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DavidR

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Posts posted by DavidR

  1. My original tweeter 200011-1 went OL on the voice coil and the other is the 200084-1 replacement that works well. I decided to go with the Midwest Speaker replica/replacements just so they would match.

    Today I got my two Midwest Speaker tweeter replacements HERE

    I'm disappointed with what I got. They do look very much like the original driver. The hook-up blades on one were bent; the other had one bent and the other loose. They were very nice when I called the Returns Dept. They offered to let me return them or $20 off if I wanted to epoxy the terminal that was loose. Both gave me a vc measurement of 4.1 ohms so I said let me listen to the one without the loose terminal. I will say that they sound VERY much like the AR tweeter except output was a bit lower. I also thought the upper treble was missing so I got my Test CD and started to listen from 6000Hz @ -10dB and up. All was good until about 14kHz. I thought the output of the Chinese replacements was lower. I then went to 18KHz (I had to turn up the volume for my old ears to hear it) the AR was good. No sound from the replica and then a loud 'snap' and no sound again. They are going back. I might try another pair.

  2. The phono box sat half done for a longtime. I had a bad slip and fall on ice while walking the dog just after Xmas. Landed hard on my pelvis. Was in bad shape for a while and then mega-bursitis  hit my left shoulder requiring cortisone shot. I don't know if you can see it but the box has a sliding plexiglas cover. Much better than stuffed into cubby holes in my desk.

  3. Got one done - FINALLY!

    I finally got around to the 10Pi speakers. I had to get some other things done that have been on the bench. One was a box I made for my phono cartridges. The AR10Pi xovers were difficult because of limited space and a LOT of wires. I had to do it in steps as I use goop to hold down the caps and resistors. So it was glue one or two pieces and come back tomorrow to wire and solder. I guess I got the wiring correct as it WORKS!!! The reason for the piece of blue tape at the end of that red wire in the center is because its supposed to be blue according to the schematic.
     
    I noticed that the 100 and 2500uF can caps had a PLUS (+) mark at one of the two terminals. As they are NPE caps I was wondering if this indicates either the inner or outer foil?
     
    Some of the screws were rusty so I picked up some stainless steel screws AND they were a bit cheaper than (a few pennies less) than the black oxide.
     
    Now it's off to do the second speaker.
     
    Oh, and they got new 5-way binding posts.

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  4. Stimpy, There's a pic above of the xover.

    I'll hold onto the one that tested OK and when I get to the 9's I'll see how those measure. Maybe I will find one good and one bad there too.

    I have no idea how good or bad the Bennics are compared to a Callins.

    Very hard to work on the 10Pi. Lots of wires and little room between points on the terminal strip. My eye sight is poor and that doesn't help. One step at a time right now. Got the 15 ohm resistor replaced and waiting for the goop to harden. Will solder it tomorrow and then on to the 40uF cap.

  5. I got the 2500uF unsoldered and measured it with my Agilent U1733C at 100 and 120Hz. It will not measure that size at a higher (i.e. 1kHz and above) frequency.

    OLD 2500: 2465 @ 100Hz; 2462 @ 120Hz

    NEW 2500 bundle: the 3 caps measured at 1kHz added up equal 2417uF and measure 2429 @ 100Hz; 2426 @120Hz.

    Based on this data the old 2500uF is still good.

    Should I use the new ones or go with the old one?

  6. I finally began to work on the xovers in my 10Pi speakers and it didn't take long before I ran into an issue. Attached is a picture of the xovers and the 100uF has a black and red wire on the same terminal. WTF? This red wire comes from the terminal board and goes over to the cap and then the transformer. I've looked at some diagrams people have posted and it does show a blue wire. Do you think they just used the wrong color?

     

     

    10pi_xo3 - Copy.JPG

  7. Dave did mine as well. I wanted all resistors changed to 1% metal film but he wouldn't do it. He did change 2 in the audio signal path. I also would have preferred something other than Sonicaps but that's what he likes to use. BIG difference in SQ; especially treble.

    Did you ever A/B your ported 901's to the acoustic?

  8. On 3/8/2018 at 11:24 PM, ra.ra said:

    David, sorry to hear about your power outage. I'm located a bit closer to city center and was just saying earlier today how thankful I was that we've retained power in these parts. Those were two hellish storms in the space of one week.

    Sounds like the time to rely on low wattage amps. :P

    My wife and I want to relocate and are now only looking at houses in areas that have all underground utilities and no big trees near the house. We will also have a Generac whole house generator.

    I'd never run an amp off of a generator. Dirty power and tend to run at high voltage - 130v to 150v.

  9. I spoke with a buddy that has an electrical back ground so I guess I'll answer my own questions.

    On 3/3/2018 at 1:39 PM, DavidR said:

    > Does anyone know if the 20uF is in the circuit when 4TT is selected ?

    The 20uF capacitor is open circuit (not in use) when the woofer switch is in the 4TT position. But is in parallel with the 100uF in the other 2 positions.

    On 3/3/2018 at 1:39 PM, DavidR said:

    > Also, what is the 10 ohm resistor doing to the xover circuit where they put it across (parallel) the cap leads of the 2500uF cap?

    It is lowering the cap resistance. Just like when you put (2) 10 ohm resistors in parallel you get 5 ohms and when you put (2) 10 ohm resistors in series you get 20 ohms.

    On 3/3/2018 at 1:39 PM, DavidR said:

    > Will a 22uF be OK to use in place of the 20uF cap?

    It's at the top end of the 10% tolerance and probably would be OK but I'll see if they have any that measure low.

     

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