Tube with Power IC Output Stage - JLTi

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#802
Hi,

Did I wrote +/-35V for ECC86? Of course to high, max +/- 15V!
Click to expand...

I just thought I'd mention it before someone just drops in a ECC86 en lieu of the ECC88 and say they don't like what they're hearing based on those findings.

Personally I don't really like low voltage valves but that's another story....😉

Here's some data on the ECC86/6GM8:

ECC86

Cheers,😉
 
#803
Franz G said:
Wrong, dear Carlos!

The difference between input and output must be within 37V.The chip itself is floating and independent of the voltage.

You could even use LM1083.

Franz
Click to expand...

Yes, you are right.
This sentence on the datasheet confused me:
"The LM117 series of adjustable 3-terminal positive voltage
regulators is capable of supplying in excess of 1.5A over a
1.2V to 37V output range."
 
#804
This sentence on the datasheet confused me:
Click to expand...

Carlos: I always feel the same about datasheets: I read them 100 times (at toilet, in the bed, watching tv and so on).

And I think: Yes, you got it, Franz.

But then, I try a new circuit. And I get a problem. Then I read the datasheet again:

The first sentence gives the solution :bawling:

This is the hard way, to learn.

What is more important? The goal or the way? (Konfuzius, isn't it?).

Franz
 
#806
Actually, I am not sure, if the version with the low voltage ECC86 or the version with higher voltage E88CC is sounding better.

I just feel, it is the E88CC, I am not total convinced about the ECC86 solution. Some dynamics missing?

Soon, I will have the chance, to compare both versions: I have an order to build and sell one VBIGC, so I produced two boards.

The number two of this boards is now playing with the ECC86. The second board, number one (for the customer) will include an E88CC with adequate voltage.

Then, I will have the chance to compare both amps.

I will inform here.

Franz
 
#807
Franz G said:
Carlos: I always feel the same about datasheets: I read them 100 times (at toilet...)
Click to expand...

planet10 said:
Around here we call that the library... 🙂
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😀
You guys should try to read the DIR1703 datasheet.😱
Hard to follow, even in the library.
The guy that wrote it didn't even know how to talk.
It must have been the same engineer that developed the chip, as it had a bug and TI removed them, not available anymore.:clown:
 
#810
Franz, **** off 86 - it is much more nonlinear than 88, so you get only bigger distortion
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Sorry, I removed the censored part of your text 😀

It must be this way: actually (with ECC86), La Traviata, does sound like through fog...

Franz

Edit: I just removed the ECC86 and put in the E88CC with only +/-11V.

Result: much more dynamics, at least. The fog is gone. And it does work!?! Amazing, isn't it? But I will of course go back to a adequate Ub (+/-50V to +/- 60V) for the E88CC.
 
#812
Franz G said:
Here again, my simple power on delay with an explanation (of course, it would be more easy to use LM3876 and LM3886 with mute function).

An externally hosted image should be here but it was not working when we last tested it.


The NE555 acts as timer. The time delay is regulated by the trimmer and the cap. The bigger the cap and the poti, the longer the delay.

The "Relais" is the relay, the coil of it. Maybe, instead of a relay you could use pin 3 and 4 to control the mute function of LM3876 or LM3886?

You could switch whatever you want with this circuit. Input, Output, PSU and so on. But be carefull to switch voltages at the primary side of your tranny!

Franz

P.S.
The circuit is out of an 555 datasheet. I am not sure, but when you increase the value of the cap, then imho a diode is needed for safe operation and long life of the 555.
Click to expand...

Franz,

You've gone this far. How about a DC sensing circuit so that the mute can be used for speaker protection?

🙂

sheldon
 
#813
You've gone this far. How about a DC sensing circuit so that the mute can be used for speaker protection?
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Yes, this would be great, but I have no circuit nor knowledge in this area.

Do you have a suggestion? 😎

This way, I would no more hesitate, to connect an Poweropamp to my Coral Beta 8 speakers (15W).

Franz
 
#814
I converted my amp back to E88CC, with +/-49.7VDC and an Rc of 10K.

The result is good. dynamics are back. No more DC at the pot, the speaker does no more move with the movement of the pot 🙄

The ordered chassis arrived, I mounted it for a first trial in one of two chassis. The mains part and the cabling are still in experimental stage, not good for kids and pets.

An externally hosted image should be here but it was not working when we last tested it.


Franz
 
#818
Planet10 wroteYou should really try some plenum grade CAT 5 strands in place of that fat zip cable for the speaker outputs.
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Dave

I understand you. But: I played a lot with every of my audio parts in the last few years, after 30 years hifi consumer.

Let me try to resume this phase:

- At the beginning, I was aware of the importance of the chain model. A weak piece within could produce failure of the whole chain.

- Today, we can be happy about the beginning of our chains, our sources (CD and so on). I still love vinyl, but we really have a big fundus of great sound, today, as we never had before (Sorry, why not MP3 in a good quality?).

- After three years of building amps, I am able today, to build reasonable good amps. I am happy about this. The difference between (very) good amps is small! (Today, we have internet, to get all circuits and informations, about the "easy" electronic topic audio-circuits).

- Interconnecting: a story of inductance, capacitivty and resistance. I tried many diy solutions. They are good, but not a real achievement over my traditional solution.

- Speakers: Here we are. Big difference. Like instruments, still and forever! Here, I will investigate, search and try, not with the cables anymore. Dont let me talk about speakers here. I just use fullrange speakers, no passive elements. Full stop.

- Last, but not least: the room...

- The music

- What did you drink/smoke, before listening (ouhhh..., not you, Dave, me...)?
.
.
.

Franz
 
#819
Franz G said:


Yes, this would be great, but I have no circuit nor knowledge in this area.

Do you have a suggestion? 😎

This way, I would no more hesitate, to connect an Poweropamp to my Coral Beta 8 speakers (15W).

Franz
Click to expand...

As long as you understand that I don't know what I'm talking about, here goes:

If we want to mute the circuit, we have to open the connection between the mute pin and the negative rail. From the internet, I understand that if voltage on pin 6 is more than 2/3 of the supply voltage, the output goes low(pull to ground?). So how about a high pass filter before two opamps, one inverted, one not. Diodes on the output of the opamp to only pass the positive signal. Then output to pin 6 of NE555. Set the gain to the desired voltage cut-off. Someone with spice or similar could model to get the right values.

Sheldon
 
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