[tommyc]

I just switched out my stock JJ 12AT7 for NOS British Military Mullards matched pair tested for low noise and harmonics. Best $100 I have ever spent. I had assumed that most reports of tube changes were the typical exagerations and hyperboli that you typically read about on these forums.

My honest assessment is that the stock tubes should immediately be removed from any MHA200 and dropped in the trash, you will not listen to them again. If you have not tried any other tubes in your MHA200, I suggest going to your local McIntosh dealer and ask if you can try out some Mullards or anything else they have on hand. If you can not hear the difference between Mullards and JJ you may need to re-evaluate your system or make sure there are not medical issues.

I have put in another order for two more pairs of these military grade tubes. As soon as I have more cash available, I plan to order several more matched pairs.

Spending money on $2000 interconnect cables, $100 fuses, $200 power cords, etc to me now seems quite foolish if you have not swapped out the stock tubes for $100. You will get much greater sonic improvement immediately (no burn in, no sitting for hours A/B testing) over any of the above. I think the best way to describe the change is to imagine all your high resolution music has been re-recorded by Chesky using Binaural microphones.

http://www.mullardtubes.com/Mullard-ECC81-12AT7-CV4024/?ID=0&ProductID=152

Totally, those stock tubes are really a hinderance to the wonderful machine below.

If you like the Mullard sound, you may want to hunt for a pair of their 1950s square getter version from the Mitcham factory. My currently favourite is a pair of Marconi branded B309 from Mullard Blackburn. I have very good result with Made in Holland Mullards too (Those are Phillips made and branded as Mullard).

Telefunken ecc801/ecc81 and Brimer 6060 yellow/white T are very good too but they sound different from Mullard.

I am waiting for a pair of GEC a2900 to arrive, they are supposed to be one of the best 12at7, but my local tube store said they might be too bass heavy for head-amp use.

P.S. Here are a couple links that I find very helpful for tube identification/selection.
Mullard factory and date codes
Factory ratings (it's just someone's personal opinion, don't take it as gospel, but a nice starting point nonetheless)

 

[Lépine]

I really appreciate sharing the info on great tubes. I now know I have been missing out on a lot. For months I have been debating about upgrading interconnects. I should have swapped out the tubes sooner for less than a tenth of the cost. I am not sure I will hear 5% improvement with interconnect improvements. But tubes, in two minutes I hear a completely different sound signature.

 

[Helderfb]

MHA 200 e Quad PA-One+, são iguais em qualidade de som? Um Quad PA - One+ apareceu pela metade do preço de um MHA 200, acho o MHA 200 mais bonito, mas se o Quad PA for tão bom quanto estou pensando em adquirir, será minha primeira experiência com tubos.. .

 

[RPKwan]

Stock 12BH7A replaced with Sylvania 12BH7S. Stock 12AT7 replaced with Philips E81CC Made in Germany.

 

[Slim1970]

Stock 12BH7A replaced with Sylvania 12BH7S. Stock 12AT7 replaced with Philips E81CC Made in Germany.

Compared to the stock tubes, what changes to the sound are you hearing?

 

[RPKwan]

Compared to the stock tubes, what changes to the sound are you hearing?

The soundstage is wider and deeper. String instruments are much more detailed and natural. Mids are slightly boosted, vocals are much more intimate and sweeter.

Obviously pairing matters, so for my GRADO GS1000i and Audeze LCD2F they sound incredibly real and natural. Pairing with my GRADO PS1000e it's slightly too warm but I think SS is a better match for those headphones.

Overall with the tube rolling and the ones I'm using it just sounds much more refined for not a very big investment.

 

[Slim1970]

The soundstage is wider and deeper. String instruments are much more detailed and natural. Mids are slightly boosted, vocals are much more intimate and sweeter.

Obviously pairing matters, so for my GRADO GS1000i and Audeze LCD2F they sound incredibly real and natural. Pairing with my GRADO PS1000e it's slightly too warm but I think SS is a better match for those headphones.

Overall with the tube rolling and the ones I'm using it just sounds much more refined for not a very big investment.

Nice, It sounds like the new tubes are working out for you. I decided to put the stock tubes back in replacing the Mullar 6201’s I’ve been using the past couple of month. To be honest they are not as bad as I thought. They have enough tube flavor to differentiate itself from any solid state amp.

I pulled out my D8K Pro’s for a listening session and they are sounding exceptional out of the MHA200. The stock tubes work well with this headphone because they aren’t as “tubey” and sound more neutral than the Mullards. The sound is fuller, more spacious, and airy than the GS-X. As a matter of fact the D8K Pro’s sound thinner on it when I switch back and forth. So I know I’m getting the sound of tubes in even stock form out of the MHA200. I’m leaving the stock tubes in the MHA200’s for now. They seem to pair with a wider variety of headphones.

 

[RPKwan]

Nice, It sounds like the new tubes are working out for you. I decided to put the stock tubes back in replacing the Mullar 6201’s I’ve been using the past couple of month. To be honest they are not as bad as I thought. They have enough tube flavor to differentiate itself from any solid state amp.

I pulled out my D8K Pro’s for a listening session and they are sounding exceptional out of the MHA200. The stock tubes work well with this headphone because they aren’t as “tubey” and sound more neutral than the Mullards. The sound is fuller, more spacious, and airy than the GS-X. As a matter of fact the D8K Pro’s sound thinner on it when I switch back and forth. So I know I’m getting the sound of tubes in even stock form out of the MHA200. I’m leaving the stock tubes in the MHA200’s for now. They seem to pair with a wider variety of headphones.

Yup, I know what you mean.

For my PS1000e I think a less tubey, warm signature suits it better.

 

[Lépine]

The military Mullards I put in sound more aggressive than the stock JJ tubes. There is also less tube noise. Still a faint bit of waterfall hiss, but about 1/4-1/5th the level of background noise. I hear faster and more forceful bass and clearer treble. I don't think I noticed a change in tonality. For that I would have to A/B back and forth, which I am not going to do with tubes that I am likely to break in the process.

I think I may have one bad military tube. I notice a bright yellow glow that lasts 1 second every time I turn on the set. A little disappointed, but what can I do but use it until it starts to not sound musical...

 

[tommyc]

The military Mullards I put in sound more aggressive than the stock JJ tubes. There is also less tube noise. Still a faint bit of waterfall hiss, but about 1/4-1/5th the level of background noise. I hear faster and more forceful bass and clearer treble. I don't think I noticed a change in tonality. For that I would have to A/B back and forth, which I am not going to do with tubes that I am likely to break in the process.

I think I may have one bad military tube. I notice a bright yellow glow that lasts 1 second every time I turn on the set. A little disappointed, but what can I do but use it until it starts to not sound musical...

The hiss very possibly comes form the 12bh7. I had pretty bad hiss on my unit, it went away completely after replacing the 12bh7 with tung-sol nos ones.

The flash you saw when the tube turns on is call the heater flash. It doesn’t affect the performance of the tube during normal operation, but the filament itself may burn out prematurely thou. It happens a lot on European tubes. I wouldn’t worry too much about it.

 

[mackmantcp]

When the first reviews for the MHA200 were coming out I remember reading an article that raved that a specific pair of high-impedance Grado or Beyer headphones sounded amazing on the 200. I'm trying (and failing) to track down that review now. Anybody able to jog my memory? Thanks -mm

 

[RPKwan]

When the first reviews for the MHA200 were coming out I remember reading an article that raved that a specific pair of high-impedance Grado or Beyer headphones sounded amazing on the 200. I'm trying (and failing) to track down that review now. Anybody able to jog my memory? Thanks -mm

I don't know about the review but I have 3 pairs of Grados that I'm pairing with the MHA that sound amazing. I actually demoed the Ferrum stack which is about the same price but it didn't pair as well with my Grados.

 

[Slim1970]

I don't know about the review but I have 3 pairs of Grados that I'm pairing with the MHA that sound amazing. I actually demoed the Ferrum stack which is about the same price but it didn't pair as well with my Grados.

Yep, not bad

 

[RPKwan]

Yep, not bad

I mentioned in a few posts back that the only Grado I find slightly too warm with the MHA is the PS1000e. How is the PS2000e?

 

[Slim1970]

I mentioned in a few posts back that the only Grado I find slightly too warm with the MHA is the PS1000e. How is the PS2000e?

It wasn’t bad, there was some bass bloat. The midrange and treble sounded phenomenal.