RCA 6N7 ??? any good for audio
Neil Brown
they look interresting.
Regards
Neil
SBench
Hi Neil,
The classic use of these is one 6N7 paralleled both sections
driving a transformer phase splitter driving a second 6N7 in
zero bias class B. (Actually runs AB2). 10 watts 8-10% distortion.
The 6N7 by itself isn't too bad, but IMHO, doesn't compare
wall against, for instance a 6CG7 or 6SN7 for driver use.
Best Regards,
Steve
Check my web page .. http://members.aol.com/sbench101/
Russ Sadd
6N7s were medium-mu double-power triodes. They're a very old type. You could
use these as 6SN7s, or as a single-envelope push-pull stage (low power class
A, reasonable power class AB/B). The one big difference is that the 6N7s
have a common cathode. Thus, these are great as Schmidt phase-splitters or
small power stages.
They have a 6.3V, 0.8A heater. The pinout is: (2) heater, (3) plate 2, (4)
grid 2, (5) grid 1, (6) plate 1, (7) heater, (8) common cathode.
As voltage amplifiers, at 250V they need a grid bias of -5V, have a plate
current of 6mA, an AC plate resistance of 11.3K, a transconductance of 3K1
micromhos, an amplification factor of 35, and should have a plate load of
20K or more.
As a class B push-pull output stage, at 300V they need a grid bias of 0V, a
load of 8K, and have a power output of 10W. Great for a radio or PA system!
Best regards,
Russ Sadd
ABS
Birmingham, UK
E-Mail: sad...@aston.ac.uk
Web Pages: http://homepages.enterprise.net/icedragon/new/index.htm
TubeGarden
I use the 6Z7-G (similar config) as a VA, one channel on each triode, and am
very happy with the sound. I do not know how linear it is, but I know what I
like. It replaced a 5670, and the scale and detail both seem more realistic to
my ears.
"Music does not tell the truth,
It tells me the lies I want to hear."
Happy Ears!
Al B^}
Al Marcy
TubeG...@aol.com
TROOBKA
>>
>>Does anyone know how linear these are? I picked up a few on the cheap and
>>they look interresting.
>>
>>Regards
>>Neil
>
>Hi Neil,
>The classic use of these is one 6N7 paralleled both sections
>driving a transformer phase splitter driving a second 6N7 in
>zero bias class B. (Actually runs AB2). 10 watts 8-10% distortion.
>
>The 6N7 by itself isn't too bad, but IMHO, doesn't compare
>wall against, for instance a 6CG7 or 6SN7 for driver use.
>
>
Anyone have a copy of Sound Practices laying around? In the last issue they
showed a "record cutting amp" that used the 6N7 as a phase splitter driving
two 2A3s. 6A6s seems to be a direct equivalent, but with the nice ST shape.
Keep em' glowin'
Mark Szumski
Pascal Sternis
I have already seen this arrangement driven by a 6L6. It always
surprised me. A 0V grid bias should give something like 20mA ip. that
gives @250V 5W per plate quiescent. it does exceed the 6N7 max plate
dissipation which is IIRC 1.7W
Maybe you have to let the music play everytime to lower the dissipation.
Strange. I know it exists but I have never seen a satisfactory
explaination about it.
BTW : Bravo for your web pages !
Regards
Pascal
--
--------
please, remove ".NOSPAM" from adress before replying
Neil Brown
<pascal....@art.NOSPAM.alcatel.fr> wrote:
>Hi Steve,
>I have already seen this arrangement driven by a 6L6. It always
>surprised me. A 0V grid bias should give something like 20mA ip. that
>gives @250V 5W per plate quiescent. it does exceed the 6N7 max plate
>dissipation which is IIRC 1.7W
Accortding to my Sylvania tube book, the max plate is 5.5 W per plate
It is used for 10 watts with an 8K output transformer (Pto P)
intresting thing is peak plate current is 35 ma and peakgrid current is
20ma!
GRID CURRENT!
can someone explain this!
Neil
TubeGarden
>
>GRID CURRENT!
>
Current flows from ground thru the grid to the plate during the posivive
portion of the signal. Call it Class B.
You can run the tube in Class A, no grid current ever, but you lose much power.
Class AB is some grid current, more than A, less than B.
More power than A, less than B.
Class BA is similar, except the plate is grounded and the current flows out the
filaments to the bit bucket. Not used in audio circuits do to dripping sound in
bucket. Hard to adjust circuit dynamically to keep up with tempo changes.
Happy current events!
Neil Brown
tubeg...@aol.com (TubeGarden) wrote:
Wel I got to loking and in the back of my Sylvania Technical Manual is th
usual RC amp specs and lo and behold there before my eyes were the figures
for using the 6n7. So I paralleled the plaates and grids and halved the
cathode and plate resistors and viola, up she came. Interesting aside though
the 6N7 doesnt seem to like floating Dc filament supply. Much quiter
refenced to ground through a 100K resister.
Anyhow with .47 uF output caps and running it into my ST70 (with Neds mod
EF86, 12BH7) it sound great. I had to reduce the supply decoiupling resister
to reduce the drop in voltage at the driver stage and merged both Dc plate
preamp suplies into one but it is running very nicely. I cant wait until a
more decent hour to listen a comfy levels!
REgards
Neil
Pascal Sternis
it seems I confused the plate dissipations ! you are right. I have
checked. plate dissipation is 5.5W for the rca too (re Ned's site
data-sheet).
This confusion arise partly because I have used the 6N7 as a signal
stage, in a differential configuration, driving a 6SN7 differential,
itself driving a 6BG6 PP. I had tested this tube on my DIY tube tester,
only in class A, negative grid voltages.
From what I have seen in the RCA curves, they do not give great details
on the negative grid curves area.
If anybody is interested, I can publish the curves I have obtained.
BTW, I think I will reconsider the arrangement in my amp for a 6SL7 or
something. I don't like wasting power capabilities of a tube ;-)
Live and learn !
thanks and Best Regards
Pascal
Neil Brown wrote:
> Accortding to my Sylvania tube book, the max plate is 5.5 W per plate
> It is used for 10 watts with an 8K output transformer (Pto P)
> 20ma!
>
> GRID CURRENT!
>
> can someone explain this!
>
>
Anthony Cirella
6N7 is primarily a class B tube, in class A the
6N7 can handle minimal current, maybe 6-7ma
@ 250v, both side tied together.
As an audio driver, I like it. The 6A6 is the
UX based version of the octal 6N7.
A.Cirella
email: hand...@ix.netcom.com
http://www2.netcom.com/~handmade
SBench
>>
>>GRID CURRENT!
>>
>
>Current flows from ground thru the grid to the plate during the posivive
>portion of the signal. Call it Class B.
>
>You can run the tube in Class A, no grid current ever, but you lose much
>power.
>
>Class AB is some grid current, more than A, less than B.
>More power than A, less than B.
Hi,
A slight clarification. Grid current is caused by the control grid (g1)
voltage being more positive than the cathode. Hence, electrons are
attracted to, and some are collected by the grid. The current path
is thru the grid circuit, not the plate circuit. In the original example,
with 35 mA plate current and 20 mA grid current, the cathode current
is 55 mA. (not counting what is happening on the "other side" of the
tube, as it has only 1 cathode).
You can tell from the description, you can tell whether or not grid
current is expected by the subscripts 1 (no grid current) or 2 (grid
current flows for at least part of the conduction cycle).
Class A can be Class A1 or Class A2. (A2 is very rare)
Class AB can be AB1 (no grid current flows) or Class AB2 (grid
current flows for part of the conduction cycle).
Class B is almost always B2, i.e. grid current flows.
Class C is always C2 (grid current flows).
Neil Brown
<pascal....@art.NOSPAM.alcatel.fr> wrote:
>Hi Neil,
>it seems I confused the plate dissipations ! you are right. I have
>checked. plate dissipation is 5.5W for the rca too (re Ned's site
>data-sheet).
>This confusion arise partly because I have used the 6N7 as a signal
>stage, in a differential configuration, driving a 6SN7 differential,
>itself driving a 6BG6 PP. I had tested this tube on my DIY tube tester,
>only in class A, negative grid voltages.
>From what I have seen in the RCA curves, they do not give great details
>on the negative grid curves area.
>If anybody is interested, I can publish the curves I have obtained.
>BTW, I think I will reconsider the arrangement in my amp for a 6SL7 or
>something. I don't like wasting power capabilities of a tube ;-)
>Live and learn !
>thanks and Best Regards
>Pascal
What is intersting is that the Syllvania tube manual I have show this tube
with a B+ of 100V or 250 V in it RC amp charts as running at 1 or 2 Ma per
section with a cathode voltage of around 2V and plate voltage of 60 and 135.
It sounds great at this operating point. Certainly better than the 6sn7 I
played with in the same circuit 2 nights ago.
I have another pair so I will have to give them a whirl in a PP stage with
an 8K output and 0V bias! Seems unnatural to me!
>Neil Brown wrote:
>> Accortding to my Sylvania tube book, the max plate is 5.5 W per plate
>> It is used for 10 watts with an 8K output transformer (Pto P)
>> intresting thing is peak plate current is 35 ma and peakgrid current is
>> 20ma!
>>
>> GRID CURRENT!
>>
>> can someone explain this!
>>
>>
>> Neil
ENjoyinhg the music...
Neil
Incidently whoever built my ST70 originally didnt put the insulating spacer
on the input socket, it played heck with my grounding till I noticed it!
TubeGarden
Happy Current Pathways!
Ned Carlson
>>>>
>>>
>>>Does anyone know how linear these are? I picked up a few on the cheap and
>>>they look interresting.
There's 4 pages of data on 6N7 at:
http://www.triodeel.com/tubedata.htm
>Anyone have a copy of Sound Practices laying around? In the last issue they
>showed a "record cutting amp" that used the 6N7 as a phase splitter driving
>two 2A3s. 6A6s seems to be a direct equivalent, but with the nice ST shape.
6A6 has different basing.
'53 is same as 6A6 but 2.5V filament.
5608 is an industrial version of '53.
I had some 5608, labelled as "Barber-Colman
Thermotrol" tubes. Instructions on the side were
to change the tube when the top of the tube went white..
I still haven't figured *that* one out..
Ned Carlson Triode Electronics,2225 W Roscoe Chicago, IL, 60618 USA
ph 773-871-7459 fax 773-871-7938
12:30 to 8 PM CT, (1830-0200 UTC) 12:30-5 Sat, Closed Wed & Sun
http://www.triodeel.com
Text file catalogs:Catalog 'Bot at cat...@triodeel.com
Bob Miller
class B audio service (mainly radio modulators and the like) Not sure if they
would be that hot in HI FI service.
bob
Neil Brown wrote:
> Does anyone know how linear these are? I picked up a few on the cheap and
> they look interresting.
>
> Regards
> Neil
Neil Brown
(Ned Carlson) wrote:
>On 27 Jul 1998 00:54:15 GMT, tro...@aol.com (TROOBKA) wrote:
>
>>>>>
>>>>
>>>>Does anyone know how linear these are? I picked up a few on the cheap
and
>>>>they look interresting.
>
>
>There's 4 pages of data on 6N7 at:
>http://www.triodeel.com/tubedata.htm
>
>>Anyone have a copy of Sound Practices laying around? In the last issue
they
>>showed a "record cutting amp" that used the 6N7 as a phase splitter
driving
>>two 2A3s. 6A6s seems to be a direct equivalent, but with the nice ST
shape.
>
>6A6 has different basing.
>'53 is same as 6A6 but 2.5V filament.
>5608 is an industrial version of '53.
>I had some 5608, labelled as "Barber-Colman
>Thermotrol" tubes. Instructions on the side were
>to change the tube when the top of the tube went white..
>I still haven't figured *that* one out..
>
>
>
>Ned Carlson Triode Electronics,2225 W Roscoe Chicago, IL, 60618 USA
>ph 773-871-7459 fax 773-871-7938
>12:30 to 8 PM CT, (1830-0200 UTC) 12:30-5 Sat, Closed Wed & Sun
>http://www.triodeel.com
>Text file catalogs:Catalog 'Bot at cat...@triodeel.com
THanks for all the comments and suggestions, info etc. I have ended up using
one per channel with approx 250 B+ and paralleled both sectinos, using 20
plate load and 470 ohm cathode resister, unbypassed. DC on the heaters. I
have a .47UF output decoupling cap on the plate to the input of my dynaco
ST70.
I tried to increase the value of the cap but it got unstable and things went
awry.
As it sit I think it sound s great . The sound is clearer than the 6sn7 in
my opinion. MOre detail squeeking through or mebbee its just cause I built
it.
regards
Neil
Multi-Volti Devices
Murray
Russ Sadd
>Maybe my memory is wrong, but I thought a 6N7 was 1/2 a 6SN7
Hi Murray,
A 6J5 is half a 6SN7. A 6N7 is a double-triode with a common cathode -
suited to phase-splitting (e.g. Schmidt) or Class B push-pull output stages.
Best regards,
Russ Sadd
SBench
>
>
>
6J5 = 1/2 6SN7. 6N7 is already a dual triode with a common cathode
pin.
Jamie
5608 is an industrial version of '53.
>I had some 5608, labelled as "Barber-Colman
>Thermotrol" tubes. Instructions on the side were
>to change the tube when the top of the tube went white..
>I still haven't figured *that* one out..
>
Well, whenever I see a tube with a cracked envelope, the getter is almost
always white. I wonder if they basically were gassy tubes that would
eventually 'gas out' or what.....
Jamie