En prend le pied....
Is a good design pratice even with triodes...see the thread at
http://www.diyaudio.com/forums/showthread.php?s=&threadid=12064...(just in cas you tel-me that is a EF86 is triode conected...)
Even if someone don't like grid stoppers is good to put some ... and after the project as been finished see if taking out they ...there are no stability issues...
Wrong...definitevely wrong...
When you increase the open loop gain of a feedback amplifier...the distortion decrease the amount of the increase of open loop gain...
I´m looking forward to read you say that is the problem is the late night hour...
Maybe...Viagra!
Take a rest...
Is a good design pratice even with triodes...see the thread at
http://www.diyaudio.com/forums/showthread.php?s=&threadid=12064...(just in cas you tel-me that is a EF86 is triode conected...)
Even if someone don't like grid stoppers is good to put some ... and after the project as been finished see if taking out they ...there are no stability issues...
Wrong...definitevely wrong...
When you increase the open loop gain of a feedback amplifier...the distortion decrease the amount of the increase of open loop gain...
I´m looking forward to read you say that is the problem is the late night hour...
Maybe...Viagra!
Take a rest...
LA VIE A GRAS.
Hi,
Not sure what you mean but I was refering to an open loop circuit.
I hope that one day you will agree with me that is a compensation for bad design, triode or penthode, a good design does not need this.
It affects sonics you know, I like to keep my signal path devoid of resistors, no point in using silver wire when the electrons are hit by a resistive brick wall.
My cocktail of vitamins, ghinseng and viagra (God forbid) is just kicking in...I feel great.cool:
Cheers, :
Hi,
Not sure what you mean but I was refering to an open loop circuit.
I hope that one day you will agree with me that is a compensation for bad design, triode or penthode, a good design does not need this.
It affects sonics you know, I like to keep my signal path devoid of resistors, no point in using silver wire when the electrons are hit by a resistive brick wall.
My cocktail of vitamins, ghinseng and viagra (God forbid) is just kicking in...I feel great.cool:
Cheers,
:
L'heur de coucher!
But Frank...we are talking about the Quicksilvers...they have overall feedback... haven't they??
But when grid stopers are needed ...what can we do!!!
Finaly i fell in this forum everyone try to ask someone and have a blind faith in what the other (pseudo guro) say...it's good that they take it as a opinion and try by themselfs...learning in the processe...
So i make the sugestion to bunedfingers to try put the 100uF and listen...if he don't like...it can take it out of the circuit...thats the fun!!!And a 100uF is inexpensive....
A tout alors!
But Frank...we are talking about the Quicksilvers...they have overall feedback... haven't they??
But when grid stopers are needed ...what can we do!!!
Finaly i fell in this forum everyone try to ask someone and have a blind faith in what the other (pseudo guro) say...it's good that they take it as a opinion and try by themselfs...learning in the processe...
So i make the sugestion to bunedfingers to try put the 100uF and listen...if he don't like...it can take it out of the circuit...thats the fun!!!And a 100uF is inexpensive....
A tout alors!
COPULATING CAPS...
Hi,
600V would be my choice.
The actual value will depend on what gridleaks you pick, the lower the gridleak the bigger the cap need to be.
I heard from Mitch (Wheezer) that he can lay his hands on some some fancy coupling caps currently used by some hi-end manufacturers...they may be worth a try.
Other than that I'm pleasantly surprised by the Audyn caps I have in some x-overs for a two way speaker.
They are well balanced and really image very well.
Moreover they're darn cheap.
Hi,
600V would be my choice.
The actual value will depend on what gridleaks you pick, the lower the gridleak the bigger the cap need to be.
I heard from Mitch (Wheezer) that he can lay his hands on some some fancy coupling caps currently used by some hi-end manufacturers...they may be worth a try.
Other than that I'm pleasantly surprised by the Audyn caps I have in some x-overs for a two way speaker.
They are well balanced and really image very well.
Moreover they're darn cheap.
Help!!...i need same body help...(Beatles)
Why not!...only need take atention to pinouts...and biasing!
I presume that the tube pins now are wired for the 8417...if yes..
then yes you need to conect the pin 1 to pin 8...to use EL34.
And why not to try the 100 uF across the 820 ohms resistor(as i have told you)...a topologie change have much more dramatic influence in sound quality that conponents change...and if you don't like the sound..is easy to take out the capacitor...
Cheers
Why not!...only need take atention to pinouts...and biasing!
I presume that the tube pins now are wired for the 8417...if yes..
then yes you need to conect the pin 1 to pin 8...to use EL34.
And why not to try the 100 uF across the 820 ohms resistor(as i have told you)...a topologie change have much more dramatic influence in sound quality that conponents change...and if you don't like the sound..is easy to take out the capacitor...
Cheers
MORE QUICKIES.
Hi,
The EL34 mod is said to be good sounding, so claim it is even the best tube for this amp, bar the 8417.
Jorge,
If you bypass the 820 R cap then the entire feedback AC component goes straight into the cathode.
I never heard an electrolytic cap that improved the sound, the designer has taken all possible measures to leave the out as much as possible.
Can you explain why you would do that?
Cheers,
Hi,
The EL34 mod is said to be good sounding, so claim it is even the best tube for this amp, bar the 8417.
Jorge,
If you bypass the 820 R cap then the entire feedback AC component goes straight into the cathode.
I never heard an electrolytic cap that improved the sound, the designer has taken all possible measures to leave the out as much as possible.
Can you explain why you would do that?
Cheers,
RE:Wath so strange about a mod....
Hi,
The reason the cathode R is split into two Rs is that it is not a good idea to inject the NFB loop directly into the cathode.
Upgrading components is one thing, changing values left and right just as an experiment is like driving around blind.
If you know what you're doing you should redesign the whole amp from scratch and see if you can do better than the original.
I don't think that is what the owner has in mind.
No offense,
Hi,
The reason the cathode R is split into two Rs is that it is not a good idea to inject the NFB loop directly into the cathode.
Upgrading components is one thing, changing values left and right just as an experiment is like driving around blind.
If you know what you're doing you should redesign the whole amp from scratch and see if you can do better than the original.
I don't think that is what the owner has in mind.
No offense,
Frank...the diyaudio attorney....
Thats is your opinion, fine!!!... my sugestion is to burndfingers...if burndfingers want to try fine!! ...if not...equaly fine!!
Anyway ...please tell us why is not a good idea to inject the NFBe loop directly into the cathode....Please???
Because is not to late yet ...
Upgrading componentes....even my 10 years old son can do....
I was especting more from you...for me the topology is the chalenge...
I'm getting tired to make post to some one and need to answer to you..
Thats is your opinion, fine!!!... my sugestion is to burndfingers...if burndfingers want to try fine!! ...if not...equaly fine!!
Anyway ...please tell us why is not a good idea to inject the NFBe loop directly into the cathode....Please???
Because is not to late yet ...
´
Upgrading componentes....even my 10 years old son can do....
I was especting more from you...for me the topology is the chalenge...
why i don't let the owner talk??? ...you are the attorney in charge??
I'm getting tired to make post to some one and need to answer to you..
FROM THE BOTTOM UP...
Hi,
Look, I don't want to upset anyone here so stick with me on this one pls.
Nobody has to answer.
What you don't know is that I've been following this topic for months...my former company has seen more QS amps than I care to mention.
And I'm not in the habbit of butchering respectable and expensive gear just for the fun of it.
Moreover I am not the judge or attorney here, I know very well what I'm doing.
Show me how to improve the amps in a reasoned and well thought out way and I may give it a look, as it stands your suggestions are no good.
People have to start somewhere, you seem to forget that this is not a scratch built item but a design that bears close resemblance to the Bogen amp.
Surely those engineers were fools too?
Not fine to me.
No, this NOT my opinion but engineers opinion.
The mod you propose does not make any sense to me, you still haven't explained what you think to gain that way and frankly I'm not surprised.
You expalin that and I'll explain why not to do it that way, deal?
Sorry Jorge,
Hi,
Look, I don't want to upset anyone here so stick with me on this one pls.
Nobody has to answer.
What you don't know is that I've been following this topic for months...my former company has seen more QS amps than I care to mention.
And I'm not in the habbit of butchering respectable and expensive gear just for the fun of it.
Moreover I am not the judge or attorney here, I know very well what I'm doing.
Show me how to improve the amps in a reasoned and well thought out way and I may give it a look, as it stands your suggestions are no good.
People have to start somewhere, you seem to forget that this is not a scratch built item but a design that bears close resemblance to the Bogen amp.
Surely those engineers were fools too?
Not fine to me.
No, this NOT my opinion but engineers opinion.
The mod you propose does not make any sense to me, you still haven't explained what you think to gain that way and frankly I'm not surprised.
You expalin that and I'll explain why not to do it that way, deal?
Sorry Jorge,
The proposed mod!!!
Sorry...it was not directed to you....
well...need to explain more than one time....
ok ..this is my last time:
In a feedback amplifier when you increase the open loop gain for the same closed loop gain ...the distortion decrease the same factor as the open loop increase in gain...
Nothyng new under the sun....
In bussines...luck isn't everything...quality and know how matters..
Sorry...it was not directed to you....
well...need to explain more than one time....
ok ..this is my last time:
In a feedback amplifier when you increase the open loop gain for the same closed loop gain ...the distortion decrease the same factor as the open loop increase in gain...
Nothyng new under the sun....
Now a can understand...why the company...is a "former" company...
In bussines...luck isn't everything...quality and know how matters..
CHEAP SHOTS.
Hi,
Cheap and silly answer.
Sorry mate, you lost on all accounts here.
The only thing you've proven so far is that you have no idea.
As it happens, quality and know how were the only reasons those companies were set up in the first place, and while one may not be alive in Belgium anymore the rest of them is still very much alive worldwide...
Again, I won't hold your ignorance against you.
All that is besides the point though, you still haven't explained anything here.
I'm still waiting for some reasonable explanation for the mods you have proposed...running away is easy...
Pfffft,
Hi,
Cheap and silly answer.
Sorry mate, you lost on all accounts here.
The only thing you've proven so far is that you have no idea.
As it happens, quality and know how were the only reasons those companies were set up in the first place, and while one may not be alive in Belgium anymore the rest of them is still very much alive worldwide...
Again, I won't hold your ignorance against you.
All that is besides the point though, you still haven't explained anything here.
I'm still waiting for some reasonable explanation for the mods you have proposed...running away is easy...
Pfffft,
When the reader...becames the jury...
I said in my last post....and in my #41 post in this thread...the same...if that don't make any sense to you...sorry!!!
I don't need to prove anything to you....i left the jugdment...for the readers...
Bye!
PS: one thing is clear...i tell people to try things and learn about...
you...said ...prouve this and that... for the people don´t try by themselfs and learn and don´t need to ask....
Frank i must do this??? or i must do that???
Better than give a fish... is to teache people to fish...
I said in my last post....and in my #41 post in this thread...the same...if that don't make any sense to you...sorry!!!
Please ...i think that i don´t need to repeat!!!
I don't need to prove anything to you....i left the jugdment...for the readers...
Bye!
PS: one thing is clear...i tell people to try things and learn about...
you...said ...prouve this and that... for the people don´t try by themselfs and learn and don´t need to ask....
Frank i must do this??? or i must do that???
Better than give a fish... is to teache people to fish...
Bias circuit pot and resistor changes
As usual my 8417 converted amps didn't have the stock value parts in the bias circuit. The 10K fixed resistor had been changed to a 20K and the only tube that would bias was the 6550. I replaced the 20K resistor with a 1.5K and installed a 100K pot. It will now bias correctly for 6550's,KT88's, and 8417's. The grid resistors I changed from the stock 150K to 100K units. It will run the 8417 GE's with rock stable bias.
Frank
The 8417's are a remarkable sounding tube. My impressions were that the high end was somewhat more open sounding even when compaired with the 6550's.
I can't help wondering what a set of EL34's would sound like. If I understand correctly a jumper is needed between pins 1 and 8.
Can I leave this jumper there and still run the other tubes? If I am looking at the tube base correctly for the 6550 and KT88 there isn't any connection to pin one. Your ideas here would be appreciated as I don't want to trash something.
Also:
Any ideas who manufactures AMC and International tubes? I have a set of AMC 8417's and a set of KT88's
I believe I experienced my first bad tube out of the box. It turned kinda red inside on one side. It was kinda shakey with the bias also. I switched the tube with another and everything was fine.
I think the "Quickey" sounds best with the ECC83 and the 12BH7 tubes on the front.
Joe
As usual my 8417 converted amps didn't have the stock value parts in the bias circuit. The 10K fixed resistor had been changed to a 20K and the only tube that would bias was the 6550. I replaced the 20K resistor with a 1.5K and installed a 100K pot. It will now bias correctly for 6550's,KT88's, and 8417's. The grid resistors I changed from the stock 150K to 100K units. It will run the 8417 GE's with rock stable bias.
Frank
The 8417's are a remarkable sounding tube. My impressions were that the high end was somewhat more open sounding even when compaired with the 6550's.
I can't help wondering what a set of EL34's would sound like. If I understand correctly a jumper is needed between pins 1 and 8.
Can I leave this jumper there and still run the other tubes? If I am looking at the tube base correctly for the 6550 and KT88 there isn't any connection to pin one. Your ideas here would be appreciated as I don't want to trash something.
Also:
Any ideas who manufactures AMC and International tubes? I have a set of AMC 8417's and a set of KT88's
I believe I experienced my first bad tube out of the box. It turned kinda red inside on one side. It was kinda shakey with the bias also. I switched the tube with another and everything was fine.
I think the "Quickey" sounds best with the ECC83 and the 12BH7 tubes on the front.
Joe
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