Video Comparison: EL-34's and 6550's in my VH-4

[guitarobert]

I agree with the poster's comments on the difference between the two. Well stated!

Ch1: 6550s add a more full bell-like tone with chime similar to 6L6s. Much better to my ears with 6550s than EL34s. 6L6s can't be beat for Ch1 though but 6550s come very close.
Ch3: 6550s have much more note definition and clarity than EL34s. Granted, EL34s have a low-mid growl that other tubes don't have. But 6550s impress my with how defined notes sound. Play a chord and do an arpeggio among each note in the chord. Even with high gain settings each note rings out clearly. Very impressive!

For ch2 and ch4 I didn't find a big difference among each tube.

Overall I like 6550s, keeping in mind that there might be tube reliability issues though! Ch1 and Ch3 are my main favorites on the VH4 so 6550s get a big thumbs up from me.

 

[mightywarlock]

Thanks !

As You mentioned I understand if people like the sound.
For me as a manufacture the 6550 is a nightmare. I had
to replace nearly 100 pieces the last year.

Anyway ...... rock on

what did you have to replace?
Tubes?
or Amps??

 

[petereanima]

however I have mine biased to 60 mA per pair,

Isnt that pretty cold for these tubes? I think i remember that the recommendation back then used to be 80-100mA per pair, wasnt it?

 

[QueenCityGuitars]

Mizati20 - Thank you for posting this! I cannot wait to get home so I can see the videos (they're blocked at work). Two questions for you: Did you do the resistor change Mark2C suggested along with the 6550 power tube change? Which manufacturer and model of 6550s did you go with?

 

[Ventura]

6550's biased at 70mA is the recommendation a la Poppa. However, they can nicely get up to 80mA but this isn't recommended a la Poppa.

Pauly is running his at like 90mA or more, per pair folks, per pair...

V.

 

[Mizati20]

Mizati20 - Thank you for posting this! I cannot wait to get home so I can see the videos (they're blocked at work). Two questions for you: Did you do the resistor change Mark2C suggested along with the 6550 power tube change? Which manufacturer and model of 6550s did you go with?

Glad the videos could be of some use, make sure and watch them in the highest quality, as it helps with the audio... I haven't done the resistor change on THIS amp, but I did it to a 2007 I previously owned, and it is my opinion the the resistor mod IS NOT necessary, the 6550's do everything you would need as far as taming the high end/fizz/compression... please understand I am speaking from experience, I had EL-34's in my amp, and had the mod done, and didn't notice much of anything, and then I got 6550's for my 2007 and WOW... now this VH-4 I currently own originally had EL-34's, and I switched to 6550's and the same big leap in audible difference is there....

However, Mark2C is a trusted member of this forum, and if he says he notices a different in his gear I believe him 110%, this is just my personal experience, the mod is EXTREMELY is to do, and very easy to reverse as well, so you really can't lose either way...

I went with the Winged =C= 6550's, absolutely love them....

 

[Mizati20]

6550's biased at 70mA is the recommendation a la Poppa. However, they can nicely get up to 80mA but this isn't recommended a la Poppa.

Pauly is running his at like 90mA or more, per pair folks, per pair...

V.

I had them biased at 70ma per pair, but they got way too hot, I understand Pauly runs them at 90, but I just love my VH-4 to risk anything, I compared the tubes when biased at 60/70/and 75 mA, and there wasn't enough audible difference to justify the increase in heat so I brought them back down to 60mA... YMMV.

 

[petereanima]

6550's biased at 70mA is the recommendation a la Poppa. However, they can nicely get up to 80mA but this isn't recommended a la Poppa.

FWIW: the manual i have states "80-100 mA" per pair for 6550 and KT88.

EDIT: see also here.