[jambaj0e]

Sorry to know that you have run into some problem with your HA-300. We resume operation today after a long break but I still can't get hold of the Engineer and get his advice on your case. Only one out of three support engineers are available today.

If the tubes are lighting up and the transformer were running warm, then the problem is likely a minor one, but troubleshooting might be a bit inconvenient. Anyway this is nothing much we can do right now. I assume the original owner will contact his dealer and the case will come back to us through other channel.

MusicTeck is a good dealer with reputable track record in customer service, he takes good care of his customers. I sincerely hope you'll have an satisfactory experience if you decided to go for HA-300 again.

Also Andy, where is the fuse for the HA-300? Are there two of them? How do I open the one under the power plug, and for the 2nd one do you have to open up the main case, which is something the dealer probably should do? These are things that are seriously lacking from the manual.

 

[Thenewguy007]

Question: Do you tend to leave your HA-300 when you're not using it? Here's an interesting video regarding if it's better to leave electronic equipment on or not:

Does leaving equipment on shorten its life?

For solid state, yes, but you DO NOT want to leave a tube amp powered on 24/7.
Those tubes have a 10,000 hour lifespan. Turn the amp on, only when you plan on using it.

 

[Benny-x]

I fire my tube amps up about 30-60mins before really listening to them. Let's everything settle in. I also log my hours in an Excel spreadsheet, damn consumables.

For solid state, pretty much 24/7 unless I'm going away or expect not ot be using them for a week.

 

[Andykong]

Also Andy, where is the fuse for the HA-300? Are there two of them? How do I open the one under the power plug, and for the 2nd one do you have to open up the main case, which is something the dealer probably should do? These are things that are seriously lacking from the manual.

If you are referring to the fuse right below the IEC power connector, you can use a small flat headed screwdriver applied at the red arrow location to replace the fuse.

In our opinion, anything related to removing the chassis cover and gain access to internal circuit is consider service instruction and we didn't include this information in User Guide. Some countries have very straight rules on the consumer safety and we have to comply all requirements.

 

[deuter]

Who sells this amp in Australia, can we demo?

 

[jambaj0e]

So happy to get my replacement HA-300! It was an open box review unit from MusicTeck, but for $2800 WITH full warranty since it's from the dealer, it's practically a steal. Curiously, it has the older-style 300b tubes. I have to say that since this was a review unit, the tubes are properly burnt in and that expansive soundstage, clarity, and sweet mids are very present in this system vs the previous I had that I received with only 50 hours on the tubes.

 

[deuter]

Will this amp power the Abyss 1266 headphones?

 

[llamaluv]

Will this amp power the Abyss 1266 headphones?

Shor can. Listening to the HA-300 w/ the TC this very moment.

 

[deuter]

Shor can. Listening to the HA-300 w/ the TC this very moment.

Nice. does it get loud?
You compared to any other amps?

 

[jambaj0e]

Has anyone rolled their 6SN7 tubes yet? While I really like the stock ones, I'm probably going to try my newly bought matched pair of Sylvania 1952 3-hole Bad Boys. I'm sure it can handle it, right?

 

[jambaj0e]

Just rolled it to my 1952 Sylvania 3-hole Bad Boys! So far, I noticed a bit less air in the treble and more body in the bass and mid-bass. Soundstage is slightly more intimate than the Shuguang, but still large enough. Vocals seem to be much more forward, though.

I may like this more for its bass performance, but may go back to the Shuguangs since I think it pairs better with the LCD3.

 

[jambaj0e]

So quick question, what are the safety measures in rolling 300b tubes? Am I not supposed to do it right away after shutting down? Do I wait after powering down and swapping for a certain amount of time before powering back on?

 

[llamaluv]

Nice. does it get loud?
You compared to any other amps?

Yes, plenty loud, at least for me. When using XLR coming from the DAVE (ie, 6 volts), I have the dial at the 2 o'clock to get the headphone to my normal listening volume of 70 dBA SPL RMS.

I'm been strongly preferring the HA300 over my Pass Labs speaker amp for the Phi TC these days. And also over the DAVE headphone-out (which I've never been crazy about as a headphone amp). I think neutral headphones like the Phi/TC or Utopia really benefit from the tonal richness and space that the HA300 can bring.

I will say, though, that choice of tubes plays a big role for getting the best synergy with the Phi TC. And more generally, I'm finding tube choice (for both the 6SN7s and 300Bs) to make a bigger difference with the HA300 than any of the previous 4 or 5 tubes amps I've had in the past..

 

[llamaluv]

Has anyone rolled their 6SN7 tubes yet? While I really like the stock ones, I'm probably going to try my newly bought matched pair of Sylvania 1952 3-hole Bad Boys. I'm sure it can handle it, right?

Now that I've had the amp for a couple months, I feel like I'm understanding differences between the 6SN7s that I have on hand a little better now. My experiences so far, but only for what they're worth (all while using EML 300B's):

• PSVane CV-181 Tii - Extra-warm and thick, to the detriment of space and air and treble. Bass is very good though on the Abyss Phi TC. They can create a positive impression for a while because they're comfortable-sounding, but there's too much being omitted, and just too unspacious (Early on I had mentioned that I thought it sounded bright compared to others, which is strange to me now. It could have been due to the amp being un-burned-in at that time? Or maybe it's just me).
  
  
• Tung Sol 6SN7GTB (unsure of the year, unfortunately) - My favorite at the moment. Very spacious and nicely imaged sound. And lots of nuance to dynamics. A little bit on the mid-forward side such that I find myself raising the bass a little with EQ, but other than that, no complaints. Having swapped these in only recently, there have been a few tracks where I've felt like I've never heard the Utopia sound so satisfying with acoustic instruments (piano, solo violin and cello come to mind).
  
  
• RCA 6SN7GTB c. 1959 - Too bright!, which does seem a little odd to me. I should probably give them another go.
  
  
• I had some Sylvanias briefly that were very nice and well balanced, but failed unfortunately. I have some 1940's Sylvanias on the way on the recommendation of Andy at vintagetubeservices.

 

[llamaluv]

So quick question, what are the safety measures in rolling 300b tubes? Am I not supposed to do it right away after shutting down? Do I wait after powering down and swapping for a certain amount of time before powering back on?

I like this post by @TomSix on the Studio Six thread:
https://www.head-fi.org/threads/alo...s-and-impressions-thread.674498/post-12985441