Music Electronics Forum - Music Electronics http://music-electronics-forum.com/ General discussion about music electronics en Thu, 23 May 2013 16:52:12 GMT vBulletin 60 http://music-electronics-forum.com/images/misc/rss.png Music Electronics Forum - Music Electronics http://music-electronics-forum.com/ Made me think of Enzo http://music-electronics-forum.com/t33196/ Wed, 22 May 2013 22:35:14 GMT Martin Rue

This seemed like a very good post and thought I'd share it.

nosaj ]]> Music Electronics nosaj http://music-electronics-forum.com/t33196/ Output line for hooking the 2nd speaker to Pyle Pro PPHP 1098A http://music-electronics-forum.com/t33194/ Wed, 22 May 2013 17:42:56 GMT What/where is the speaker output of the Pyle Pro PPHP 1098A to drive the PPHP 1093 speaker ?? The speaker has 2 strange looking 2 pin i/o jacks,... What/where is the speaker output of the Pyle Pro PPHP 1098A to drive the PPHP 1093 speaker ??

The speaker has 2 strange looking 2 pin i/o jacks, and also 2, 1/4" jacks on the back.... The powered side does not seem to have an output to drive it that I can see.

I have searched the user manual and found no reference for attaching the other speaker to system.

Thanks, CW ]]> Music Electronics CraigW http://music-electronics-forum.com/t33194/ Speaker magnetizer repair http://music-electronics-forum.com/t33184/ Tue, 21 May 2013 19:15:13 GMT A local speaker company has asked for help in getting their speaker magnetizer working again. It reportedly stopped working a couple of years ago... A local speaker company has asked for help in getting their speaker magnetizer working again. It reportedly stopped working a couple of years ago after a lightning storm, though that could simply be coincidence. It was custom built for them years ago, so all they have is this hand-drawn schematic.

Click image for larger version.  Name: Magnetizer.jpg  Views: 30  Size: 105.8 KB  ID: 23473

It's obviously a brute-force three-phase rectifier with a timing circuit.

For switching, it uses an octal plug-in relay inside the box to control the SCRs.

Based on what I can make out, the timing circuit's 20uF and 0.1uF capacitors are charged to a positive voltage when power is turned on to the unit via a large breaker box. Then, I'm guessing that when the switch (a big red momentary button on the front) is pushed, the discharge of the 0.1uF capacitor across the relay's coil is enough to trip it, at which point, the relay stays on until the 20uF capacitor discharges through the relay's 10k coil.

The other pole of the relay apparently switches to allow gate current to flow in the SCRs, turning them on. I've been told by a friend that the devices at the input are "Thyrectors," though I'd never heard of these before. He suggested that they were there to prevent spikes from getting fed back into the line.

If I help them fix it, I get free use of it for the foreseeable future. I'm thinking that my strategy should be to check the timing circuit first and them proceed to the heavier-duty components. The 20uF electrolytic capacitor in it looks pretty old, so it might have shorted.

Any advice/feedback is appreciated. With high-current power circuits like this, I understand how they work, but not necessarily the finer points of whether it's a good or a marginal design.
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]]> Music Electronics Rhodesplyr http://music-electronics-forum.com/t33184/ Electronics for dummies http://music-electronics-forum.com/t33177/ Tue, 21 May 2013 09:14:50 GMT Dear members of Music Electronics Forum, I am sorry for posting this silly question. I am moving the first steps into this subject, and I need... Dear members of Music Electronics Forum,

I am sorry for posting this silly question. I am moving the first steps into this subject, and I need some help.
I must draw the schematics for an FX loop, using op amp.
The effects loop output impedance should be 100 ohms and the effects loop input should be 100 kohms. Assume that a +/- 15 V power supply is available to power your circuit. The nominal level appearing at the effects loop output should be –10 dBV; and I should preserve the signal phase, with unity gain. I then should be able to switch it on and off.

Please, where should I start from?

Thanks in advance.

All the best ]]> Music Electronics pianolife http://music-electronics-forum.com/t33177/ JBL PRX-515 low output http://music-electronics-forum.com/t33171/ Mon, 20 May 2013 16:41:47 GMT This is one I wish I'd passed up....

Getting lower than expected output (242w RMS into 2 ohms dummy load) on the bass output at the point the overload LED comes on. The factory spec shows 400w. Sweeping the input frequency from 30hz to 1khz maintains a nice output waveform, but 242w is the most it will give.

Similarly, the High output only gives 72w at best into 4 ohms (should be 100w) with a sweep of 1khz to 10khz.

Does anyone have any service notes or has come across a similar problem with this model? ]]> Music Electronics Mick Bailey http://music-electronics-forum.com/t33171/ Part number for Boss rectangular DC connector wanted http://music-electronics-forum.com/t33151/ Sat, 18 May 2013 20:28:40 GMT Does anyone have the part number for the slotted rectangular Boss DC connector (as used on the DM-2)? Does anyone have the part number for the slotted rectangular Boss DC connector (as used on the DM-2)? ]]> Music Electronics Mick Bailey http://music-electronics-forum.com/t33151/ Behringer Potentiometer switch for DSP2024p http://music-electronics-forum.com/t33142/ Fri, 17 May 2013 10:52:45 GMT Got in an Behringer DSP2024P with the right potentiometer switch (24 clicks ?) already removed by the owner. Any idea what replacement part to... Got in an Behringer DSP2024P with the right potentiometer switch (24 clicks ?) already removed by the owner.

Any idea what replacement part to order ? ]]> Music Electronics verano http://music-electronics-forum.com/t33142/ Schematic help - Blackstar HT-5 http://music-electronics-forum.com/t33133/ Thu, 16 May 2013 16:23:37 GMT Hi guys, Having a few issues with this schematic, been staring at it for a while now, hope someone can shed some light on it for me. You can... Hi guys,

Having a few issues with this schematic, been staring at it for a while now, hope someone can shed some light on it for me.

You can download the schematic as a PDF from this link: FBM BLACKSTAR HT5 Service Manual free download,schematics,datasheets,eeprom bins,pcb,repair info for test equipment and electronics



It's probably really simple and I'm missing something blatantly obvious, but there are a few connections that don't seem to go anywhere. For example on page 2 the first diagram (top left) it says "HT_PRE" out, but I can't find anywhere that it goes into. Also on the 3rd page the schematic for connector 1 says +15V out and -15V out, but I can't see where the 240AC changes into +/-15V DC and is sent into the connector...

Also (yes there's more) around and about the schematic it says "+15V", or "-15V" or "0V" next to part of the schematic, but it doesn't look like a connection. I'm guessing this is something like a reference voltage?

Thanks for any help guys.

Jamesg ]]> Music Electronics jamesg3373 http://music-electronics-forum.com/t33133/ Trannie question http://music-electronics-forum.com/t33130/ Thu, 16 May 2013 11:22:52 GMT I'm looking for the best way to power these Raindirk modules.
http://music-electronics-forum.com/t33102/

I received an email from them regarding schematics and also a multiple rail DC PSU board they sell minus transformer. ( Shipping from the UK with trannie is prohibitive)

"I suggest a 20 - 0/ 20 -0v 100VA transformer " . Is he referring to the secondary winding voltages?

]]> Music Electronics bramley http://music-electronics-forum.com/t33130/ Mackie 808M http://music-electronics-forum.com/t33128/ Thu, 16 May 2013 02:28:44 GMT Hi, I need the monitor master volume pot for a Mackie 808M powered mixer. I have the pot out but can't find any ID info on it other than Alps 02C503. Seems to be a 50k pot but I'm having trouble locating a schematic. All I need is a part number & supplier for this part, it has a broken shaft, that's all. It's a plastic D shaft.
Thanks ]]> Music Electronics Dave Johnson http://music-electronics-forum.com/t33128/ Carvin X-amp with footswitch issues http://music-electronics-forum.com/t33126/ Thu, 16 May 2013 01:24:49 GMT Hey guys, I'm working on a carvin X-amp X-60 model. It appears to be a pretty early model, PCB# 1024B. It has an issue with the footswitch and this amp does not have the effects loop. Instead it has a switchable volume boost. Everything else appears rather close to the schematic. The FS-36 footswitch has been somewhat sloppily re-wired. The x-60 schematic I found on the Carvin site is for the model with effects loop and the area in question, around the footswitch and the CD4049UBF CMOS IC chip that drives the footswitch, is different in this amp then on the schematic. Anybody know where to get the proper schematic? What about the schematic for the original footswitch that would have come with this amp? I can't rule out the rewired FS36 as either the source or a part of the problem without a little more info. The CD4049UBF is hot to the touch within a few seconds of power-up so I believe it is cooked, but I would still like to find the proper schematic.

Thanx ]]> Music Electronics Mr Johnny Birchwood http://music-electronics-forum.com/t33126/ <![CDATA[KURZWEIL PC2X STUCKS (it's a problem !!!)]]> http://music-electronics-forum.com/t33101/ Mon, 13 May 2013 12:29:05 GMT Hi all, Yesterday I had 2 bothersome events on my KURZWEIL PC2X 1) Reset while I was playing (similar to switch off/on the keyboard) 2)... Hi all,

Yesterday I had 2 bothersome events on my KURZWEIL PC2X

1) Reset while I was playing (similar to switch off/on the keyboard)
2) Keyboard stucked.... no sound, no dial, no ENTER, ESC keys working.... I switched off/on and then it started to function again.

I never had such problems in 5 years

Did anyone get a similar situation ?
Which kind of problem may it have ?

I am worried because I have a show in 15 days
Any help is wellcome. ]]> Music Electronics ioannes http://music-electronics-forum.com/t33101/ Silvertone 528 59230 http://music-electronics-forum.com/t33094/ Sun, 12 May 2013 11:23:37 GMT Hi folks-
I'm looking for a schematic for a Slivertone chassis# 528 59230. Any help is greatly appreciated! Thank you. ]]> Music Electronics jadams http://music-electronics-forum.com/t33094/ Service Manual or schematic for HK Audio Opera Sub12 wanted http://music-electronics-forum.com/t33051/ Wed, 08 May 2013 12:36:32 GMT I got in an HK Audio Sub12 active subwoofer. Woofer coil was burned, And the Sap16 P transistor and Ifrp transistor where defective. Also two I... I got in an HK Audio Sub12 active subwoofer. Woofer coil was burned, And the Sap16 P transistor and Ifrp transistor where defective. Also two I replaced the woofer, and the transistors, and two fuses It now powers on. but goes into protect mode....

Anyone got a schematic ? ]]> Music Electronics verano http://music-electronics-forum.com/t33051/ Trouble with Main Output on Behringer Europower PMP2000 http://music-electronics-forum.com/t33037/ Mon, 06 May 2013 21:15:07 GMT Hello all! I need some help troubleshooting a Behringer Europower PMP2000 I acquired used a few years ago.

Sometime within the past year (I don't recall exactly when) the Right/Mono Main output started acting up on me. I would set up the system as usual but the signal would be abnormally quiet, particularly compared to the Left/Monitor output set to the same volume. On some occasions it would remain at this abnormal quiet state but at other times it would reset to its proper level (which usually resulted in feedback because I had carelessly increased the volume to compensate for the low signal).

I don't recall if the signal indicator on the board corresponded to what I was actually hearing when the problem occurred (ie, it only registered a low amount of signal) or if it still registered the typical amount of signal even though that was not what was coming out.

This happened to me several times so subsequently I just used the Left/Monitor output only so I wouldn't have to deal with the Right/Mono Main potentially giving out on me again.

Today I disassembled the board to see if I could discover any obvious issues internally, which I did not (though granted, I'm not entirely sure what to look for, either than loose connections). I reassembled it and played some music through the system to test out the Right/Mono Main output and it seems to be working fine. However, I would like to see if there's anything that can be done to continue to troubleshoot the issue because I really would like to return the board to a reliable state of operation.

Any suggestions or advice you can provide would be most appreciated.

Thanks!

David ]]> Music Electronics The David Dude http://music-electronics-forum.com/t33037/