What is doing V1b in this schematic ???

[kagliostro]

I'm not able to understand what does there the second triode of V1 


Franco

[shooter]

Best I could do is color 


WAG; some sort of G2 "stabilizer"??

[PRR]

There should be an article where the Designer explains his brilliant thought.

[tubeswell]

Who drew that schematic?

[kagliostro]

Ciao

I'm trying to recover the article link

Franco

[kagliostro]

Sorry, I've find the same schematic in some pages but no one Is the original page I've seen and on this pages there are no explanations


Franco

[sluckey]

I've never seen anything like that. I have no idea what it is supposed to do or even if it is wired correctly.

[kagliostro]

Thanks Steve


Franco

[PRR]

I can't find the whole article either.

V1B acts like a NFB path, so the power pentode might act more like a triode.

The pot changes something, but can't turn all the way no-NFB, so I do not understand the point.

I'm sure this is not a guitar amp. For hi-fi, you could try it, but it may be less interesting than it looks.

[kagliostro]

Thanks PRR

I'm exhausted, do you remember that some years ago my father had a brain stroke ... not that today was the same, but I spent many many hours at the hospital with him

Franco

[PRR]

My little dog passed last week.

My best wishes for you and your family.

[kagliostro]

I'm so sorry about

I know what It means

Franco

[66Strat]

Sorry to her about the loss of your dog PRR. They bring so much joy when they are with us, it hurts when they leave.

Franco, how is your father doing? I hope that he is well.

[kagliostro]

My father ... Is not simple to explain, brain is too old and many problem follow


Franco

[shooter]

My Dad changed addresses a couple years back, while we no longer hang out, he's there in every tool I use, every discission I make....


Figuring out your circuit, comes from Dad, "If you start something, You Finish it."  circa '72






The circuit appears to work both DC an AC.  My brain recalls something about "Combining 2 in phase signals there's an effective signal gain" 1.414 keeps ratlin around 

[kagliostro]

I think the original link Is this

http://www.ne.jp/asahi/evo/amp/Dnfb/DNFB.htm

However, hard if not impossibile to understand text

Franco

[mresistor]

Looks like it is for hi-fi stereo.   http://www.ne.jp/asahi/evo/amp/Dnfb/dnfbamp.htm

[PRR]

> hard if not impossibile to understand text

Google website Translate is certain that is Czech.

If I scrape the Japanese text and put it in text translate I get this. Something about amplifier but still Greek to me.
__________________________________
Easily

In R 1 and R 2, the target operating point moves, so the point is changed by changing the lower, lower, lower, and lower points.

Moving the 100kΩ volume slider from ground to the first grid side will increase the positive return and reduce the output.
It is safe to make the impedance too small, so it is safe to make it small, and it is safe to make it oscillate and oscillate.

In addition, I will introduce an easy way to read the output impedance directly. .. ..
When the output voltage is connected, the output voltage of the Read the voltage
Is 1.2 mph. 1.2 cm

The status is status.

2000/6/26

BACK TO TOP

Increase the number of inns

In the low and low 12AU7, the input gage of the app was about 5 times higher, so we replaced it with a larger μ 12AT7.

L-stage cardo-like peaches, what, what, what, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay?
R L = 8 Ω f = 1kHz is ha
THD = 0.023%
Zo = 0.9 Ω
Av = 13
Yo yo yo yo.

[sluckey]

Google website Translate is certain that is Czech.

MS Edge does a much better job. See attached...

[kagliostro]

Many Thanks for the translations


I tried Chrome web page translator and obtained an aceptable italian version


Franco

[PRR]

Is this from Pinterest ?? Seen on DIYaudio today:

link
more

Tubelab's comments on a 12AT7 connected to power tube plate and OT and played like a maniac may be of interest: "will flash over internally, and once the fireworks cease, the tube may or may not still function, but it will likely have a H-K short or degraded isolation"....

[shooter]

Good to know it that is better to use this kind of circuits with horn loaded fullrange speakers due to their almost constant impedance vs frequency, and so stick on Hi-Fi use.

seems as long as you stay in your lane, might be worth testing if someone's secretly building Hi Amps 
all my stuff is in deep stores awaiting major room overhaulin

[tubeswell]

> hard if not impossibile to understand text

Google website Translate is certain that is Czech.

If I scrape the Japanese text and put it in text translate I get this. Something about amplifier but still Greek to me.
__________________________________
Easily

In R 1 and R 2, the target operating point moves, so the point is changed by changing the lower, lower, lower, and lower points.

Moving the 100kΩ volume slider from ground to the first grid side will increase the positive return and reduce the output.
It is safe to make the impedance too small, so it is safe to make it small, and it is safe to make it oscillate and oscillate.

In addition, I will introduce an easy way to read the output impedance directly. .. ..
When the output voltage is connected, the output voltage of the Read the voltage
Is 1.2 mph. 1.2 cm

The status is status.

2000/6/26

BACK TO TOP

Increase the number of inns

In the low and low 12AU7, the input gage of the app was about 5 times higher, so we replaced it with a larger μ 12AT7.

L-stage cardo-like peaches, what, what, what, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay, okay?
R L = 8 Ω f = 1kHz is ha
THD = 0.023%
Zo = 0.9 Ω
Av = 13
Yo yo yo yo.

[kagliostro]

An italian friend (elettronic engeener, tube Amp passionate for Guitar and HiFi) simulated the circuit and told it is very interesting and he want to build a real circuit to hear to it


Franco

[shooter]

 
I want to build it also, just can't at the moment!


have your friend bring it up slow n easy