6SL7 question

6SL7 question

What 9 pin tube is most like a 6SL7 in electrical characteristics? A 12AT7?

Thanks in advance,

Jon

Re: 6SL7 question

What 9 pin tube is most like a 6SL7 in electrical characteristics? A
12AT7?
-------
I believe 5751

Re: 6SL7 question



RS McCown wrote:
>
> What 9 pin tube is most like a 6SL7 in electrical characteristics? A
> 12AT7?
> -------
> I believe 5751

not 12AT7.

12AY7 is very similar.

Patrick Turner.

Re: 6SL7 question

in article 47F7EF00.595530E8@turneraudio . com .au, Patrick Turner at
info@turneraudio . com .au wrote on 4/5/08 5:28 PM:

>
>
> RS McCown wrote:
>>
>> What 9 pin tube is most like a 6SL7 in electrical characteristics? A
>> 12AT7?
>> -------
>> I believe 5751
>
> not 12AT7.
>
> 12AY7 is very similar.
>
> Patrick Turner.


Thank you, Patrick!

Re: 6SL7 question

In article <C41D6034.B9B70%jono_1@bellsouth . net >,
Jon Yaeger <jono_1@bellsouth . net > wrote:

> What 9 pin tube is most like a 6SL7 in electrical characteristics? A 12AT7?

The plate resistance of the 12AT7 is way too low to be remotely like a
6SL7, I would say that the 12AX7, 7025, ECC83 family is a closer match
for the 6SL7.


Regards,

John Byrns

--
Surf my web pages at, * fmamradios . com /

Re: 6SL7 question

Thank you, John.

With that in mind, your suggestion about a 5751 ought to be spot on.

Jon




In article byrnsj-B4EC5E.16141905042008@newsclstr03.news.prodigy . net , John
Byrns at byrnsj@sbcglobal . net wrote on 4/5/08 5:14 PM:

> In article <C41D6034.B9B70%jono_1@bellsouth . net >,
> Jon Yaeger <jono_1@bellsouth . net > wrote:
>
>> What 9 pin tube is most like a 6SL7 in electrical characteristics? A 12AT7?
>
> The plate resistance of the 12AT7 is way too low to be remotely like a
> 6SL7, I would say that the 12AX7, 7025, ECC83 family is a closer match
> for the 6SL7.
>
>
> Regards,
>
> John Byrns

Re: 6SL7 question

On Apr 5, 10:14 pm, John Byrns <byr...@sbcglobal . net > wrote:
> In article <C41D6034.B9B70%jon...@bellsouth . net >,
>  Jon Yaeger <jon...@bellsouth . net > wrote:
>
> > What 9 pin tube is most like a 6SL7 in electrical characteristics?  A =
12AT7?

12AT7 has a super precision sound but 12AT7 is a dumb sub for the
6SL7: totally different, much drier sound; 12AT is a sonic sub for the
6SN7. Always presuming that Yaeger has the discrimination to
understand that one uses the 12SL7 for its warmth and liquidity.

> The plate resistance of the 12AT7 is way too low to be remotely like a
> 6SL7, I would say that the 12AX7, 7025, ECC83 family is a closer match
> for the 6SL7.
>
> Regards,
>
> John Byrns
>
> --
> Surf my web pages at,   * fmamradios . com /

Nah, 12AX7/ECC83 will sound awful and probably need extra NFB to wash
off the 50% more gain, which aggravates the problem.

Sonically, in a quality amp the right 9-pin to sub for 6SL7 is 6072
but whether there are any 6072 that haven't yet migrated Eastwards is
another story. 12AY7 is a more common possibility, except that I don't
think it ever was all that common; super sound though. I built the
front end of a 211 with 12AY7 and was tres mucho impressed.

Of the 12xx7, the good-sounding ones are the 12AT7 and the 12AY7 --
and the 6CG7 (yeah, I know, it's a 6xx7), of which the first and the
last are 6SN7 sonic subs, and the 12AY7 is the only 9-pin 6SL7 sub
known to mankind. The 12AX7 is best left to guitar amps.

Andre Jute
Visit Jute on Amps at * members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

Re: 6SL7 question



Andre Jute wrote:
>
> On Apr 5, 10:14 pm, John Byrns <byr...@sbcglobal . net > wrote:
> > In article <C41D6034.B9B70%jon...@bellsouth . net >,
> > Jon Yaeger <jon...@bellsouth . net > wrote:
> >
> > > What 9 pin tube is most like a 6SL7 in electrical characteristics? A 12AT7?
>
> 12AT7 has a super precision sound but 12AT7 is a dumb sub for the
> 6SL7: totally different, much drier sound; 12AT is a sonic sub for the
> 6SN7. Always presuming that Yaeger has the discrimination to
> understand that one uses the 12SL7 for its warmth and liquidity.
>
> > The plate resistance of the 12AT7 is way too low to be remotely like a
> > 6SL7, I would say that the 12AX7, 7025, ECC83 family is a closer match
> > for the 6SL7.
> >
> > Regards,
> >
> > John Byrns
> >
> > --
> > Surf my web pages at, * fmamradios . com /
>
> Nah, 12AX7/ECC83 will sound awful and probably need extra NFB to wash
> off the 50% more gain, which aggravates the problem.
>
> Sonically, in a quality amp the right 9-pin to sub for 6SL7 is 6072
> but whether there are any 6072 that haven't yet migrated Eastwards is
> another story. 12AY7 is a more common possibility, except that I don't
> think it ever was all that common; super sound though. I built the
> front end of a 211 with 12AY7 and was tres mucho impressed.

The 12AY7 has similar gain when used in a circuit to 6SL7 which was why
I suggested it.

6SL7, or 12SL7 etc at Ia = 2.3mA gives Ra = 44k, µ = 70, Gm = 1.6mA/V

12AY7 at Ia = 3mA gives Ra = 23k, µ = 40, Gm = 1.75mA/V.

For 12AY7, the gm falls and Ra rises and µ stays about the same as Ia is
lowered to
typical values used with 6SL7.

The gain from each tube with about 100k RL would be similar.

12AY7 is a more linear tube than 12AT7.

Perhaps it sounds better.
>
> Of the 12xx7, the good-sounding ones are the 12AT7 and the 12AY7 --
> and the 6CG7 (yeah, I know, it's a 6xx7), of which the first and the
> last are 6SN7 sonic subs, and the 12AY7 is the only 9-pin 6SL7 sub
> known to mankind. The 12AX7 is best left to guitar amps.

6CG7 has µ only 20, and electronically the same as 6SN7, so gain is to
low where
one wants the higher gain of around 30 to 40 with 6SL7.

Patrick Turner.
>
> Andre Jute
> Visit Jute on Amps at * members.lycos.co.uk/fiultra/
> "wonderfully well written and reasoned information
> for the tube audio constructor"
> John Broskie TubeCAD & GlassWare
> "an unbelievably comprehensive web site
> containing vital gems of wisdom"
> Stuart Perry Hi-Fi News & Record Review

Re: 6SL7 question


"John Byrns" <byrnsj@sbcglobal . net > wrote in message
news:byrnsj-B4EC5E.16141905042008@newsclstr03.news.prodigy . net ...
> In article <C41D6034.B9B70%jono_1@bellsouth . net >,
> Jon Yaeger <jono_1@bellsouth . net > wrote:
>
> > What 9 pin tube is most like a 6SL7 in electrical characteristics? A
12AT7?
>
> The plate resistance of the 12AT7 is way too low to be remotely like a
> 6SL7, I would say that the 12AX7, 7025, ECC83 family is a closer match
> for the 6SL7.

Also a Russian 6N2P. It has mu=100, as ECC83, but can not be wired for 12,6V
heater supply. The only pinout difference is that its 6.3V heater is
connected only to pins 4 and 5. Pin 9 is connected to an internal screen
separating the two triodes. This screen is a good feature to minimise
cross-talk, if the triodes are used in left and right channels respectively.

Regards,
Alex
>
> Regards,
>
> John Byrns
>
> --
> Surf my web pages at, * fmamradios . com /

Re: 6SL7 question


"John Byrns" <byrnsj@sbcglobal . net > wrote in message
news:byrnsj-B4EC5E.16141905042008@newsclstr03.news.prodigy . net ...
> In article <C41D6034.B9B70%jono_1@bellsouth . net >,
> Jon Yaeger <jono_1@bellsouth . net > wrote:
>
> > What 9 pin tube is most like a 6SL7 in electrical characteristics? A
12AT7?
>
> The plate resistance of the 12AT7 is way too low to be remotely like a
> 6SL7, I would say that the 12AX7, 7025, ECC83 family is a closer match
> for the 6SL7.
>
>
> Regards,
>
> John Byrns
>
> --
> Surf my web pages at, * fmamradios . com /

IMHO 12AX7s sound soft and fat. The 12AT7s are better if you must have a
high mu min. tube. All 12AU, AY, AV, & AZ7s should be sent to the ham radio
guys. The SN7s, BL7s, & BX7s are some of the best driver tubes that do not
need negative feedback for the most part. If you have to have a high mu dual
triode, go for 6SL7GT. Single? 6K5GT. Got turned in this direction, a while
back from the Boss' suggestions, after I built a preamp using 3 12AX7s, CF
and was not totally satisfied with the sound.

Cordially,
west

Re: 6SL7 question



West wrote:
>
> "John Byrns" <byrnsj@sbcglobal . net > wrote in message
> news:byrnsj-B4EC5E.16141905042008@newsclstr03.news.prodigy . net ...
> > In article <C41D6034.B9B70%jono_1@bellsouth . net >,
> > Jon Yaeger <jono_1@bellsouth . net > wrote:
> >
> > > What 9 pin tube is most like a 6SL7 in electrical characteristics? A
> 12AT7?
> >
> > The plate resistance of the 12AT7 is way too low to be remotely like a
> > 6SL7, I would say that the 12AX7, 7025, ECC83 family is a closer match
> > for the 6SL7.
> >
> >
> > Regards,
> >
> > John Byrns
> >
> > --
> > Surf my web pages at, * fmamradios . com /
>
> IMHO 12AX7s sound soft and fat.

Well, just how they sound to you or anyone else depends the brand and
age and how they are used and where.



> The 12AT7s are better if you must have a
> high mu min. tube.

Again the jury is still out trying to make up its mind.
12AT7 are both loved and hated by many, so are 6DJ8 and many other
toooobs.

> All 12AU, AY, AV, & AZ7s should be sent to the ham radio
> guys.

They'd only waste them.

The 12AU7 is a fabulous audio tube. The AY7 also is, and was developed
for low noise,
meaning low hum. The AV7 and AZ7 can be used for audio, but ain't,
because they suit RF use better.


> The SN7s, BL7s, & BX7s are some of the best driver tubes that do not
> need negative feedback for the most part.
Drivers, inputs, line stage amps, you name it, these tubes are kings.

> If you have to have a high mu dual
> triode, go for 6SL7GT.
Yeah, not bad, but where I can I'll use a 6CG7 instead.

> Single? 6K5GT. Got turned in this direction, a while
> back from the Boss' suggestions, after I built a preamp using 3 12AX7s, CF
> and was not totally satisfied with the sound.

6K5 is OK, but if ever I was wanting to have a 6K5, there wouldn't be
one around,
so I'd parallel a 6SL7....

Patrick Turner.
>
> Cordially,
> west

Re: 6SL7 question


"Patrick Turner" <info@turneraudio . com .au> wrote in message
news:47F85D31.8732FDC2@turneraudio . com .au...
>
>
> Again the jury is still out trying to make up its mind.
> 12AT7 are both loved and hated by many, so are 6DJ8 and many other
> toooobs.

The 12AT7 must the most microphonic tube known to man, the 12AU7 is far
preferred by most people of my aquaintance.

Keith

Re: 6SL7 question



keithr wrote:
>
> "Patrick Turner" <info@turneraudio . com .au> wrote in message
> news:47F85D31.8732FDC2@turneraudio . com .au...
> >
> >
> > Again the jury is still out trying to make up its mind.
> > 12AT7 are both loved and hated by many, so are 6DJ8 and many other
> > toooobs.
>
> The 12AT7 must the most microphonic tube known to man, the 12AU7 is far
> preferred by most people of my aquaintance.

Microphony depends on the electrode rigidity in the tube.

A newly made one might be excellent, but an old one
that's done 10,000 hours in a guitar amp could be terrible.

Same exactly can be said of 12AU7 and many tubes.

A guy sent me a batch of about mainly used 60 x 12AU7 with an option to
buy for $3 each.
I tested every one, and 1/2 were either microphonic or too noisy, ie,
gassy,
or spluttery, or both, and I sent these all back to the guy. but I
purchased all the gooduns.

I have used a lot of 12AT7 and found them very good, ditto 12AU7.

The AT7 makes a good input tube for a power amp where gain is wanted,
and also for the second stage of a phono amp, because of the gain.

For the input of an MM phono, AT7 is OK also, but I do prefer fets these
days for
any phono input.

Patrick Turner.





>
> Keith

Re: 6SL7 question


"Patrick Turner" <info@turneraudio . com .au> wrote in message
news:47FA2223.AFA0332@turneraudio . com .au...
>
>
> keithr wrote:
>>
>> "Patrick Turner" <info@turneraudio . com .au> wrote in message
>> news:47F85D31.8732FDC2@turneraudio . com .au...
>> >
>> >
>> > Again the jury is still out trying to make up its mind.
>> > 12AT7 are both loved and hated by many, so are 6DJ8 and many other
>> > toooobs.
>>
>> The 12AT7 must the most microphonic tube known to man, the 12AU7 is far
>> preferred by most people of my aquaintance.
>
> Microphony depends on the electrode rigidity in the tube.

Exactly

> A newly made one might be excellent, but an old one
> that's done 10,000 hours in a guitar amp could be terrible.

Unless you either overdrive them like hell or physically kick them around
there is no reason why a tube should become microphonic with age. Old tubes
lose gain as their cathodes get used up, the harder you drive them the
faster it happens, but that should be all.

> Same exactly can be said of 12AU7 and many tubes.
>
> A guy sent me a batch of about mainly used 60 x 12AU7 with an option to
> buy for $3 each.
> I tested every one, and 1/2 were either microphonic or too noisy, ie,
> gassy,
> or spluttery, or both, and I sent these all back to the guy. but I
> purchased all the gooduns.

Gassy tubes are easy to tell fom the getter magnesium deposits losing their
metallic sheen and turning white.

> I have used a lot of 12AT7 and found them very good, ditto 12AU7.
>
> The AT7 makes a good input tube for a power amp where gain is wanted,
> and also for the second stage of a phono amp, because of the gain.
>
> For the input of an MM phono, AT7 is OK also, but I do prefer fets these
> days for
> any phono input.

Yech I wouldn't use a 12AT7 in any position where there is a lot of gain
involved either in that stage or after it. 12AT7s used to make good flip
flops back in the days before we used transistors for the job back in the
days before we used ICs for the job.

keith

Re: 6SL7 question



keithr wrote:
>
> "Patrick Turner" <info@turneraudio . com .au> wrote in message
> news:47FA2223.AFA0332@turneraudio . com .au...
> >
> >
> > keithr wrote:
> >>
> >> "Patrick Turner" <info@turneraudio . com .au> wrote in message
> >> news:47F85D31.8732FDC2@turneraudio . com .au...
> >> >
> >> >
> >> > Again the jury is still out trying to make up its mind.
> >> > 12AT7 are both loved and hated by many, so are 6DJ8 and many other
> >> > toooobs.
> >>
> >> The 12AT7 must the most microphonic tube known to man, the 12AU7 is far
> >> preferred by most people of my aquaintance.
> >
> > Microphony depends on the electrode rigidity in the tube.
>
> Exactly
>
> > A newly made one might be excellent, but an old one
> > that's done 10,000 hours in a guitar amp could be terrible.
>
> Unless you either overdrive them like hell or physically kick them around
> there is no reason why a tube should become microphonic with age. Old tubes
> lose gain as their cathodes get used up, the harder you drive them the
> faster it happens, but that should be all.

You are not quite right again. Repeated on-off cycles gradually loosens
up the
mica washers used to hold the elements of anode, grid, cathode all
tightly,
so they begin to rattle or sway around in the bottle.

Sure old tubes can sustain eventual decline in emission, and hence lower
gM,
but many suffer gassiness and loose electrode support before the cathode
looses emission.
>
> > Same exactly can be said of 12AU7 and many tubes.
> >
> > A guy sent me a batch of about mainly used 60 x 12AU7 with an option to
> > buy for $3 each.
> > I tested every one, and 1/2 were either microphonic or too noisy, ie,
> > gassy,
> > or spluttery, or both, and I sent these all back to the guy. but I
> > purchased all the gooduns.
>
> Gassy tubes are easy to tell fom the getter magnesium deposits losing their
> metallic sheen and turning white.

They only turn white when air is allowed into the tube.
But gettering in old tubes gradually combines with gas to form brown
dull edges
to the silvering, not whitness, which is the result of a sudden large
oxygen ingress through
cracked glass.


>
> > I have used a lot of 12AT7 and found them very good, ditto 12AU7.
> >
> > The AT7 makes a good input tube for a power amp where gain is wanted,
> > and also for the second stage of a phono amp, because of the gain.
> >
> > For the input of an MM phono, AT7 is OK also, but I do prefer fets these
> > days for
> > any phono input.
>
> Yech I wouldn't use a 12AT7 in any position where there is a lot of gain
> involved either in that stage or after it. 12AT7s used to make good flip
> flops back in the days before we used transistors for the job back in the
> days before we used ICs for the job.

That may be the case, but well chosen 12AT7 like many other tubes well
chosen
are fine for general audio use.

A batch of 6J6 I have were all very micophonic and despite the high gm
and theoretical suitability for an MC front end, they could not be used.

Patrick Turner.
>
> keith