Dlite el34

[Ed de Jager]

Hi,i am in the progress of building a Dumble light whitch i intend to use with 6V6 and EL34 output tubes.
Now i am wondering,should i change the 500 Ohm resistors on the output tubes for 1K Ohm resistors?
Thanks in advance,Ed

[Bob-I]

Hi,i am in the progress of building a Dumble light whitch i intend to use with 6V6 and EL34 output tubes.
Now i am wondering,should i change the 500 Ohm resistors on the output tubes for 1K Ohm resistors?
Thanks in advance,Ed

I would.

[RJ Guitars]

Hi Ed,

What model do you plan to build? I was thinking of making a D-Lite with EL-34's. Would mind sharing info as you nail down the build parameters for using the EL-34's?

Thanks,

rj

[Ed de Jager]

Bob-I;thank you very much!
RJ:sure i will,the boards are populated,chassis drilled but time is scarse these days so i don`t know when i will finish it.Hopefully this week!

Ed

[jelle]

Hi Ed,

Good luck with your amp. I hope she will turn out nice.

Jelle

[Fischerman]

I've read (can't remember where) that the 'standard' screen resistor values of 470 ohm for Fender (which was usually 6L6 or 6V6) and 1K for Marshall (usually EL34 or 6550) were fairly arbitrary values (within limits) and people just tend to stick with them for no other reason than familiarity. But there's supposedly nothing wrong with using 470 ohm for EL34s or 1K for 6L6s or whatever. The higher the value the less stress on the tube but at some point you start noticing a loss of volume and punch.

[Ed de Jager]

Jelle;thanks,i am doing my best !
Fisherman;i will stick to the 1k at first,can allways change can`t i ?

[Drumslinger]

So would it be better just to stick a 1k ohm resistor in there to use 6V6s, 6L6s and EL34s or would there be some tone loss for the 6V6s and 6L6s? What about adding a switch which gives the choice of using 500 ohms or the 1k ohm. I as well will be tackling the D-Lite build and am looking forward to all the helpful tweaks, mods and suggestions.

[Darkbluemurder]

I use 1k 5W for all tubes and have not noticed any ill effects.

[Normster]

1K is fine. That's what I used on the final build. If you're going to use EL34s, make sure you ground pins 1 & 8. You can run the 1k5 grid resistor between pins 5 & 6 (with the grid wire connected to pin 6), and hang the 1K screen resistor from a 1-terminal strip with each 1k going to pin 4 on the output tubes. Makes everything neat and tidy.

[Ed de Jager]

Normster,do you do mind reading too?
I got the answer on the placing of the resistors before i even asked it
Thanks!

Ed

[ampgeek]

Great stuff as usual. Thanks for sharing!

Next question for this topic: What, if anything, should be done to allow proper biasing of both tube types? I haven't run any calcs yet but it just feels like a "range" resistor (either pre or post bias pot) would need to be tweaked to get to the right value/range.

IIRC, EL-34's need -34'ish while 6V6's will be in the -20'ish. Does anyone know if that range can be obtained with the standard D'Lite biasing plan?

Also, I notice an extra dropping resistor in the B+ supply chain in the previously posted picture (to ground from the final node). Purpose? Gets us closer to the "desireable" ~200V on preamp plates?

Thanks again!
Dave O.

[Bob-I]

Great stuff as usual. Thanks for sharing!

Next question for this topic: What, if anything, should be done to allow proper biasing of both tube types? I haven't run any calcs yet but it just feels like a "range" resistor (either pre or post bias pot) would need to be tweaked to get to the right value/range.

what I did was increase the bias pot from 10K to 25K and decrease the range resistor from 15k to 10k. This seemed to get the range needed, your mileage may vary.

Also, I notice an extra dropping resistor in the B+ supply chain in the previously posted picture (to ground from the final node). Purpose? Gets us closer to the "desireable" ~200V on preamp plates?

Thanks again!
Dave O.

Exactly.

[Ed de Jager]

I copied the october bias circuit from ax84 for now because i have no transformer with a seperate bias tap and i wanted a dual bias



Ed

[brownnote]

I've found that a 10K bias pot with 10k tail resistor gives all the range I need for 6v6, 6l6, kt77