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Modding the Pyle PAMP1000 (and some Soldering Lessons)

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  • marstedt
    replied
    Looking at picking up a few of the AMP-100. Any comments on alternative opamps for the out-of-stock lm4562? I think there's still some stock on the NJM4562.

    Update, here's the response:
    http://techtalk.parts-express.com/fo...91#post1273091

    Last edited by marstedt; 03-14-2016, 03:14 PM.

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  • silverD
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    Thanks tyger. I'll pickup the caps from Digi-Key.
    Nate

    Leave a comment:


  • tyger23
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    I'd probably go with these:

    http://www.mouser.com/Search/m_Produ...vesCT0sEX4c%3d

    The FG's are in stock at digikey if you want.

    Leave a comment:


  • silverD
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    Hi tyger,
    I just picked up 2 PAMP1000's from Menards and plan on doing the mods. I was about to place the parts order from mouser when I noticed that the UFG1E470MEM are on backorder for some time. What do you recommend as a replacement?
    Thanks,
    Nate

    Leave a comment:


  • tyger23
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    Originally posted by Pete Basel View Post
    I see that you change the main PSU caps to an excellent quality, low ESR, 105 deg C type,
    do you hear an audible difference as a result of the better caps or is it just a precaution?
    Do you see a change in measurements?
    What brand were the original caps?
    I'm looking at the very cheap Sherwood 4109 and the caps are all from Samyoung, lol!
    The original PSU caps had no name brand, and no marking as to their value. They measured at about 3300uF, which is half of the 6800uF, 50v value stated on the silkscreen of the board (and the value used in the AudioSource original design). Also, the original caps, despite their relatively large size, were light as a feather.

    Changing those PSU caps probably has no effect at very low volumes, as they were still doing an adequate job of smoothing out the power supply under light loads. However, changing the caps to the better quality allows for the amp to perform well under loads that the amp is actually rated for, and it very much improved the bass punch. Please note, however, that I changed ALL the caps on the board. After measuring the PSU caps, I didn't trust any of them.

    When re-capping an amp, I generally go for an all Nichicon solution. For the signal path, I try to use Nichicon FG or KZ caps. I prefer KZ caps when I can get them to fit. I've used Elna Silmic II's in the past, but they're a bit shrill to me. I personally prefer the "smoothness" of the Nichicon. For the power supply and bypass caps, I like to stick with Nichicon KA or KW. KA for the 105 degree stuff and KW for the less heat or load sensitive stuff. I've also used Panasonic TSHC for power supply bulk caps with good success, but I saw that they are being discontinued. That's why I decided to try the Vishay stuff for this project. I like to stay at 105 degree caps for the power supply regardless of the proximity to heat because the 105 degree caps are rated for a much longer lifespan at 85 degrees than a typical 85 degree rated cap. Enjoy!

    Leave a comment:


  • Pete Basel
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    I see that you change the main PSU caps to an excellent quality, low ESR, 105 deg C type,
    do you hear an audible difference as a result of the better caps or is it just a precaution?
    Do you see a change in measurements?
    What brand were the original caps?
    I'm looking at the very cheap Sherwood 4109 and the caps are all from Samyoung, lol!

    Leave a comment:


  • Psycoacoustics
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    Originally posted by tyger23 View Post
    I tried running these in bridged mode, and there's a good bit of hum coming through the speakers when that's enabled (and a source is connected). This seems to echo the experience that Psychoacoustics had with trying to bridge the AMP-100's. I think the issue is the obfuscated way that they route the feedback from the right channel to the left amplifier, but I'll have to experiment to be sure. If anyone's interested, I'll try and figure this out.

    However, they sound great in normal stereo mode, and they've got a lot more power on-tap than they seem rated for.
    I'm not happy your getting a hum but,,,,,, I am happy it wasn't just ME!

    If you can figure it out it may talk me into trying a couple. Later, Mark

    Leave a comment:


  • tyger23
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    I tried running these in bridged mode, and there's a good bit of hum coming through the speakers when that's enabled (and a source is connected). This seems to echo the experience that Psychoacoustics had with trying to bridge the AMP-100's. I think the issue is the obfuscated way that they route the feedback from the right channel to the left amplifier, but I'll have to experiment to be sure. If anyone's interested, I'll try and figure this out.

    However, they sound great in normal stereo mode, and they've got a lot more power on-tap than they seem rated for.

    Leave a comment:


  • tyger23
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    Here's a video showing how to solder op-amps, capacitors, and IC's. Enjoy:



    In case anyone was wondering - the soldering equipment you see in this video is:

    1. Metcal SP-200 solder station (discontinued)
    http://www.testequipmentdepot.com/me...tems/sp200.htm

    2. Metcal SSC-626A soldering tip.
    http://www.techni-tool.com/551TI134

    3. Edsyn Deluxe Soldapullt, Heavy Duty, High Vacuum
    http://www.techni-tool.com/330ED082

    4. Xcelite Diagonal Cutters
    http://www.techni-tool.com/294PL158

    5. Stainless steel precision tweezers:
    http://www.techni-tool.com/758TW450
    Last edited by tyger23; 05-03-2015, 02:42 PM.

    Leave a comment:


  • tyger23
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    This video shows how to replace the relay. You'll note that this is similar to the process I used for the RCA connector.

    Leave a comment:


  • tyger23
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    Here's one showing how to remove a resistor. This also works for some ceramic disc capacitors.

    Leave a comment:


  • tyger23
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    This video shows a technique for removing IC's like the opamps. This also works for the pots. There's also a small bit on removing a cap.

    Leave a comment:


  • tyger23
    replied
    Re: Modding the Pyle PAMP1000 (and some Soldering Lessons)

    The videos are uploading and it's taking a while. In the mean time, here's the schematics I re-created and edited to indicate which components to change.

    https://drive.google.com/file/d/0B_P...ew?usp=sharing

    Here's a video that shows how to remove the RCA connector from the rear I/O board. The technique can apply to most connectors and large thru-hole parts like the main power supply caps.

    Last edited by tyger23; 05-03-2015, 12:49 PM.

    Leave a comment:


  • tyger23
    replied
    Modding the Pyle PAMP1000 (and some Soldering Lessons)

    Main Board Reworks:
    1. Replace the snubber capacitors around the DC converter circuit.
      • Change C9 and C10 to quality film caps (0.1uF, 250V). (MMK10104K250A01L4BULK)
      • Change C3 and C4 to quality film caps (0.1uF, 100V). (MMK7.5104K100K00L4BULK)
    2. Replace the power supply capacitors with quality versions that actually measure what they advertise.
      • Replace C1 and C2 with snap-in capacitors (6800uF, 50v, 25x40mm). (MAL225631682E3)
      • Change C5 and C6 to Nichicon KA series (470uF, 25V). (UKA1E471MPD)
      • Change C7 and C8 to quality MLCC capacitors (0.1uF, X7R, 50V). (K104M15X7RF53H5)
      Click image for larger version

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    3. Remove the RF trap capacitors from the input section (C200 and C300). Do not replace.
    4. Change the pots out for better quality Bourns potentiometers.
      • Click image for larger version

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      • VR2 will change to a 100K linear taper pot. (PDB182-K220K-104B)
    5. Remove the series capacitors and short across them (C201 and C302). You can see the shorts in the picture of the bottom of the board above.
    6. Change the op amp and optimize the gain through this circuit:
      • IC5 changes to LM4562. (LM4562NA/NOPB)
      • Change R204 and R304 to 3.9K, 1%, 1/4W. (271-3.9K-RC)
      • Change R203 and R303 to 34L, 1%, 1/4W. (271-34K-RC)
      • Remove the low-pass filter capacitors C203 and C303.
    7. Optimize the gain and circuitry around the amplifiers:


    Here's what the top of the board looks like when you're done:
    Click image for larger version

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    Fix any Remaining Mess Ups (if applicable):
    1. If your left and right channels are swapped, the issue is likely at the speaker switching PCB. I had to swap my white and yellow wires. When I was done, it looked like this.
      Click image for larger version

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    Last edited by tyger23; 05-03-2015, 05:21 AM.

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  • tyger23
    replied
    Modding the Pyle PAMP1000 (and some Soldering Lessons)

    Disassembly:
    1. Disconnect all power.
    2. The top cover has 8 screws to remove. 2 on top, 2 on each side, and 2 in the back. The top cover then slides backwards off the unit.
    3. To remove the front faceplate, first pull off the volume and balance knobs. They just pull off. Then remove 3 screws on top, 3 screws on bottom, and 1 on each side.
    4. Using pliers or a wrench, remove the retention nut and washer from the volume pot and the balance pot.
    5. With the main board still attached to the chassis, it’s easier to remove the cables with the white connectors. There are 6 of these connectors. The manufacturer has glued all of these connectors with some red glue, so start by scoring the red glue with an Xacto knife (around all 4 sides). I then remove the connectors by pulling up on the top half with pliers and using the Xacto knife or a flat-blade screw driver to push down on the bottom half to separate them. I find it easier to separate the two if I wiggle the connector side to side while pulling up with the pliers. If the bottom half pulls up off the board, then you can simply push it back down.
      • X1 – the main connector for the power from the transformer – can be tricky. You need to push the tab towards the wires while pulling up.
    6. With the connectors dis-connected, we can remove the main board assembly from the chassis. Remove the 3 screws on the bottom of the chassis that are holding down the heat sink. The main board will then pull backwards from the front of the unit. Flip the main board over and lay it on top of the main transformer so that you can access the bottom of the board.
    7. There are 4 thick wires that lead from the main board to the speaker selector switch. We need to de-solder these wires from the main board. Using your soldering iron, heat up the bottom of the board where the wires are connected while gently pulling the wires out from the top side of the board. Once the wires are disconnected, set the main board assembly aside.
      • Do not disconnect the heat-sink from the main board. There’s no need to do this.
    8. Note how the rear I/O board is twisted. You don’t have to fix this, but if you want to, I’ll explain how later. Remove the rear I/O board by removing one screw on the inside of the chassis (left side of the I/O board) and two screws that are on the outside of the chassis (between the RCA connectors).
    9. Pull out the rear I/O board and set the entire chassis aside.



    Rear I/O Board Reworks (Note that these reworks keep the auto-switching circuit intact. If you want to remove the auto-switching, PM me and I'll write up some instructions.):
    1. If you want to fix the fact that the Rear I/O board is twisted, perform these steps. This is not required, unless you’re obsessive-compulsive like I am.
      • Using a solder iron, heat up the area holding on one of the 9 solder tabs of the RCA jack connector. Using a solder sucker, remove the solder around the tab. Repeat for all 9 tabs and the RCA connector should pull out.
      • When all 9 solder tabs are loose, pull out the RCA connector. Clip off the “mounting tabs” along the bottom edge of the connector. Re-insert the connector and solder it back.
    2. Replace the capacitors:
      • C108 and C109 get replaced with Nichicon KA series 220uF, 16V. (UKA1C221MED)
      • Replace C111, C112, C113, and C114 with Nichicon FG series 47uF, 25V. (UFG1E470MEM)
      • Replace C115 with a quality MLCC capacitor (0.1uF, 50V, X7R). (K104M15X7RF53H5)
    3. Replace the pull-down resistors (R126, R127, R128, R129) with metal film, 20K ohm, 1%, 1/8 W resistors. (270-20K-RC)
    4. Replace IC1 and IC2 with National LM4562 op amps. (LM4562NA/NOPB)
    5. Replace the relay RL1 with a quality Panasonic version. (DS2Y-S-DC12V)


    When you're done, it should look like this:
    Click image for larger version

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    Last edited by tyger23; 05-03-2015, 01:01 PM.

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