Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

My Project:  Pilot 602
My Project:  Pilot 602
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 13th December 2010, 03:42 PM   #11
Eli Duttman is offline Eli Duttman  United States
diyAudio Member
 
Join Date: Apr 2004
Location: Monroe Township, NJ
Specialty brushes for cleaning tube sockets are available, but they're somewhat pricey. A periodontal brush from the "drug" store works well on 7 and 9 pin mini sockets.

DeOxit yes, vinegar no!
__________________
Eli D.
  Reply With Quote
Old 6th June 2017, 06:46 PM   #12
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
My Project:  Pilot 602
The Pilot 602 has a "Press to Test" feature -- i am guessing that you turn the DC bias pot until no "click" is heard when the PTT is pressed.
Attached Images
File Type: jpg Pilot_PTT_Back.jpg (120.1 KB, 189 views)
File Type: png Pilot_PressToTest.png (156.5 KB, 193 views)
  Reply With Quote
Old 7th June 2017, 05:23 PM   #13
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
My Project:  Pilot 602
Interesting find, the center tap of the output transformers are wired to the screen grid pin of the 6BQ5's. This means that the screen potential might even be higher than the anode. Apparently, someone forgot to tell the soldering mavens that the red-yellow wire was to be connected to the junction of the 100R/40uF capacitor.

Diodes replaced with UF4007, so will pick up ~4V.

All the can electrolytics are shot, so replaced with new.

100R 10W resistor replaced with a Caddock affixed to the chassis -- this will remove some of the heat from the under-compartment.
Attached Images
File Type: png Pilot602_Power.png (109.8 KB, 154 views)
File Type: jpg Pilot620_PlateScrn.jpg (162.6 KB, 150 views)
File Type: jpg Pilot_Power_Orig.jpg (167.1 KB, 148 views)
File Type: jpg Pilot620_NewDiodes_Elec.jpg (149.6 KB, 53 views)
  Reply With Quote
Old 8th June 2017, 03:54 AM   #14
PRR is offline PRR  United States
diyAudio Member
 
PRR's Avatar
 
Join Date: Jun 2003
Location: Maine USA
> the screen potential might even be higher than the anode.

This is Not A Problem.

These are pentodes, not True Triodes.
  Reply With Quote
Old 8th June 2017, 03:43 PM   #15
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
My Project:  Pilot 602
Quote:
Originally Posted by PRR View Post
> the screen potential might even be higher than the anode.

This is Not A Problem.
Not a big problem, but it in simulation it worsens THD by ~2.4dB.

Will have to measure. Just jumper the 100R resistor.
  Reply With Quote
Old 19th June 2017, 04:31 PM   #16
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
My Project:  Pilot 602
C2 is now replaced with 3x 47u/350V electrolytics, R117, R118 replaced with Dale 2.5 watters.
Attached Images
File Type: jpg Pilot602_C2.jpg (150.2 KB, 54 views)
  Reply With Quote
Old 20th June 2017, 12:43 PM   #17
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
My Project:  Pilot 602
Finished up C3 last night -- replaced R116 -- a 10K 2W showing signs of fatigue with a 10K Caddock affixed to the chassis. R119 100R 10W replaced with a 100R caddock also affixed to the chassis.
Attached Images
File Type: jpg Pilot602_C3.jpg (180.8 KB, 50 views)
  Reply With Quote
Old 21st June 2017, 01:33 AM   #18
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
My Project:  Pilot 602
First tests -- had to replace one of the ECC83's, the bypass caps from the phase splitter were replaced with 0.1u/630V Panasonic polypropylenes as the old film caps were leaky. One of the DC balance pots was completely shot and replaced with a spare CTS unit found in the junk box.

1W, 1kHz THD 0.1%

I think that the 100uF cathode bypass cap has to go...
  Reply With Quote
Old 21st June 2017, 02:25 PM   #19
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
My Project:  Pilot 602
Cathode resistors on the 6BQ5's are running really hot -- they are carbon comp 1W 330R, but are pumping close to that already. (yes, there was smoke before I replaced the 500R DC balance pot!)

New blocking caps after the phase splitter:
Attached Images
File Type: jpg Pilot602_BlockingCaps.jpg (181.1 KB, 43 views)
  Reply With Quote
Old 29th June 2017, 04:45 PM   #20
jackinnj is offline jackinnj  United States
diyAudio Member
 
jackinnj's Avatar
 
Join Date: Apr 2002
Location: Llanddewi Brefi, NJ
My Project:  Pilot 602
New Panasonic ECG 330R resistors in the cathodes, new DC balance pot, replaced the cathode bypass electrolytic cap with 100u 100V Muse. Some results:
Attached Images
File Type: png Pilot602_THDvsPWR.png (32.2 KB, 32 views)
File Type: png Pilot602_Bandpass.png (31.3 KB, 19 views)
  Reply With Quote

Reply


My Project:  Pilot 602Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
pilot light ideas please gary h Tubes / Valves 3 30th July 2008 03:48 AM
Pilot SA 260 bias baltimoreblues Tubes / Valves 1 3rd February 2008 06:00 PM
magic smoke pilot aa903 coyotesgator Tubes / Valves 12 27th December 2007 12:41 PM
Pilot Lamp Draws Too Much? CarlosT Chip Amps 1 27th December 2006 04:21 PM
pilot 264 jaron Tubes / Valves 17 13th March 2006 03:32 PM


New To Site? Need Help?

All times are GMT. The time now is 06:20 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki