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Double Bass WW 2 channel amp - how to bridge?

C

CPike

May 28, 2005
344
10
Dallas, TX
#1
I have a Walter Woods 2 channel amp, ca. early/mid '90s. On the bottom of the amp it mentions something about bridging the two channels for more power, but I can't figure out how to do this. Years ago, I did a web search and discovered some info regarding a special cable that is needed to bridge the channels. Does anyone know what kind of cable is needed, where to buy it, or how to make it?

Thanks, Chris
 
#2
call walter. he'll be happy to tell you how to make one. google him and you'll find his digits. I did just this a couple of weeks ago and he said something to the effecting of taking a couple of regular speaker cables apart to make a Y cable that's NOT grounded, so the lead is hot . . . . at least that's what I remember. I wrote it down somewhere and forgot about when I realized I'd be getting the mono version.

Whatever you do, DO NOT go out and buy a Y cable with male 1/4s. You just may destroy your amp. This part of the conversation I had with Walter I remember quite well.

Mono or Stereo, cheers for a great amp.
 
#8
bassphase said:
It's easy. Flip switch to "bridge'--make a cable with ONE conductor to each speaker out (tip of standard quarterphone)> the other end will be a conventional quarterphone(soldered tip and sleeve) to the speaker cab.

Use at least 14 guage speaker wire.

bob
Click to expand...
This is correct that the output is derived from the tip connections in bridge mode, however it is very important that the handle of the phone plug at the speaker end of the cable be insulated, since it is not at ground potential and the amp could be damaged if the plug were to be connected to ground in any way. If a metal handled phone plug is used, it should be covered with heat shrink tubing or electrical tape for this reason. You could also use a Speakon connector if your speaker cabinet is compatible.

From the WW owner's manual:

"BRG\STR (BRIDGE/STEREO) SWITCH: To bridge speaker(s) between the two power amps, set this switch to
BRG and connect speaker via the special "bridging" adapter cord. IMPORTANT: EXCEPT FOR BRIDGING, THIS SWITCH MUST BE KEPT IN THE STR (STEREO) POSITION; OTHERWISE, SPEAKERS CONNECTED TO POWER AMPS A AND B WILL BE OUT OF PHASE. Also set both PAN POTS at 1: 1. PRECAUTION: In order to prevent shock hazard and/or high current discharge when operating in BRIDGE MODE it is ABSOLUTELY necessary to use speaker plugs, including "Y" cords, with PLASTIC or MOLDED CAPS ONLY. Do NOT USE METAL CAPPED PLUGS OR CONNECTORS. Also, do not connect or disconnect speakers or TOUCH CONNECTORS while amplifier is in use or switched on."
 
#9
Update:

I recently bought a WW MI-200-8 stereo. I went ahead and confirmed the instructions for making the bridging cable with Walter over the phone. I then ordered the cable from Butch at bayoucables.com. Butch went ahead and added it to his 'new products for april' list. So if you go to his webpage and scroll down, you will see 'bridging cable for walter woods amplifier'. Note that I ordered the cable with a speakon to go into the speaker cabinet as to avoid any grounding problems. At the other end are phone plugs (ie 1/4" male jacks) as the woods amps are 1/4" throughout. The cable costs 28 dollars plus shipping.

and Butch is really good at customer service. I will receive the cable in about 1 week and will report back.
 
#10
Sorry it took me so long to report!

Basically, the cable is working just as it should.

BUT . . .

I just got a PM from a interp in Germany who ordered two of these, and neither of them work. Don't know what to say exactly, maybe Butch tried to make em from memory and messed up or something. He's very good at customer service though, so hopefully that will work out for our fellow TBer.
 
#11
UPDATE:

TBer Interp visited walter in the dessert, and the amp itself was fine. Turns out it was the cable. Butch didn't (forgot?) to connect the two positive leads to the 1+ and 1- terminals on the (four-terminal) speakon. Problem solved.

I can tell my bridging cable from Butch is working due to the huge increase in watts. You can really feel the increase going from 250W versus 750W into 8ohms.

I will be emailing Butch with the necessary info.
 
#12
UPDATE 2:

Talked to Butch. He says he wired everything correctly. human error? I don't know. I still have faith in Butch. He's a good man and his service is excellent. I'm sure if Interp had the time to mail the cables back Butch would've fixed em. Everything I've received from him has worked perfectly.
 

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