[Relaxasaurus]

Back to using this as my daily driver in the winter months. Still sounds great with my Empy.

I don't know if someone has mentioned this before, but I just found out today that putting the cage on your ha-6a helps to quiet down any noise that the tubes catch from nearby interference (wireless radio, wifi AP, etc).

I was rolling tubes today and found the new tubes were quite noisy compared to the original. When I put the cage back on, the amp was significantly quieter!

Speaking of which, has anyone tried using preamp tube shields for this amp? I was getting some random noise when using the Verite, but when I placed my hand over one of the 12au7's it went away.



I see there are screws to secure the shield bases to the amp (as well as grounding them) but I'm unable to access them on the preamp tubes:

 

[Andykong]

Back to using this as my daily driver in the winter months. Still sounds great with my Empy.



Speaking of which, has anyone tried using preamp tube shields for this amp? I was getting some random noise when using the Verite, but when I placed my hand over one of the 12au7's it went away.



I see there are screws to secure the shield bases to the amp (as well as grounding them) but I'm unable to access them on the preamp tubes:

I am not sure if something like THIS will help.

Maybe you can secure the tube shield with blu tack and then add a shielded wire to connect the tube shield to the back panel of the amplifier for grounding. This won't look good but with a black shielded wire, this is doable. Lastly, I have seen users drill two small holes in the chassis so that they can secure tube shields like this to the chassis directly, this is an extreme case and will definitely affect the secondhand value of the amplifier, but it is a pretty straightforward mod..

Tube shields can keep noise and radio signals from getting into the amplifier, but they also act as a shunt capacitor and affect the tone of the amplifier. So please make sure you have tested this thoroughly before you plunge into it.

By the way, which 12AU7 is used in your HA-6A? Some 12AU7 is noisier than others, so changing to a quieter driver tube is another option.

 

[Michaels1963]

I am not sure if something like THIS will help.

Maybe you can secure the tube shield with blu tack and then add a shielded wire to connect the tube shield to the back panel of the amplifier for grounding. This won't look good but with a black shielded wire, this is doable. Lastly, I have seen users drill two small holes in the chassis so that they can secure tube shields like this to the chassis directly, this is an extreme case and will definitely affect the secondhand value of the amplifier, but it is a pretty straightforward mod..

Tube shields can keep noise and radio signals from getting into the amplifier, but they also act as a shunt capacitor and affect the tone of the amplifier. So please make sure you have tested this thoroughly before you plunge into it.

By the way, which 12AU7 is used in your HA-6A? Some 12AU7 is noisier than others, so changing to a quieter driver tube is another option.

 

[Michaels1963]

A few months ago, I placed IsoAcoustics Orea Isolation Pucks Indigo (Blue) under my HA-6A they Help the sound No more outside effects of vibration helps quite the sound floor.
Today's Currently used tubes Driver 1950 Sylvania 12AU7 Black Plates, 1990 Made in Yugoslavia Gold Lion KT90 and Rectifier GE 22DE4

 

[busseysound]

I placed IsoAcoustics Orea Isolation Pucks Indigo (Blue) under my HA-6A they Help the sound No more outside effects of vibration helps quite the sound floor

I did the same thing with the same pucks a couple of weeks ago.

 

[krude]

Fellow HA6a owners, I need some recommendations. Running Sophia Electric KT88 optimising for Utopia ... want to explore 12AU7 options.

At the moment the best gelling one for me is Electroharmonix (got the normal not the gold version).

I'm looking for the best midrange clarity and crip and detailed top end extension and air, so the best technicalities and clarity possible, hence EH taking the top spot from the tubes I've got (which are mostly warm-ish from my previous Susvara setups).

Any recommendations highly appreciated : )

 

[jamato8]

Fellow HA6a owners, I need some recommendations. Running Sophia Electric KT88 optimising for Utopia ... want to explore 12AU7 options.

At the moment the best gelling one for me is Electroharmonix (got the normal not the gold version).

I'm looking for the best midrange clarity and crip and detailed top end extension and air, so the best technicalities and clarity possible, hence EH taking the top spot from the tubes I've got (which are mostly warm-ish from my previous Susvara setups).

Any recommendations highly appreciated : )

Raytheon 5814 black plate with holes in the plate. Grey plate is more common and good but the black plate is the best.

 

[busseysound]

Raytheon 5814 black plate with holes in the plate. Grey plate is more common and good but the black plate is the best.

Same is true for the Sylvania 12AU7. Black plates of those are impressive (triple mica if you can find them). The Telefunken ECC802S is the real deal but they're crazy expensive. Watch out for fakes. However I'm currently using Telefunken E80CC's (Philips SQ is fantastic too from what I understand). E80CC's are MUCH less expensive and although they have a bit more floor noise they beat the 12AU7's hands down imo with better sound stage and top end is smoother.

 

[jamato8]

Same is true for the Sylvania 12AU7. Black plates of those are impressive (triple mica if you can find them). The Telefunken ECC802S is the real deal but they're crazy expensive. Watch out for fakes. However I'm currently using Telefunken E80CC's (Philips SQ is fantastic too from what I understand). E80CC's are MUCH less expensive and although they have a bit more floor noise they beat the 12AU7's hands down imo with better sound stage and top end is smoother.

The problem is most people don't give a tube long enough to burn in. The 5814 Raytheon can start off a little flat, too warm and lacking a top end. Give it 50 hours or more and all that opens up and it becomes a different tube. Unless you buy used, then you never know what it will do unless only a few hours on it and then it really isn't used unless in a circuit that applied the wrong voltages.

 

[shafat777]

I believe my search is complete....... My HA6A is whole now.

NOS Mullard LC84 E80cc drivers with Coke Bottle Sophia Electric KT88 Power Tubes + Sylvania 22DE4 Rectifiers = Bliss.

To add even more clarity to the sound, I am using Audiomagic M1 fuse. Audioenvy Elite 3p power cable connected to a Furman Elite power conditioner. No hum what so ever with planars on any output. Very minimal hum with high sensitivity dynamic cans but dead silent using the 4.4mm out. Overall I cannot be happier with how it all turned out. I am beyond blown away by just how musical this amp truly sounds.

 

[AudioPowerHead]

I believe my search is complete....... My HA6A is whole now.

NOS Mullard LC84 E80cc drivers with Coke Bottle Sophia Electric KT88 Power Tubes + Sylvania 22DE4 Rectifiers = Bliss.

To add even more clarity to the sound, I am using Audiomagic M1 fuse. Audioenvy Elite 3p power cable connected to a Furman Elite power conditioner. No hum what so ever with planars on any output. Very minimal hum with high sensitivity dynamic cans but dead silent using the 4.4mm out. Overall I cannot be happier with how it all turned out. I am beyond blown away by just how musical this amp truly sounds.

Very nice. It’s an enviable position you’re at. I also found the perfect set of tubes combo on the 6A that is well aligned to my preference and couldn’t be happier.

Enjoy the music !

 

[ThanatosVI]

Hey guys,

I used to own the Ha-6a before I upgraded to my Octave V16.
I consider the Octave to be a rare direct upgrade to the Ha-6a also utilizing just a pair of KT88 type tubes. So that you can continue to use your tube collection.

I have the opportunity to trade in my Octave by the end of the week (I will switch to 300B tubes with the Feliks Envy)
Therefore I will offer the amp at an especially low price this week, maybe someone wants to have the opportunity to walk the same road.
Either it finds a buyer till friday or it will be with the dealer afterwards.

That means starting next week when the amp is gone I will start to sell my tube collection.

If someone is interested there will be the following pairs up for grabs:
Sophia Electric KT88
S4A 6550C Carbon
Shuguang Black Treasure KT88
Gold Lion KT88
Gold Lion KT77
Electro Harmonix EL34

Gold Lion 12au7
PSVane 12au7
Electro Harmonix Gold pin 12au7

Maybe this was interesting for some, if not please excuse the shameless plug

 

[ArkNerevar]

You call the V16 a "rare direct upgrade to the HA-6A" could you perhaps elaborate a little on the differences and maybe on the amps performance in general, this is a highly obscure amp, I cant find any sort of reviews or even peoples detailed opinions on it.

 

[ThanatosVI]

You call the V16 a "rare direct upgrade to the HA-6A" could you perhaps elaborate a little on the differences and maybe on the amps performance in general, this is a highly obscure amp, I cant find any sort of reviews or even peoples detailed opinions on it.

With a rare direct upgrade I meant in particular that it utilizes the same power tubes and you can continue to use your tube collection. (as compared to an indirect upgrade switching tube families). Additionally the Octave can use KT120 and KT150 tubes.

The amp approach and architecture are quite different to the Ha-6a. The Octave is a Single Ended Triode amp (that uses pentodes in a triode circuit). The general shortcomings like rolloff at the frequency extremes have been countered by a very sophisticated inhouse transformer design.
The result is an amp that has the seductive midrange you know from Triode mode Ha-6a coupled with the frequency extension from ultralinear mode - both at the same time.

On top the Octave has also speaker taps for efficient loudspeakers.

Internationally it's actually quite rare to find Octave reviews and impressions (most are german, where the brand is known) but here some:
https://stereo-magazine.com/review/octave-v-16-se-and-octave-re-320-sbb-review
https://www.octave.de/flipbook/press/PR_V16_STEREOPLAY_201708_EN_H5/#p=2
https://www.[SUPA BEST AUDIO BROS].org/index.php?threads/octave-v16-a-european-totl-single-ended-tube-amplifier.5185/ (you know how to make the link work )

 

[jamato8]

Installed 4 new coupling caps in the HA-6A. They are Duelund. The .22uf are the cast copper internally bypassed with a silver cap and the .33 is a .47 copper cast Duelund.

The tonal changes are extremely good. I already enjoyed the HA-6A and have other amps to compare to, like the 300BMK2, that I also changed out the coupling caps. The mids are more present and wonderfully rendered. Transparency, layering etc., realism are all enhanced. I have done changes over the years and didn't like the results and then went back to square one but I have say, the Duelunds do not disappoint at all. And it is also a complement to the HA-6A.

I am using some Japanese 22DE4 tubes, extremely rare 7318 Raytheon (12AU7 20,000 hour tube) and some black plate Tungsol 6550.

The Duelund caps are not small. :^)