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A tube for SE with 1k-1k5 load

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Hi guys, i'm working on a low cost amplifier using a putput transformer with 1k or 1.5k primary 100mA rated and i'm wondering what tube for the output stage and B+ value ?

The goal is 8W but 5W is enough...i would avoid GNFB :)

What about using EL34 triode connected ?

EL86 maybe ? i've seen this tube driving low load at low B+ without problems

6080 can drive 1K easily but need a lot of drive voltage at grid.

thank you all :)
 
For EL34 triode connected you need 3k or 5k OPT
Thank you, i've tried :D

maybe 6c33c
Isn't a bit overkill ? and expensive at least here :(

PL 504 with cathode feedback
Cathode feedback, intresting i can give it a try having a bunch of them...maybe screen drive?

About 2A3 and F2a , i don't have any ...

I have some 6P13S , 6P31S , EL36 , GU32 (832) , GU29 (829)

Thanks
 
hello ,

it is curve exploited for PL 504

so good for approximalty 200 or 250 V= , OPT = 3.0 K , power out at 8 ohms = 7 W ~

;)
 

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How about GU-29 in parallel? (Both sections in parallel)
I can try this :)

it is curve exploited for PL 504

so good for approximalty 200 or 250 V= , OPT = 3.0 K , power out at 8 ohms = 7 W ~

Yes but my OPT is 1 - 1.5K :(

Very suitable and cheep decision is 6S19P /Russian/ in parallel

man i've never seen this tube before...amazing, i like it so much :)

I'm just a bit worried about shipping most ebayers who sell this tube are from russia and they can't guarantee for deadline to italy.
Anyway i found this seller :

6S19P Russian MATCHED QUAD VERY STRONG TUBES !!!!! | eBay

Do you think is ok ? Anyone with experience in buying tubes from russia to italy?
Thanks :)
 
Hi Tesla88

Maybe the 6CB5?

It is said that the 6S19P is like half a 6AS7, with a mu of ~2. It is also said that these tubes work best with low voltage/high current (like 100V at 100mA for 6AS7). In this case it will require about -30V bias, or 130V on the plate and 300R cathode resistor. Generating a signal of 60V PP (about 22VRMS) to drive this is not very hard and can be done with a single stage. As the mu of neither 6AS7 ot 6S19P is very high, miller capacitance will be low, which is good.

What you can also consider is the accordion amp by Broskie Here is a thread with an example. This is something I want to try out myself one day.

as always, a thousand possibilities :)
 
Hi Tesla88

Maybe the 6CB5?

It is said that the 6S19P is like half a 6AS7, with a mu of ~2. It is also said that these tubes work best with low voltage/high current (like 100V at 100mA for 6AS7). In this case it will require about -30V bias, or 130V on the plate and 300R cathode resistor. Generating a signal of 60V PP (about 22VRMS) to drive this is not very hard and can be done with a single stage. As the mu of neither 6AS7 ot 6S19P is very high, miller capacitance will be low, which is good.

What you can also consider is the accordion amp by Broskie Here is a thread with an example. This is something I want to try out myself one day.

as always, a thousand possibilities :)
But 1 - 1.5 kohm are small for one triod of 6AS7. 100 ma current doesn't enough for two paralleled triods. Every triod sound good with current more 60-70 ma.
 
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