Ref 5 / 5se and different 6550 tubes

[Barry1]

My Ref Anniversary 40 originally shipped with 6550 C's for the power supply. Replacements were the 6550 WE variant. I don't think they sound as good. Highs are just a little harder, almost crystalline, after 80 hours of use. Any one else hear a difference or have an opinion?
Does anyone know the plate & screen voltage values for the 6550s so I can better match them when ordering from other than ARC?

[Asterisk]

Originally Posted by Barry1

My Ref Anniversary 40 originally shipped with 6550 C's for the power supply. Replacements were the 6550 WE variant. I don't think they sound as good. Highs are just a little harder, almost crystalline, after 80 hours of use. Any one else hear a difference or have an opinion?
Does anyone know the plate & screen voltage values for the 6550s so I can better match them when ordering from other than ARC?

At a little over 1000 hrs, one of the 6550C's in the PS of my Ref Anniversary failed. The replacements I got from the dealer were 6550WE. Have the same observations. The midrange has nice detail and the high's seem cleaner at moderate listening levels but the balance tilts when you push up the volume. Like you say a bit brash. Was hoping they would still change as it accumulates more hours ( have just about 40 hrs now). In some systems it might be a welcome change.

While I have to stick the dealer supplied replacements for warranty reasons, I'm getting a bit impatient. Didn't think that it would affect the sound that much.

Interesting though is that my Ref phono 2SE came with 6550WE as opposed the 6550C's specified in their brochure. The Reference 750 also uses 6550WE.

Whether its due to availability, reliability or performance reasons, I don't know.

[analog brother]

anybody try the black sable 6550c's?

[Barry1]

I think one of the reasons the difference in sound is so noticeable, now that I'm thinking about it, is that I'm comparing a new 6550WE to an old 6550C with over 1,300 hours on it (and it's shot)! I don't exactly remember what the "C" sounded like when new and the unit was breaking in too. I too would like to know if anyone has tried the Black Sable tube. I'd also like to know if any of the old black plate Tung Sols will fit. The 2 regulator tubes are very close together in the Ref 40. There are posts on some other sites about rolling 6550 PS tubes but nothing really conclusive.

I did measure plate voltage at 450V - that's higher than the average of 300-350V that these tubes are usually run at according to the data sheets (but less than the maximum). I'm ordering some 6550Cs from another source and will let you know what I find out.

[microstrip]

Originally Posted by Barry1

I did measure plate voltage at 450V - that's higher than the average of 300-350V that these tubes are usually run at according to the data sheets (but less than the maximum). I'm ordering some 6550Cs from another source and will let you know what I find out.

Barry1,

The 6550s are typically used at plate voltages around 500 - 550V or even higher. I would say that ARC is just one the few exceptions to this rule in high-end design - they operate them between 420-450V as you say.

[sander]

I replaced my original 6550c with a Tung Sol but wasn't happy with it.
The sound became too "round". Everything became too warm and the focus was gone.

So i ordered an original Audio Research 6550c but receaved a 6550we. (for my Ref 3 by the way)

It seems a bit less refined and introduces a hole new problem;

When i now open the volume right after it stopped blinking 'mute', there is an enormous hum banging through the speakers.
Loud enough to give you a heartattack.

So now i have to wait an extra 10 seconds or so to "un-mute" and open the volume. After that everything is fine.

Did anyone else here encounter the same issue with the new 6550we tube?
Does anyone with a new 6550we dares to try open the volume directly after it stopped blinking "mute"?

My dealer is thinking of making some adjustments to the Ref 3.
I just want a new tube.

What do you guys think?

Thanks and greetings from the Netherlands.
Sander

[sander]

I loaned an original Audio Research supplied 6550c "winged C" tube from a friend to test the difference between the "new" 6550we and the "old" 6550c ARC now uses for it's powersupply in their Ref pre-amps.

The 6550we had about 300 hours and the 6550c around 1200.

I was shocked!

The 6550c is much better. It sounds much cleaner and therefore the music sounds more free in the air with better focus. The differents is comparable with playing with a good (Shunyata) powercord or not.

I don't understand why ARC would make this change.

Maybe (speculation) they came up with their Ref 5SE so fast to cover up their inferier tube that they're now using. Or have to use.
I can't imagine this change was for sonic reasons.

I returned my 6550we to my dealer and got my money back. (I bought it in november because my original 6550c was getting really old)

Now I'm looking for a new 6550c "winged C".

Does anyone has some advice regarding the specs or values this tube must have?

My old 6550 has the numbers 363 122 V6 written on it. I have no idea what they mean.

Any input would be welcome.

Greetings from the Netherlands.
Sander

[Lunchy]

Originally Posted by Barry1

I think one of the reasons the difference in sound is so noticeable, now that I'm thinking about it, is that I'm comparing a new 6550WE to an old 6550C with over 1,300 hours on it (and it's shot)!

I understand the 6H30s are said to last about 10,000 hours. Is this not the case for the 6550 tube?

[MPS]

Originally Posted by Lunchy

I understand the 6H30s are said to last about 10,000 hours. Is this not the case for the 6550 tube?

No, they are different type of tubes. 6H30-DR was military specs with 10 000 operating hours. 6550 is a power tetrode which has life expectancy of 2000-3000 operating hours. (if used within specs) A tube could sound "bad" even before end of life.

[Maxflo]

6h30 are standard one and acording to ARC manual they are for around 4k hours. 6h30-DR are spec version/military one with longer oper. hours. I changed 6h30 for DR verison in both Ref5 and CD8