I just built a speaker extension cabinet for a friend of mine.  12" cannabis rex for a Fender Super Champ XD.  I'm mounting a 1/4" mono jack on the external cabinet so he can unplug the speaker out coming from the champ and use a 1/4" mono male to male cable to connect the external cabinet to the champ XD.  Does the cable need to be SPEAKER cable or will a regular instrument cable work just as well?  Thanks in advance.

Gallien-Krueger 1001RB-II : A friend of mine was playing this amp the other night and suddenly he lost all power to his speakers but the direct out was still working.  He continued to play it, no smoke.  I hooked it up and get the same thing.  

My first step in troubleshooting it is to test the toroidal power supply and see if it's working.

The second picture shows a group a wires that come from the transformer and attach to the main board via spade connectors at the far edge of the board.  I haven't been able to test the voltages on these yet.  I assume these are to power the preamp and stuff like that.

The third picture shows group of secondary wires going to what I presume is the power section.  These wires are connected to a modular plug terminal that connects to the plug in between the big capacitors.  The voltages I'm getting off of these wires with the power on can only be measured in millivolts.  Does the plug need to be plugged into the board in order to read the voltages properly or can I just disconnect it from between those big caps and get accurate readings?

Will a continuity test between ANY of these wires and the transformer primary tell me if the transformer is any good?

The following information is taken directly from the power supply label as seen in the pictures :

Input AC:
0-100V-110V-120V
(BRN)RED-ORG-YEL-GRN

0-100V-120V ~50/60Hz
BLE-GRY-VIO

Does 0 in these specs indicate gound?
Why are there two input specs with only one having the ~50/60Hz designation?
What does (BRN) mean?

Output AC:
40.2V 7.74A RED-RED
40.2V 7.74A YEL-YEL
29.9V-0-29.9V 6.44A ORG-BLK-ORG

Assuming the power transformer is on and functioning properly I should be able to hook up my voltmeter and measure :

40.2V AC with one probe on red and the other grounded to what?
29.9V with one probe on orange and the other on orange
approximately 15V with one probe on orange and the other on black

Am I on the right track here?

Thanks in advance.

I'm building the "Eighteen" Marshall 18W stompbox at runoffgroove.com http://runoffgroove.com/eighteen.html

I'm puzzled about the following :

-  In both the schematic and perfboard layout I don't see what the ground connector from the battery connects to on the perfboard.  It just shows the +9V connection in both instances.  Where does the negative terminal of the battery connect to the circuit?

-  When connecting the circuit to a guitar there are two connections for the guitar cable.  I see the connection labeled IN on both schematic and layout but where does the other connector go?

-  Which connector on the guitar cable is the IN connection?  Is it the Tip or the Sleeve?

-  I'd like to use some real POTs instead of the plastic little boxes with the small plastic screws inside so I can mount it in an enclosure and easily turn the parameters from the outside once it's built.  Any suggestions on POT brands and ideal impedance levels?  Any better than others?  Under the tweaking notes it suggests trying different spec POTs.  Just wondering if any of you have built this before and had recommendations.

- BOM is there a parts list for this thing anywhere?  I don't see it on their site.  From a beginners standpoint it's difficult to source the right parts.  Sometimes there are so many options I get lost trying to order parts because there are so many options and I'm not sure what some of them mean.

Thanks in advance.

I need someone to call Castley guitars and find out the power transformer requirements for the Castley GA-30.  Please help me if you can.  Their phone number is : +36 071 7825422  Thanks!

More relevant information about my problem is in the following thread :

http://www.ssguitar.com/index.php?topic=1640.0

I picked up this amp about a year ago and I need some advice on how to convert it from 220 to 120.  I live in United States and my wall current is 118V AC.  Please see attached pictures for more information.

I'm assuming I need to :

- get a transformer 120V AC to 18V DC output.
- change the power connectors(can I user the same mains wire?)
- switch issue(can I use the same on/off switch?)
- change the fuse specifications(what type of fuse do I need?)

Can you guys tell me what basic parts I need to construct a 9 volt DC 500mA power supply?  I live in United States and my home socket voltage is : 118 volts AC.  

I see after reading about wall warts / AC adapters on Google that some are straight AC, some are rectified AC, some are rectified and smoothed AC.  Any way to tell by the picture which category this adapter falls into?  After messing around with some more complicated audio projects and not getting acceptable results I'm beginning to realize how much I don't know about electronics.  I thought I'd give this project a try because it should be simple, right?

I attached a picture of the transformer back label for all the technical specs I have.  This power supply powers a Studiologic keyboard controllerhttp://www.studiologic.net/sl-990xp.html.  Thanks

I've got some old televisions I've been cannibalizing for parts.  Unfortunately, ALL of them are solid state and from the late 90's early 2000 era.  Most of the transformers and power sections seem to be built into a larger circuit board making it difficult to extract transformer without damaging it.  Are any of these parts worth keeping (for audio projects like discussed in the forums here) besides the heatsinks or am I just creating a huge pile of crap to clutter up space and make more of a mess?

Attached are the schematics for the Peavey Studio Pro 40 / StudioPro 40 combo amplifier.

I'm trying to fix a friends Peavey Studio Pro 40.  It shows no signs of life when plugged in.  I pulled out the chassis and checked the fuse (is there only one?) and voltage levels coming into the amp.  Those were OK.  Now I'm looking at the power transformer.  The numbers on the transformer are 705-18712 .  A google search on this number yields nothing.  Am I looking in the right direction to start at the PT transformer from this point.  Is it safe to check power transformer voltages without a load on them?

Peavey parts no longer carries the transformer but a substitute transformer number of 705-18762 was given to me at a price of $ 42.99.  Google search for 705-18762 part number yields nothing.  If the problem turns out to be the transformer can I get something that will do the job elsewhere for less ?  Can anyone tell me transformer specific requirements based on the schematics I posted in the schematics section.  It may sound like I'm cheap but the guy I'm trying to fix this for is even more broke than I am right now and I can't have this situation end up COSTING me money like these things sometimes do.

Thanks in advance.

How do I wire this thing to a grounded (USA 3 pin) socket?  I'm assuming the far left terminals labeled L and N represent LIVE and Neutral.  What about the ground pin coming from the wall?  Do I connect it to the pin with the ground symbol?  I'm assuming if I connect this correclty that I should get approximately +24V and -24V AC coming out of -V and +V.  Is that correct?

Could I power a couple of LM3886 chips with this power supply?  Is this power supply adequately suited for this application?  I'm really low on cash right now and I stumbled onto this for $10 new.  Thanks in advance.

Mean Well S-60-24 PDF link below
http://www.meanwell.com/search/s-60/default.htm

I've got both of these speaker cabinets on the drawing board right now :

AX84 1 x 12" Speaker Enclosure

AS112A Plans

I have one of them (AS112A) about half way through assembly and I realized there won't be any space between the front edge of the speaker(once installed) and the front of the speaker cabinet itself.  This leaves me with no room for putting a protective screen or something in front of the speaker unless the protective screen/shield extends beyond the front of the speaker.  Am I missing something here?

What do you guys use for protective speaker mesh / screen ?

I realize at this point that a simple solution to this is to increase the depth of the cabinet box so I can inset the speaker mounting position more but I've already cut the wood and from my understanding these cabinets are designed so that the internal cabinet volume/area is critical to the way they sound.

Thanks in advance.

The AS112A speaker design PDF calls for using "2NR M5 tee nut" to secure the carrying handle to the top of the speaker cabinet. I'm here in the US and everything is in "standard" measurements at the hardware stores for this type of fastener. Can someone please tell me what 2NR and M5 mean in this specification? If those numbers pertain to metric sizes what should I be looking for in a standard size equivalent?

reference link : http://www.award-session.com/award-session_projects.html

Thanks very much in advance

I need some help with this combo amplifier.  I purchased it recently knowing it was damaged in some way.  The fuse was blown so I replaced it with proper one.  First power up blew the fuse again instantly and the unit started smoking inside.  So far I've removed the amplifier chassis assembly(all the electronics) from the wooden speaker enclosure and the attached pictures are what I'm looking at.  What's the best way to test the toroidal transformer without damaging it?  Is this where I should start?

I don't see any visual clues that would indicate what was burning.  The only odd thing was something that looked like ash next to the led assembly on the front of the chassis.  Should I risk throwing in another fuse with the chassis out of the cabinet so I can possibly see something burning? 

Any help greatly appreciated.

***Linked content removed due to malware***

I recently purchased an oscilloscope(PROTEK 6502 20Mhz-2 channel trace Oscilloscope) that didn't have any probes.  By mistake I bought a probe (Avex 10x oscilloscope probe 100Mhz) that has a higher frequency rating.  Can I use the probe with this scope?  What are the implications of using these two together or will they even work at all?

Thanks!

The chipamp build list I got from bryan calls for MUR860GOS-ND.  Digikey is out of stock on these until 12-23-09.  Mouser is out of stock as well.  Can I substitute these MUR860 8A 8 Amp 600V Power Rectifier Diodes that I found on ebay without sacrificing performance/quality of the final product?  Any advice greatly appreciated.

How do I measure the output signal strength of my guitar?  Can I do this with a voltmeter?  I'm trying to start my first SS guitar amp and I'm trying to trace the signal levels from the guitar to the final output stage.  This may sound like a stupid question for someone building their won amp but I'm stuck at square one.  Any help greatly appreciated.

I just got one of these amps.  It has a european power connector on it and I'm in the United States.  What do I need to hook it into AC mains in US?  Will I need to change the power transorfmer?  I know it's not the greatest amp but it is very unique.  I've never seen one before.  I don't want to blow it up before hearing what it sounds like.  I can't find any official tech pages on the web for information on it.  Any help greatly appreciated!

I'm having second thoughts about dual mono vs. stereo chipamp kit for guitar amp build.  I purchased the non-inverting LM3886 stereo kit.  My intentions are to use it as the power amp for my various preamps.  For example PodXT, home built Marshall eighteen, Digitech 2101, etc...  Some are stereo pres, some are mono.  I plan on driving a 2x10 or 2x12 stereo cabinet with it.  The more I read about this stuff the more confused I get.  Can someone explain to me the advantage of using the dual mono kit for this application vs. the stereo kit ?  Thanks for any help.

I'm putting together my first chipamp.  The instructions say that you need Phoenix 22Kohm SFR16S resistors.The parts search on digikey brings brings me hundreds of matches that appear to all be very similar.  Is the manufacturer important when acquiring these components?  How do I know which one to choose when they're all so similar?

Can you tell me what the following specification choices mean when searching for components:

Temperature Coefficient (which of the following are better for this application?)

+- 100ppm/C VS. +- 250ppm/C

packaging

cut tape VS. tape and reel

The instuctions also don't mention anything with respect to TOLERANCE or POWER RATING.  Maybe I'm missing something in the documentation.

Is there a predefined BOM (build of materials) on digikey or mouser?

Thank you.

I'm putting together my first stereo chipamp circuit boards that I intend to use as a guitar amp.  I'm assembling the the amplifier PCB at this point.  In section 1.7 it refers to a feedback capacitor being optional.  Should I be using the feedback capacitor for guitar?  Please help me with this I'm stuck.  What are the implications either way?  Thanks