I got my tube amp today, but...

Hello all. I received my Eico HF-89 today, but I am having some problems.

When I started up the unit, the tubes began to warm up as normal, then I saw a blue color inside the EL34's, so I shut the unit off immediatly. Is this blue color normal?

 

The blue should be on the glass, and not floating in the middle of the tubes.

If they look like this, then yeah, it's ok. The blue is a neat bonus, and looks even better with the lights dimmed.

 

I am up and running! The blue is only in one tube. This thing sounds amazing! The highs are smooth and extended, dynamics go forever! And the bass, the bass is better than my SS amp. This thing really rocks! I will give more details later! I am going to go listen now!

It is VERY conservatively rated at 50wpc, this thing really cranks with really low distortion, dynamic peaks are reproduced accurately with no distortion!

 

Time for some tube rolling!!

 

I didn't know that...............................................
.................................sorry, I had to go check: they're all orange! Whew!

 

Yes, the Eico HF-89 produces a very clean 50wpc. However, I am using this amp with my AR-2's which is a two way system that has two tweeters in it. The AR-2 is a bit more rugged than the AR-3 and 3a. Eventually I would like to get a second HF-89, and bridge them for mono. Bridged, they produce 100 watts.

Solid state clipping is more dangerous to AR speakers than tube clipping. When transistors reach their max output, they can release dangerous DC to the speakers, and the tweeters are the weakest link!

 

Here is a good explanation from Vacuum Tube Valley

1) Most modern glass power tubes show FLUORESCENCE GLOW. This is a
very deep blue color. It can appear wherever the electrons from the cathode
can strike a solid object. It is caused by minor impurities, such as cobalt,
in the object. The fast-moving electrons strike the impurity molecules,
excite them, and produce photons of light of a characteristic color. This is
usually observed on the interior of the plate, on the surface of the mica
spacers, or on the inside of the glass envelope. THIS GLOW IS HARMLESS. It
is normal and does not indicate a tube failure. Enjoy it. Many people feel
it improves the appearance of the tube while in operation.


2) Occasionally a tube will develop a small leak. When air gets into
the tube, AND when the high plate voltage is applied, the air molecules can
ionize. The glow of ionized air is quite different from the fluorescence
glow above--ionized air is a strong purple color, almost pink. This color
usually appears INSIDE the plate of the tube (though not always). It does
not cling to surfaces, like fluorescence, but appears in the spaces BETWEEN
elements. A tube showing this glow should be replaced right away, since the
gas can cause the plate current to run away and (possibly) damage the amplifier.


One of my EL34's is like the first example, a bit of blue on the glass of the tube. The other three have a bit of a blue glow on the inside of the plates, however, it goes away after a few minutes of being on. I do not hear any of the characteristic signs of worn tubes, like lack of dynamics, muddiness etc. My amp has four EL34's in it. Currently, two are Mullard and two are Realistic.

Also, the tubes hiss a bit, not through the speakers, but the tubes themselvs.

The amp sounds fantastic! Unlike any tube amp I have ever heard. The bass is tight, contoled, and very deep. Most of the tube amps I have heard get kind of muddy in the bass range. The mid and upper end are of course, silky smooth!

 

My 300Bs that came with my power amp also have that harmless florescence blue glow. It's nothing to worry about like the explaination above indicates, so enjoy your light show...I know I do.

 

Joe,

Do me a favor and lay some juicy pics on us, will ya?? I love audio-porn.

 

Ok, this afternoon when my father is home, and I can use the car, I will run up and get some poloroid film for my poloroid camera. I dont have a digital camera, but I have a poloroid and a scanner.

 

Here are the pics!

Here are the pictures! I know, the quality is crappy, I dont have a digital camera, and I did not feel like using my good 35mm camera, so I used my Poloroid.

The first two shots are of the amp. The third shot is to show you just how big the output transformers are. I put a 12AX7 in front of one for a size reference.

 

Don't ever trust tubes that shipped with the unit. Either have them tested or look on to replacements....

 

Since I cant afford NOS tubes, I think that I am going to get the Tesla EL34's. Hopefully they dont explode or something weird like that.

 

They look great Joe!

My neighbor has two of these running 100W monoblock. He got his about two years ago when he found them at a surplus store for $100 each and told me there was more(about 8 to 10 more), but when I rush down there they were all gone...

 

These might be worth the extra expense.

 

Back to the blue in the tubes:

If they look like my avatar, this is 100% normal and actually cool as heck to look at, especially in the dark!

If there is BLUE (and ONLY blue) inside the plates or appearing to 'coat' the grids, etc. it is also a flourescence factor and is likely no cause for concern. (I have a Dynaco ST70 with pre-JJ Tesla EL34s in it that has had this 'inside-the plates' blue glow since the tubes were installed and the amp operates perfectly) Both blue glows may or may not pulsate with the music and may also come and go at random.

If you see ANY COLOR OTHER THAN BLUE, especially pink or purple inside the plates of ANY vacuum (not gas-filled) tube, it likely is gassy and should be replaced. (Note that voltage regulator tubes such as the OA2 and OC3 will glow usually pink or neon orange due to the gas contained within them for their operation, and mercury vapor rectifiers such as the 83 will glow deep blue or purpleish blue due to the mercury vapor doing its job).

Beautiful pics of your amp by the way

Good luck!

-Aaron

 

When you get some time (and money), those interconnects look like they could use some love and kindness.

 

I know. I normaly use Audioquest Diamondbacks, but they are too big to fit in the jacks on the Eico. The jacks are too close together. I am going to install nice gold plated jacks so that I can use good interconnects.

 

Rather than Hijack this thread I will start a new one entitled EH 6CA7....Reviews and opinions??

 

hey Nino, thx for the pics, that thing looks great!!


what made you choose that particular amp? did you have any others in mind while you were looking?

thx!




( I am also about to dive into tube audio....there's a Fisher 400 out there with my name on it if that goes well, I may end up looking at some Big Bertha setup too, in the future )

 

I got it because, I have listened to other Eico amps, and they all sound great. The output transformers are huge on this thing. This amp has very low distortion, and is capable of driving my inefficient AR speakers quite well. This amp also sounds very transparent. It does not color the sound in any way.