SY? I have Photoshop... I can make miracles...
You guys are very funny 
Anyway, please don't bother finding me a scope. I better like tubes, sockets and output transformers
I think today I'm going to the repairman's place to say what the forum thinks of him
Thanks so much to everyone. I took a look at the Akido linestage, it looks very interesting but...
...
...
... I've come to an hard, hard decision. I've decided to build only the phono stage. I know I'll be blasphemous on this, but why the heck I need a linestage? My CD player has a Zout of 200ohm. A line stage without gain is almost useless, and can only introduce noise and distortion, a line stage with gain is far noisier.
I'm not saying that I wouldn't build a linestage: maybe in the future I will. But not now, with limited component avability, few (and bad) tubes, no money etc etc.
So I will stick to the phono stage. 2 ECC83...
but here's the question: it has been said several times that with a phonostage you have somewhat high Zout, because of the grounded cathode topology in the last stage. So, do I have to add a CF at the output? I think yes... and it will of course be DC coupled to the plate of the last ECC83. It will use a ECC81, for the aforementioned need for a high gm tube.
I have about 100V on the plate of the ECC83, so I need a 18k cathode resistor on the ECC81.
See now? I can design a DC coupled cathode follower, and it's all with your great help and kindness, that you took some time of your day to help a newbie to design his preamp
I'm so grateful, to all of you! Thanks!
I will delete the line stage and build a CF for the phono stage. The plans are to build (in the future) a tube power amp: obviously it will need to have a volume control, so it will be a sort of "integrated". And I also thought of a PP of EL84... but that's the story for another thread
Anyway, please don't bother finding me a scope. I better like tubes, sockets and output transformers
I think today I'm going to the repairman's place to say what the forum thinks of him
Thanks so much to everyone. I took a look at the Akido linestage, it looks very interesting but...
...
...
... I've come to an hard, hard decision. I've decided to build only the phono stage. I know I'll be blasphemous on this, but why the heck I need a linestage? My CD player has a Zout of 200ohm. A line stage without gain is almost useless, and can only introduce noise and distortion, a line stage with gain is far noisier.
I'm not saying that I wouldn't build a linestage: maybe in the future I will. But not now, with limited component avability, few (and bad) tubes, no money etc etc.
So I will stick to the phono stage. 2 ECC83...
but here's the question: it has been said several times that with a phonostage you have somewhat high Zout, because of the grounded cathode topology in the last stage. So, do I have to add a CF at the output? I think yes... and it will of course be DC coupled to the plate of the last ECC83. It will use a ECC81, for the aforementioned need for a high gm tube.
I have about 100V on the plate of the ECC83, so I need a 18k cathode resistor on the ECC81.
See now? I can design a DC coupled cathode follower, and it's all with your great help and kindness, that you took some time of your day to help a newbie to design his preamp
I'm so grateful, to all of you! Thanks!
I will delete the line stage and build a CF for the phono stage. The plans are to build (in the future) a tube power amp: obviously it will need to have a volume control, so it will be a sort of "integrated". And I also thought of a PP of EL84... but that's the story for another thread
Hi Giaime,
Don't be hard on the service guy. If he is any good, he will be busy. This is doubly true running up to Christmas. I have been in that very situation many times myself.
So he is doing you a favour, I believe he means well and I am sure he is able to do this repair. He does have to service his paying customers first. Also, I will bet he feel bad about the scope sitting there not done yet. Bring the poor guy a coffee.
-Chris
Don't be hard on the service guy. If he is any good, he will be busy. This is doubly true running up to Christmas. I have been in that very situation many times myself.
So he is doing you a favour, I believe he means well and I am sure he is able to do this repair. He does have to service his paying customers first. Also, I will bet he feel bad about the scope sitting there not done yet. Bring the poor guy a coffee.
-Chris
Actually,
I learned that from jneutron... who has too much time on his hands (as do I at the moment). I am only violent with children and students.
Giaime,
If the repair guy lacks the time, post the scope schematic and we will make it work. If you have a dot in the screen... that is good... can't be so hard to fix.
I learned that from jneutron... who has too much time on his hands (as do I at the moment). I am only violent with children and students.
Giaime,
If the repair guy lacks the time, post the scope schematic and we will make it work. If you have a dot in the screen... that is good... can't be so hard to fix.
poobah said:Giaime,
Wait for the ECC88 and build your phono pre with 83/88... the Thorsten (Yang Wang) one is good design... In the meantime, study your math!
Oh yes, I'll wait for the ECC88s... if they'll arrive
I guess you're right about math
monday I'll have the exam.burnedfingers said:
Exactly
He's the best around here
funny one! You can clearly see some 0.1% crossover distortion with that one
That is so cool dude... that's a real find... probably get small fortune for that on EBAY. That window is so small... hell... everything would look like it was working right to me.
There are some cool boneyards around here for old equipment. Some days when I'm cruisin by with an hour to kill I go rummage around and gawk at the equipment. It always weird to see things that must have cost 2 million 20 years ago, sitting outside with birds living in them.
One of these days I want to buy one of those old process vessels or electronscope and turn it into a distilling device... uh... uh... for water.
There are some cool boneyards around here for old equipment. Some days when I'm cruisin by with an hour to kill I go rummage around and gawk at the equipment. It always weird to see things that must have cost 2 million 20 years ago, sitting outside with birds living in them.
One of these days I want to buy one of those old process vessels or electronscope and turn it into a distilling device... uh... uh... for water.
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