The Red Light District - another PP EL84 amp - Page 3

mod_evil · 15th June 2006, 01:45 AM

This amp will be a circus! tsc tsc tsc...

Variac · 15th June 2006, 03:50 AM

Building on EC's efforts, 86 LED's. One LED on each symbol could be used as a standby indicator

You have to scroll to see it with my pdf reader

Variac · 15th June 2006, 04:20 AM

Maybe easier to see:

poobah · 15th June 2006, 05:51 AM

Good detail work Variac,

The cat missed one swish on the feet of the second symbol.

My infinitely limited knowledge of Kanji tells me that could be huge.

The first symbol means "city" or "city of". I'll leave it to everyone's imagination as to what the second symbol means.

SY · 15th June 2006, 06:15 AM

Well, it IS the name of Tokyo's Red Light District.

poobah · 15th June 2006, 06:19 AM

SY,

We're workin' on it... asbestos we can.

kenev · 15th June 2006, 08:09 AM

SY,

Nery nice and interesting project.

What about some impressions on the sound of this amp?

Regards, Evangelos

pinkmouse · 15th June 2006, 08:24 AM

Well, the original version I saw had another parallel row, 7 x 7 x 2, giving us 98 leds to play with...

Merlinb · 15th June 2006, 11:07 AM

LED's are notioriously unreliable when run in series or parallel from the same supply without individual surrent limiters- just a warning.
Won't a 133k anode resistor on the first ECC81 triode be pushing way into non-linear operation?
You might want to add a build-out resistor to the cathode of the cathodyne for balanced output.

SY · 15th June 2006, 12:20 PM

Quote:

Originally posted by Merlinb

Won't a 133k anode resistor on the first ECC81 triode be pushing way into non-linear operation?

Quite the contrary, that's a particularly linear spot to operate it. At the full 11V peak output needed to drive the output stage, THD of the voltage amp is less than 0.03%.

Regarding LED reliability, you might check out what Bob Pease had to say in his book "Troubleshooting Analog Circuits."

15th June 2006, 01:45 AM	#21
mod_evil diyAudio Member Join Date: Dec 2004 Location: Rio	This amp will be a circus! tsc tsc tsc... __________________ Brazilian Tube Amp Builder.

15th June 2006, 06:15 AM	#25
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX Blog Entries: 1	Well, it IS the name of Tokyo's Red Light District. __________________ "...we stumble and get up, we are sad, confident, insecure, feel loneliness and joy and love. There is nothing more; but I want nothing more.” - Christopher Hitchens 1949-2011

15th June 2006, 08:24 AM	#28
pinkmouse diyAudio Moderator Join Date: Apr 2002 Location: Chatham, England	Well, the original version I saw had another parallel row, 7 x 7 x 2, giving us 98 leds to play with... __________________ Al I conceive of nothing, in religion, science or philosophy, that is more than the proper thing to wear, for a while. Charles Fort

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15th June 2006, 05:51 AM	#24
poobah diyAudio Member Join Date: Nov 2005	Good detail work Variac, The cat missed one swish on the feet of the second symbol. My infinitely limited knowledge of Kanji tells me that could be huge. The first symbol means "city" or "city of". I'll leave it to everyone's imagination as to what the second symbol means.

15th June 2006, 06:19 AM	#26
poobah diyAudio Member Join Date: Nov 2005	SY, We're workin' on it... asbestos we can.

15th June 2006, 08:09 AM	#27
kenev diyAudio Member Join Date: Oct 2002 Location: Athens, Greece	SY, Nery nice and interesting project. What about some impressions on the sound of this amp? Regards, Evangelos

15th June 2006, 11:07 AM	#29
Merlinb diyAudio Member Join Date: May 2006 Location: York	LED's are notioriously unreliable when run in series or parallel from the same supply without individual surrent limiters- just a warning. Won't a 133k anode resistor on the first ECC81 triode be pushing way into non-linear operation? You might want to add a build-out resistor to the cathode of the cathodyne for balanced output.

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