[Newsee]

The red dot is the heating of the cathode. I am not an expert, but I would not worry until I hear an imbalance between the right and left side.
Swapping the right and left tube can tell if that is caused by the tube properties or the amp.

This green light looks pretty in the darkness. Time for me to remove the protective cover again?

 

[ochre korg]

The red dot is the heating of the cathode. I am not an expert, but I would not worry until I hear an imbalance between the right and left side.
Swapping the right and left tube can tell if that is caused by the tube properties or the amp.

That’s a great idea, I will do that when the sound will get bad, now the sound is just beyond great

 

[louis9]

Regarding tube ruggedness (aka its ability to resist microphonics and vibrations), one might want to pay attention to whether the tubes are designated military spec (for example vacuum tubes used in aviation or in naval applications). Another sign of ruggedness is the use of triple mica spacers, being more stable than tubes with double mica. One will encounter these terms questing for decent vintage 12AT7 tubes for the MHA200

do you have any tube recommendations for MHA200?

 

[qboogie]

Vintage Sylvania gold brand triple mica black plates if you like smooth and balanced across the spectrum. These, as I have mentioned before, are highly desirable.

Old British Mullard 6201 which I got from here

http://mullardtubes.com/Mullard-ECC81-12AT7-6201-GOLD-PIN/?ID=0&ProductID=204

The mullard tubes are what I have in place right now and they sound like a better fit for the MHA200 and verité open. Compliments the mid-range even more and has less softness than the Sylvania.

I might sell the Sylvania gold brand if anyone is interested

 

[Slim1970]

Vintage Sylvania gold brand triple mica black plates if you like smooth and balanced across the spectrum. These, as I have mentioned before, are highly desirable.

Old British Mullard 6201 which I got from here

http://mullardtubes.com/Mullard-ECC81-12AT7-6201-GOLD-PIN/?ID=0&ProductID=204

The mullard tubes are what I have in place right now and they sound like a better fit for the MHA200 and verité open. Compliments the mid-range even more and has less softness than the Sylvania.

I might sell the Sylvania gold brand if anyone is interested

The 6201's are what I'm currently rolling in my MHA200. It's a great sounding tube in this amp.

 

[TSAVJason]

I just received my Mullard CV4024's. Agree with Jason - more aggressive dynamics by a tad. Sounds great though. Jason, or others, what other differences besides dynamics do you hear when you compare the Mullards to the stock JJ tubes?

Sorry for the late replay. I was in the hospital with a back injury. Not much else for a difference ….maybe just a slight decrease in the sound stage but a slight pick up in the upper mids.

 

[Deleeh]

Sorry for the late replay. I was in the hospital with a back injury. Not much else for a difference ….maybe just a slight decrease in the sound stage but a slight pick up in the upper mids.

Get well soon and hope your back gets better.

 

[TSAVJason]

Get well soon and hope your back gets better.

Thank you! I'm already doing much better

 

[mlundy57]

I received my MHA 200 a couple weeks ago. The sound was very good and was dead quiet with all my headphones except my favorite ones, the 50mm open back model from Swansong Audio. These are very revealing, low impedance, high sensitivity (24 ohm/110ish dB) headphones that demand a really low noise floor. I've tried them with many headphone amps that are described as dead quiet with high sensitivity IEMs only to find they are not dead quiet with the Swansong Audio headphones. Maybe I'm spoiled, but noise, even if it's only audible between tracks, really bugs me.

Based on recommendations I read earlier in this thread, I picked up a pair of Mullard CV4024s that were matched for high gain, low noise and microphonics, and balanced triodes. Replacing the stock tubes with these reduced, but did not totally eliminate the audible tube noise. That left the 12BH7s. I was able to get some matched super low noise (phono grade) NOS RCA 12BH7As. After replacing the stock 12BH7As with the RCAs the MHA was dead quiet even with the Swansong Audio headphones. With the new tubes, the MHA200's sound is fuller, smoother, more dynamic, and more resolving. All in all, a much more pleasing listening experience. One I'm very satisfied with and feel the amp was worth the wait.

The MHA 200 is being fed by a PS Audio DirectStream DAC with the network bridge via balanced connections. Music sources are the PS Audio PerfectWave SACD transport and a music server running ROON. The volume control on the MHA 200 is set a little past the detent, around 1 o'clock and left there. Volume is controlled by the DAC.

 

[Slim1970]

I received my MHA 200 a couple weeks ago. The sound was very good and was dead quiet with all my headphones except my favorite ones, the 50mm open back model from Swansong Audio. These are very revealing, low impedance, high sensitivity (24 ohm/110ish dB) headphones that demand a really low noise floor. I've tried them with many headphone amps that are described as dead quiet with high sensitivity IEMs only to find they are not dead quiet with the Swansong Audio headphones. Maybe I'm spoiled, but noise, even if it's only audible between tracks, really bugs me.

Based on recommendations I read earlier in this thread, I picked up a pair of Mullard CV4024s that were matched for high gain, low noise and microphonics, and balanced triodes. Replacing the stock tubes with these reduced, but did not totally eliminate the audible tube noise. That left the 12BH7s. I was able to get some matched super low noise (phono grade) NOS RCA 12BH7As. After replacing the stock 12BH7As with the RCAs the MHA was dead quiet even with the Swansong Audio headphones. With the new tubes, the MHA200's sound is fuller, smoother, more dynamic, and more resolving. All in all, a much more pleasing listening experience. One I'm very satisfied with and feel the amp was worth the wait.

The MHA 200 is being fed by a PS Audio DirectStream DAC with the network bridge via balanced connections. Music sources are the PS Audio PerfectWave SACD transport and a music server running ROON. The volume control on the MHA 200 is set a little past the detent, around 1 o'clock and left there. Volume is controlled by the DAC.

I may have to look into replacing the 12BH7 after reading this. I don’t have a problem with the noise floor of my MHA200, but I like the way you are describing what the RCA tubes are adding to the sound.

 

[mlundy57]

I can't tell how much of the sonic differences are from the Mullard 12AT7s and from the RCA 12BH7s individually. This is because I was focusing on getting rid of the noise first. Since there was still some noise present after replacing the 12AT7s, I immediately replaced the 12BH7s. After this the noise was gone. Since the noise was now gone, I allowed the tubes to warm up for a few hours before listening. This means the sonic improvements I'm hearing are likely due to the combination of the Mulards and RCA. Also, the tubes are no where near burned in yet so there may be more changes ahead.

 

[qboogie]

I am thinking about replacing my MHA200 with the Feliks Euforia (AE or standard edition).

Can anyone who has experience with both talk me out of it?

 

[Newsee]

Right now I am listening to 'The Tunnel' from the Tord Gustavsen Trio.
Empyrean driven by the MHA200. Sublime.

Why would you change? I have no experience with the Euforia, but someone wrote here that the tubes types for tube rolling on Euforia are pretty much sold out, not available, very expensive. Based on price it would be anyway a sidegrade. If something, go for the Envy!

(I hope it was at least a nice try )

 

[Slim1970]

I am thinking about replacing my MHA200 with the Feliks Euforia (AE or standard edition).

Can anyone who has experience with both talk me out of it?

Not sure, if they are better amps. You may get more ”tube” flavor but it will come at with a loss of some detail and transient snap. My next move it I were to move on from the MHA200 would be the Cayin HA-300Mk2.

 

[qboogie]

Not sure, if they are better amps. You may get more ”tube” flavor but it will come at with a loss of some detail and transient snap. My next move it I were to move on from the MHA200 would be the Cayin HA-300Mk2.

Yeah that monster has me intrigued, but I'm trying to keep my gear minimal because I'm moving soon.