yes, think you must do a bit fine tuning,
the power follower you mentioned is a construction of my own,
I did it back in the ninetees.
Reinhard (Hoffmann)
the power follower you mentioned is a construction of my own,
I did it back in the ninetees.
Reinhard (Hoffmann)
How about the filaments?
Would it be safe to wire 4 6C19 in a series connection and feed the whole chain with ~25V DC?
Seems like that would be an easier solution than connecting all eight tube sockets to a separate twisted pair of wires that connets to a 6,3VAC 8A transformer.
I don´t like hum, you see...!
Would it be safe to wire 4 6C19 in a series connection and feed the whole chain with ~25V DC?
Seems like that would be an easier solution than connecting all eight tube sockets to a separate twisted pair of wires that connets to a 6,3VAC 8A transformer.
I don´t like hum, you see...!
Se Otl
Hello Fuling,
Bruce Rozenblit uses a 2 * 12 Volt toroid for filaments,
one winding for 2 * 2 tubes in series. Frome the same toroid he generates the - 12 V grid bias.
Reinhard
Hello Fuling,
Bruce Rozenblit uses a 2 * 12 Volt toroid for filaments,
one winding for 2 * 2 tubes in series. Frome the same toroid he generates the - 12 V grid bias.
Reinhard
SE 1.5W
Hello Reinhard,
I know the SE OTL is a class A amp.,
However, 6c19 under 100v plate voltage with bias 12v,
how many current it will draw,is it over rate.
Regards CHOW
Hello Reinhard,
I know the SE OTL is a class A amp.,
However, 6c19 under 100v plate voltage with bias 12v,
how many current it will draw,is it over rate.
Regards CHOW
Max contionous current is specified to 140mA, see here http://www.jogis-roehrenbude.de/Russian/6C19N.htm
Note that anode dissipation is max 11W
Regards Hans
Reinhard: Excellent, I have a pair of 12V 50VA toroids.
Is it AC or DC in the original schematic?
Regarding the cathode load, what about some kind of hybrid White follower? Results should be equal to a mirrored Aleph CCS but with less components involved.
Is it AC or DC in the original schematic?
Regarding the cathode load, what about some kind of hybrid White follower? Results should be equal to a mirrored Aleph CCS but with less components involved.
SE OTL
The heater is AC,
regarding to the white follower, no experience, try it and tell us your results.
Reinhard
The heater is AC,
regarding to the white follower, no experience, try it and tell us your results.
Reinhard
Yes, of course it can but how long? A problem in class A OTLs is that the idle current need to be high which will limit life of the tube, using 140mA with 100V give 14W dissipation which is over the dissipation spec, how much over the spec are you willing to go?
I use 6C33C in my OTL and use a peak current of 2.5A which is more than 4 times the specified cathode current without any ill effects, BUT! The idle anode dissipation is 2/3 of max and the idle current is only 200mA. I have used the same tubes without adjustments now for more than 6 years.
Regards Hans
Yes of course, it is class AB push-pull, it is the only way to get useable power AND reliability in an OTL amp. Class A SE is possible but it will give low power and low reliability, there is no way around that.
Regards Hans
Hi,
You could do that but why not a fully tubed WCF as I've been suggesting for ages?
Think about it, the amp is probably going to be seeing an efficient LS load which hopefully is well behaved across the band.
If it isn't a impedance correction network can still help.
The use of multiple //ed output tubes is only done to increase power and lower Zout.
The WCF is incredibly linear and sports very wide bandwidth indicative of good phase behaviour. Zout is about as low as it comes...........
Granted you may be wasting a tube but there are considerable upsides to it too.
Re: the 6C19, pulling peak current continously is not what you want but why should you have to anyway? It's not as if you'd expect a SE OTL to be able to drive a short or, is it?
Anyway, thought I'd throw you guys a bone to chew on. 😀
Cheers, 😉
You could do that but why not a fully tubed WCF as I've been suggesting for ages?
Think about it, the amp is probably going to be seeing an efficient LS load which hopefully is well behaved across the band.
If it isn't a impedance correction network can still help.
The use of multiple //ed output tubes is only done to increase power and lower Zout.
The WCF is incredibly linear and sports very wide bandwidth indicative of good phase behaviour. Zout is about as low as it comes...........
Granted you may be wasting a tube but there are considerable upsides to it too.
Re: the 6C19, pulling peak current continously is not what you want but why should you have to anyway? It's not as if you'd expect a SE OTL to be able to drive a short or, is it?
Anyway, thought I'd throw you guys a bone to chew on. 😀
Cheers, 😉
Well, in spite of all the potential advantages in using active current sources and stuff I´ve decided to stay basic and use chokes.
The ones I already have is a bit bulky and the inductance is on the low side, so I´ve ordered a couple of 45VA EI-cores and half a mile of 0,5mm magnet wire😀
Winding transformers and chokes is no news for me, so I dont expect too much trouble here.
A friend told me that regulator pass tubes (like 6C19) generally dislikes to have B+ on the plates before the cathodes are fully heated, so some kind of delay circuit would be nice.
My idea is to use the warmup time in an indirectly heated tube diode (PY82 because I have a bunch) to control the reference voltage in a capacitance multiplier (non feedback regulator).
PY82 requies 19V 300mA on the heater, and the warmup time can be increased a lot by feeding it with a 300mA CCS.
Maybe a thermistor would give the same results?
The ones I already have is a bit bulky and the inductance is on the low side, so I´ve ordered a couple of 45VA EI-cores and half a mile of 0,5mm magnet wire😀
Winding transformers and chokes is no news for me, so I dont expect too much trouble here.
A friend told me that regulator pass tubes (like 6C19) generally dislikes to have B+ on the plates before the cathodes are fully heated, so some kind of delay circuit would be nice.
My idea is to use the warmup time in an indirectly heated tube diode (PY82 because I have a bunch) to control the reference voltage in a capacitance multiplier (non feedback regulator).
PY82 requies 19V 300mA on the heater, and the warmup time can be increased a lot by feeding it with a 300mA CCS.
Maybe a thermistor would give the same results?
Attachments
Thermister
Fuling,
Thermister is surely an option to
delay the plate voltage; BR used to
do with it in his projects.
BTW anyone has idea about high current CCS
to replace the inductor in the SEOTL?
Regards CHOW
Fuling,
Thermister is surely an option to
delay the plate voltage; BR used to
do with it in his projects.
BTW anyone has idea about high current CCS
to replace the inductor in the SEOTL?
Regards CHOW
Has anyone made an attempt to draw a schematic of this OTLSE amp ? I'm really interested too ! 🙂🙂🙂
I think I will try it ....
What about the choke ?
There aren't any specs, what are its inductance and the max dc current ?
Regards
lagroute
What about the choke ?
There aren't any specs, what are its inductance and the max dc current ?
Regards
lagroute
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