Tube heaters combination?
 borislavgajic
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is it possible to connect two different tubes....ecc83 and ef86....on 12,6V heater voltage?
and how...if that can be done.....?
thanks
boris
and how...if that can be done.....?
thanks
boris
 briggs
 Tube Twister
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 himister
 Resistor Ronker
Hi. Boris.borislavgajic wrote:is it possible to connect two different tubes....ecc83 and ef86....on 12,6V heater voltage?
and how...if that can be done.....?
thanks
boris
Try serial connection with this two. Also connect 2x100R resistors between filaments and ground to even the current flow on both sides and prevent hum. You can use a pot instead of resistors.
"It's a fairly common noisereducing trick to elevate the heater winding's CT a bit."
Cheers bro.
 borislavgajic
 Opamp Operator
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 Posts: 1542
 Joined: 27 Feb 2008, 14:23
 Completed builds: ...script phase90,ETI phaser,Ross phaser,mutronC200,vox wah,WH10,FW3,mutronIII,DrQuack,Penfoldautowah,Tubezipper,
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...CE2,ibanez fL301,EH theCloneTheory
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thank you very much !!!!!!!
it was quick answering....
boris
it was quick answering....
boris
 marshmellow
 Cap Cooler
Hey Boris,
don't do it like that!! The ECC83 will be extremely underheated,
while the filament of the EF86 will glow like a christmas tree.
Just calculate for yourself...
And you can't heat the EF86 with 12,6V. If you really have to
use that voltage: ECC83 in series and in parallel a voltage regulator
(only with DC source of course) or a resistor with the EF86.
Volker
don't do it like that!! The ECC83 will be extremely underheated,
while the filament of the EF86 will glow like a christmas tree.
Just calculate for yourself...
And you can't heat the EF86 with 12,6V. If you really have to
use that voltage: ECC83 in series and in parallel a voltage regulator
(only with DC source of course) or a resistor with the EF86.
Volker
 frequencycentral
 Cap Cooler
ECC83: 6.3 volts @ 300ma
EF86: 6.3 volts @ 200ma
Therefore run the two in series from 12.6v, but with a 63 ohm 1 watt resistor in parallel with the EF86 heater. That should give each heater what it needs. You can measure where they meet to confirm that it's 6.3v right in the middle.
So:
 ECC83 pins 4 and 5 to ground,
 ECC83 pin 9 to EF86 pin 4,
 EF86 pin 5 to 12.6v,
 63 ohm / 1 watt resistor from EF86 pin 4 to EF86 pin 5.
You should be able to measure 6.3v at ECC83 pin 9.
I think I got the math right! http://en.wikipedia.org/wiki/Kirchhoff's_circuit_laws
EF86: 6.3 volts @ 200ma
Therefore run the two in series from 12.6v, but with a 63 ohm 1 watt resistor in parallel with the EF86 heater. That should give each heater what it needs. You can measure where they meet to confirm that it's 6.3v right in the middle.
So:
 ECC83 pins 4 and 5 to ground,
 ECC83 pin 9 to EF86 pin 4,
 EF86 pin 5 to 12.6v,
 63 ohm / 1 watt resistor from EF86 pin 4 to EF86 pin 5.
You should be able to measure 6.3v at ECC83 pin 9.
I think I got the math right! http://en.wikipedia.org/wiki/Kirchhoff's_circuit_laws
 lolbou
 Old Solderhand
+1 Rick!frequencycentral wrote:I think I got the math right!
Calculations checked OK. Please accept this A+ grade from an humble physics teacher!
May I explain to all:
R(ECC83) = 6.3/.3 = 21 ohms
R(EF86) = 6.3/.2 = 31.5 ohms
To get a proper 1/2 voltage divider (giving 6.3V to both heaters), you need to get 21 ohms out of a parallel combination of the EF86 heater and a resistor (to compute), which I call R.
You get:
1/R +1/31.5 = 1/21
Maths gives:
R= (31.5 x 21) / (31.521)
R= 63 ohms
That's the hard trick (or shall I say tRICK)...
....
A simpliest way is to think "well, I need a resistor paralled with R(EF86) that would suck the extra 100mA that the heater don't need"...
R = U x I = 6.3 x 0.100 = 63 ohms...
.....
Choose your prefered method!
 Are you a mod or a rocker?
 Uh, no, I'm a mocker.
 Uh, no, I'm a mocker.
 marshmellow
 Cap Cooler
EF86 needs 200mA heater current and you want to drop half of 12,6V:
R = 6,3V / 0,2A = 31,5 Ω
It needs to dissipate 1,26W so make it at least 2W.
Connect it like that.
/edit: of course it would work with the parallel one as well. Didn't even think about that.
R = 6,3V / 0,2A = 31,5 Ω
It needs to dissipate 1,26W so make it at least 2W.
Connect it like that.
/edit: of course it would work with the parallel one as well. Didn't even think about that.
 lolbou
 Old Solderhand
Well, not really...
Paralleled resistors is a trick to dissipate more power with lower rated components.
edit: just seen your edit, and do agree about your set up too , but you need a bigger resistor...
The heaters are in series in my mind as Rick mentioned, so this way the resistors gets 0.1 mA, and only dissipates 0.63W (P=RxI²)...frequencycentral wrote:Therefore run the two in series from 12.6v
Paralleled resistors is a trick to dissipate more power with lower rated components.
edit: just seen your edit, and do agree about your set up too , but you need a bigger resistor...
 Are you a mod or a rocker?
 Uh, no, I'm a mocker.
 Uh, no, I'm a mocker.
 frequencycentral
 Cap Cooler
Hahaha! I got some maths correct! Maths is not my strong point. Thanks for the A+.....!!lolbou wrote:+1 Rick!frequencycentral wrote:I think I got the math right!
Calculations checked OK. Please accept this A+ grade from an humble physics teacher!
 briggs
 Tube Twister
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Ahhh, very nice solutions! I apologize for my earlier BULLSHITE answer when I hadn't bothered to check datasheets. I hope it caused no distress!
Ok  now here is another question for the heater calculators! I'm going to need to run a 6112 submini a 7327 submini and an ECC99 off of either 18.9V or 12.6V, how do you lot think it would be best to do this
Ok  now here is another question for the heater calculators! I'm going to need to run a 6112 submini a 7327 submini and an ECC99 off of either 18.9V or 12.6V, how do you lot think it would be best to do this
 frequencycentral
 Cap Cooler
Easiest way would be to run the 6112 and the 7327 in series from 12.6v. And the ECC99 from 12.6 volts, not using the centre tap. That way the 6112 and the 7327 draw 300ma combined, and the ECC99 draws 400ma.briggs wrote:Ahhh, very nice solutions! I apologize for my earlier BULLSHITE answer when I hadn't bothered to check datasheets. I hope it caused no distress!
Ok  now here is another question for the heater calculators! I'm going to need to run a 6112 submini a 7327 submini and an ECC99 off of either 18.9V or 12.6V, how do you lot think it would be best to do this
 briggs
 Tube Twister
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Having thought about it again  here is the situation I find myself in (see the attached picture). Now I need to power this setup from the 15Vdc supply I have. Confusion ensues especially after a few beers on a friday eve! Legitimate values for R1 & R2 are required!
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 heaters.jpg (6.32 KiB) Viewed 6458 times
 frequencycentral
 Cap Cooler
Why not just use a 7812 to regulate the 15v down to 12v and dispense with the resistors?briggs wrote:Having thought about it again  here is the situation I find myself in (see the attached picture). Now I need to power this setup from the 15Vdc supply I have. Confusion ensues especially after a few beers on a friday eve! Legitimate values for R1 & R2 are required!
 frequencycentral
 Cap Cooler
Or place a 16 ohm / 5 watt resistor between the 15v and the tube heaters. Again, dispense with the two resistors to ground.
EDIT: 16.8 ohm
EDIT: 16.8 ohm
 briggs
 Tube Twister
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Indeed that is an idea I shall use. I (again!) am guilty of not checking datasheets and assumed that the regulator wouldn't be able to provide enough current. I WAS WRONG. God, today has been a poor one! Cheers again Freq. I'll buy a large batch and just keep trying them unitl I find one that puts out ~12.312.6Vfrequencycentral wrote:Why not just use a 7812 to regulate the 15v down to 12v and dispense with the resistors?briggs wrote:Having thought about it again  here is the situation I find myself in (see the attached picture). Now I need to power this setup from the 15Vdc supply I have. Confusion ensues especially after a few beers on a friday eve! Legitimate values for R1 & R2 are required!
EDIT  When I calculated it like that Rick I got 18 ohms, I must have done something wrong>! What method did you use? I could do with some practice!
 frequencycentral
 Cap Cooler
DC voltage = 15 voltsbriggs wrote:EDIT  When I calculated it like that Rick I got 18 ohms, I must have done something wrong>! What method did you use? I could do with some practice!
Tube heater's (combined) power requirement = 12.6 volts @ 700ma
Voltage drop required = 2.4v (15  12.6 = 2.4)
2.4 (volts) x 7 (hundred ma) = 16.8 (ohms)
2.4 (volts) / 0.7 (amps) = 3.4285 (watts)
Therefore 16.8 ohm 3.4285 watts. In reality a difficult value to find, so go for the nearest 'easy' value, 18 ohm 5 watt. Always better to have the wattage overspec'd.
If Loubou agrees, I might get another A+......!!
 briggs
 Tube Twister
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When I go back over my working I've done the same thing. I must have pushed the wrong buttons somewhere  it's like being back at school  "check your workings!", I never did it then and I guess I've not learntfrequencycentral wrote:DC voltage = 15 voltsbriggs wrote:EDIT  When I calculated it like that Rick I got 18 ohms, I must have done something wrong>! What method did you use? I could do with some practice!
Tube heater's (combined) power requirement = 12.6 volts @ 700ma
Voltage drop required = 2.4v (15  12.6 = 2.4)
2.4 (volts) x 7 (hundred ma) = 16.8 (ohms)
2.4 (volts) / 0.7 (amps) = 3.4285 (watts)
Therefore 16.8 ohm 3.4285 watts. In reality a difficult value to find, so go for the nearest 'easy' value, 18 ohm 5 watt. Always better to have the wattage overspec'd.
If Loubou agrees, I might get another A+......!!
EDIT
Oh ho! Hang on  I've found it, the error that is, I had each of the submini tubes requiring 300mA while you have them as only needing 150mA each.
 lolbou
 Old Solderhand
Well, it turns to be A+ for everyone here ... Try and learn, again and again! I sometimes wish my pupils were as good willing in trying as you are...
 Are you a mod or a rocker?
 Uh, no, I'm a mocker.
 Uh, no, I'm a mocker.