Question about using Burmester RCA to XLR adapters and phase ...

[jdebonth]

Originally Posted by Rayooo

My "ASSumption" is that in the case of Factory monoblock 911s, this isn't an issue, only with the stereo version of the 911??????

I believe the internals of the stereo and mono amps are 100% the same, the difference being the use of the external Y adapter with the stereo vs. this being soldered internally with the factory mono.

Questions like this is why I think Burmester themselves need to be contacted.

[Rayooo]

I'd be curious myself, in any case they seem to be working fine for Joe as monoblocks driven by single ended input through the Burmester adapter.

[jdebonth]

Originally Posted by Rayooo

I'd be curious myself, in any case they seem to be working fine for Joe as monoblocks driven by single ended input through the Burmester adapter.

Because if what I am saying is correct only 1 out of the 2 channels in each of the 911's is being utilized. Effectively you have 2 stereo 911's each of which you are using only one of the two channels of.

[Rayooo]

Originally Posted by jdebonth

Because if what I am saying is correct only 1 out of the 2 channels in each of the 911's is being utilized. Effectively you have 2 stereo 911's each of which you are using only one of the two channels of.

yes that was/is my thought and concern as well!

[Tremayne]

[QUOTE=jdebonth;323251]

Does this mean that both pins on the XLR need to be 'live' so that both halves of the amp see the signal? I hate to say it but is it possible that with the single ended GAT only one out of two of the 911's amplification channels is being utilized?
[QUOTE]

The Burmester adaptor plug has the centre XLR pin connected to inner part of the phono socket, the two outer pins of the XLR are connected to the outer part of the phono socket.

[joeinid]

My 911 monos ONLY have ONE xlr input. At this point they are no different than any other 700 wpc. mono amps into 4 ohms except Burmester uses pin 2 negative, opposite the standard we use here.

[jdebonth]

Joe, your right about the pinout, see below how it is done.



The thing is that your mono 911's are expecting to see live signals on both pin 2 and pin 3 (pin 1 is ground). It is expecting to see these signals in opposite phase, one of which will be reversed in the amp and then they are added together. With the adapter in case of your CJ GAT pin 2 carries a ground signal, and the effect of this is unclear...

Honestly Joe, if I were you I would call Burmester about this right now (you have an hour left in European business hours) just to be 100% clear on what is happening inside the amp with this configuration. They state very explicitly in their manual that the mono's can only be run in balanced mode.

[joeinid]

Thanks Joost,

I hooked up the 077 last night. Holy cow! The 077 + 911 monos = SOTA for sure.

[jdebonth]

Originally Posted by joeinid

Thanks Joost,

I hooked up the 077 last night. Holy cow! The 077 + 911 monos = SOTA for sure.

It's possible that with the 077 with XLR's you are running 2 x 2 channels of the 911, and with the GAT you are running 2 x 1 channel.

[Rayooo]

Originally Posted by jdebonth

It's possible that with the 077 with XLR's you are running 2 x 2 channels of the 911, and with the GAT you are running 2 x 1 channel.

From everything stated so far, unless the "factory monoblocks" have some kind of internal phase splitter to generate the "anti-phase" version of the single ended input...it sure seems like the amps would not be running optimally. ???????

Heck it seems that at the very least, they would not have same output power level for given input level as would be expected. ???????