[kimdeug]

Hey HA-6A lovers.
Try to order few 22DE4 tubes for spare stock collection (just in case). But can not find them as pair or big lot for sell.
Any links will be appreciated.
Regards, Kim

 

[Zachik]

Actually the original Genalex (made in Russia) are very good for their price.

What do you mean by ORIGINAL?
Do you refer to those: https://www.thetubestore.com/genalex-gold-lion-kt88 ?

I have KT88: GEC, Genalex Golden Lion (made in England), Svetlana, Psvan MK-II and original Genalex (made in Russia).

what are your impressions of the Psvane MK-II KT-88 tubes?

 

[ThanatosVI]

What do you mean by ORIGINAL?
Do you refer to those: https://www.thetubestore.com/genalex-gold-lion-kt88 ?


what are your impressions of the Psvane MK-II KT-88 tubes?

He refers to the Originals produced before 1980 (background Story in product description)

The offered product in the link are the reissues tho not the NOS tubes

 

[Gr3g277]

Hey HA-6A lovers.
Try to order few 22DE4 tubes for spare stock collection (just in case). But can not find them as pair or big lot for sell.
Any links will be appreciated.
Regards, Kim

Hello I bought a quad of Sylvania 22de4 from eBay for cheap, they appear to be exactly the same as the RCA originals.
No change in sound detected
they seems to be hard to find indeed, I don't see them very often, and there is no new production tubes to replace them, or suitable NOS replacement that I know of
I believe Cayin must have the world's supply of those tubes in house.

Any more information would be appreciated.

 

[Andykong]

Hey HA-6A lovers.
Try to order few 22DE4 tubes for spare stock collection (just in case). But can not find them as pair or big lot for sell.
Any links will be appreciated.
Regards, Kim

Theoretically, 22DE4 as a rectifier tube has a very long expected life span, they can easily last 5 years of regular use. You don't need to have matched pair with 22DE4. They are meant to isolate the power supply from each other, so each team is working independently, and they will age at a different pace, so you can swap out one tube only instead of changing two tubes at the same time.

 

[Zachik]

He refers to the Originals produced before 1980 (background Story in product description)

The offered product in the link are the reissues tho not the NOS tubes

Interesting - everything that is NOT reissue that I can find is made in the UK. Not Russian.

 

[Gr3g277]

Thank you brother!
Yes, kt77 gold lions! These are winner of competition for el34 replacement for sure! 6L6gc is very good but kt77 more rich in harmonix..
so should I try more options from the manual like kt100, kt90, el37, 6ca7, 5881 and kt66?

I think the kt66 may be worth a try as well, those are evolution from the 6l6 family.
Tung sols 7581A are also highly regarded....
So many options !
I also have tried the blackpkate kt88 from tad, they have super bass, and very linear and energetic sound, great for metal music !
( you should listen to the latest gojira album, it is great ! )

 

[kimdeug]

What do you mean by ORIGINAL?
Do you refer to those: https://www.thetubestore.com/genalex-gold-lion-kt88 ?


what are your impressions of the Psvane MK-II KT-88 tubes?

Sorry for confusion. I was thinking by "original" the KT88 Genalex tubes, which came with HA-6A amplifier.
They are Russian made Genalex KT88, which I like a lot, so decided to buy 5-6 pairs and stay with them.
In opposite Genalex Gold Lion made in England or GEC are cost on eBay 1000$ for pair. I have one pair as Luxman pack (pictures somewhere above in this forum).
They sound fantastic, very similar as GEC KT88. More Dynamic, extended bass and juicy reach mids. Highs are so detailed, like you just heve swapped for Focal utopia headphone. IMHO KT88 GEC and Genalex (England) are the best, but very pricey. That's why I decided to stay with "original" ="russian" Genalex and do more experiments with 12AU7 tubes, as the range of last is huge. Regards, Kim

 

[rulerofrecords]

If it is the one from Auditorium, chances are high that you receive my unit which is pretty much indistinguishable from a new one.
However the stock 12au7 in the right slot is noisy and you can hear a slight hiss on the right channel. This can be easily solved by rolling tubes.
Just in case it is my old one.

My experience with them Was purely on the phone and worked very well and fast.

Well, it's a small world after all. Good to hear as I got nothing out of them. I have two pairs of 12Au7 waiting here (Sylvania and EI aka the "Jugolavian" Telefunken) so I'm curious if I can verify your observations on the infamous hiss topic. Again, cool ...

 

[atya35mm]

hi all, curious about the impedance setting you guys are on with your headphones.

Is there a hard and fast rule i.e. the amp impedance must match the impedance of your headphones? I'm currently running on Susvara and using High Impedance to take advantage of as much power out of the amp even though the headphone is rated 60 ohms which to match I will have to use low impedance on the HA-6a.

From my impressions, the key difference switching from low to high impedance is an improvement on the lower frequency and the slam / attack i.e. on certain tracks such as drum hits etc you can feel the bass instead of just hearing it. Mid / high frequency changes is not that apparent to me, but might be cleaner on the low impedance, but could also because I feel it's cleaner with lower bass. :/ So currently leaving on high impedance.

 

[Gr3g277]

hi all, curious about the impedance setting you guys are on with your headphones.

Is there a hard and fast rule i.e. the amp impedance must match the impedance of your headphones? I'm currently running on Susvara and using High Impedance to take advantage of as much power out of the amp even though the headphone is rated 60 ohms which to match I will have to use low impedance on the HA-6a.

From my impressions, the key difference switching from low to high impedance is an improvement on the lower frequency and the slam / attack i.e. on certain tracks such as drum hits etc you can feel the bass instead of just hearing it. Mid / high frequency changes is not that apparent to me, but might be cleaner on the low impedance, but could also because I feel it's cleaner with lower bass. :/ So currently leaving on high impedance.

hello,

the rule of thumb about impedance matching for TUBE amps, is you should try to match the amp and transducer impedance to have optimal power transfer .

tubes being voltage amplification devices, they tend to be more powerful with higher impedances loads ( more Volts into more ohms for the same power )
Solid state devices are the other way around, they are Current amplification devices so they tend to be more efficient with lower impedance loads ( more amps into less Ohms, therefore less volts for the same power )

this is especially true for dynamic headphones, as they usually dont have a flat impedance curve, so the output impedance of the amp has it's importance
for planars, they are usually a straight line in impedance, so they shouldn't be affected as much sound wise by the output impedance of the amp.

If i remember correctly the output impedance are :
Low : 32-64ohm
mid : 64-300ohm
high: 150-600ohm

I would try the medium setting with your susvara. maybe the high Z is less controlled so the bass is bloomier ?
I wouldn't worry too much about it for you planar, it shouldn't have a big impact.
do you use the susvara balanced or single ended ?
with my aryas I use Balanced and Low impedance mode. If I go to High Z mode, it gets a bit louder, so my first impression is to think it is better, but if go back to low Z and give it 1 click more on the pot, loudness is the same again.

YMMV

On the other hand, I will take the example of my 80ohms utopia cans.
A lot of reviewers say they are thin in the bass... but they only ever listened to them on solid state amps with low output impedance.
when you look for the impedance graph :

you can see a big jump to 300 ohms in the bass region.
So with a tube amp that can put out a lot of voltage, it means you have more power coming to the drivers at those frequencies.
Therefore the utopias sound a lot fuller.
I use them on the medium setting, and the difference with a SS amp is quite something ! now they are engaging !
High Z sounds great as well but I get too much hiss so I stick to mid.
Low Z sounds more like SS

here is your susvara for comparison

Seeing this graph, I would go mid Z, KT88, balanced out for max power.

 

[atya35mm]

hello,

the rule of thumb about impedance matching for TUBE amps, is you should try to match the amp and transducer impedance to have optimal power transfer .

tubes being voltage amplification devices, they tend to be more powerful with higher impedances loads ( more Volts into more ohms for the same power )
Solid state devices are the other way around, they are Current amplification devices so they tend to be more efficient with lower impedance loads ( more amps into less Ohms, therefore less volts for the same power )

this is especially true for dynamic headphones, as they usually dont have a flat impedance curve, so the output impedance of the amp has it's importance
for planars, they are usually a straight line in impedance, so they shouldn't be affected as much sound wise by the output impedance of the amp.

If i remember correctly the output impedance are :
Low : 32-64ohm
mid : 64-300ohm
high: 150-600ohm

I would try the medium setting with your susvara. maybe the high Z is less controlled so the bass is bloomier ?
I wouldn't worry too much about it for you planar, it shouldn't have a big impact.
do you use the susvara balanced or single ended ?
with my aryas I use Balanced and Low impedance mode. If I go to High Z mode, it gets a bit louder, so my first impression is to think it is better, but if go back to low Z and give it 1 click more on the pot, loudness is the same again.

YMMV

On the other hand, I will take the example of my 80ohms utopia cans.
A lot of reviewers say they are thin in the bass... but they only ever listened to them on solid state amps with low output impedance.
when you look for the impedance graph :



you can see a big jump to 300 ohms in the bass region.
So with a tube amp that can put out a lot of voltage, it means you have more power coming to the drivers at those frequencies.
Therefore the utopias sound a lot fuller.
I use them on the medium setting, and the difference with a SS amp is quite something ! now they are engaging !
High Z sounds great as well but I get too much hiss so I stick to mid.
Low Z sounds more like SS

here is your susvara for comparison


Seeing this graph, I would go mid Z, KT88, balanced out for max power.

Wow thanks for this, fantastic information! When I switched between low to medium impedance is when I noticed the most change now that you mentioned it, the switch from medium impedance to high impedance is quite minor, and I'm not sure whether it's an improvement or not, but stuck to high as from the power output table published by Cayin high impedance gives more power. But of course there is a relationship to the impedance of the headphone to determine final power output to headphone, which I don't quite know how to calculate. And yes I'm using balanced out.

But will stick to medium now per your suggestion! Thanks @Gr3g277!!!!

 

[rulerofrecords]

If it is the one from Auditorium, chances are high that you receive my unit which is pretty much indistinguishable from a new one.
However the stock 12au7 in the right slot is noisy and you can hear a slight hiss on the right channel. This can be easily solved by rolling tubes.
Just in case it is my old one.

My experience with them Was purely on the phone and worked very well and fast.

Yes, it is most definitely your unit. The hiss in the right channel was exactly as described! And indeed tube rolling solved that issue and made the amp pretty much silent - at least with the two high impedance headphones I'm driving single ended. And thanx for taking good care of the amp. looks and feels new. Now back to getting used to that sledgehammer ...

 

[ThanatosVI]

Yes, it is most definitely your unit. The hiss in the right channel was exactly as described! And indeed tube rolling solved that issue and made the amp pretty much silent - at least with the two high impedance headphones I'm driving single ended. And thanx for taking good care of the amp. looks and feels new. Now back to getting used to that sledgehammer ...

Enjoy, it is an amazing amp and I only gave it away because I had the opportunity to get my Octave V16 for cheap.

 

[Andykong]

hi all, curious about the impedance setting you guys are on with your headphones.

Is there a hard and fast rule i.e. the amp impedance must match the impedance of your headphones? I'm currently running on Susvara and using High Impedance to take advantage of as much power out of the amp even though the headphone is rated 60 ohms which to match I will have to use low impedance on the HA-6a.

From my impressions, the key difference switching from low to high impedance is an improvement on the lower frequency and the slam / attack i.e. on certain tracks such as drum hits etc you can feel the bass instead of just hearing it. Mid / high frequency changes is not that apparent to me, but might be cleaner on the low impedance, but could also because I feel it's cleaner with lower bass. :/ So currently leaving on high impedance.

@Gr3g277 has provided a very good description of our impedance matching output feature, I just want to add one point to your case. The Susvara is rated right in between the L and M impedance setting, so both setting is applicable to this headphone. You can select either L or M impedance according to your preference.