Review: Cayin HA-1A headamp

[Mackie 0]

Ok folks, I've just added the latest findings onto the main post after having conducted a comparison of Ei Yugoslavia, JJ and GE EL84 power tubes.

[N@Z 0]

You have very good ears Mackie. Although I have not listened to them back to back yet I could hardly tell the difference between the JJ & Ei Yugo power tubes. However, I was able to tell a difference between them & the GE from memory. I felt the GEs had less 'air' and exhibited a slight grain at the very top end but was typically lush sounding for a GE.

[mychew 0]

hiuh...i take a long time to finish the review while doing my work...

anyway, enjoy the review..hehe...nice and sweet

[Mackie 0]

You have very good ears Mackie. Although I have not listened to them back to back yet I could hardly tell the difference between the JJ & Ei Yugo power tubes. However, I was able to tell a difference between them & the GE from memory. I felt the GEs had less 'air' and exhibited a slight grain at the very top end but was typically lush sounding for a GE.

Thanks Naz. The GEs sounded much better than the stock OTK and rather faithful to the sound. Only a direct comparison with the JJ and Ei did the weakness become obvious albeit not to an astounding degree. Difference between JJ and Ei are relatively harder to spot and in the end, a choice boils down to personal preference IMO.

Edited September 29, 2003 by Mackie

[N@Z 0]

Mackie/Oak,

 

Can the input 12AX7 & 12AU7 output tubes be swapped with equivalent tubes like 5751 etc or do they have to be specifically the same types.

[Northern Oak 0]

Nay, I don't think you need it to be specifically the same type. Below are the combinations I've tried on the Cayin.

 

12AU7 -> CV4003 -> 5751

 

12AX7 -> ECC83 -> 5751 (CV4004 seem to be Mackie's choice and going to be mine too!)

 

(All are possibly equivalent)

Edited September 29, 2003 by Mackie

[N@Z 0]

Thanks, I have a couple of 5751 & 12AU7 used NOS tubes from the MG Head which is a shame not to be able to use should I eventually get the Cayin.

[Northern Oak 0]

BTW, the GE 5751 sounds like AKG K501, dry Martini.

[Rameish 0]

There;s a new Ei Elite EL84 EG that I saw at www.thetubestore.com. Maybe one of you guys may want to test them out.

 

Cheers

 

[N@Z 0]

Thanks for the head's up Rameish, it's been a while since I last looked at that site. I think it works out cheaper to get the JJs from there (although shipping might negate that) whereas the Ei is cheaper in SG as Mackie quoted me $36/pair for both the Ei & JJ EL84s. However I'm not sure if that is for a matched pair (which is not an issue with the Cayin nor MG Head).

[headphonecrazy 0]

However I'm not sure if that is for a matched pair (which is not an issue with the Cayin nor MG Head).

N@z you are right bout the Cayin n MG head, they are auto biasing no need for match pairs.

[Rameish 0]

Headphonecrazy,

 

Actually almost no amps today are auto biasing (ie using a servo to bias the tubes - this is because it's a) very expensive introduces biasing circuits that make the amp very complex and c) the biasing isn't very accurate - as compared to manual bias or even cathode bias using resistors). In today's audio language auto bias is cathode biasing and unfortunately do require matched pairs or quads etc (depending on the amp). I posted the reasons why sometime back http://www.sgheadphones.com/index.php?showtopic=1155

 

look at part II of Roger's article. Essentially, a matched pair would provide a more even wear of the tubes over time. However in the Cayin, the ECC82 and ECC83 tubes do not need to be matched to each other as the ECC83 tube handles gain while the ECC82 is the drives the EL 84 tubes. So the Only matching that's required for the ECC82 and ECC83 is that both sections within one tube (dual triode) is as close as possible. The EL84 being power tubes should be matched as closely as possible. Otherwise the tone would be slightly different between the 2 channels. Ie you wont notice an in-balance but they will be tonally different - initially at least. Usually NOS tubes (espicially Mullards/Telefunkens/the real Amperex BB etc) are very closely matched within a tube.

 

 

But it get worse. As the power tubes start to age, there will come a point where there will be in-balance between the 2 channels as the actual output of one tube will be less than what the cathode bias allows for. Ie the "tap" valve is bigger/larger than the flow. BTW that's why the British call tubes valves. Because they are electron valves.

 

 

N@Z, these are not the same as the regular Ei Elite EL84.

[N@Z 0]

Ahh... good to know.

 

So what is the difference compared with normal Ei Elites?

[Rameish 0]

That N@Z, is what I would like to know as well as I may be getting the Cayin for myself LOL. The Tube Store doesn't explain it very much other than stateing that the Ei Elite EL84 EG is a premium selected tube.

 

Anyway here's a EL84 review for guitar amplifiers that could be a useful guide. Now if we only knew at what plate voltage and cathode current the Cayin is running at then we can guess a little better - you see when you push a given power tube differently (ie at lower plate voltage or biased at a different ma/millivolt then the same tube sounds different. Generall at a lower bias you'll get less tight bass and slight roll off at the top end (the negative in this is of course lower output). The harder you push the tube the brighter and tigher it sounds ( the negative in this is shorter lifespan of the tube).

 

So depending on the cathode biasing of the Cayin, the sound in a given tube will sound different than in another tube amp with different bias. Here's a somewhat informative article on biasing:

 

http://www.aikenamps.com/WhatIsBiasing.htm

 

It seems confusing at first but it isn't.

 

 

Here's another simple article on both biasing and matching of power tubes in particular.

 

http://www.tubefreak.com/tubesbias.htm

Edited January 10, 2004 by Rameish

[Rameish 0]

Okay got some BS info on the EL84EG from www.tube-shop.com

 

"The Ei EL84EG is the preferred choice of many leading amp manufacturers and is generally considered to be the finest EL84 currently available in the world. The classic design ensures sweet tonality and smooth overdrive with long life. The Ei EL84EG comes as standard with gold pins for improved electrical connectivity"

 

While the Ei EL84E is described as:

 

The Ei EL84E is the preferred choice of many leading amp manufacturers and is generally considered to be the finest EL84 currently available in the world. The classic design ensures sweet tonality and smooth overdrive with long life.

 

So I guess the only difference are the pins LOL. One is gold plated while the other is not. I may be wrong though.