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Results 1 to 8 of 8. What are your thoughts on this unit? The manual Link above is copyrightwhich makes them year old gear. Based on the schematic, its quad op amp circuits – generally called jbo feedback design.
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Thats older tech, and not as clean as the better designs of today. If you can get one cheap and spend some money to jjbl up the power supply caps and such, its probably fine, but if you want to upgrade from what you have – there are better crossovers around.
Have you seen Bo’s comments on his system? Originally Posted by wpod. Greetings- I ‘ve been using a JBL M electronic crossover for biamping my s for about the last two years and have been quite pleased with the results. I would anticipate an audible difference.
Without mods I can hear ScottyJ coming down the hall already Still would be biamping? Came running from down jbll hall, thanks Grumpy!
Stock, its untity gain in and out. Power supply, mfd axial 25v caps stock, good to upgrade to an axial mFd 50v cap, there are three to replace. You may want to consider better diodes high speed, soft recovery, Vishay diodes come to mind for the power supply rectification as well.
Gain, both input and output IC feedback loop resistors should be changed to increase available gain, how much is the question! There is a row of yellow “Century” brand caps, I think these are film caps, and they can be upgraded to a better quality cap, will make an audible and positive difference. IF you increase the output gain, there are thru holes for additonal disc capacitors in the quad IC feedback loops, stock units have four 33pf caps, and two for the last TLO84 IC, upgrade by adding the additional caps in the the trhu holes already provided, same value.
You could use silver mica disc caps, said to be superior.
Some prefer the with the output transfomers removed from the signal path, this may or may not be to your liking. The had a nice sound, and with work, still does, IMO, BUT, know this, there are crossovers avaialble today that legitimately surpass that crossover in sonic traits. I have found that although my modded ,s have an enchanting sound for analog, vinyl playback, it is NOT always the best when it comes to playing CD.
Another thing, is while I still do love the sound of theI love it with certain speakers, and NOT with others. So, not knowing what amps, and speakers you have, I dont know what I would tell you as my 1 nbl.
If you have vintage speakers, that are less highly resolving, you might like the coloration the produces. But, it is coloration, for sure. Another thing to point out, is jlb although the Urei can produce what I call a charming sound, hit it a bit too hard, you will hear the IC,s distort. Fantastic power supply, discrete circuitry, and high quality components, with superb engineering at work here.
Then, another thing to consider is the state variable filter frequency controls of the and m5552 level attenuator pots. That is a known problem with the I mean, if you have an excellent tweeter, and your crossover point is hz, you want it to be hz, not hz, or changing drifting on jb, own.
You will also want to have the silver contact wafer switches cleaned. Sometimes, its a bitch getting the EXACT setting you had when you futz with the trying to dial it in to sonic perfection.
Yet still another known problem, most ,s had waffle IC sockets, so, the IC plugs into the socket, and these can be intermittent. Sometimes, you lose the output on ch 1, ch 2, ch 3, etc, and a tap obn the faceplate brings it back. Jbbl would have a tech solder the IC,s directly to the boards IC pinouts, or you can do it yourself if your handy with a soldering iron!
IMHO, a “WORKED ” Ureiin the right system, can make some enchanting sounding vinyl playback, but, I’m telling you the known problems of the unit, as well as the fact that I feel that sound can be, and has been surpassed today, especially for ,552 playback of Cd and downloads. I, personally, have been a long time urei user, AND Jjbl loved it back in the vinyl days.
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However, I have moved on, to bryston, and I havent looked back yet. As well m5522 any frequency you desire can be dialed in, and the output level controls allow one to find those in between settings, unlike detented controls with their factory settings in 1DB increments. If you find a mintM55 will be more than happy to pass modification info to you, and whatever assistance you want, to achieve the best you can get from the If you would like to talk further on the pro’s and cons of the what I think are the ,s strong and weak points, please feel free to PM me, I am happy to try to help!
The one thing I k552 disagree with about current trends in filter technology today, is slopes, I like 12 and 18 DB slopes. I do not like 24DB slopes.
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I find 24Db to not have quite enough overlap between filter bands, sometimes 12db too much. However, this is also VERY dependent upon your speakers and their design. With just about EVERY speaker I, and my friend, who also does commercial audio, we just find 18db Butterworth filters allow us to create a much more seamless sound with 3 way or 4 way active setups.
This flies in the face of current engineering trends and practices and is to some, highly questionable, but, we find the sound between the ranges to gel together seamlessly, and eminate as ONE using 3rd order butterworth filters, BUT higher order slopes 24db, 36db 48db, etc jb a sound that to our ears, make the ranges BASS, MIDRANGE, HIGHS sound like they are sparate from each other, and lacks the seamless image I consider natural sounding.
Of course, 24db slopes, and higher, allow higher power to be used for compression drivers and tweeters, but, unless your doing HIGH POWER commercial sound, I don’t think this is a problem for you. The other thing about 24db slopes, is they are acoustically in phase at crossover point, ,552 is considered out of phase at crossover point.
M52, 18db Butterworth sums flat at unity, which I m5522 sounds nicer.
TODAYS top quality crossovers, like Bryston, have selectable slopes, and the dsp crossovers have 6,12,18,24,36,48, and 52 db slopes, as well as one dsp unit having db brick wall linear phase filters available. DSP crossovers also have the option of selectable jlb types as well. I just am not totally into digital crossovers at this time, but, at some point, I feel they will jbo it to the point where I believe digital crossover filters will become indiscernible, sonically, from the best analog filters.
Originally Posted by Baron Without having ever seen a urei schematic, upgrading from 1,mfd to 2,mfd caps should reduce the hum level by about 6. And I am basing this value solely on the estimated reduction of the power supplies ripple voltage. When dramatically increasing the size of the power supply capacitors, it is certainly a good idea to also increase current handling capacity of the rectifier diodes.
During start up the initial surge current will be higher with the much larger capacitors, which could potentially over load and fry the original rectifier diodes. So, if you are going to change the caps, then change the diodes as well. Otherwise, your project could go up in smoke. Seeing as that was almost a decade ago, I wouldn’t wait up for a reply.
Earliest JBL crossover with hi-frequency level control? By glen in forum Lansing Product General Information. All times are GMT The time now is Extra Tabs by vBulletin Hispano.