Most likely.

Could it be that you have changed input signal (PCM to DSD) or anything else?

Yes, now these rectifiers are cheap although not easy to get. If I had at least one spare set of them, I most likely already bought the HA-300. My current speaker amp can use different rectifiers available worldwide. That’s why I’m not going to purchase another one. Anyway we’ll see how the...

Well, it seems that driver tubes are not the source of an issue. Maybe power tubes or anything else? I’m not that knowledgeable to define.

Have you kept the stock tubes? Try them for the comparison.

I’ve read some about the ZMF Aegis. It seems to be a great amp for headphones alone, but HA-300 is better for speaker users like me. Interestingly, even American users don’t want “oddball” 22DE4. Since the actual manufacturer of the Aegis is Cayin, I strongly believe they will learn the lesson.

IMHO it’s not an issue at all.

Many thanks to The Abyss 2022 for the tube recommendation. I planned to purchase the HA-300 next, but feel quite content with the HA-3A so far. I’ve bought some beautiful things instead. While listening to beautiful music you want see the beauty around you.

It definitely is, since whole chassis is grounded (connected to ground).

I never heard any noise from my HA-3A as well as from my other gear with exception of the speaker tube amp, but that very faint hum seems inherent to my unit. I always plugged the whole setup into one inexpensive Supra distributor.

As far as I know the best way to avoid ground loop issues is to power all of your audio chain from ONE outlet, using power distributor (filter).

If I had to connect the May with HA-300 I wouldn’t go cheap:)

Of course, but why people say the good priced valuable things “it’s steal”? Funny English:) Anyway, most of us prefer to get more paying less.

“For the first time in my life I feel like I’ve stolen enough” (Bender Rodriguez):)

Soldering is like one way ticket. Might be more future proof to purchase one (or better two sets of solder-free connectors to easily try different wires and compare them). Of course, the good ones aren’t cheap. Again, this way is better for silver or silver plated wires because copper ones are...

Could that issue be related with the caps modification?

Seems like Duelund mod became a mainstream:)

Audiophile(samurai) has no goal, only path… My path is tubes (or serpentine road from tube to tube). Moving forward slowly you can breathe in fresh air and see the endless sky above. Being translated into audio that means listening to beautiful music in its natural beauty. JSBach’s harpsichord...

There is military belief that shell(bomb) never falls twice in the same place:) Good luck!

So everything is fine, just follow LXMc’s advice.

Well, you should push really hard to flex anything made of that thick steel:)

Screws get loosened sometimes, it’s normal.

As the sockets aren’t wobbling you have nothing to do. If they are, just tighten the screws.

I read about Aurium recently in HA-300 thread, it seems to be decent for not too hard to drive headphones.

Unfortunately dealer rarely even knows what he’s selling. Community of users knows much more. In theory you’re right, of course.