Antique Sound Lab MG Head DT / OTL MK III Headphone Amp
Feb 17, 2006 at 5:43 PM Post #2 of 79
I have and MG HeadDT. The HD-600 is probably the ideal can for that amp. Sound is smooth and romantic, but lacks the transparency present in more expensive amps. Highs tend to be a bit rolled-off, which could account for the perceived lack of transparency. This occurs even with very good tube sets. Quality control was pretty poor in the early going, and some of these amps have hum issues (although they can sometimes be fixed easily). Even so, it can sound very good driving Sennheisers.
 
Feb 17, 2006 at 8:18 PM Post #3 of 79
I have an MG-Head OTL Mark III and a HeadRoom MicroStack. Personally I prefer the MicroAmp with my HD-595s. The Senns tend to sound a little dark and the MKIII has a midbass hump in the 40-80 Hz range. The combined effect make my HD-595s (50 ohms by the way) sound extra dark and muddy. HeadRoom amp are tailored to Sennheisers, and you might find one of their amps a better match.

A while back I did some frequency response measurements of the MG-Head OTL MKIII. I did not use any Senns in the test, but the results might not be too far off. I used Grados for low impedance (32 ohms) and DT-250/250s for high impedance (250 ohms). See this thread for the data:

http://www4.head-fi.org/forums/showthread.php?t=158534
 
Mar 5, 2006 at 11:34 AM Post #4 of 79
Quote:

Originally Posted by dag655321
I have an MG-Head OTL Mark III and a HeadRoom MicroStack. Personally I prefer the MicroAmp with my HD-595s. The Senns tend to sound a little dark and the MKIII has a midbass hump in the 40-80 Hz range. The combined effect make my HD-595s (50 ohms by the way) sound extra dark and muddy. HeadRoom amp are tailored to Sennheisers, and you might find one of their amps a better match.

A while back I did some frequency response measurements of the MG-Head OTL MKIII. I did not use any Senns in the test, but the results might not be too far off. I used Grados for low impedance (32 ohms) and DT-250/250s for high impedance (250 ohms). See this thread for the data:

http://www4.head-fi.org/forums/showthread.php?t=158534




i tried the hd595 (50ohm) with the MG HEAD, and they had a really strange behaviour...with transf. they totally lost the low end, in OTL they had freaking boomy bass...that's quite weird...

with hd 650 (and many others low and high imp. cans) i don't have any problem at all
 
Mar 5, 2006 at 12:08 PM Post #5 of 79
I really enjoy my MGhead otl MK 111.I use it with all of my phones including my Grados.I have had no problems out of mine at all.
 
Mar 7, 2006 at 3:45 PM Post #6 of 79
I have the original or II version. I'm pretty sure it was the original. I bought it used and put in RCA NOS "black plates" - It is very synergistic with the Senn 600's, but as mentioned above not the best out there. However, for the price, it's very good. I can use my Grado RS-1's in OTL mode and need the transformers for the 600's, but it is very enjoyeable to listen to.

It's somewhat dark and the top end is rolled off, but those are both attributes to the Senn 600, so I don't blame the amp.

If you want to spend lots and lots of money buy a headroom.

I did have to send mine in for repair because of humm issues. Since then it's been dead quiet - the repair was $100, the amp was $200 (used), the tubes were $350
eek.gif
, so mine isn't stock.
 
Mar 7, 2006 at 3:53 PM Post #7 of 79
Quote:

Originally Posted by robm321
I have the original or II version. I'm pretty sure it was the original. I bought it used and put in RCA NOS "black plates" - It is very synergistic with the Senn 600's, but as mentioned above not the best out there. However, for the price, it's very good. I can use my Grado RS-1's in OTL mode and need the transformers for the 600's, but it is very enjoyeable to listen to.

It's somewhat dark and the top end is rolled off, but those are both attributes to the Senn 600, so I don't blame the amp.

If you want to spend lots and lots of money buy a headroom.

I did have to send mine in for repair because of humm issues. Since then it's been dead quiet - the repair was $100, the amp was $200 (used), the tubes were $350
eek.gif
, so mine isn't stock.




rca black plates for 350$?????? are you talking about the command series??

however i have that tube too ( rca 5751 command black plate paied 60$), and i think is the worst tube for the hd650 because is by far one of the most dark tube (it has a very heavy low end)
i think for sennh the best are the JJ, or telefunken if you want a NOS tube, they are much brighter than rac/sylvania/mullard tubes
 
Mar 7, 2006 at 6:42 PM Post #8 of 79
Quote:

Originally Posted by Blasyrkh
rca black plates for 350$?????? are you talking about the command series??

however i have that tube too ( rca 5751 command black plate paied 60$), and i think is the worst tube for the hd650 because is by far one of the most dark tube (it has a very heavy low end)
i think for sennh the best are the JJ, or telefunken if you want a NOS tube, they are much brighter than rac/sylvania/mullard tubes




I'm not sure exactly which ones. If I remember I'll check my receipt. But I think you are right. They have a dark sound which doesn't help matters. Whatever tubes I have, they are awesome, but as U mentioned not the greatest compliment to the Senns. They are perfect in my asl aq1001dT tube amp for my K1K cuz the K1K's can be aggresive on the top end with the wrong tubes.

Thanks for the suggestions. I may swap them out for JJ or telefunken - and try that. I'm not a tube roller, so I have to really on others.
 
Mar 7, 2006 at 6:54 PM Post #9 of 79
Quote:

Originally Posted by robm321
I'm not sure exactly which ones. If I remember I'll check my receipt. But I think you are right. They have a dark sound which doesn't help matters. Whatever tubes I have, they are awesome, but as U mentioned not the greatest compliment to the Senns. They are perfect in my asl aq1001dT tube amp for my K1K cuz the K1K's can be aggresive on the top end with the wrong tubes.

Thanks for the suggestions. I may swap them out for JJ or telefunken - and try that. I'm not a tube roller, so I have to really on others.



you're welcome, try the jj first (ECC803S), so if you find them too bright you'll not waste lots of money on the nos telefunken
 
Mar 8, 2006 at 4:31 AM Post #10 of 79
I have a MK III and have found it fantastic in OTL mode with my Senn 580's. Transformer mode is probably best left to the low ohm phones. 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?
I do know my unit is DEAD quiet and fulfills all my expectations. I have also tried some tube rolling with older tubes and have yet to better the sound of the original tube set.
And...I purchased a "$200" EL-34 amp from Hong Kong (jennychan) and it came with "12AX7's" that glow bright blue at the bottom (little blue flame effect). Anybody ever seen a 12AX7 that did that (without help from an LED)? And where do you get um?
FYI...the amp has a volume control that looks like it was made by a blacksmith, obvious cosmetic reject caps, and required a dremmel tool to make the knobs turn smoothly....However the little sucker sounds great to me and verrry tubey (which is exactly what I wanted). For $250 to my door I am more than pleased. Highly recommended (if you enjoy taking risks).
eggosmile.gif
 
Jul 17, 2006 at 1:56 PM Post #11 of 79
I find the Head III dead quiet and pretty refined with my HD650/Carda in OTL mode. I have used the finest 12AX7s (AMperex long plate foil-d- getter delta 1958) and 5751 (Syl GB, GP, 3M, GP) are my favs; and many EL84 (Amperex my favorite--early '60s). Hi-bit (320) MP3s or Cal Delta CDT into Cal ALpha eith GE 3M/BP (1953).

The sound is quite refined--and I can alter the highs from bright to smooth with no harshness with the EL84s I choose. The stage allows localization just like my excellent Ayre 3-VDA-VR3.5, though no the same width or space, of course. I could not be more pleased and want to try a SP one day.

The Head III is totally non fatigueing, even at high volumes, no matter what the music--even hard core rap or techno. Jazz vocals (sinatra) are wonderful.

Happy camper.
 
Jul 17, 2006 at 3:19 PM Post #12 of 79
I've tried lots of 12ax7 new and nos...and i find many of the nos too heavy in the bass region...syl 5751 jhs or rca command are heaviest...and telefunken the brightest...in the middle there are mullard and amperex.

about the el84 i've never tried nos, but all the new productions, jjs are the best.


i find the hd650 + OTL combo not neutral, and it's the only fault of this combo, i think...
i like the warm sound with very good detail (even if it's not fast as a solid state amp)...but still i think the best combo is mg head+hd600 for a more neutral sound
 
Jul 17, 2006 at 10:49 PM Post #13 of 79
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.
 
Jul 18, 2006 at 12:03 AM Post #14 of 79
I owned the MG Head, sold it, and now bought it again. I should never have sold it in the first place. It is great with Senns in OTL mode and very sensitive to tube rolling. I am actually mostly using it as a pre-amp (in OTL mode) with a t-amp and some efficient speakers and it sounds very warm, although there is some noise with the t-amps volume pot maxed, it's not noticable when music is playing at moderate volumes. I do not have any problem with this noise with headphones though. I find it too bright for my Beyer DT-880's with the tubes I'm using (Sylvania GB-5751 and JJ EL84's) but perfect for my Senn 580's and I am looking forward to getting some 650's for it like I used to use with my last one, because the Senns seem to match so well with it. I never use transformer mode, I think it sounds a lot less full and natural compared to OTL mode, and as it's been mentioned before the MG Head doesn't really do Grados.
 
Jul 18, 2006 at 2:08 AM Post #15 of 79
I have the original otl model. They have a great synergy with my hd600's. I'm planning some mods on it to see if I can solve some of it's shortcomings. Bought a demo for $225 and never regretted it. I always heard that the Audio Valve was a better mg head. Anyone had both of them? I've got Ei el84's and Raytheon 5751 (windmill getter) and they made a large improvement. I thought about selling it a couple of times and I'm glad i didn't. I mean, what could I get for the money,.. 4-5 tanks of gas?
 

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