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Custom EL84 Based SEP Monoblock Amps - KS


Jonathan Wood

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Sold sold sold

These are amazing amps. I'm re-posting the info that the builder posted when I bought them... he tells it way better than I do. What I can tell you is that these amps are AMAZING. I ran them with my Klipsch KPT-904's and they just make music, beautifully... plain and simple. These make about 5 beautiful watts per channel.

PICS BELOW

The bases are solid maple with bubinga splines on the corners for a nice detail.. I'm not a pro woodworker... but they are pretty nice. I rabbited out the top to recess the top-plates as well as the bottom and added a thin piece of ply to cover the electronics. I also added some small aluminum feet with rubber inserts to make them easier to pickup. There are a couple small flaws in the wood if you wanna really bust my chops, but not bad. I finished them using Osmo Poly-X oil.

The only reason I'm selling them is cause I've simplified this system and gone to an integrated amp instead. It's not a step up at all, but it works for my current situation. I wish I could keep these, but I just have too much gear around and I need to let them go to a new home where they will be used and enjoyed.

$1250 Shipped.

PP Gift preferred or buyer to pay fees

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Here's what the builder had to say about them:

Redboy EL84 amps

Build Pics Here >> http://s176.photobucket.com/user/whobody/library/KeggerAmps?sort=3&page=1

Build Thread Here >> http://audiokarma.org/forums/index.php?threads/finished-kegger-designed-se-el84-monoblocks.300554/

These little amplifiers have been a mainstay of my system for over four years now, but it’s time for someone else to enjoy them.

These little amplifiers have been a mainstay of my system for over four years now, but it’s time for someone else to enjoy them.

What are they? Why, they’re SEP Ultralinear EL84 monoblocks, of course! The circuit design is Kegger’s work, but the build is all mine.

First, a little history to bore you…

I’ve got a soft spot for the humble EL84. My first exposure to the single-ended tube sound was a cruddy little stereo EL84 console amp that I picked up for $10. It was a budget brand, no-frills, cheaptastic uglybox that I recapped on a whim. Good soldering practice, I figured… When I fired it up for the first time, I was absolutely floored by the sound! It was a game changer, and it wasn’t long after that I built my first amp, an SE 2A3 stereo amp.

The 2A3 amp was very nice but I loved that little EL84 amp. I built clones of it, and I tinkered with parts selection. It sounded great and it got me to wondering: what would a “proper” SE EL84 amp sound like? While the 2A3 is a darling of the SET world and often gets built into modern kilobuck audiophile amplifiers, the EL84 has a reputation as just a "good" tube. It’s better known for its use in grungy guitar amplifiers, consoles and push-pull tube receivers from the vintage HiFi era. Many people's assessment of it is based on their experience listening to an old console amp, with cheaply wound output transformers smaller than the average deck of cards.

Most people haven't heard the EL84 treated properly, so that was one of my design goals: I wanted to see if this little tube could play with the big boys if it were supported by a robust power supply, quality output transformers and audiophile-approved components. These amps are the result.

The power supply is really overbuilt (the 125mA Edcors barely get warm). It’s a tube rectified, dual choke design without any electrolytic capacitors. It’s not a true choke input supply but it is close – the first capacitor after the EZ81 rectifier is a lower value film cap used more to “tune” the voltages than for any filtering. There follow two 8H chokes and two 50uf ASC oil-filled polypropylene film capacitors in LCLC configuration to round out the B+ supply. A third ASC capacitor (40uf) supplies the input tube.

Output transformers can make or break a single-ended amp. These are from James Audio: they’re a high quality potted iron known in DIY circles for very good performance.

I used my favorite Kiwame resistors and the coupling caps are Mundorf silvers. Good stuff all ‘round.

The amps will come equipped with a nice selection of vintage glass. Tube complement is EL84 power tube, a 6AU6 driver, and an EZ81/6CA4 rectifier.

How do they sound? For reference, I’ll compare to the 2A3 amp I had. They've got distinctive tonal traits, but the two tubes are more similar than they are different. The EL84 excels at high end detail and is very sweet in the midrange. It has good tonal balance across the audio spectrum. The 2A3 is excellent in these areas too, and might have a slight edge over the EL84 in its ability to throw a larger soundstage... maybe. If I were pressed to choose between the two, I would probably pick the 2A3 but it would be a tough choice to make.

I’ve paired these with some very nice speakers over the years: they have driven Edgarhorns and Tannoy Golds, SABA Resos and most recently my Feastrex field coils. They spent a time driving Altecs 604s, and they’ve traveled to a couple of audio meets where they played nicely with Klipsch and some Altec/JBL homebrew horn contraptions.

PICS:

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Edited by Jonathan Wood
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I've got one of Nate's EL-84 amps.  Its this little guy right here.  LOVE LOVE LOVE the way it sounds.  Nate really has a talent for making great sounding stuff. 

He is a very talented guy. I'm tempted to keep these and just build some little full-rangers to use with them... only problem is it seems like overkill when the only place I really have to use a system like that is in a bedroom. So I think I'm better off passing these along to someone who can REALLY enjoy them.

 

- Woody

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