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Messages - Zappacat

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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.

Tubes and Hybrids / Re: PhAbb NowWatt
« on: July 07, 2011, 06:28:06 PM »
Thanks for posting that.  I'm very interested in building something like that. 

Can you recommend a power supply to start with?  I'd like to make it fit in a 2U rack mount space without external wall wart type transformer.

Would it be possible to drive a Behringer Eurolive 1520 with the setup?

Amplifier Discussion / Re: Line 6 Spider 3 amp
« on: September 01, 2010, 01:38:10 AM »
This is known as "black box syndrome" with respect to the Spider III series that have the LCD displays.  It has been well documented.  Google it.  If you play your cards right you can get them to repair it for free.  I did.  Good luck.

re speaker at very front of cab
 mount the speaker on the back of the baffle

use a tone ring  (sets the speaker back)

Tone ring?  Can you elaborate on this a little.  What material do you make it out of?  Dimensions?

Will either of the pictured power supplies work as a substitute?  The issue that really concerns me is the Amperage discrepancy.  If something goes wrong in the keyboard would the circuit start pulling more current than it should due to the increased amperage capacity of either transformer?

I get voltage readings of 9.6 volts for the Philips transformer and 12.6 volts for the ENG transformer.  The Philips transformer is VERY light and small.  Similar to a cell phone charger.  It feels like it doesn't have any coil in it.  The ENG feels like it has coils in it.  Would the ENG be giving me a higher voltage rating because there isn't a load on it when testing it with my voltmeter?


I've been trying to find a schematic for this.  Requested it from GK 2 days ago.  Still no response.  Do you have the schematic?

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-120V ~50/60Hz

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.

Thanks Rowdy,
  I have a lot more questions about the answers you just gave me.  I'm having problems with the quote mechanism in the forum.  Have a nice evening/day.

I'm building the "Eighteen" Marshall 18W stompbox at

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 thought it had to have dual secondaries?

Personally I would try to go a little higher on the VA rating and check to see if transistor and cap voltages were not exceeded but...

using your criteria the closest I see in Digikey is the Hammond 166J36 @36VA single primary 36 V single secondary center tapped

unless I'm missing something that should work.

I didn't check Physical size and fit though

There are other ballpark ones LISTED but not stocked.

Sorry Zappacat,, yep Jayfett got it.

Jayfett, if you wish I can post all the circuits I use?
My setup does at least deliver the *touch response* that blues type chaps yearn for. 8|

I'd sure like to look at those circuits.  Please post them.

Hi Zappacat.
I suggest you provide links to pages where you can order transformers , whatever's convenient to you, and we help you choose one from all those which appear there.
I forgot: post the measures of the iron core, that´s to say the height,width and thickness of the packed sheet iron "E" and "I".
Or: what size is the rectangle where the label is glued?

Measurements for rectangle where label is glued  :  60mm X 27mm = 2.3" X 1"

Links :

right now the transformers I'm looking at are based on going to the transformer area at the digikey site and specifying ONLY the following as filter elements :

TYPE :  single primary
SECONDARY WINDINGS : dual, center tap

Assuming the above are correct, what should I be specifying in terms of "Series Output Voltage @ Current" ?

Thank you very much.  I'm guessing the amp should at least be interesting to mess with.


Can you please tell me what "S/hand Graphic EQ" and "Bdrive" mean ?  Thanks

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 :

I've looked EVERYWHERE on the amp and don't see any wattage numbers.  At first I was assuming it's a 30 (only because of the name GA-30 ) watt amp but really have no idea.

Their web site sucks.  I see the amp in some weird tilting flash thing under products but there's no information about ANY of their amps.  Just pictures.  I don't see any way to email them either.  Anyone on the board live in Italy that might be able to contact them for me and ask about the power transformer requirements for the GA-30?

Their telephone # is : +36 071 7825422

Incidentally, (assuming it's a 30 watt amp)  and using this formula : Volts X amps = watts .  Do I use 18V or 36V for the voltage value ?


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