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Antique Sound Lab MG Head DT / OTL MK III Headphone Amp - Page 2

post #16 of 77
Quote:
Originally Posted by robm321
I'm suprised at all the Senn users using OTL mode. I tried it and although it gave the benefits of OTL, it became slow and slughish clearly needing more power.
what did you use? TO mode? which tubes were you using?
i'm now using JJ el84 and tube groove 12ax7M mullard reissue, and i changed the cable too, i don't find it slugghish at all. maybe slightly slow, but fast enough to andle heavy metal or orchestra very well.


maybe here i'm the only one finding the TO mode very good?
yes it is less "full" than the OTL, but look at the freq. response posted some time ago by a user and you'll see that OTL mode bumps the bass and treble...the TO is much more linear.
TO has more speed and definition than OTL, and is a perfect match with very warm cans like hd650 or grado.
for me OTL has the magic of the warmest tubes...fat&big, but with transformers you have more neutrality, that can be the best choice with some recordings and cans.
post #17 of 77
Quote:
Originally Posted by Jbucla2005
and as it's been mentioned before the MG Head doesn't really do Grados.
if you ask me, mg head TO mode + sr60 is a great combo...it is good even in OTL.

i don't really know where did you find that mg head+grado combo isn't a good match...in this forum i've always read that it's quite good
and here is a (positive) review by srajan ebaen of the head+rs1 ....

http://www.soundstage.com/systems/systems200006.htm
post #18 of 77
Quote:
Originally Posted by Blasyrkh
if you ask me, mg head TO mode + sr60 is a great combo...it is good even in OTL.

i don't really know where did you find that mg head+grado combo isn't a good match...in this forum i've always read that it's quite good
and here is a (positive) review by srajan ebaen of the head+rs1 ....

http://www.soundstage.com/systems/systems200006.htm
Thanks I will try it again.
post #19 of 77
Quote:
Originally Posted by Blasyrkh
what did you use? TO mode? which tubes were you using?
i'm now using JJ el84 and tube groove 12ax7M mullard reissue, and i changed the cable too, i don't find it slugghish at all. maybe slightly slow, but fast enough to andle heavy metal or orchestra very well.


maybe here i'm the only one finding the TO mode very good?
yes it is less "full" than the OTL, but look at the freq. response posted some time ago by a user and you'll see that OTL mode bumps the bass and treble...the TO is much more linear.
TO has more speed and definition than OTL, and is a perfect match with very warm cans like hd650 or grado.
for me OTL has the magic of the warmest tubes...fat&big, but with transformers you have more neutrality, that can be the best choice with some recordings and cans.
TO mode?

I use the transformer with the 600's - in OTL there was clearly a slower response with a slightly muddy sound.

With the RS-1's in OTL there was enough power and I strongly disagree with the above poster saying Grado's don't work well with this amp. My RS-1 midrange is terrific with this amp.

I'm using RCA "black plate" - prolly not the best with the Senns but terrific with the Grados.
post #20 of 77
Quote:
Originally Posted by robm321
TO mode?
hem, yes...i mean tranformer output


about the muddy sound, i don't think it's a power problem, first of all beacuse with high impedance can the OTL gives lots of power.
however i find OTL slower than TO, but with every cans, maybe with sennh it's more emphasized than with grados, but still the impedance mismatch (grado and OTL) makes the grado bass less punchy and slow
post #21 of 77
Quote:
Originally Posted by robm321
TO mode?

I use the transformer with the 600's - in OTL there was clearly a slower response with a slightly muddy sound.

With the RS-1's in OTL there was enough power and I strongly disagree with the above poster saying Grado's don't work well with this amp. My RS-1 midrange is terrific with this amp.

I'm using RCA "black plate" - prolly not the best with the Senns but terrific with the Grados.
I only tried Grado's with the transformer mode, not the OTL mode (I presumed it would be worse.) So I will be checking it out. Right now in fact... (walks to other room to grab 225's)...

Cool! They sound very nice. However it seems I am hearing some distortion at higher volumes, particularly in the bass.
post #22 of 77
Quote:
Originally Posted by Jbucla2005
I only tried Grado's with the transformer mode, not the OTL mode (I presumed it would be worse.) So I will be checking it out. Right now in fact... (walks to other room to grab 225's)...

Cool! They sound very nice. However it seems I am hearing some distortion at higher volumes, particularly in the bass.
why don't you like them with transfs?

well in OTL it is normal you don't have much power, so it can easy distort with very high volumes or with low volum level recorded material
with the sr60 I get distortion very rarely in OTL, but i prefer using TO...maybe because i use reversed hd414 pads that are very very warm
post #23 of 77
Quote:
Originally Posted by Jbucla2005
I only tried Grado's with the transformer mode, not the OTL mode (I presumed it would be worse.) So I will be checking it out. Right now in fact... (walks to other room to grab 225's)...

Cool! They sound very nice. However it seems I am hearing some distortion at higher volumes, particularly in the bass.
Now I'm really confused.

People enjoy the harder to drive Sennheisser phones with the less powerful OTL mode.

But the much easier to drive Grados need the transformer or they distort?

I did listen to the GS-1000 with the TO mode last night and it did help to keep their speed in tact.
post #24 of 77
Quote:
Originally Posted by robm321
Now I'm really confused.

People enjoy the harder to drive Sennheisser phones with the less powerful OTL mode.

But the much easier to drive Grados need the transformer or they distort?

I did listen to the GS-1000 with the TO mode last night and it did help to keep their speed in tact.
i'll explain you why...it's all about impedance

high impedance cans (sennhs) need low current and high voltage...
in OTL mode this is achieved, its output has high impedance too.

low imp. cans need high current and low voltage, these are given by tranformers, that change the low current/high voltage of the tube in higher current/lower voltage, and has a low impedance output.

power is a matter of impedance matching...so if you connect a sennh to the OTL you have more power than TO, the exact opposite happens when you connect a grado. you can easly check this by switching otl/to modes with the cans...if you plug a sennh, you'll get louder volumes in OTL than TO, the opposite happens with a grado.

in addition, you have to consider the impedance line of the cans too (there are graphs on headroom), beacause the imp. mismatching can cause a different beahviour in some regions (especially bass where you can see a bump in the cans' impedance on the graphs)...for example an attenuation of the highs if the amp output impedance is much higher than the cans' imp.

i hope i've been clear, sorry for my english
post #25 of 77
Quote:
Originally Posted by Blasyrkh
i'll explain you why...it's all about impedance

high impedance cans (sennhs) need low current and high voltage...
in OTL mode this is achieved, its output has high impedance too.

low imp. cans need high current and low voltage, these are given buy tranformers, that change the low current/high voltage of the tube in higher current/lower voltage, and has a low impedance output.

power is a matter of impedance matching...so if you connect a sennh to the OTL you have more power than TO, the exact opposite happens when you connect a grado. you can easly check this buy switching otl/to modes with the cans...if you plug a sennh, you'll get louder volumes in OTL than TO, the opposite happens with a grado.

in addition, you have to consider the impedance line of the cans too (there are graphs on headroom), beacause the imp. mismatching can cause a different beahviour in some regions (especially bass where you can see a bump in the cans' impedance on the graphs)...for example an attenuation of the highs if the amp output impedance is much higher than the cans' imp.

i hope i've been clear, sorry for my english
I understand - You've explained that well. I will have to try different combinations out with this amp!! Thanks!
post #26 of 77
Quote:
Originally Posted by Blasyrkh
why don't you like them with transfs?

well in OTL it is normal you don't have much power, so it can easy distort with very high volumes or with low volum level recorded material
with the sr60 I get distortion very rarely in OTL, but i prefer using TO...maybe because i use reversed hd414 pads that are very very warm
I have never been much into transformer mode. OTL seems to have a much more fluid, natural sound with better bass and treble extension.
post #27 of 77
Quote:
Originally Posted by robm321
I understand - You've explained that well. I will have to try different combinations out with this amp!! Thanks!
well, let us know what you find
post #28 of 77
Quote:
Originally Posted by Jbucla2005
I have never been much into transformer mode. OTL seems to have a much more fluid, natural sound with better bass and treble extension.

i see, treble extension is the same, bass extension is different, better extended in OTL mode (not that much), but with a 60hz boost.
in OTL highs too are bumped...it is like a slightly loudness response.
look a these graphs made by dag:

32ohm



250ohm

post #29 of 77
Quote:
Originally Posted by Blasyrkh
well, let us know what you find
I will - I should be getting my Cardas cable for my Senn 600s back soon and after my vacation next week, I'll test it out again.
post #30 of 77
Quote:
Originally Posted by Bruce Henness View Post
... I did look under the hood and EVERYTHING says Mark II on the boards. My best guess is that the Mark III is a Mark II with the power supply in a separate box.
(and a chrome tube cover) Anybody out there got a Mark III with the Mark III designations on the boards? ...
Let me revive this thread.

Can anyone confirm that the only difference between Mark II and III is the power supply?

Nothing changed in the circuitry or in the sound? Thanks...
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