The MG Head OTL 32....a disappointment!

[regular.guy]

Hi head-fi guys! I am a newbie to the headphone scene, not just 1 week ago I purchased a pair of Sennheiser 650's and an ASL MG DT/OTL 32 from audioadvisor. They have good customer service and a forgiving return policy. Note, however, on their website it reads that the 32 has an OTL/transformer output switch, but this is false. It has a high/low impedence switch and headphone/preamp switch. First impression was that the 32 is quite heavy, well built, and looks good on my rack (love the exposed tubes, and the glow they put off at night). Upon closer inspection the headphone jacks were slightly crooked, but it did not bother me. After plugging in all the appropriate cables, I fired it up. Well, immediately I noted that the remote control and/or the motor driving the source selection was inoperable. Being that I am up frequently to change cd's anyway and do not change sources much, this was no big deal. The manual was sparse and not very professional, but perhaps ok for a budget product.

I was only able to evaluate the ASL with the Sennheiser's, no AKG's available. The 1/4" jack locked in snugly with a click. The sound, right out of the box was surprisingly good. It is my first tubed product, perhaps it had a good first impression because I'm used to all solid state

. My home system is a Pioneer PD65, Musical Fidelity A3cr, Bryston 4bsst, and Thiel 2.3's. I let the amp and phones burn in for at least 50 hours before I listened to them again.

I had read the professional review on 6moons on the 32 and thought that he may have received a bum unit, as the review was less than good. After reading many other sources on ASL products with good reviews, I decided to try the 32 out. The reviewer stated there was a distinctive grain on the trailing ends of notes, especially on the lower frequency notes. Well, I definitely heard this grain, quite objectionable! This grain was not noticeable on all albums. The last album I listened to was Sade's greatest hits before I made the decision to send it back, the trailing grain was too much! Many cd's were used for the test including; Pantera "Vulgar Display", Infected Mushroom "BP Empire", Sarah McLachlan "Touch", Tool "Undertow", and others. I thought it might just need more break-in time, but the grain only got worse. Besides the grain, the tube sound from the 32 was relieving, enticing, musical, involving, and non-fatiguing. It gave me everything my solid state speaker based system did not. I'm gonna trade the 32 for the OTL mk III, asap.

By the way, the 32 as a preamp, is quite good. Being that it was my first tubed preamp, I was not sure what to expect. It gave much of the relaxing and smooth sound that the headphone output did. The midrange tonality was fantastic. The bass was good, a tiny bit fuzzy, but deep. The highs were a little rolled, but still there. The 32 would be a good choice for a mid fi system. My only gripes would be that is gets congested on complex material. Being that my speaker system was bright, etched, and at times harsh, I would perfer the 32 over my Musical fidelity. Oh great, now I want a new tubed preamp too, the wife is gonna beat me.

Thanks for all the other posts guys, they were quite informative!

 

[clarke68]

Welcome to Head-Fi, and sorry about your wallet!

I know almost nothing about the ASL products, but I have read that they improve with new tubes. Lots of threads about it, the one I found with the most intriguing title is MG Head owners, unleash your amp! (My life changing revelation).

Have fun!

 

[elrod-tom]

It's too bad that your experience with the OTL-32 was unfavorable. I'm very fond of mine, and have not experienced the noisiness that you have. It's IMHO one of the better values out there, especially when one considers the ability to drive the K1000.

 

[Yikes]

I agree with elrod-tom. Once retubed the ASL MG Head OTL/32 drives my K1000’s exceptionally well. For the K1000’s it’s a wonderful amp. With my HD-650’s I prefer my solid state amplifiers. Now that I think about it I’m not fond of the OTL/32 with any of my dynamic headphones.

It’s with the AKG K1000’s where the OTL/32 truly sings.

 

[Iron_Dreamer]

Quote:

Originally Posted by regular.guy Many cd's were used for the test including; Pantera "Vulgar Display", Infected Mushroom "BP Empire", Sarah McLachlan "Touch", Tool "Undertow", and others.

LOL I have all of those CD's on my computer, some strange coincidence.

 

[go_vtec]

I had owned OTL32 for a while and I thought it was a fairly good. Have you tried a good pair of NOS 12au7s? RCA cleartop will do wonder for OTL32.

 

[dave-g]

I think that I have an older model as I do have the Transformer/OTL switch on mine. I have to say that I had similar results when using the standard Chinese tubes and a pair of Senn HD 600's.
I opted for a pair of JJ electronics output tubes and a NOS telefunken preamp tube and WOW, what a difference. I really thought I was listening to a totally different amp, in a good way.
I think that the preamp tube made the biggest difference though, as just about every tube i tried (JJ, Svetlana, RCA) except the telefunken had a very noticeable microphonic effect, which I really didn't understand at the time but could easily hear. I'd start rolling a few tubes before you're ready to throw in the towel.
I have other tube amps and I found that I like the sound of one set of tubes for jazz, another for classical, another for downtempo etc. so have some fun and explore some other tubes to see what sounds best for your setup and listening preferences.

 

[regular.guy]

Thanks for all the replys. After hearing the same grain on my unit as did the professional reviewer did (6moons.com) on his, I automatically sent it back. I am new to tubes and I didn't want to be stuck with a bad unit and then have to spend $100's more on tube rolling to try to alleviate it on a $700 dollar product. Maybe ASL's quality control missed a few units. I have not lost faith in ASL products, however. The MG head Mk III is on it's way. I was just totally blown away by the tube sound to give up! I even had to buy an Ah! Tjoeb 4000 cd player ($700) for the speaker system, that's on it's way too. Hey, what's a few missed mortgage payments and a few days without food? At least I'll have some good stuff!

 

[e_dawg]

Quote:

Originally Posted by regular.guy Note, however, on their website it reads that the 32 has an OTL/transformer output switch, but this is false. It has a high/low impedence switch and headphone/preamp switch.

The high/low impedance switch is almost certainly the same thing as the transformer-coupled / OTL switch -- transformer-coupled being low impedance, and OTL being high impedance.

Quote:

I'm gonna trade the 32 for the OTL mk III, asap.

You gotta be kidding. Get a SinglePower or something else. You don't like the ASL MG Head sound, and you're downgrading to the DT/OTL Mk3? BTW, I had the MG Head DT/OTL Mk3 and was not impressed with the sluggish bass.

 

[mackay maus]

Hello fellow OLTers.

I had mine about two months now, and am pleased with the build quality and sound. makes a dandy preamp for my system as well.I like it better with my RS1 than 650s, but it drives both well.

The remote controls volume, but does look like something you'd carve in prison to use in an escape. (Look out warden-he's got a remote!)

I have two questions that i hope one of you can answer.

First question to you folks is. Does anyone own and use the K1000s with the OTL32? I'd read the six moons review, which I think (Hard to tell with 6moons sometimes) was positive. But would be interested in more comments.

Secondly, I'm using stock tubes in the 32. Any suggestions which tubes to roll first. With 7 to choose from, I'd like to focus on one set first. Which would make the biggest difference, and any suggestions of tubes to try.

I live in canada, so postage and duties prevent me from randomly buying and trying and reselling without hassle and ccosts.

thanks

Matthew

 

[elrod-tom]

I use the K1000 with the OTL-32, and I think it does a good (but not great) job driving them. I listen at low volume, and my MSB DAC sends the signal out at a relatively hot 7.5v (as opposed to 2.5v), so it's not a problem for me at all. However, when I've used other players, and I've cranked it up higher than usual, I've noticed that it starts to strain a bit. I've been told that retubing can fix this very nicely, but I've not gone down that road yet.

I actually think it does a better job driving dynamic headphones. I've not heard the crackling sound discussed here. Oh well...hope this helps.

 

[go_vtec]

Quote:

Originally Posted by mackay maus Secondly, I'm using stock tubes in the 32. Any suggestions which tubes to roll first. With 7 to choose from, I'd like to focus on one set first. Which would make the biggest difference, and any suggestions of tubes to try. I live in canada, so postage and duties prevent me from randomly buying and trying and reselling without hassle and ccosts. thanks Matthew

You should start with a pair of 12au7s since it seems to have biggest impact on how 32 sounds. My recommendation is try NOS RCA cleartop!

 

[KZEE]

Quote:

Originally Posted by mackay maus Secondly, I'm using stock tubes in the 32. Any suggestions which tubes to roll first. With 7 to choose from, I'd like to focus on one set first. Which would make the biggest difference, and any suggestions of tubes to try.

I'm pretty sure I there are some threads from the past where some of the fellas discussed and made recommendations as to what tubes work best in ASL headamps - give the search function a try.

 

[Sovkiller]

Quote:

Originally Posted by regular.guy ".....I am new to tubes and I didn't want to be stuck with a bad unit and then have to spend $100's more on tube rolling to try to alleviate it on a $700 dollar product......"

If you go the tubes way, do not expect any manufacturer to place in your amp decent tubes, sovtek, JJ, EI, etc...is mostly the only tubes you will get, besides maybe a GE, or RCA militar tube or the like from recent productions.....Why? simply it is not posible, the supplies for really good tubes are mostly dry right now, and they need regular production tubes for their products, that they can get in any moment, that is the main reason what I stay away of the tubes, you spend a fortune on the amps, get regular to bad tubes on it, that needs to be replaced for expensive ones, what is the big deal then? Sorry but the MGHead was enough for me, the tube hunting is not an easy task unless you have a lot of spare time, or a huge supply of them, stay away of tubes man....

 

[regular.guy]

I had sent the OTL 32 back to audioadvisor, as I stated originally, and ordered the MG head Mk III. It's much better! Good sound right out of the box. All the knobs are tight, not jiggly. No horrible coarse grain (just a very suble fine grain, which is barely noticable). Besides the source selection motor being broken on the OTL 32, I still think there was something else wrong with it. A bad capacitor, resistor, switch (?).. that would explain why my unit sounded so poor and others were able to get decent sound out of thier OTL 32. The Mk III's sound isn't perfect, and I expect to roll it. There is certainly some great advice on that subject here. I had recently read nick dangerous' article on rolling his mg otl mk ?.