KT66SE

[6B4G]

Could I change the EF184 for a better tube?
Also I would love to use the EL37's in the place of the KT as I built a similar amp of the KNIGHT KB-85 and I used the EL37's
they sound fantastic.
I have acquired quite a few tubes in the past and also heaps of cc resistors.

[6B4G]

Thanks again have to go to bed now have a great night guys.

[Geek]

What do you want out of the EF184?

Trioded they have a gain factor of 60, are crazy linear, low noise, high transfonductance and sound fantastic.

Cheers!

[azazello]

Suitable are triodes:
12AU7, ECC81, 6DJ8, 6SL7.
Instead EF184, You can use E180F, E186F, EF861, C3g, 6S45P, 6N6P, 6N30P

[6B4G]

Azazello are you saying that the EF184 is good enough?

Also please feel free to ask for any resisters I might have and you need at
no cost. I have a few thousand if I don't have the value you need we
could probably make it with one or two.

[azazello]

1. Yes..../but my favorite is E180F, Russian analog are 6J9P, 6J11P, if You need I can send You a pair, of course free/.
2. Probably I might ask You...Thanks!!

[6B4G]

Thanks for that I really do appreciate the help and offer.
Your not "lci_electronics" on ebay by chance?
If you want to contact me you can on gregt@on.gr

Thanks

[6B4G]

Hi again, another quick one.
There is a meter on the Cathode to gnd, I find that if a current passes threw meter there is a potential
rot the resistance of the meter to clime due to the heat.
Is that a problem?

[azazello]

Don't worry....

[6B4G]

Hi Nikola here is the parts list and the schematics.

MX-205
320V-280V-0-70V-280V-320V/0,205A AC (210mA DC CT)
0-5V/3A + 3X 0-6,3V/2A


FC-30-3.5S
30W
3,5K
4,6,8,16
20Hz-100KHz
80/170mA


TC-10-130W
10H (130mA)
150mA
130


R1 560 [kO] 1/2 [W]
R2 2.2 [kO] 1/2 [W]
R3 51 [kO] 1 [W]
R4 240 [kO] 1 [W]
R5 2.4 [kO] 1 [W]
R6 51 [kO] 2 [W]
R7 150 [kO] 1 [W]
R8 1 [kO] 1/2 [W]
R9 250 [O] 20 [W]
R10 180 [O] 1 [W]
R11 18 [kO] 6 [W]
R12 2.7 [kO] 3 [W]
R13 120 [kO] 1 [W]
R14 ~ 16 0.5 [O] 5 [W]
VR1 RV24A104 (100 [KO] A)
C1 0.068 [uF]
C2 10 [V] 170 [uF]
C3 0.33 [uF]
C4 50 [V] 150 [uF]
C5 500 [V] 47 [uF]
C6 500 [V] 47 [uF]
C7 500 [V] 47 [uF]
C8 500 [V] 47 [uF]
C9 ~ 14 16 [V] 10000 [uF]
T1 FC-30-3.5S
T2 MX-205 breaks
D1 ~ 3 D15XB60
L1 TC-10-130W
V1 ECC32
V2 EL37
V3 GZ37
R-NF 170 [kO] (9 [dB])
R-NF 375 [kO] (6 [dB])
R-NF 1 [MO] (3 [dB])

[azazello]

From the first look, schematic probably is good, You can start.
You can change input potentiometer to 10 kohm and connect between middle it point and grid resistor 1 kohm, and the same - in grid of next tube.
You can try increase C1, C2 and C4 maybe 2-3 time.
You can use in Power transformer wires for 280 v.
You can't use maybe rectifiers D1, D2, D3 for heating of tubes, because maybe Uheat. will drop down 6,3 v. Better connect heaters direct.
You can try decrease R13 2-3 times and decrease R2 to about 1.5 kohm and listen how ampl. will sound with more current and more +Uplate.
Better Increase C6 to 300-400 uF For more energy in strong moment of sounding.
And decrease R11 to 20 ohm 6-10 Wt /18kohm is maybe mistake.../.
And You will need power transformer for every channel.

[6B4G]

Just a quick one
I have a transformer that is 230 primary and 680 secondary
The current of the secondary is unknown.
V1/V2 = I2/I1
is it correct to say 680/230=0.338
therefore secondary is 680VAC 338mA ????????

[azazello]

No. What is current of primary?

[6B4G]

I see now that there are a lot of calculations Faraday's Law, Ampere's Law etc.
This is an old but never used transformer that I picked up some time ago when I lived in Australia
I found them while I was looking for some parts in the back room. Unfortunately I have no info
on them I just ran some volt tests and found them to have 680vct 12vct 5v and a 50v pair.
Primary has a 13.3 ohm resistance and the 680 has a 97 ohm resistance.
I spent about 3 hours this morning listening to an Indian fellow that had a runny nose and was sniffling ...
talking about transformers and I just gave up. Not worth the time or agitation

Best Regards
Greg

[mesherm]

http://www.angelfire.com/electronic/funwithtubes/Programs-98.html

Scroll down to Power Transformer Evaluator and download the free software.