Pcc88 - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves

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

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 21st July 2003, 06:15 PM   #1
diyAudio Member
 
Join Date: May 2002
Location: Hong Kong
Send a message via ICQ to leo529
Default Pcc88

hi, anyone know what is the heater voltage of this tube? i searched in the net, some datasheet said its 7V, and some said its 7.6V.
  Reply With Quote
Old 21st July 2003, 06:57 PM   #2
diyAudio Member
 
Pjotr's Avatar
 
Join Date: Nov 2002
Location: Netherlands
My good old Philips databook says 7.6V / 300 mA

  Reply With Quote
Old 21st July 2003, 08:00 PM   #3
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

Quote:
My good old Philips databook says 7.6V / 300 mA
My good old Philips databooks say 7V/300mA and another Philips databook says 7.6V/300mA.

The important part, IMO, is the 300 mA since it was designed for series heating.

If I'd use a single tube like this I'd use both voltage and current regulation on it, if I'd get picky.

Cheers,
__________________
Frank
  Reply With Quote
Old 21st July 2003, 08:34 PM   #4
dhaen is offline dhaen  Europe
diyAudio Moderator Emeritus
 
dhaen's Avatar
 
Join Date: Jun 2002
Location: U.K.
Default Longevity question...

Hi,

How long do these things last at audio-frequency?
I remember them as UHF RF amplifiers, only lasting about a year.

Cheers,
  Reply With Quote
Old 21st July 2003, 08:48 PM   #5
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

Quote:
I remember them as UHF RF amplifiers, only lasting about a year.
Most owners of gear using this type of valve tend to replace them every 18 months.

In some so called high-end gear they are often dead after a year and even less...too high heater voltage, gives you a tad more detail for a while, too much of a twisted application...all of that makes sure that the pundit is sent to the till paying through the nose for a matched pair of candles.

Sorry to be sarcastic, my ECC88s haven't been replaced once in 20 years and they still measure 100% on the testers.
Same goes for all my tubes bar the 6080s...well those are the workhorses anyway.

Cheers,
__________________
Frank
  Reply With Quote
Old 21st July 2003, 09:01 PM   #6
diyAudio Member
 
Pjotr's Avatar
 
Join Date: Nov 2002
Location: Netherlands
The Philips data book here is the 1967 edition. The RCA Tube Handbook from 1957 also states 7V.

But you are right Frank, tubes designed for series connection (P types and U types) are best powered by constant current.

E types designed for constant voltage heater power certainly not, the heater of E types draw virtually a constant current by themselves at varying heater voltages.

Cheers
  Reply With Quote
Old 21st July 2003, 09:03 PM   #7
diyAudio Member
 
Join Date: Feb 2003
Location: Birmingham, UK
Interesting about the heaters - my Brimar manual says 7.6 volts but both Mullard and Tungsram say 7 volts...

I once read an article in an old radio mag which made great claims for the PCC88 as a small pp output stage. With fixed bias of -6v and a 200v on the anodes, output of 1.5w was claimed, and at its maximum ratings, with fixed bias of -5v and 210v on the anodes, output was supposed to be about 2.5w. The output tranny had a 10k anode to anode impedence. If I remember rightly the article warned of not exceeding the valve's limitations, or it deteriorates very quickly.

I saw this in an old Practical Wireless mag from about 1967-8, but I cannot remember the exact issue...if I find it out I'll post the reference.
  Reply With Quote
Old 22nd July 2003, 01:26 AM   #8
diyAudio Member
 
Brett's Avatar
 
Join Date: Jan 2002
Quote:
Originally posted by fdegrove
If I'd use a single tube like this I'd use both voltage and current regulation on it, if I'd get picky.
I do this for almost everything now. I picked up a ton of LM317 and LT1083 for dirt so I do a voltage then current reg setup. The tubes come on slower and they're always set at just the right voltage. I haven't used series string tubes in a while, but I'd probably do the same, with the current as the set item.

Using this configuration on DHT fils is indistinguishable to my ears from AC, except without the hum. Use the LT's though.
  Reply With Quote
Old 22nd July 2003, 02:32 PM   #9
diyAudio Member
 
Join Date: May 2002
Location: Hong Kong
Send a message via ICQ to leo529
Default thanks

thanks all, so the best way to heat up my pcc88 is using a 300mA current sourse, am i right?
  Reply With Quote
Old 22nd July 2003, 02:49 PM   #10
diyAudio Senior Member
 
fdegrove's Avatar
 
Join Date: Aug 2002
Location: Belgium
Hi,

Quote:
so the best way to heat up my pcc88 is using a 300mA current sourse, am i right?
Yes, stay around 7V 300 mA and you'll be fine.

Cheers,
__________________
Frank
  Reply With Quote

Reply


Hide 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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tube preamplifier with PCC88 r!sc! Tubes / Valves 37 17th November 2012 12:45 PM
finished my PCC88 preamp Roemhild Tubes / Valves 12 18th January 2012 08:04 AM
ECC88 and PCC88 filament voltages sith Tubes / Valves 5 1st April 2004 09:30 PM


New To Site? Need Help?

All times are GMT. The time now is 03:18 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2