34. The high range is sweeter and all in the Amplifier is consderably improved. Highly recommended.
At Audion, we can supply most of the extra components listed here including the 10 henry choke, valve bases and most of the passive components but not necessarily those listed above. Our mains transformer is new and much higher rated than previously and will not generate as much heat as the previous one did.
The above circuit can also be modified for use with the 2A3 tube very easily - we can supply components and details if you require.
Another review from Julien M of Audio Asylum
Here's my review of the Edison 60 Mk2 kit from Audion. It's a 6922 and EL-34 based class A integrated amplifier.
This kit took me a long time to assemble since I've done major parts upgrade based on my experience with my Jolida 502b modifications. I've decided to have faith on the design and built the ultimate (in parts quality) Edison 60 I could afford. I've taken a lot of attention to detail to make as perfect an amp as I could based on the original design. All these obsession made the price more than double (roughly $2,500 total) and it took me about three weeks of non continuos work (I've been very busy at work). The extra time was mainly due to fitting these audiophile parts that are much larger than the stock ones. A little re-routing on the PCB was needed as well as enlarging many holes. I also wanted to enjoy at maximum my building experience, so I worked slowly and very carefully.
I've also used brass screws for holding the PCBs, EAR damping material on the chassis, and Marigo dots on PS caps and PCBs.
Some other difficulties were encountered mainly because of inconsistencies on the assembly instructions. The mains transformer have a different wire color coding than specified in the manual. Also, in my case I got the two power supply PCBs without any markings. Dave from Audion faxed me the PCB diagram but there was a mistake which made me invert two diodes. The result was a blown fuse at first fire up. This was fixed after closed inspection of the assembly and schematics. Apparently this problem have been fixed.
Among the many configurations possible (PP or SE in ultra-linear, pentode or triode), I've chosen to wire the Edison 60 in push pull triode. I'm not sure exactly how much power it can deliver in PP triode but the rated power in PP UL is 30W per channel.
Now, the sound:
A little note about feedback and bypass caps:
In conclusion, I couldn't have spent my money and time more wisely. The Edison 60 elevated the quality of my system a great deal. It's a true high-end amplifier. My system has never sounded so good. Its level of musicality is breath taking. I'm enjoying my CD collection as I've never had before. The Edison 60 is an extremely involving little amp. Highly recommended.
The Edison 60 Kit can be ordered by emailing us at the following address: firstname.lastname@example.org or alternatively buy online NOW! using the PayPal option shown above.
The Edison 60 Kit can be ordered by emailing us at the following address: email@example.com or alternatively buy online NOW! using the PayPal option shown above.
This page will be updated with information and specifications soon when the kit will be available for purchase. Picture is of first prototype. Expected price 999.00 GBP. Due to current volatility in material costs the release date is currently on hold until pricing stabilises
Kit almost ready, due to write instruction manual soon, and waiting final metalwork parts.
The preamp kit will released as line level only, with passive switching between inputs. Later, by a line level with phono stage to cater for those of you using vinyl. Anyone purchasing the initial batch of kits that are line level only need not worry, as they will be fully upgradeable to the line/phono version with a couple of add-in boards and few modifications.
Having spent time redesigning the chassis to accomodate the phono stage, its plans are now with our metalworker to have a pre-production model made available soon. We are trying to get a modern, yet, at the same time retro look that will be stylish, functional and above all else “a sound investment”.
Specifications and full pricing to follow......