6L6's Vs EL34's in a Diezel Herbert

[mindseye]

Thanks for the input guys!!!
Looks like I have some experimenting to do.
I scored a good deal on some 6L6's last night so I guess I will give them a shot first, what are yall setting the bias to per pair for 6L6's?

I will probably end up running the Herbert stereo with a JVM 410 so I will get some EL34 bite from it that's another reason I am looking to run some different tubes in the Herbert.

KILLERTONE, that clip sound great but all of your clips sound awesome!!

 

[Ventura]

Killertone is on the money with the mixing of 6550 and EL34 in the Herbert.

You're definitely not going to lose any inet points for not knowing about 6550s, they're an interesting bottle.

I'd give these a shot - see how it goes. If you wanted to go exotic you could go:
=C= 6550 x 2
=C= EL34 x 2
Gold Lion KT77 x 2

I know Peter needs to put forth his "professional manufacturer recommendations" and I wholly respect these recommendations. However, the beauty of the Herbert is the mixing of its glass. Providing you know how to bias effectively and correctly, you can't go wrong with experimenting to fit your tastes.

Good luck,
Uncle Mo

 

[pstar]

 

[Nodnarb25]

Hmmmm... Makes me want to try a pair of 6550's along with the EL34's I currently have in it.

But, I'm not too hip to the appropriate voltages required for the different tube types. How does one determine that? I'm interested in learning more about this.

Hypothetically say I was to mix and match pairs of 6550's, EL34's and KT77's... How many ma should each pair get? Does it vary per brand of 6550/EL34/KT77?

Anyone who has the knowledge to drop on me, much appreciated!

 

[FIREBALL]

i absolutely hate my herbert with el34s..............6l6s and kt88s all the way

 

[FIREBALL]

Thanks for the input guys!!!
Looks like I have some experimenting to do.
I scored a good deal on some 6L6's last night so I guess I will give them a shot first, what are yall setting the bias to per pair for 6L6's?

I will probably end up running the Herbert stereo with a JVM 410 so I will get some EL34 bite from it that's another reason I am looking to run some different tubes in the Herbert.

KILLERTONE, that clip sound great but all of your clips sound awesome!!

this is what i do

 

[guitarobert]

But, I'm not too hip to the appropriate voltages required for the different tube types. How does one determine that? I'm interested in learning more about this.

Hypothetically say I was to mix and match pairs of 6550's, EL34's and KT77's... How many ma should each pair get? Does it vary per brand of 6550/EL34/KT77?

Anyone who has the knowledge to drop on me, much appreciated!

Plate voltage of the amp determines how many mA each tube type is biased at for that amp. I think the Herbert is 475V, but if you have a bias probe that lets you measure it, you can see exactly what the plate voltage is. It can vary a bit, but should be around 475V.

Then use a chart like this one.

http://www.webervst.com/tubes1/calcbias.htm

I'd choose a number close to the hot (70%) figure. Maybe take the hot setting and reduce it by 2mA.

Then you get this for the Herbert.

EL34/KT77: 35mA
6L6/KT66: 42mA
6550/KT88: 50mA

You can also pull out your calculator and get the number from the plate voltage directly. This gets the bias current in mA:

.7*P*1000/V

P is the tube's power (EL34: 25, 6L6: 30, 6550: 35) and V is the plate voltage (475, or whatever is measured if your bias probe does it). The .7 is for 70% (biased hot) and 1000 is just to have it display as mA instead of A.

 

[HerbieBoogie]

I haven't seen this topic in a long time. I remember people going crazy for 6550s a while ago. those suckers run hot!