monoblock compatable SDAs ?

[W WALDECKER]

which model SDAs Have the pin/blade innerconnect cable which make them compatable with non common ground monoblocks ? thanks....WCW III

[george daniel]

Since have have 1 c's with the pin/blade interconnect,and am close to purchasing the odyssey mono's, I shall watch this thread closely :D

[BobMcG]

Take a look at these #1 redo

[BobMcG]

#2 If this is bigger I'll redo the first one.

[BobMcG]

#3 (#2 was bigger so I re-did #1)

[BobMcG]

Some of the early B/B 1Cs could make use of an AI-1 along as it's a custom jobber like this one made for my brother a long time ago by Polk's Ken Swauger.

At this forum page link,

http://www.polkaudio.com/forums/atta...achmentid=8335

[schwarcw]

Polk made a non-commomground interface cable to use with monoblocks or non common ground amps. Several Polk forum members have used this suggesfully. Scompracer for one used them with Carter TFM bridged. I'm sure there are others. I currently don't use mine. It is brand new, never unwound from the Nylon ties. I thought about selling it on the Forum. But decided to keep it since the Polk OEM model is as rare as hen's teeth, and I may want to cinsider monoblocks at some poing. I also heard that someone else on the forum makes these for a small price $100. There are sketches out the on the polksda website if you care to make one yourself.

carl

[BobMcG]

Polk made a non-commomground interface cable to use with monoblocks or non common ground amps. Several Polk forum members have used this suggesfully.

That's what the above four posts are about. :)

[ESavinon]

Hey schwarcw why wont you be a nice chap and sell or trade me that nice ai-1. ;) ;) I promise to put it to good use :D :D .

[madmax]

compatable with non common ground monoblocks ?

Do you know your monoblocks are non common ground or are you assuming?

There are different types of monoblocks. Most you can connect the grounds together but some you cannot.

Most common design tube models have no potential between grounds therefore the grounds can be tied together. An exception to this is TTL design which does not use output transformers.

Most SS designs are OK as well. The exception here are the ones which use a "bridged" amplifier design. Internally these are configured the same as a "bridged" stereo amp.

Of course any "bridged" stereo amp is not compatible.

The older "blade-blade" connection SDA's if used with a compatible set of monoblocks should have the two grounds tied together physically with a wire.

How do you find out if your monoblocks can be used with the "blade-blade" or standard "pin-blade" cable (with no isolation transformer)? Contact the manufacturer and tell them you want to run a wire between the two grounds and ask if that will hurt anything. Hopefully you will get a knowledgeable answer.

Do not assume any monoblock will or will not work. Contact the manufacturer to be sure.

madmax


PS: I am not responsible for smoke in your home or amplifier replacement no matter what you do. :D

[danger boy]

this would scare the hell out of me trying this with my SDA's. so i won't or can't consider it... my serial number are 3007 for my SDA SRS's. so i can't.
why not just get a common ground amp and not monkey around with is my amp common ground or not and risk damaging something fierce?

[W WALDECKER]

this would scare the hell out of me trying this with my SDA's. so i won't or can't consider it... my serial number are 3007 for my SDA SRS's. so i can't.
why not just get a common ground amp and not monkey around with is my amp common ground or not and risk damaging something fierce?

i own common ground amplifiers but i want to use the hotrods. i know other folks that use the same monoblocks that i am using with thier SDAs.dbjnh bought his SDA 1Cs new from the PX when he was in the Army and uses the same Extreme monos to drive his SDAs so i will contact him for advice. i wanted to get a list to find out what models are worth buying that are compatable with non common ground amplifiers.thanks....WCW III

[madmax]

this would scare the hell out of me trying this with my SDA's. so i won't or can't consider it... my serial number are 3007 for my SDA SRS's. so i can't.
why not just get a common ground amp and not monkey around with is my amp common ground or not and risk damaging something fierce?

Well,
How do you know your stereo amp is common ground? Ponder that for awhile. :)
madmax

[anonymouse]

Well,
How do you know your stereo amp is common ground? Ponder that for awhile. :)
madmax

Turn off the amp, unplug it and test to see that the resistance between the two negative speaker terminals at the back of the unit is zero. You can do this with a $15 digital multimeter purchased from RS, Home Depot or similar store. The multimeter will not damage the amp. If the resistance is zero, it is common ground. If it is not zero, it is not common ground.

[madmax]

Turn off the amp, unplug it and test to see that the resistance between the two negative speaker terminals at the back of the unit is zero. You can do this with a $15 digital multimeter purchased from RS, Home Depot or similar store. The multimeter will not damage the amp. If the resistance is zero, it is common ground. If it is not zero, it is not common ground.

That would say the grounds are tied together. What about a dual mono design where they are not tied but are at the same potential? For that you would have to ask.

All I'm saying is you shouldn't give up on 60% of the amplifiers available just because they aren't in the same case with a wire attached between the two grounds.

madmax

[anonymouse]

That would say the grounds are tied together. What about a dual mono design where they are not tied but are at the same potential? For that you would have to ask.

All I'm saying is you shouldn't give up on 60% of the amplifiers available just because they aren't in the same case with a wire attached between the two grounds.

madmax

If it is not a common ground amp as will be revealed by the simple test above, then you need the A1 cable to be safe rather than sorry. Even if the grounds are at the same potential, that amp has not been designed to be coupled the way SDA's use them. I realize what you are suggesting might work; I just would not feel safe doing it. But thats me, and I probably have far less experience than others in this area. But I have built power amplifiers from discrete components in my time, so I do know a little about them.

[madmax]

Even if the grounds are at the same potential, that amp has not been designed to be coupled the way SDA's use them.

No amp was designed to work the way SDA's use them. I've had a lot of cool stuff hooked up to mine. I just hate to see people shy away from SDA's or cool amps just because they are worried about a problem which probably doesn't exist. Is it so hard to ask the manufacturer?
madmax


Edit: BTW, McAlister says his amps are OK to use with SDA's if anyone is interested. The Jolida 302 and 502 are as well. Also the Manley Lab 100 monoblocks. Couldn't get an answer on the Silver 9t's but I used them and saw no current between the two grounds while playing.

[danger boy]

Well,
How do you know your stereo amp is common ground? Ponder that for awhile. :)
madmax

good point.. but it seems that more stereo amps are common ground than mono amps. just my take on it, that's all. And i understand why someone would want to use mono block amps.. i use a few in my HT, but not for my SDA's.

[ND13]

I wonder if I can strap the negs togther on my ASL AV20s and run them on my 2As????

Anyone know if that's cool or not? Seeing that I just found out that I have 2As and not 2Bs the sensitivity jumped up quite a bit to 92db, so I'd think that I wouls get adequate volume from 20 wpc of tube power.

[Dennis Gardner]

I wonder if I can strap the negs togther on my ASL AV20s and run them on my 2As????

Go ahead and strap 'em together and report back on the smoke level. :D

I hooked up my AV20s to my 1Cs without the SDA cable, so just using them in stereo and get nice volume levels. I know they have more mids than your 2As, but I was surprised how much louder they were than througn the RT55s I had them hooked to, so I will probably keep them for an alternative amp to my Stratos.

I will let you know if I get brave and try them with the cable or strapped at the neg. posts.

DG

[ND13]

I don't think there's anyone to call and ask about it without having to call China, and my Chinese isn't up to par. :D

[madmax]

I think the guy who designed the ASL stuff is on audioasylum.
madmax

[ND13]

Chuck,

Have you ever ran ASL monos on SDAs?

[madmax]

No.

But normally if they are standard design and use an output transformer there are no problems. TTL would be a problem though.

madmax

[madmax]

I think the guy to talk to about ASL is Tash Goka. divergent@divertech.com
madmax

[dbnh]

I also heard that someone else on the forum makes these for a small price $100...carl

Ok, I haven't had a problem running my SDA 1-Cs with a pair of mono amps. However, if that "someone" mentioned above by Carl would please pm me, I'd be happy to discuss having one of these made up for the peace of mind. Yes, I believe in insurance...

EDIT: Please note that subsequent to this post, I had the non-common ground amplifier interface IC made for me. Peace of mind now reigns supreme.

[dbnh]

....

[F1nut]

That "someone" isn't welcome here any longer after ripping off a forum member.

[dbnh]

....