Tube positions in Peavey VMP-2?

[Guest]

Archived from groups: rec.audio.pro (More info?)

Anyone know what each tube does in this preamp? (I am an electronics
idiot)

Looking at it from the front, the there are two rows of four tubes.
The two on the right are 12AT7s the other are 12AX7s. I have some nice
NOS tubes that I would like to use in the most critical gain stage(s)
to improve the sound (or at least see if there is a difference). I
have heard the stock tubes in these things can stand improvement. I
assume some of the tubes are only used in the EQ circuit?


Thanks,

Tyler

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

> Looking at it from the front, the there are two rows of four tubes.
> The two on the right are 12AT7s the other are 12AX7s. I have some nice
> NOS tubes that I would like to use in the most critical gain stage(s)
> to improve the sound (or at least see if there is a difference). I
> have heard the stock tubes in these things can stand improvement. I
> assume some of the tubes are only used in the EQ circuit?

There is no such thing as non-critical tubes, and all recent production tube
gear benefits greatly from tube upgrades. Keep in mind if you need the two
channels to be matched, you have to buy matched tube pairs for each
position.

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

In article <b6b7a391.0409292135.d6ba3f2@posting.google.com> tyler@dhiw.com writes:

> Anyone know what each tube does in this preamp?

Amplifies the signal.

> I have some nice
> NOS tubes that I would like to use in the most critical gain stage(s)
> to improve the sound (or at least see if there is a difference). I
> have heard the stock tubes in these things can stand improvement.

How do you know your NOS tubes are "nice" other than what a seller may
have said about them? When you choose to get fussy about tubes, there
are many characteristics that can affect what comes out the output of
the device, depending on the circuit the tube is used in. The guitar
amplifier community has a large enough population of experimenters so
that there MAY be some validity to the folk recommendations to use a
certain brand of tube in a certain position in a certain amplifier for
a certain kind of sound, but the Peavey mic preamp doesn't have that
large of a population base.

I'd suggest that if you want to play around with swapping tubes, just
go ahead and do it. It will take you some time and some careful
listening (and probably a lot of confusion and indecision) but you
might get a sense for which tube makes what differences (and which
ones don't make any difference at all). I'd first start listening for
background noise at a fairly high gain setting and get it as quiet as
you can. Then see what it sounds like with that combination of tubes.
If it sounds at least as good as what you started with, then you're
ahead of the game. If it doesn't, then you need to decide if it sounds
bad enough to back up and go with more noise, or if you want to
continue.

This is what manufacturers and experimenters do. Have fun!


--
I'm really Mike Rivers (mrivers@d-and-d.com)
However, until the spam goes away or Hell freezes over,
lots of IP addresses are blocked from this system. If
you e-mail me and it bounces, use your secret decoder ring
and reach me here: double-m-eleven-double-zero at yahoo

 

[Agent86]

Archived from groups: rec.audio.pro (More info?)

Sugarite wrote:

> all recent production tube gear benefits greatly from tube upgrades.

That's a pretty sweeping statement. Wonder if Eve Anna Manley & Doug Fearn
would agree?

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

> > all recent production tube gear benefits greatly from tube upgrades.
>
> That's a pretty sweeping statement. Wonder if Eve Anna Manley & Doug
Fearn
> would agree?

Show me a current-production tube that competes with even Phillips ECG or
JAN, which are only average compared to much better vintage examples from
Telefunken, Mullard, Amperex, Siemens, etc. I can't see Peavey stocking the
VMP-2 with better than Sovteks, which leave plenty to be desired.

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

TYY <tyler@dhiw.com> wrote:
> Anyone know what each tube does in this preamp? (I am an electronics
> idiot)

> Looking at it from the front, the there are two rows of four tubes.
> The two on the right are 12AT7s the other are 12AX7s. I have some nice
> NOS tubes that I would like to use in the most critical gain stage(s)
> to improve the sound (or at least see if there is a difference). I
> have heard the stock tubes in these things can stand improvement. I
> assume some of the tubes are only used in the EQ circuit?

I think I once investigated this, simply by removing tubes with the
EQ section bypassed. I don't think there was any tube that could
be removed and have it pass sound. But I am not sure of this.
Anyone else?

To me it doesn't make a difference since the VMP is better equaliser than
a mic preamp, for me.

Rob R.

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

> I think I once investigated this, simply by removing tubes with the
> EQ section bypassed. I don't think there was any tube that could
> be removed and have it pass sound. But I am not sure of this.
> Anyone else?
>
> To me it doesn't make a difference since the VMP is better equaliser than
> a mic preamp, for me.
>
> Rob R.

Finally, somebody answered my question! I love the wealth of knowledge
in this forum, but sometimes it is tough for someone to get a straight
answer, and not a lecture about why their question is not worth
answering.

I made no absolute assumptions about my tubes being better than what
is stock in the peavey; I even explicitly questioned whether NOS tubes
would make a difference. I simply wanted to know if some tubes were
only used in the EQ section or were otherwise less important (yes, I
know the EQ is important too) than others.

Anyway, Rob answered my question- I guess all the tubes are in the
signal path of the preamp at all times, so I should swap all the
tubes. I have a handful of blackplate and greyplate RCAs, some
phillips, amperex.

I realize tubes from channel-to-channel should be matched, but what
about matched triodes within each tube?



Tyler

 

[Nuke]

Archived from groups: rec.audio.pro (More info?)

>> > all recent production tube gear benefits greatly from tube upgrades.
>>
>> That's a pretty sweeping statement. Wonder if Eve Anna Manley & Doug
>Fearn
>> would agree?
>
>Show me a current-production tube that competes with even Phillips ECG or
>JAN, which are only average compared to much better vintage examples from
>Telefunken, Mullard, Amperex, Siemens, etc. I can't see Peavey stocking
>the
>VMP-2 with better than Sovteks, which leave plenty to be desired.


Tube snobs and Peavey snobs. I love 'em.

My VMP-2 came from Peavey factory equipped with NOS 12AT7WCs installed, in fact
the Phillips ECG ones you just mentioned.

It's been a great little box ever since the day I plugged it in.


--
Dr. Nuketopia
Sorry, no e-Mail.
Spam forgeries have resulted in thousands of faked bounces to my address.

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

On 30 Sep 2004 18:49:14 -0700, tyler@dhiw.com (TYY) wrote:

>Finally, somebody answered my question! I love the wealth of knowledge
>in this forum, but sometimes it is tough for someone to get a straight
>answer, and not a lecture about why their question is not worth
>answering.
>
>I made no absolute assumptions about my tubes being better than what
>is stock in the peavey; I even explicitly questioned whether NOS tubes
>would make a difference. I simply wanted to know if some tubes were
>only used in the EQ section or were otherwise less important (yes, I
>know the EQ is important too) than others.
>
>Anyway, Rob answered my question- I guess all the tubes are in the
>signal path of the preamp at all times, so I should swap all the
>tubes. I have a handful of blackplate and greyplate RCAs, some
>phillips, amperex.
>
>I realize tubes from channel-to-channel should be matched, but what
>about matched triodes within each tube?

I have an opinion about that question. Why should you value my
opinion?

Chris Hornbeck

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

TYY <tyler@dhiw.com> wrote:
>> I think I once investigated this, simply by removing tubes with the
>> EQ section bypassed. I don't think there was any tube that could
>> be removed and have it pass sound. But I am not sure of this.
>> Anyone else?
>>
>> To me it doesn't make a difference since the VMP is better equaliser than
>> a mic preamp, for me.
>>
>> Rob R.

> Finally, somebody answered my question! I love the wealth of knowledge
> in this forum, but sometimes it is tough for someone to get a straight
> answer, and not a lecture about why their question is not worth
> answering.

> I made no absolute assumptions about my tubes being better than what
> is stock in the peavey; I even explicitly questioned whether NOS tubes
> would make a difference. I simply wanted to know if some tubes were
> only used in the EQ section or were otherwise less important (yes, I
> know the EQ is important too) than others.

> Anyway, Rob answered my question- I guess all the tubes are in the
> signal path of the preamp at all times, so I should swap all the
> tubes. I have a handful of blackplate and greyplate RCAs, some
> phillips, amperex.

Err thanks, but just remember, I was not 100% certain that it was on this
unit that I performed the test. So please open her up and try it to
be certain. In fact, if I am wrong, I would like to know it!

It is also worth having a look since others have suggested that Peavey
didn't always equip them with the same tubes.

Lastly, I believe there is some sort of jumper setting inside that can
affect the type of sound. I think it was Scott who once mentioned it.
Perhaps Scott will see this and fill us in again...

Rob R.

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

I apologize if my reply sounded unnappreciative. I have learned much
from Mike Rivers' posts for the couple years or so I have been reading
this group. I understand that some assumptions are made about a poster
who asks a question. While it is valid to address these assumptions,
it is also nice to address the actual question posed, unless of course
it is un-answerable as it often is with ultra-newbies.

BTW, my peavey has phillips 12AT7s in it as well.

I have a bunch of new EI "elite" (and older, "standard") 12AX7s, that
I have been impressed with in the preamps of some of my vintage
fenders. They are said to sound very similar to old telefunkens. I
have not made a direct comparison, so I cannot comment. They are also
criticized for having a high rate of microphonics in guitar
amplifiers. Is potential microphony a real issue in a microphone
preamp (assuming otherwise quiet operation of the tube)? It is not
subjected to anywhere near the vibration as a guitar combo amp.

Thanks all

 

[Guest]

Archived from groups: rec.audio.pro (More info?)

In article <b6b7a391.0410011153.77883b4@posting.google.com>,
tyler@dhiw.com (TYY) wrote:
> Is potential microphony a real issue in a microphone
> preamp (assuming otherwise quiet operation of the tube)? It is not
> subjected to anywhere near the vibration as a guitar combo amp.

Yeah, it'd be pretty annoying to have the control room monitors bleed
into a mike amp via microphonic tubes. Not out of the question either.


Regards,

Monte McGuire
monte.mcguire@verizon.net

 

[steve]

Archived from groups: rec.audio.pro (More info?)

TYY wrote:

>
> I made no absolute assumptions about my tubes being better than what
> is stock in the peavey; I even explicitly questioned whether NOS tubes
> would make a difference. I simply wanted to know if some tubes were
> only used in the EQ section or were otherwise less important (yes, I
> know the EQ is important too) than others.
>

Any tube change will make a difference, an "improvement" is in the eye
of the beholder. The answer is try it and see.

If both channels sound pretty much the same now, change tubes on one
channel only, run a splitter to both channels and the output to separate
tracks. On playback, level match the tracks and have someone A/B them
while you listen.