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-   -   Classic 16.0 (http://www.diyaudio.com/forums/tubes-valves/110161-classic-16-0-a.html)

Lowrider 16th October 2007 11:18 AM

Classic 16.0
 
My first post here, and my first DIY, dont be too hard on me... :smash:

I got bored, no euros to upgrade my system, so I started playing with my amplifier... :xeye:

1. replaced all tubes with Siemens NOS...

2. removed uneccessary gadgets, inputs and selector, volume control, usage timmer, relays, etc...

3. removed global negative feedback

4. replaced 12AT7 with E80CC, replaced R28 on the power supply to cope with extra current of this babies, and removed cathode CAP to decrease gain further...

5. rewired input stage point-to-point with Allen-Bradley resistors and replaced WIMA coupling capacitors with Russian PIOs...

http://www.melorib.com/data/Classic_mod.jpg

TugaTweaker 16th October 2007 12:57 PM

Classic 16.0
 
Its seems a nice job . But good tube circuitry at are simplier with fewer components, and more solid state free the best .
Regards

tugat

Lowrider 16th October 2007 02:39 PM

A bit messy, but it plays very well with my OB fullrange speakers, this is how it was originally:

http://www.melorib.com/data/Classic_old.jpg

Lowrider 16th October 2007 02:39 PM

Re: Classic 16.0
 
Quote:

Originally posted by TugaTweaker
Its seems a nice job . But good tube circuitry at are simplier with fewer components, and more solid state free the best .
Thanks, it doesnt look as good with enough resolution photo... :xeye:

I did remove 20 components and 2 meters wire from the signal path, plus some not needed accessories... :angel:

It looks fuller because of the size of the Russion PIOs...

What else do you suggest, simple enough for me to do... :confused:

http://www.melorib.com/data/Classic_schema_mod.jpg

http://www.melorib.com/data/Classic_schema_ps.jpg

TugaTweaker 16th October 2007 04:23 PM

Classic 16.0
 
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 .


Tugat

AndreasS 16th October 2007 06:18 PM

Re: Re: Classic 16.0
 
Quote:

Originally posted by Lowrider
...
http://www.melorib.com/data/Classic_schema_mod.jpg

How this global feedback works? The condenser C1 is shorting the feedback path for AC.

Regards Andreas

TubeHead Johnny 16th October 2007 06:36 PM

Modding/replacing/removing can be quite addicting and I agree with tugat on the simpler the better. But I think it's important to know when to stop. I've built an amp over a year ago and it's been modded so many times that it's now a completely different beast. The sad part of it is, I really not convinced that it sounds better than it did last year! Sound is so damned subjective!

~~~John~~~

TugaTweaker 16th October 2007 08:43 PM

Classic 16.0
 
Lowrider .
Removing R6 did you left it open . No negative feedback ?! Doesn't it sound more distorted ? Maybe it was better to reduce the amount of feedback instead .

Tube_Dude 17th October 2007 01:04 AM

Hi Lowrider

It seams that exist an error in your schematic.

R18 and R19 must be connected between the pin 8 of the EL34 ( cathode ) and ground.

It is used to measure bias.

Maybe the error is only in the schematic and not in the implementation... :)

Welcome!! :drink:

Lowrider 17th October 2007 07:27 AM

Re: Classic 16.0
 
Quote:

Originally posted by AndreasS


How this global feedback works? The condenser C1 is shorting the feedback path for AC.

Regards Andreas


Quote:

Originally posted by TugaTweaker
Lowrider .
Removing R6 did you left it open . No negative feedback ?! Doesn't it sound more distorted ? Maybe it was better to reduce the amount of feedback instead .

The components in "red" where removed, no global negative feedback...

Maybe there is more distortion, but it sounds much better now, particularly, more real, more lively, nicer mids and highs...


Quote:

Originally posted by Tube_Dude
Hi Lowrider

It seams that exist an error in your schematic.

R18 and R19 must be connected between the pin 8 of the EL34 ( cathode ) and ground.

It is used to measure bias.

Maybe the error is only in the schematic and not in the implementation... :)

Welcome!! :drink:

Hello Jorge,

Nice to meet you again, had to get into DIY for it... ;)

Maybe the schema is wrong, I didnt change anything there, if I have time, I will open it on the weekend and test how it is really connected... :rolleyes:


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