Cayin HA-1A Headphone Amp

I did my headphone listening with Sennheiser HD800 with Cardas headphone cable and my current amp was a
Stello HP-1000. I was very satisfied with this combination, however after reading several reviews about the Cayin,
 I decided to pick one up. Bought a used Cayin on Audiogon in excellent condition.

However, when I first hooked up the Cayin, I was very disappointed in that it did not sound as good as the Stello.
So, first thing I did was replace the stock power cable with a Shunyata Black Diamond Cable – the sound improved
immensely. But I was still not satisfied with overall sound as it equaled the Stello but did not surpass it.

Then I began to roll (substitute the tubes). I made the decision to go with vintage tubes, most were used and I
purchased all of them on Ebay. The most I paid for any one tube was $35.00. I have to admit, I got a little carried away,
buying this tube and that – seeking audio nirvana.

First I will talk about the EL 84’s. These are the power tubes and although the sound improved, they are not the secret
to unlocking the Cayin’s true potential.

One note on the power tubes, I bought a Siemens-Halske as a backup and it was not matched to the other two, which
resulted in one channel being louder than the other. No matter what you buy, make sure they are matched. Every tube
listed above was a sonic improvement over the stock tubes.

12AX7

This is the most important tube that you will replace, this tube affects the sound the most.

My first tube that I really liked was the Vintage Sovtek, however I found that certain AU7’s that I thought would sound really good, were lacking. The Mullard and the Bugle Boy matched well with their AU7’s, however the RCA 5951 made every AU7 sound better. The 5951 has lower gain than a AX7, however it fit the Cayin really well. Open soundstage, you now can hear layers in the music.

12AU7

The second most important tube to replace in regards to great sound. Not all AU7’s sounded the same with all AX7’s, -
so in my opinion, very important to get the right match up between these two tubes. However, every AU7 on this list
surpassed the stock tube. The comparison chart below was done with the RCA 5951, which is my fave of all my AX7’s
and it matched up with every AU7 easier than the other AX7’s.

With these modifications, the Cayin surpassed even my greatest expectations. I am hearing layers (individual
 instruments), breath on the vocals, extended bass, and an incredible open soundstage. Audio nirvana has been
reached. The sound of the Cayin coupled with the Senn 800’s is so spectacular that I am sure I would need to
spend $20,000 or more to equal it with speakers and amp. The sound is warm, which is my preference, the better
the recording the better the sound, however even when the source material is not great – the sound is still unbelievable.

I am finding that I am listening to music that I have known for years with new appreciation.

In regards to buying tubes, I have found that tubes with black plates and a square getter normally sound better
than their counterparts with gray plates and a halo getter. The only exception to this, are the excellent Mullards
and Bugle Boys. You have probably noticed the absence of Telefunkens; that is my preference as I used
Telefunkens on an older tube amp that I had and was never satisfied with the sound over long periods of time.
They would gave me listener fatigue and did not have the warmth that I prefer.

If you are a headphone listener, I heartily recommend this combo. The Cayin HA-1A with modifications is one
serious piece of audio equipment.