Critical resistors

Baard · 27th March 2005, 09:51 AM

Hello

What are the ten most critical resistors in this design?

http://www.audiokit.it/ITAENG/UpElet...Sch401-1-1.jpg

I have a Copland 501, and this design is close to the 401. I have done capacitor upgrade - but will like to do a similar upgrade to "better" resistors.

And what brand or type of resistor too choose carbon, tantalum or...

SY · 27th March 2005, 11:38 AM

By far, the most critical are plate resistors (use non-inductive wirewound for lowest noise and VCR) and feedback resistors.

analog_sa · 27th March 2005, 12:10 PM

Feedback resistors (R17/R14) and grid stoppers will probably be as far as i would go - no point to go crazy improving this circuit.

As the quality of the voltage used for fixed bias is very audible (really marginal in this design) i would spend some some attention on it. A small choke will be very nice and probably good quality caps bypassing R29/R30.

Sch3mat1c · 27th March 2005, 10:41 PM

Quote:

Originally posted by Baard
Hello

What are the ten most critical resistors in this design?

http://www.audiokit.it/ITAENG/UpElet...Sch401-1-1.jpg

P1-P3, and yeah anything in the signal path or that will bring down other things on faliure (open or shorted). Carbon film is fine, except for the bias pots, which should technically be something better than conductive plastic (i.e. cermet or WW), but I haven't had any problems there either.

Quote:

Originally posted by analog_sa
As the quality of the voltage used for fixed bias is very audible

Huh? Howso? (Assuming the driver is something stiff like 12AU7/6DJ8/6SN7, and the grid leaks are reasonably large (100k or so).)

Tim

analog_sa · 28th March 2005, 07:23 AM

Quote:

Huh? Howso?

Sorry, i should have been clearer. Only audible to those willing to listen.

Sch3mat1c · 28th March 2005, 10:26 PM

LOL...

IOW, it doesn't exist. Gotcha!

Tim

27th March 2005, 09:51 AM	#1
Baard diyAudio Member Join Date: May 2002 Location: Oslo	Critical resistors Hello What are the ten most critical resistors in this design? http://www.audiokit.it/ITAENG/UpElet...Sch401-1-1.jpg I have a Copland 501, and this design is close to the 401. I have done capacitor upgrade - but will like to do a similar upgrade to "better" resistors. And what brand or type of resistor too choose carbon, tantalum or...

27th March 2005, 11:38 AM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	By far, the most critical are plate resistors (use non-inductive wirewound for lowest noise and VCR) and feedback resistors. __________________ “Listening to records is like ****ing a picture of Brigitte Bardot.” - Sergiu Celibidache

28th March 2005, 10:26 PM	#6
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	LOL... IOW, it doesn't exist. Gotcha! Tim __________________ See my Electronics webpage -- the home of Vacuum Tube Drag Racing. The key to being a successful Audiophile: "I reject your reality and substitute my own!"

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
The Critical Ear	fauxpas	Tubes / Valves	36	18th December 2007 05:16 PM
Critical Q Sub Question	needtubes	Subwoofers	12	14th June 2005 05:08 AM
Critical Q Subwoofer	Cruiser	Subwoofers	11	2nd December 2004 09:42 PM
critical Q for car	Chris8sirhC	Subwoofers	9	28th October 2004 09:47 AM

27th March 2005, 12:10 PM	#3
analog_sa diyAudio Member Join Date: Aug 2002 Location: Sofia	Feedback resistors (R17/R14) and grid stoppers will probably be as far as i would go - no point to go crazy improving this circuit. As the quality of the voltage used for fixed bias is very audible (really marginal in this design) i would spend some some attention on it. A small choke will be very nice and probably good quality caps bypassing R29/R30.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read