I had a Joule LA 150 mk II in my system for a summer while awaiting repair of my main system line stage. I seem to remember that there were jumpers inside the cabinet that could change the output impedance of the line stage, but without an owner's manual or some direction from an owner, I wouldn't try to advise you. I gather the company is no longer- there is one web page that collects some info on Joule equipment but I didn't see anything about this in the quick perusal I did. I'm confident an owner with a manual can help you.
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I owned both of these pieces, but not at the same time. The 4004 MkII is a very good value for the money and has held its value amazingly well. The 4004 MkII has a low'ish input impedance of 22K ohms (similar to some Pass amps). The LA-150 MkII has adjustable output impedance of either 400 or 1200 ohms. Most believe a ratio (input/output impedance) of 20 or better is sufficient to prevent audible frequency roll-offs, and some say a ratio as low as 10 should be sufficient. Your proposed combination should work fine together and you can experiment with the Joule's jumper to determine which output impedance sounds better. One caveat, many manufacturers report the average output impedance or the value at a frequency of 1,000 Hz, while the highest value can occur at the lowest frequencies, particularly with preamps that use an output coupling capacitor. Not sure about the Joule but in any case the 400 ohm setting should work fine for you. |
Klipsch claims 101 db sensitivity on that speaker. I suspect that won't work well with the Aragon. The reason is that the amplifier will be operating for the most part at very low power. Most amps like this make more, not less, distortion at powers of less than about 5-7% of full power, which means that you won't be able to hear what the amp can do unless you play it too loud for comfort. I recommend an amplifier of less power; no more than 60 watts for sure. If you want to go solid state, some of the First Watt amps made by Nelson Pass would be a better choice, and the JA can drive them just fine. |
@foster_9 I think I can help. Reach out to me via e-mail and I can e-mail you a 150MKII manual I have in PDF (the manuals were often copies of copies, so some pages may not be easy to read, but it will do the Job). My Joule Info web-page ( http://sigsound.com/classic-product-info/joule-electra-info-page/ ) has a bunch of product info/literature, but I don't have any manuals up there yet though I do have a number of them (I think they are a few I still need to scan in). The jumpers in question are the two located towards the rear of the circuit board. The default higher impedance setting is the jumper used on/across the front two (of three) pins. The lower output impedance setting is with the jumpers on the rear most two pins. P.S. Yes, Joule-Electra is no longer in business - Jud retired and close up shop several years ago. I do provide service, support, and upgrades for Joule-Electra gear (even though it can be very challenging to work on gear with next to no technical documentation!) Feel free to reach out to me via Audiogon or e-mail, phone etc. I'm not on these forums alot, but will get any audiogon messages. Cheers Rich |
Good catch Ralph. I was not even looking at the speaker interface and simply got lost answering the Joule/Aragon compatibilty question - sorry foster. If I were driving Klipsch speakers with a sensitivity of 101 db, I would look hard at a tubed amplifier such as an S-30 or the M-60 monos (both made by a pretty good company) or the First Watt amps (great recommendation) if SS were the goal. The nice thing about high efficiency speakers is that the power then becomes relatively cheap. I have long driven fairly inefficient speakers so have ended up with large SS amps of which the Aragon was a stop along the way. If money were not the object, and I didn't need a bunch of power but wanted a SS amp, I would like to try the Class D SPEC amplifiers....but I digress. Will the Joule/Aragon combo work, yes, will it sound best with the Klipsch speakers, probably not for the reasons Ralph states, but it will sound good with other less efficient speakers. |
If you really are thinking about vintage, Dynaco made a wonderful little amp called the SCA-35. Its class A and makes about 15 watts per channel. If you find one it would have to be refurbished, and there are several inexpensive mods that will give it slightly more power with slightly less distortion. Unless you have an enormous room, this will be plenty of power with speakers of 101 db. |
@atmasphere Boy Ralph, that brings back some (fond) memories! Me and my older brother shared one of those in my early teens. My dad picked it up used - basically it was my first amplifier! No wonder I like tubes so much! I have to imagine a refurbished one with some updates/improvements would be pretty sweet on a pair of HE speakers. |
Interesting about the SCA-35 since I have high regard for both Ralph and Rich. My first stereo included Dynakits which I built, although not the SCA-35. Still, due to nostalgia I read comments on the old Dyna gear from time to time. From that, the one piece of tube gear with the least respect seems to be the SCA-35. So now maybe some of those folks were not well informed. At some point years ago I ended up with a SCA-35 and FM-3 from some trading. I also had a Lowther corner horn (one channel only) which I used to demo the Dyna components. The first person to come audition them bought them. That may not have pleased a critical audiophile but it certainly was musical. ;^) |
