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Old 17th October 2007, 08:01 AM   #11
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Default Re: Classic 16.0

Quote:
Originally posted by TugaTweaker
Sorry i meant "good tube circuitry at best...".In my personal
experience , rectifying the filament supply of preamp and driver tubes is a good shoot . I like Black Gate electrolytics, Auricap props , and high voltage SiC Schottkys as rectifiers . Here , [urlhttp://www.tentlabs.com/Products/page6.html[/url] you can find more interesting matter to go further , as in my point of view an upgrade is never finnished .
From your very interesting link:

Quote:
Lowering the overall feedback is not interesting for all of you. Some speakers become 'fluffy' in the bass. If you consider lowering the feedback, I would suggest to perform audible experiments, because the effects become very apparant if things go wrong. For this purpose, I just apply a potmeter over the resistance, so that I can experiment very quickly. If the effect works for you, the result is a overall improvement of dynamics and imaging.
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Old 17th October 2007, 08:34 AM   #12
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http://www.tentlabs.com/Products/Tub...ter/index.html

Interesting, but I need higher output current to be able to use existing connections...
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Old 17th October 2007, 07:30 PM   #13
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There are options to cope , two E80 plus two 6SN7 heaters, not a big current problem as you will see consulting specific tubedata . But you said nothing about the feedback mod . You removed R6 and C3 , any subsequent mod is unnefecttive then , unless you have connected the wire to the next component in the circuit .

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Old 18th October 2007, 05:40 AM   #14
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Quote:
Originally posted by TugaTweaker
There are options to cope , two E80 plus two 6SN7 heaters, not a big current problem as you will see consulting specific tubedata . But you said nothing about the feedback mod . You removed R6 and C3 , any subsequent mod is ineffective then , unless you have connected the wire to the next component in the circuit .
Good morning,

I need 4 x .6 A = 2.4A, Tentalabs modules are 1.5A maximum, Machmat needs at least 10V input, my transformer tap is 6.3V, of course, what would you suggest...

Anyway, I dont hear any hum, even with my ear against the speaker, it was one more experiment...

I broke the global feedback loop, no global NFB in my amplifier now, also hardwired triode mode...

I know the majority use and recommend global NFB, I tried both options, and preferred the sound in my system without...

I am very sensitive to crossover distortion, only like first order, or none, maybe NFB has a similar effect on sound, besides the known benefits...

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Old 20th October 2007, 07:33 AM   #15
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Tube_Dude,

Verified, and the schema corresponds to the circuit, 0 ohms between cathode, point 8, and ground, 10 ohms between supressor, point 1, and ground, or cathode, of course...

Maybe the Chinese do things different, but it works...

I replaced a couple more CAPs with Nichicons, aligned the PIOs on the right, and took a better picture, see first post...

The power supply schema is already updated with some more mods I am going to do next weekend, ordered a bunch of Philips 0.13 uF 1600V, to apply all over...
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Old 21st October 2007, 02:38 PM   #16
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Quote:
Originally posted by Lowrider
Tube_Dude,

Verified, and the schema corresponds to the circuit, 0 ohms between cathode, point 8, and ground, 10 ohms between supressor, point 1, and ground, or cathode, of course...

Lowrider

Strange!

Let's see, try to put the switch for monitoring the bias to one output tube , and measure again the resistance in that tube.

Maybe the 10 Ohms resistor is only used for measurement purposes , and is shunted by the switch in normal conditions of operation.
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Old 21st October 2007, 03:07 PM   #17
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The switches are used one by one only measuring/adjusting bias, how could they shunt the resistor...


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Old 21st October 2007, 03:13 PM   #18
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Quote:
Originally posted by Lowrider
The switches are used one by one only measuring/adjusting bias, how could they shunt the resistor...
Try it!

With the amp disconnected , of curse !
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Old 21st October 2007, 03:16 PM   #19
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Next weekend I open it again to install all the bypass CAPs, I will try to do that, the problem is that I have to remove the EL34 to put it upside down, to open...
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Old 21st October 2007, 03:30 PM   #20
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Quote:
Originally posted by Lowrider
Next weekend I open it again to install all the bypass CAPs, I will try to do that, the problem is that I have to remove the EL34 to put it upside down, to open...
You don't need to open the amp to do that experience.

Take out one EL34, and measure the resistance between pin 8 and ground ( the outer part of the RCA inputs are a good ground).

Then , see if rotating the switch for that tube position , change the reading...
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