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Old 30th Jan 2007, 9:37 am   #41
oldeurope
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Default Re: making an audio output triode...

Quote:
Originally Posted by ECC8100 View Post
Fantastische Arbeit, Darius. entschuldigen Sie bitte mein Deutsch.

Hi Darius, I hope you will excuse my opening in my poor German (my Grandmother was German, so I hope you will excuse me!)

Very impressive
And you wound all of the wound components yourself.

Looking at the scope shots, looks like mainly third harmonic distortion?
What are the HF and LF breakpoints?
How does it respond to square waves?

Impressive lab you have there, any chance of some pics, please? (In another thread to keep the mods happy!)
Good morning and thanks ECC8100.
I have a transformer factory in my neighbourhood, so I can get all components and I can wind what I want.

"Looking at the scope shots, looks like mainly third harmonic distortion?"
I don't think so.

Please note there is no negative feedback of course.
The high frequency breakpoint (-3dB) is at 30KHz.
I set the low frequency breakpoint to 14Hz with the 22nF 510KOhms at the g1 of the output triodelington. I want the low breakpoint multiplied by high breakpoint = 400000. At this 14Hz breakpoint the reactance of the transformer (1K3Ohms) is still higher than the output resistance of the triodelington (1KOhms). The output load resistance is 2KOhms.

Kind regards,
Darius
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Old 30th Jan 2007, 5:17 pm   #42
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Smile Re: making an audio output triode...

Good evening,
I made some measurements for you.

THD+N output power

0,5% 38mW
1% 280mW
2% 1,1 W
3% 2,0 W
4% 3,13W
5% 4,12W
6% 5,12W
7% 5,89W
8% 6,13W

You can see the slow rising THD+N with the output power. This is typical for a triode.

Kind regards,
Darius DD3ET

The sweep and THD+N measurement is done with Neutrik Minirator ML1 and Minilyzer ML1
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Old 8th Feb 2007, 10:49 am   #43
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Wink feedback...

Hi, mabe there is a confusion. I don't want any negative voltage or current feedback in my triode amp ! Negative and positive feedback in this thread is wanted of course.

Kind regards,
Darius
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Old 8th Feb 2007, 5:05 pm   #44
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Default Re: making an audio output triode...

I'm still waiting for you to show screen shots of the triode being HEAVILY overdriven, like 90% THD!
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Old 8th Feb 2007, 6:06 pm   #45
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Question Re: making an audio output triode...

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Originally Posted by Merlin View Post
I'm still waiting for you to show screen shots of the triode being HEAVILY overdriven, like 90% THD!
Ah, that is what you are waiting for. There are different kinds possible depending in the driving stage . When the voltage g1 K goes positiv a grid current takes place.
If you have a very low output resistance at the driving stage, the sine wave of the driver stage output is not destored. Because of the RC coubling the biasing goes more nevative and the average current of the output stage will get lower. This causes distortion. Do you want to see this one?
Coubling the driving stage via transformer makes it possible to give positive grid voltages and grid current. Do you want to see this one?
I am using an half ECC82 driving stage. Kathode resistor 1KOhms; decoubling cap 47uF; plate resistor 82KOhms connected at 250VDC, at the moment. This stage is coubled via 22nF to the triodelington grid (ECC82 two systems in parallel) grounded via 510KOhms.
Overdriving it, the driver stage is strong enough to change the biasing but the top of the sinewave is clipped a little bit when grid current takes place. This distortion is added to the one caused by the output stage current cut of. Do you want to see this one? (I hope so, because this is the easiest to work out.)

I have just finished the mainstransformer. I tried out the account of windings to get exactly 6V3AC for the heaters. Tomorrow it goes to the transformer factory for "Vakuumtränken", sorry I don't know the english word for this procedure.

Kind regards,
Darius
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Old 8th Feb 2007, 6:12 pm   #46
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Default Re: making an audio output triode...

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Originally Posted by oldeurope View Post
Tomorrow it goes to the transformer factory for "Vakuumtränken", sorry I don't know the english word for this procedure.
Tränken translates to soak. Thanks to Google for that. Vacuum impregnation should be a good colloquial translation
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Old 8th Feb 2007, 6:23 pm   #47
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Smile Re: making an audio output triode...

Quote:
Originally Posted by ppppenguin View Post
Tränken translates to soak. Thanks to Google for that. Vacuum impregnation should be a good colloquial translation
Thanks for the quick reply, Jeffrey. Vacuum impregnation, ok.

What is the correct spelling triodemultipler or triodemultiplier?

Kind regards,
Darius
(I am back tomorrow.)
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Old 12th Feb 2007, 1:54 pm   #48
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Default Re: making an audio output triode...

I think "triodemultiplier" is what you want.

Yes I would like to see the easy one! I want it heavily overdriven from a high impedance source (between 10k and 40k for example). I want to see how hard the signal is clipped, and how close to a square wave it can be pushed!
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Old 12th Feb 2007, 3:40 pm   #49
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Question Re: making an audio output triode...

Quote:
Originally Posted by Merlin View Post
I think "triodemultiplier" is what you want.

Yes I would like to see the easy one! I want it heavily overdriven from a high impedance source (between 10k and 40k for example). I want to see how hard the signal is clipped, and how close to a square wave it can be pushed!
Hi Merlin,
how many times of the biasing voltage should the driving voltage be?
If you have enough driving voltage you'll get a square wave from any triode.

Darius
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Old 12th Feb 2007, 8:58 pm   #50
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Default Re: making an audio output triode...

The most interesting thread on the forum!
Excellent work!

Does it sound like a power triode?

The distortion doesn't seem quite in the same league as a PX4!
But it does seem to behave like a power triode.

Am I right in assuming most of the gain is in the combined output stage?
Is that why it's got both grid and anode stoppers?

So the combined output stage is an ECC82 with both systems in //?
What is the driver stage; half an ECC82?

Sorry, your circuit diag wasn't clear. Your circuit diag. shows only one triode stage in the output, but your description quotes two.

Great work.
I'd certainly give it a go, I'm interested in hybrid stuff like this.
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Old 13th Feb 2007, 9:11 am   #51
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Smile Re: making an audio output triode...

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Originally Posted by miller_effect View Post
The most interesting thread on the forum!
Excellent work!

Does it sound like a power triode?

The distortion doesn't seem quite in the same league as a PX4!
But it does seem to behave like a power triode.

Am I right in assuming most of the gain is in the combined output stage?
Is that why it's got both grid and anode stoppers?

So the combined output stage is an ECC82 with both systems in //?
What is the driver stage; half an ECC82?

Sorry, your circuit diag wasn't clear. Your circuit diag. shows only one triode stage in the output, but your description quotes two.

Great work.
I'd certainly give it a go, I'm interested in hybrid stuff like this.
Hi miller_effect,
I didn't test it in a living room. This comes up when the mains transformer and the mains input is mounted.
The PX4 has 4% destortion at 3,2Watts, AD1 has 5% at 4,2Watts...
These values are measured at the plate site without destortion of the driver stage and losses of the output transformer. My measurement is at the speaker terminals.
I don't like the "low micro" valves sound. This is a compromise to get a better efficiency. My oppinion is a micro between 10 to 20 gives the best sound.
The ECC82 has u=17 , the AD1 has u=4, the 300B has u=3,8 ,the EL34 triode u=11 ,the EL86 triode u=8, the EL84 triode u=19, the RL12T15 u=14,4. I like the RL12T15 and the EL84 triode very much, but they don't have enough power and it is difficult to find good RL12T15. So a "big" ECC82 is the thing I want. The triodelington application makes this possible!
There are various kinds of ECC82s out there, they all sound different if you don't have negative feedback and run them with nearly micro (u)!!! So I can select your sound.
Attached is a graph of a single system of the ECC82.(Valvo-Handbuch 1962-63)
Uieff is input voltage RMS in Volts on the left Y axis.
Ia is plate current in mA on the left Y axis.
Kges. is the "THD+N" distortion in % on the right Y axis.
No is the sound output power measured at the output resistor Ra. (X- axis)

I don't like this biasing and output load. I my amp I have both systems in parallel. The equivalent Rk for both systems is 1K2 and Ra = 20K. The output power must be multiplied by eleven.
I didn't find a graph for this application.

I will measure the gain exactly after making the schematic. I remember it is about -13 for the triodelington output stage (plate/grid), the driver stage makes -u (17).

What are stoppers?

Yes, 1/2 ECC82 for the driver stage and both systems in parallel at the triodelington.

The handmade graph at the beginning showes one single system in the triodelington (and I connected the heater wrong )

I'll draw a provisorial schematic soon .

Kind regards,
Darius
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Last edited by oldeurope; 13th Feb 2007 at 9:20 am. Reason: text
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Old 13th Feb 2007, 3:03 pm   #52
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Smile Re: making an audio output triode...

Quote:
Originally Posted by miller_effect View Post

So the combined output stage is an ECC82 with both systems in //?
What is the driver stage; half an ECC82?

Sorry, your circuit diag wasn't clear. Your circuit diag. shows only one triode stage in the output, but your description quotes two.
In the lunch hour I made a provisorial schematic.
I will update it with values and voltages soon.

Duscussion in the schematic wanted!

Kind regards,
Darius
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Old 14th Feb 2007, 1:48 pm   #53
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Default Re: making an audio output triode...

Oldeurope, I'd like to see photos of the output when the driver triode is delivering full output swing to the triodelington. I suspect this will be about 100Vrms. Some shots of lower drive leves would be good too, say 20Vrms and 50Vrms.
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Old 14th Feb 2007, 3:22 pm   #54
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Smile Re: making an audio output triode...

Quote:
Originally Posted by Merlin View Post
Oldeurope, I'd like to see photos of the output when the driver triode is delivering full output swing to the triodelington. I suspect this will be about 100Vrms. Some shots of lower drive leves would be good too, say 20Vrms and 50Vrms.
Hi Merlin, the driver stage is able to provide 20Vrms max.
Grid current takes place at the triodelington at 10V rms.

Kind regards,
Darius
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Old 15th Feb 2007, 1:30 pm   #55
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Default Re: making an audio output triode...

That doesn't make sense to me, you're using an HT of 250V? With an anode resistor on the driver, you should easily be able to get about 100Vrms swing?
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Old 15th Feb 2007, 4:34 pm   #56
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Default Re: making an audio output triode...

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That doesn't make sense to me, you're using an HT of 250V? With an anode resistor on the driver, you should easily be able to get about 100Vrms swing?
Hi Merlin,
I didn't use a biasing for max output voltage.
Linearity is more importand for me.
I will make the measurements in the testcircuit. So I can get a large level from another amp.
Darius
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Old 17th Feb 2007, 1:51 pm   #57
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Smile Re: making an audio output triode...

Hi,
I mounted the mains transformer and connected it.
Attached some pics of the current state.
The kathode resistors of the triodelington are outside now. You can see them in the top view picture. Next is picking up some voltages...

Thanks for having a look,
kind regards,
Darius
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Old 17th Feb 2007, 5:58 pm   #58
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Default Re: making an audio output triode...

What a nice looking amplifier!

With those gleaming golden sockets it would probably sell for thousands on e-bay

On a serious note, I suspect that I may build one myself when I get my workshop finished - good work.

Regards,
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Old 20th Feb 2007, 8:57 am   #59
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Default Re: making an audio output triode...

Hi Darius,

this might be a silly question. In the 1970's I have build a small valve-based audio amplifier without output transformer for headphones. I used 18 V d.c. and a PCC88 as the audio triode. Do you think it is possible to update your triodelington in such a way that an output transformer is not necessary? I think with 12 or 24 V d.c. this should be possible. Perhaps you have to look for an other transistor. But in this update you can take the filament voltage direct from the 12 or 24 V d.c. source.

Kind regards,
Eckhard
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Old 20th Feb 2007, 2:26 pm   #60
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Smile Re: making an audio output triode...

Thanks Brian!

Hi Eckhard, I think this is possible, maybe with an ECC86?
As posted in #17 I wanted to do it as usual, a classic design.
At the moment I am testing the perfect values for the driving stage.

Kind regards,
Darius
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