JAN Sylvania 7308 vs. JAN Sylvania 6922 - 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 24th July 2007, 04:29 AM   #1
Rodango is offline Rodango  United States
diyAudio Member
 
Rodango's Avatar
 
Join Date: Jul 2007
Location: Salem, OR
Send a message via AIM to Rodango Send a message via Yahoo to Rodango
Default JAN Sylvania 7308 vs. JAN Sylvania 6922

Test Lashup
=========
Njoe Tjoeb 4000 CD player with USN 7308s
Ming-Da MC67-HA Preamp

Chinese TM300
Three 6DJ8s in the preamp
Four KT88s (New issue Gold Lions)

6DJ8 set #1
JAN Phillips 7308 phase splitter
JAN Sylvania 7303 amplifiers

6DJ8 set #2
JAN Sylvania 6922s -all three

Both sets, '78 - '79 vintage

Test track - 2002 "Falling through time"

I started the shootout believing the 7303s would win. I rolled the sets back and forth and listened intently. At first, I heard absolutely no difference so I rolled and compared some more. Finally I heard it. The 7308s were great on the high-end but were a little shy on the mids whereas the 6922s smooth and eloquent across the entire range.

Who would have thought the 6922s would have won my shootout? Not me. Perhaps I should take the Phillips out of the 7308 lineup and replace it with a Sylvania. Phillips tend to be a bit 'tizzy' but I really like Sylvanias

The only difference I could find 'in the book' between 7308s and 6922s was that 7308s have a TINY bit more heater current.

Has anyone has similar 7308/6922 comparisons? Does anyone know why both these tubes were manufactured if they're so almost identical?

Thanks!
  Reply With Quote
Old 24th July 2007, 05:01 AM   #2
diyAudio Member
 
Join Date: Jan 2006
Location: SAO PAULO - SP
Hi Rodango ,

The 6922 was the normal commercial tube , and was sold
and used anywhere . They was the standard tube , made
by Sylvania and many other manufacturers .

BUT the 7308 , was a Sylvania Gold Brand , PREMIUM
TUBE version of the common 6922 , and was designed and
manufactured for CRITICAL industrial and commercial
applications. The 7308 is the BEST , everything what any
6922 would like to be .

I agree with you , always that is possible , I prefer the Sylvania
branded tubes .

Regards ,

Carlos
  Reply With Quote
Old 24th July 2007, 08:49 AM   #3
diyAudio Member
 
the_manta's Avatar
 
Join Date: Nov 2006
Location: Munich, Bavaria
hi !
Way back I did some similiar tests. At that time I didn't had ECC88. I used following:

Click the image to open in full size.

Maybe my test were not as enthusiastic as yours , but I couldn't hear any difference. Would be a good reason to sell this siemens CCa and E88CC junk.

Regards, Simon
__________________
Терпенье и труд все перетрут
  Reply With Quote
Old 24th July 2007, 10:30 AM   #4
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
I've tested a wide range of ECC88 types. Of them all, the CCa showed the best linearity. So don't be too quick to throw them out.
__________________
You might be screaming "No, no, no" and all they hear is "Who wants cake?" Let me tell you something: They all do. They all want cake.- Wilford Brimley
  Reply With Quote
Old 24th July 2007, 03:46 PM   #5
diyAudio Member
 
Join Date: May 2003
Location: Morton, Illinois
Default A

The E88s are harder to design around because of their higher frequency capabilities. Alot of people don't know how to design around this tube and trash it.
  Reply With Quote
Old 24th July 2007, 05:21 PM   #6
diyAudio Member
 
zigzagflux's Avatar
 
Join Date: Oct 2006
Location: Charlotte, NC
Quote:
Originally posted by Positron
Alot of people don't know how to design around this tube and trash it.
That would be me.
Blasted tube.

Had 5MHz oscillation; never found the problem. Could have been heater borne RF (my best guess).

I'm sure it's a good tube if used with extra special precautions.
  Reply With Quote
Old 2nd September 2007, 06:42 PM   #7
diyAudio Member
 
Join Date: Jul 2007
Default Sylvania's

Yep,

Tuff to beat.

Then again a pair of Amperex/Holland 7308 PQ's w/2 Stars (circa 1961) maybe the ticket,
if you've deep pockets.

pc
  Reply With Quote
Old 3rd September 2007, 09:39 AM   #8
diyAudio Member
 
Join Date: Sep 2007
If I remember correctly, the PCC88, ECC88, and E88CC all have the same curves, but different heaters. I haven't seen any information indicating the plates and grids are the same for each of those tubes, just the curves.

The E188CC and E288CC have different plates and different curves than the CC88 and 88CCs.

I believe the internal resistance is the same for the CC88 and 88CCs but is different in the 188 and 288s

The rumor I head was that the E88CC has dual winding for the heater--if one winding broke, the tube keeps functioning--very helpful for military and commercial applications.

Best Wishes
Bob
__________________
Still a novice with electronics.
  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
sylvania valve tester johnf1 Introductions 2 20th August 2009 04:54 PM
sylvania & GE tubes airframe Tubes / Valves 5 31st July 2006 10:31 PM
Sylvania News Bas Horneman Tubes / Valves 14 25th April 2004 04:42 PM
Sylvania JAN 6L6WGB max plate V? Salas Tubes / Valves 5 14th January 2004 10:13 PM


New To Site? Need Help?

All times are GMT. The time now is 05:44 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