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Audio Note L4 Series Power Amplifier - EL34 Edition
EL34 Push-Pull Hi-Fi Power Amplifier - 35W per channel
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We have been selling single ended amplifiers since we started the kit business and I always felt that push-pull was just not in the same league. However, when we finished the first prototype I was absolutely stunned by the sound - I had this look on my face and Andy could see that my push pull vs Single Ended ideas were now seriously being challenged. He told me that push-pull designs get a bad rap because most of them are not designed properly. In the case of the L4 amplifier, Andy had custom designed the output transformers and then designed the circuitry and then spent hours optimizing the circuitry for the most absolutely tuned sound. The result is a spectacular amplifier with 35W of Class AB1 power.
But the sound is enormous - warmth, detail and amazing slam - Andy explained that anybody who replaces their current amplifier with the L4 will be blown away...”
See the bottom of this page for a link to Andy Grove's write-up and description about the L4.
Brian Smith
This is a very rugged EL34 Based Tube Power Amplifier operating in Class AB1. We are squeezing 35W of pure smooth and warm EL34 wattage out of this unit. The driver section for each channel consists of an ECF80 tube. This part of the amplifier (the driver stage) is a high quality thick PCB with highest grade copper tracks - The feedback and compensation circuitry is on this board - and makes for a straightforward build!
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Drive Board schematic
For ultimate sound reproduction the EL34 section is hardwired with our custom aluminum plate. We have also just introduced a heavy-duty PCB version of the EL34 section that makes for a simpler build - see below for more details.
We are shipping JJ EL34's with the kits as we feel these offer one of the best price/performace ratios.
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The power supply uses a huge Mains transformer and choke along with some ultra fast diodes to supply the AC filaments to the driver and power tubes. An optional Mundorf M-Cap can be simply connected to the circuit as an optional high qulaity upgrade (or you can buy your own and add it at a later date if you wish).
The L4 EL34 Power amp chassis is made of ultra strong 3mm aluminum powder coated black. It is the same width and length as our pre-amplifier and DAC chassis but 40mm taller. The cover is well ventilated for airflow on the sides and top.
Once the ultra heavy duty PCB's are populated it is a just matter of inter-wiring with the Power Supply and the EL34 section. We are providing a large schematic on a 3'x2' sheet that shows clearly all the detailed schematics and inter-wirings between modules. The Manual also takes you on a complete test procedure (AC, DC, and amplification factors) with dummy loads provided to ensure a fully working amplifier prior to connection to a system.
Hardwired version of the EL34 output section
The new L4 EL34 based Power amp is now available with a PCB for the EL34 section or Hardwired.
The newly introduced PCB is a thick board with large traces for Filament and Power/GND - this makes for a really easy build and interconnection with the driver board and the output transformers!
Simply specify your preference when ordering.
PCB version of the EL34 output section
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We supply a very large (3' x 2') printed schematic showing the full circuit and all its connections that can be referred to throughout the build process.
This, coupled with its detailed manual and wiring digram (see below) ensures a trouble-free build. |
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Here we see the overall wiring scheme for the kit builder - Once the power supply, driver, and EL34 HW sections are completed, the builder will perfrom the inter-wiring between the modules which are clearly marked on the circuit boards.
A full size wiring diagram is supplied along with the manual. |
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The unit weighs about 35 lbs and measures 14"x15"x 5" and comes in a 3mm thick aluminum chassis power coated black.
An attractive faceplate on the front matches the AudioNote Kit line of products and is an ideal match with an L2 or L3 pre-amp! It is shown here matched up with our L3 Line Pre-amplifier.
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We are making available a fast download / low resolution copy of the instruction manual so you can see for yourself the quality and detail of the build instructions.
You will, of course, recieve a high resolution printed manual of the latest version with your kit. A CD containing all high resolution manual pictures is also supplied with each kit. Click here to view the manual. |
We have completed our Beta period for the new L4 amplifier and making the unit available shipping June 15.
| L4 EL34 Standard Version | $1,650(USD) |
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| L4 EL34 Signature Version | $2,050(USD) |
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32x Audio Note 1/2W Tantalum resistors |
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4x Audio Note Copper Foil Film Signal Capacitors |
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cathode Black gates |
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4x EL34 cathode black gates |
| Mundorf Power Supply Cap Upgrade | Add $125(USD) |
| 10 Guage Power Cable | Add $125(USD) |
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Brief History
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The new EL34 stereo CLASS AB1 amplifier from AudioNote Kits was designed by master craftsman Andy Grove of Audio Note UK – This amp is near & dear to Andy’s heart and he has used many years of amplifier design knowledge to come up with this awesome new EL34 tube amplifier for the DIY market! As one customer recently put it – it sounds ridiculous! (that means very good!)
I asked Andy to write me an article on how the design came about – what were some of the reasons you went with the Pentode wiring instead of the Ultra linear mode as used in the famous DYNA ST-70 – Its been about a year of R&D from the development of the output transformers, the overall circuit design– the prototype building, the tuning and optimizations of the circuits, the partitioning of the circuits into hardwired and PCB – the overall layout of the amplifier, the manual and all the parts sourcing – the end result is a DIY kit of the highest quality with amazing sound results! At 35W it is very flexible and running in CLASS AB1 it has many of the benefits of a single ended sound with the advantages of push pull!
Below is Andy’s article – Enjoy!
Brian Smith
Quite an achievement this amp, I find it hard to even drag my old one out of the cupboard now. So Andy (Grove) was right - this is a new type of sound - full of punch.........soul..........and detail! Yet it carries loads of finesse as well !
Quentin Gore-Rowe
"I just want to say that I've spent the evening with the most wonderful EL 34 amp I can ever imagine. I just listened to Ruggiero Ricci on a London Blueback totally mesmerized by the performance. I just couldn't move. I switch to Alison Krauss - So Long Wrong and am equally impressed." --- I find it extremely engaging.
Great job!!!
John Geisen
"One of the fantastic things with this amp is that it has a lot of body and weight in the sound. And that is without losing any detail. And the dynamics will totally rock your socks off! To this day I have not heard an amp that can perform as the L4. Playing that good in all levels is something I have not heard from any other amp so far. And I have had many really expensive amps tested in my system!"
"an amp that gives you a huge soundstage, transparent full bodied sound and totally kicks ass"
See Olof's extreme build by clicking on the pictures below:
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Olof Lilja
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