Looking for 12AX7A tubes

[Powell]

With about 40 hours on a tubed microphone pre-amp I'm
now interested in increasing the timbre and micro-dynamics
resolution particularly in the 80 to 500 Hz range. My first
thoughts would be: Sovtek, RAM or Jan Philips NOS.
Any empirical suggestions?

[dave weil]

On Fri, 9 Apr 2004 15:51:16 -0400, "Powell" >
wrote:

>With about 40 hours on a tubed microphone pre-amp I'm
>now interested in increasing the timbre and micro-dynamics
>resolution particularly in the 80 to 500 Hz range. My first
>thoughts would be: Sovtek, RAM or Jan Philips NOS.
>Any empirical suggestions?

Try here:

http://www.pentalaboratories.com/product.asp?dept%5Fid=1604&pf%5Fid=ECC83+%2F+12AX7A%2ENOS

Mullards would be better, of course, but they'll cost an arm and a
leg.

Here are some other possibilities:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=50598&item=3089306564&rd=1
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=64629&item=3089747730&rd=1
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=64629&item=3089747947&rd=1
This looks good as well. Almost as good as Mullards:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=7275&item=2237221530&rd=1

Basically, what I'm saying is that you can search for 12AX7s on eBay,
I guess.

Also, that's a common tube, so you might be able to find NOS GEs and
the like if you look around locally. Sometimes you can find an
old-timey TV repair shop that still has tubes floating around.

[Arny Krueger]

Powell wrote:
> With about 40 hours on a tubed microphone pre-amp I'm
> now interested in increasing the timbre and micro-dynamics
> resolution particularly in the 80 to 500 Hz range. My first
> thoughts would be: Sovtek, RAM or Jan Philips NOS.
> Any empirical suggestions?

Try rec.audio.tubes or rec.audio.pro

[Powell]

"dave weil" wrote

> >With about 40 hours on a tubed microphone pre-amp I'm
> >now interested in increasing the timbre and micro-dynamics
> >resolution particularly in the 80 to 500 Hz range. My first
> >thoughts would be: Sovtek, RAM or Jan Philips NOS.
> >Any empirical suggestions?
>
> Mullards would be better, of course, but they'll cost an arm and a
> leg.
>
"Would be better"... in what regard?


> Also, that's a common tube, so you might be able to find NOS
> GEs and the like if you look around locally. Sometimes you
> can find an old-timey TV repair shop that still has tubes floating
> around.
>
Finding vendor sources for tubes isn't the problem. It's the
brand name I'm asking about in regards to the specific
application.

[Powell]

"Arny Krueger" wrote

> > With about 40 hours on a tubed microphone pre-amp I'm
> > now interested in increasing the timbre and micro-dynamics
> > resolution particularly in the 80 to 500 Hz range. My first
> > thoughts would be: Sovtek, RAM or Jan Philips NOS.
> > Any empirical suggestions?
>
> Try rec.audio.tubes or rec.audio.pro
>
"rec.audio.pro".... hehehe, dweebs.

[dave weil]

On Sat, 10 Apr 2004 11:51:15 -0400, "Powell" >
wrote:

>
>"dave weil" wrote
>
>> >With about 40 hours on a tubed microphone pre-amp I'm
>> >now interested in increasing the timbre and micro-dynamics
>> >resolution particularly in the 80 to 500 Hz range. My first
>> >thoughts would be: Sovtek, RAM or Jan Philips NOS.
>> >Any empirical suggestions?
>>
>> Mullards would be better, of course, but they'll cost an arm and a
>> leg.
>>
>"Would be better"... in what regard?

I think that they're considered to be longer lasting, for instance.
Depending on the application, they are usually considered to be the
best in terms of microphonics as well.

The person to ask would be Kevin Deal. He's at:

http://www.upscaleaudio.com

I forgot to put that link into the previous post.

He's probably the guy who knows the most about matching tubes with
specific gear.

>> Also, that's a common tube, so you might be able to find NOS
>> GEs and the like if you look around locally. Sometimes you
>> can find an old-timey TV repair shop that still has tubes floating
>> around.
>>
>Finding vendor sources for tubes isn't the problem. It's the
>brand name I'm asking about in regards to the specific
>application.

Well, since you didn't bother to list the specific component, I'm not
sure what your beef is here. The reason I mentioned this is that you
can get tubes from those sources usually a lot cheaper than buying
them from "tube vendors" and so you can afford to experiment for
yourself. Those that you don't like can be disposed of on eBay.

[Bruce J. Richman]

Dave Weil wrote:


>On Sat, 10 Apr 2004 11:51:15 -0400, "Powell" >
>wrote:
>
>>
>>"dave weil" wrote
>>
>>> >With about 40 hours on a tubed microphone pre-amp I'm
>>> >now interested in increasing the timbre and micro-dynamics
>>> >resolution particularly in the 80 to 500 Hz range. My first
>>> >thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>> >Any empirical suggestions?
>>>
>>> Mullards would be better, of course, but they'll cost an arm and a
>>> leg.
>>>
>>"Would be better"... in what regard?
>
>I think that they're considered to be longer lasting, for instance.
>Depending on the application, they are usually considered to be the
>best in terms of microphonics as well.
>
>The person to ask would be Kevin Deal. He's at:
>
>http://www.upscaleaudio.com
>
>I forgot to put that link into the previous post.
>
>He's probably the guy who knows the most about matching tubes with
>specific gear.
>
>>> Also, that's a common tube, so you might be able to find NOS
>>> GEs and the like if you look around locally. Sometimes you
>>> can find an old-timey TV repair shop that still has tubes floating
>>> around.
>>>
>>Finding vendor sources for tubes isn't the problem. It's the
>>brand name I'm asking about in regards to the specific
>>application.
>
>Well, since you didn't bother to list the specific component, I'm not
>sure what your beef is here. The reason I mentioned this is that you
>can get tubes from those sources usually a lot cheaper than buying
>them from "tube vendors" and so you can afford to experiment for
>yourself. Those that you don't like can be disposed of on eBay.
>
>
>
>
>
>
>
>

I've purchased Mullard 12AX7 tubes from Kevin Deal at Upscale Audio. I use
them in both my tubed DAC, a California Audio Labs Alpha, and also in my Conrad
Johnson PV-12 preamplifier, In both cases, the tubes have performed very well,
and have lasted a long time. I found Mr. Deal to be very professional, and as
Dave says, very knowledgable about what tubes seem to work best in different
applications. He also usually has a large stock of just about every type of
tube you might be looking for.



Bruce J. Richman

[Sander deWaal]

dave weil > said:

>Basically, what I'm saying is that you can search for 12AX7s on eBay,
>I guess.

I'd strongly recommend that one buys tubes NOT from Ebay.
Practices like selling old, worn out tubes with new logos and freshly
golded pins are not that unusual.
Go with a reputable vendor like Ned Carlson www.triodeelectronics.com
or perhaps Willie "Lord Valve" if you can stand his attitude :-)
These guys don't just sell, but can also advise you better than anyone
in this newsgroup, including myself.

BTW Powell, 12 AX7s in a microphone amp, are you seriously looking for
noise and microphony? :-)
In any case, when the design calls for AX7, try 7025 RCA.

For a microphone amp, a better choice would be EF86 in triode, IMHO.

--
Sander deWaal
Vacuum Audio Consultancy

[Arny Krueger]

Powell wrote:
> "Arny Krueger" wrote
>
>>> With about 40 hours on a tubed microphone pre-amp I'm
>>> now interested in increasing the timbre and micro-dynamics
>>> resolution particularly in the 80 to 500 Hz range. My first
>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>> Any empirical suggestions?
>>
>> Try rec.audio.tubes or rec.audio.pro
>>
> "rec.audio.pro".... hehehe, dweebs.

IOW, a bunch of smart guys who figured you out for the fraud you are in
almost no time at all.

[Marc Phillips]

Arny said:

>Powell wrote:
>> "Arny Krueger" wrote
>>
>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>> now interested in increasing the timbre and micro-dynamics
>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>> Any empirical suggestions?
>>>
>>> Try rec.audio.tubes or rec.audio.pro
>>>
>> "rec.audio.pro".... hehehe, dweebs.
>
>IOW, a bunch of smart guys who figured you out for the fraud you are in
>almost no time at all.

You, too.

Boon

[Arny Krueger]

Marc Phillips wrote:
> Arny said:
>
>> Powell wrote:
>>> "Arny Krueger" wrote
>>>
>>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>>> now interested in increasing the timbre and micro-dynamics
>>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>>> Any empirical suggestions?
>>>>
>>>> Try rec.audio.tubes or rec.audio.pro
>>>>
>>> "rec.audio.pro".... hehehe, dweebs.
>>
>> IOW, a bunch of smart guys who figured you out for the fraud you are
>> in almost no time at all.
>
> You, too.

You don't know what happened to Powell over in RAP, do you?

[Marc Phillips]

Arny said:

>Marc Phillips wrote:
>> Arny said:
>>
>>> Powell wrote:
>>>> "Arny Krueger" wrote
>>>>
>>>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>>>> now interested in increasing the timbre and micro-dynamics
>>>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>>>> Any empirical suggestions?
>>>>>
>>>>> Try rec.audio.tubes or rec.audio.pro
>>>>>
>>>> "rec.audio.pro".... hehehe, dweebs.
>>>
>>> IOW, a bunch of smart guys who figured you out for the fraud you are
>>> in almost no time at all.
>>
>> You, too.
>
>You don't know what happened to Powell over in RAP, do you?

I know what happened to you in RAHE. That's a lot funnier, I bet.

Boon

[Arny Krueger]

Marc Phillips wrote:
> Arny said:
>
>> Marc Phillips wrote:
>>> Arny said:
>>>
>>>> Powell wrote:
>>>>> "Arny Krueger" wrote
>>>>>
>>>>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>>>>> now interested in increasing the timbre and micro-dynamics
>>>>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>>>>> Any empirical suggestions?
>>>>>>
>>>>>> Try rec.audio.tubes or rec.audio.pro
>>>>>>
>>>>> "rec.audio.pro".... hehehe, dweebs.
>>>>
>>>> IOW, a bunch of smart guys who figured you out for the fraud you
>>>> are in almost no time at all.
>>>
>>> You, too.
>>
>> You don't know what happened to Powell over in RAP, do you?

<no response from Phillips related to RAP>

Ignorance noted.

[S888Wheel]

>From: "Arny Krueger"
>Date: 4/11/2004 2:07 PM Pacific Standard Time
>Message-id: >
>
>Marc Phillips wrote:
>> Arny said:
>>
>>> Marc Phillips wrote:
>>>> Arny said:
>>>>
>>>>> Powell wrote:
>>>>>> "Arny Krueger" wrote
>>>>>>
>>>>>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>>>>>> now interested in increasing the timbre and micro-dynamics
>>>>>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>>>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>>>>>> Any empirical suggestions?
>>>>>>>
>>>>>>> Try rec.audio.tubes or rec.audio.pro
>>>>>>>
>>>>>> "rec.audio.pro".... hehehe, dweebs.
>>>>>
>>>>> IOW, a bunch of smart guys who figured you out for the fraud you
>>>>> are in almost no time at all.
>>>>
>>>> You, too.
>>>
>>> You don't know what happened to Powell over in RAP, do you?
>
><no response from Phillips related to RAP>
>
>Ignorance noted.
>
>
>
>
>
>
>
>

I guess that makes the world's population save for a handfull of people
ignorant. Is your perspective so skewed now that you think there is something
wrong with not knowing the goings on for a particular Usenet group?

[dave weil]

On Sun, 11 Apr 2004 17:07:24 -0400, "Arny Krueger" >
wrote:

>Marc Phillips wrote:
>> Arny said:
>>
>>> Marc Phillips wrote:
>>>> Arny said:
>>>>
>>>>> Powell wrote:
>>>>>> "Arny Krueger" wrote
>>>>>>
>>>>>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>>>>>> now interested in increasing the timbre and micro-dynamics
>>>>>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>>>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>>>>>> Any empirical suggestions?
>>>>>>>
>>>>>>> Try rec.audio.tubes or rec.audio.pro
>>>>>>>
>>>>>> "rec.audio.pro".... hehehe, dweebs.
>>>>>
>>>>> IOW, a bunch of smart guys who figured you out for the fraud you
>>>>> are in almost no time at all.
>>>>
>>>> You, too.
>>>
>>> You don't know what happened to Powell over in RAP, do you?
>
><no response from Phillips related to RAP>
>
>Ignorance noted.

Ahhh, but he *did* point out what happened to you at RAHE.

Pretty much banned.

Now *that's* funny!

[Arny Krueger]

S888Wheel wrote:
>> From: "Arny Krueger"
>> Date: 4/11/2004 2:07 PM Pacific Standard Time
>> Message-id: >
>>
>> Marc Phillips wrote:
>>> Arny said:
>>>
>>>> Marc Phillips wrote:
>>>>> Arny said:
>>>>>
>>>>>> Powell wrote:
>>>>>>> "Arny Krueger" wrote
>>>>>>>
>>>>>>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>>>>>>> now interested in increasing the timbre and micro-dynamics
>>>>>>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>>>>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>>>>>>> Any empirical suggestions?
>>>>>>>>
>>>>>>>> Try rec.audio.tubes or rec.audio.pro
>>>>>>>>
>>>>>>> "rec.audio.pro".... hehehe, dweebs.
>>>>>>
>>>>>> IOW, a bunch of smart guys who figured you out for the fraud you
>>>>>> are in almost no time at all.
>>>>>
>>>>> You, too.
>>>>
>>>> You don't know what happened to Powell over in RAP, do you?
>>
>> <no response from Phillips related to RAP>
>>
>> Ignorance noted.

> I guess that makes the world's population save for a handfull of
> people ignorant. Is your perspective so skewed now that you think
> there is something wrong with not knowing the goings on for a
> particular Usenet group?

non sequitur

[Arny Krueger]

dave weil wrote:
> On Sun, 11 Apr 2004 17:07:24 -0400, "Arny Krueger" >
> wrote:
>
>> Marc Phillips wrote:
>>> Arny said:
>>>
>>>> Marc Phillips wrote:
>>>>> Arny said:
>>>>>
>>>>>> Powell wrote:
>>>>>>> "Arny Krueger" wrote
>>>>>>>
>>>>>>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>>>>>>> now interested in increasing the timbre and micro-dynamics
>>>>>>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>>>>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>>>>>>> Any empirical suggestions?
>>>>>>>>
>>>>>>>> Try rec.audio.tubes or rec.audio.pro
>>>>>>>>
>>>>>>> "rec.audio.pro".... hehehe, dweebs.
>>>>>>
>>>>>> IOW, a bunch of smart guys who figured you out for the fraud you
>>>>>> are in almost no time at all.
>>>>>
>>>>> You, too.
>>>>
>>>> You don't know what happened to Powell over in RAP, do you?
>>
>> <no response from Phillips related to RAP>
>>
>> Ignorance noted.
>
> Ahhh, but he *did* point out what happened to you at RAHE.

non sequitur

[S888Wheel]

>From: "Arny Krueger"
>Date: 4/11/2004 5:25 PM Pacific Standard Time
>Message-id: >
>
>S888Wheel wrote:
>>> From: "Arny Krueger"
>>> Date: 4/11/2004 2:07 PM Pacific Standard Time
>>> Message-id: >
>>>
>>> Marc Phillips wrote:
>>>> Arny said:
>>>>
>>>>> Marc Phillips wrote:
>>>>>> Arny said:
>>>>>>
>>>>>>> Powell wrote:
>>>>>>>> "Arny Krueger" wrote
>>>>>>>>
>>>>>>>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>>>>>>>> now interested in increasing the timbre and micro-dynamics
>>>>>>>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>>>>>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>>>>>>>> Any empirical suggestions?
>>>>>>>>>
>>>>>>>>> Try rec.audio.tubes or rec.audio.pro
>>>>>>>>>
>>>>>>>> "rec.audio.pro".... hehehe, dweebs.
>>>>>>>
>>>>>>> IOW, a bunch of smart guys who figured you out for the fraud you
>>>>>>> are in almost no time at all.
>>>>>>
>>>>>> You, too.
>>>>>
>>>>> You don't know what happened to Powell over in RAP, do you?
>>>
>>> <no response from Phillips related to RAP>
>>>
>>> Ignorance noted.
>
>> I guess that makes the world's population save for a handfull of
>> people ignorant. Is your perspective so skewed now that you think
>> there is something wrong with not knowing the goings on for a
>> particular Usenet group?
>
>non sequitur
>
>
>

Wrong but amusing. Why the sudden meltdown?

[Marc Phillips]

Arny said:

>Marc Phillips wrote:
>> Arny said:
>>
>>> Marc Phillips wrote:
>>>> Arny said:
>>>>
>>>>> Powell wrote:
>>>>>> "Arny Krueger" wrote
>>>>>>
>>>>>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>>>>>> now interested in increasing the timbre and micro-dynamics
>>>>>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>>>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>>>>>> Any empirical suggestions?
>>>>>>>
>>>>>>> Try rec.audio.tubes or rec.audio.pro
>>>>>>>
>>>>>> "rec.audio.pro".... hehehe, dweebs.
>>>>>
>>>>> IOW, a bunch of smart guys who figured you out for the fraud you
>>>>> are in almost no time at all.
>>>>
>>>> You, too.
>>>
>>> You don't know what happened to Powell over in RAP, do you?
>
><no response from Phillips related to RAP>
>
>Ignorance noted.

<no response from Krueger related to RAHE>

<total defeat noted>

Boon

[Marc Phillips]

Arny said:

>dave weil wrote:
>> On Sun, 11 Apr 2004 17:07:24 -0400, "Arny Krueger" >
>> wrote:
>>
>>> Marc Phillips wrote:
>>>> Arny said:
>>>>
>>>>> Marc Phillips wrote:
>>>>>> Arny said:
>>>>>>
>>>>>>> Powell wrote:
>>>>>>>> "Arny Krueger" wrote
>>>>>>>>
>>>>>>>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>>>>>>>> now interested in increasing the timbre and micro-dynamics
>>>>>>>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>>>>>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>>>>>>>> Any empirical suggestions?
>>>>>>>>>
>>>>>>>>> Try rec.audio.tubes or rec.audio.pro
>>>>>>>>>
>>>>>>>> "rec.audio.pro".... hehehe, dweebs.
>>>>>>>
>>>>>>> IOW, a bunch of smart guys who figured you out for the fraud you
>>>>>>> are in almost no time at all.
>>>>>>
>>>>>> You, too.
>>>>>
>>>>> You don't know what happened to Powell over in RAP, do you?
>>>
>>> <no response from Phillips related to RAP>
>>>
>>> Ignorance noted.
>>
>> Ahhh, but he *did* point out what happened to you at RAHE.
>
>non sequitur

Post ignored.

Boon

[dave weil]

On Sun, 11 Apr 2004 20:25:57 -0400, "Arny Krueger" >
wrote:

>dave weil wrote:
>> On Sun, 11 Apr 2004 17:07:24 -0400, "Arny Krueger" >
>> wrote:
>>
>>> Marc Phillips wrote:
>>>> Arny said:
>>>>
>>>>> Marc Phillips wrote:
>>>>>> Arny said:
>>>>>>
>>>>>>> Powell wrote:
>>>>>>>> "Arny Krueger" wrote
>>>>>>>>
>>>>>>>>>> With about 40 hours on a tubed microphone pre-amp I'm
>>>>>>>>>> now interested in increasing the timbre and micro-dynamics
>>>>>>>>>> resolution particularly in the 80 to 500 Hz range. My first
>>>>>>>>>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
>>>>>>>>>> Any empirical suggestions?
>>>>>>>>>
>>>>>>>>> Try rec.audio.tubes or rec.audio.pro
>>>>>>>>>
>>>>>>>> "rec.audio.pro".... hehehe, dweebs.
>>>>>>>
>>>>>>> IOW, a bunch of smart guys who figured you out for the fraud you
>>>>>>> are in almost no time at all.
>>>>>>
>>>>>> You, too.
>>>>>
>>>>> You don't know what happened to Powell over in RAP, do you?
>>>
>>> <no response from Phillips related to RAP>
>>>
>>> Ignorance noted.
>>
>> Ahhh, but he *did* point out what happened to you at RAHE.
>
>non sequitur

Nope. Look it up.

[Powell]

"Arny Krueger" wrote

> >>> With about 40 hours on a tubed microphone pre-amp I'm
> >>> now interested in increasing the timbre and micro-dynamics
> >>> resolution particularly in the 80 to 500 Hz range. My first
> >>> thoughts would be: Sovtek, RAM or Jan Philips NOS.
> >>> Any empirical suggestions?
> >>
> >> Try rec.audio.tubes or rec.audio.pro
> >>
> > "rec.audio.pro".... hehehe, dweebs.
>
> IOW, a bunch of smart guys who figured you out for the
> fraud you are in almost no time at all.
>
Sooo... what’s your excuse, mr. Fraud?

[Powell]

"Sander deWaal" wrote

> Go with a reputable vendor like Ned Carlson
> www.triodeelectronics.com
>
Thank you.


> or perhaps Willie "Lord Valve" if you can stand his attitude :-)
>
I know Willie... thanks, I'll pass :).


>These guys don't just sell, but can also advise you better
> than anyone in this newsgroup, including myself.
>
> BTW Powell, 12 AX7s in a microphone amp, are you
> seriously looking for noise and microphony? :-)
>
I'm interested in increasing the timbre and micro-dynamics
resolution particularly in the 80 to 500 Hz range. I'm looking
for a similar resolution to that of my ARC pre-amp.

Here's an interesting comparison of 12AX7 design types:
http://store.yahoo.com/thetubestore/12ax7review.html

And a description of design use:
http://catalog.rell.com/scripts/SkuSearchResults2.asp?Sku=12ax7&radio=3&maxrecs=50&T3=2&prevkey=+&recfirst=0&reclast=0&searchtotal=%2D1

Information on NOS tubes, too.
http://www.soundstage.com/tubeor/tube4.htm


> In any case, when the design calls for AX7, try 7025 RCA.
>
And, I understand it ECC83, which is very pricey:
http://store.yahoo.com/thetubestore/12ax70ectyp.html


> For a microphone amp, a better choice would be EF86 in
> triode, IMHO.
>
I didn't see where the EF86 was a 12AX7 substitute... are
you sure it is? And it appears appears to be a pentode
design.

I'm leaning toward a highly sorted RAM tube because
of the noise factor. Or maybe purchase both the
Sovtek 12AX7LPS and Ei12AX7 types... can't justify
all three purchases, unfortunately.
http://www.tubeaudiostore.com/tubes.html

Interesting article by Roger Modjeski on "why sound
changes when you change tubes:
http://store.electron-valve.com/soundandtubes.html

[Sander deWaal]

"Powell" > said:

>> In any case, when the design calls for AX7, try 7025 RCA.

>And, I understand it ECC83, which is very pricey:
>http://store.yahoo.com/thetubestore/12ax70ectyp.html

ECC83 is just the European nomenclature for 12 AX7.
There are as many different ECCs as there are AX7s.
I use the Mullard CV4004 for a phono preamp, which has to deal with
similar small voltages as a mic preamp.
This is a very expensive tube if you have to buy them today.
I'm glad I bought some stock 15 years ago, when prices weren't
skyhigh.
The RCA7025 is a very silent substitute, and would be my second choice
in a RIAA or mic preamp.
Forget about Telefunken E83CC, they're way overhyped.
Strange enough, their ECC803S is a far better tube for these purposes,
it's just damned hard to find.

>> For a microphone amp, a better choice would be EF86 in
>> triode, IMHO.
>>
>I didn't see where the EF86 was a 12AX7 substitute... are
>you sure it is? And it appears appears to be a pentode
>design.

Correct, I'm talking about diy designs.
This won't work in an existing amp, obviously.
BTW, any pentode can be converted into a triode just by tying the
screen grid to the anode.

>I'm leaning toward a highly sorted RAM tube because
>of the noise factor. Or maybe purchase both the
>Sovtek 12AX7LPS and Ei12AX7 types... can't justify
>all three purchases, unfortunately.
>http://www.tubeaudiostore.com/tubes.html

Hmmmm.......I'm not very fond of the Sovtek 12 AX7LPS.
It probably would be better to use this tube in a higher level stage
such as a phase splitter in a poweramp, where its sonics are not that
critical.
Sadly, I don't have experience with the EI.

But be aware that between the same brand and type, differences may
exost that are larger than between different brands altogether.
As the famous Alan Marcy (Tubegarden) already pointed out, just
plug'em in and listen :-)

--
Sander deWaal
Vacuum Audio Consultancy