[Sovkiller]

I was emailing and PMing some of the more active Hifiers members (sorry, even Joe Lau) without success, it seems that maybe has to be exposed on a open thread to be answered??? So here I go, I don't like to look as an ignorant but I prefer to ask first, than to try, I don't want to blow anything!!!! Please can anybody tell me if there is anything wrong in driving two pairs of headphones with differents impedances (32 and 300) at the same time with the MGHead OTL, one form the OTL jack and the other from the transformer jack, with or without the feedback? Does it result in any damage of the amplifier or the cans?

 

[Kevin P]

The transformer jack is disabled when anything is plugged into the OTL jack, so using both jacks won't work. The amp can't function in transformer mode and OTL mode at the same time; they're mutually exclusive.

You could use a splitter on one jack to run two pairs of cans, but I'd stick with 300-ohm phones for both sets in this case.

KJP

 

[Sovkiller]

Sorry Kevin, I don't know in yours, or in another one you've tried, but I tried last night as a curiosity and just for a minute, and in mine the transformer jack works when the other is in use, just that the transformer jack volume drops about 30% of the regular level on this jack, and it becomes very similar to the level that we can reach for the same headphones on the the OTL jack, I suppose that maybe is due that is taking the signal from that OTL jack or so, is it supposed that it works like that? Let me know if you have any other info....

note: I would like that Joe Lau as a designer, please, have the gentility of answering me that question, if is possible, what do you think about that Joe, how is supposed that this works?

 

[Joe Bloggs]

I dunno, I suggest you just give it a try.

Joe

 

[Joe Lau]

Quote:

Originally posted by Sovkiller Sorry Kevin, I don't know in yours, or in another one you've tried, but I tried last night as a curiosity and just for a minute, and in mine the transformer jack works when the other is in use, just that the transformer jack volume drops about 30% of the regular level on this jack, and it becomes very similar to the level that we can reach for the same headphones on the the OTL jack, I suppose that maybe is due that is taking the signal from that OTL jack or so, is it supposed that it works like that? Let me know if you have any other info.... note: I would like that Joe Lau as a designer, please, have the gentility of answering me that question, if is possible, what do you think about that Joe, how is supposed that this works?

Yes ! It is possible to use a High impedance Can in OTL mode and Low impedance mode. It will drop in output power due to in shunt by high impedance Can. Just try it ! It will not harmful on your can and Mg-Head OTL.

 

[Sovkiller]

Thanks Joe:
I have another question for you please: Do they work together, both jacks in its original configuration, that means, one in OTL and the other in transformer, or both with the OTL? (or both with the transformer, which has the preference?)

 

[Joe Lau]

Use same type of Headphone & use a splitter is better.

 

[Sovkiller]

Sorry Lau but the same type of headphones is out of the question, simply I don't have them, I just have one of 32 ohms and another of 300 ohms, so I have no other choice of using them together, or not, or better, if you consider adecuate or not, according to your design if I can use them in this configuration or not, sorry but my question is still unanswered, can anybody answer me please???
Do the jacks work at the same time, in their original configurations (that means, one in OTL and the other in transformer coupled) when used at the same time? Or both take the signal from the OTL, or both from the transformer coupled one? Which jack excludes or disconnect the other, when you use both at the same time? Or are still active but for any reason is not adecuate to use both at the same time?
sorry but it seems that I was not clear enough, so I will ask the same, in a different way, when you use the OTL jack, is the other, the transformer coupled one, in any way disconnected, or is still completelly active? Is it posible to use it with a low impedance headphone (32 Ohm) at the same time, when the one of 300 Ohms is plugged into the OTL jack....

 

[Joe Lau]

It is hard to tell you How the sound quality change when use 2 difference in MG-Head OTL. I 'm don't have much can on hand to test it ! I only can tell you. It will not damage the amps ! Just try it !

 

[eric343]

FYI, the MG Head is not good at driving low impedance headphones in the first place...

 

[Sovkiller]

Thanks Eric I know that, bad for the Grados and Sonys, is a pretty good amp, the sound is horrible with the low impedance cans I know, but I'm gonna be on the other side, sorry for the one who has to hear the low Z side, but I don't have any other choice....
AND nobody wants to answer my prior question???? Nick or Hirsch, maybe?, tube entusiasts com'on!!!