Tube preamp in front of solid state amp

[Tim McNamara]

Something Jack mentioned about using a pedal in front of his AI amp to
warm things up a bit started a train of thought. I've been using a tube
amp that I built from a kit (Mission Amps 5E3 kit), put in a head cab
and have been using with my Raeer's Edge 12". It's rather bassy (as
that circuit tends to be) and often results in feedback, although the
warmth and roundness of the sound is very nice.

I often use my AI Clarus 2r for gigs where I'll be close to the amp
because the bass is more controllable. Today I dug out my ART Tube MP
preamp, using an XLR cable between the preamp and the amp; I hadn't done
this for a long and and found I really liked the slightly warmer sound
plus the extra boost in gain. I got very close to the sound of the 5E3
without the bass problem. That got me wondering about whether there is
a tube preamp that runs off of 48V phantom power, since the AI can
provide that; the ART Tube MP uses a wall wart and I just don't want to
mess around with pedals and boxes that require an external power supply
on stage. Does anyone here have any knowledge of/experience with this
sort of thing? Google has not been all that helpful.

[Lord Valve]

Ain't gonna happen.

The tube needs two flavors of juice to work; high-voltage DC
for the plate(s) and low-voltage AC or DC for the filament. The
filament is the hassle - no phantom supply I'm aware of can
provide enough current to heat the tube. Stick to the wall-wart.

Lord Valve
Organist

[jaz]

LV, have you seen this?

http://www.gizmag.com/demeter-mighty-minnie/29289/

If this had a line out and a Belton Reverb block it would be perfect for a jazz guitar head. Could you do something like that?

[Nate Najar]

That looks terrific. The tga3 is one if the best amps I have ever played and everything Demeter I have come across has been well made. What a great idea and a good price point.

[cjenki...@gmail.com]

sometimes i'll load a SS amp with a lexicon LXP-1....it definitely can warm things up.

[Steve Freides]

Tim McNamara wrote:

> ... That got me wondering about

> whether there is a tube preamp that runs off of 48V phantom power,
> since the AI can provide that; the ART Tube MP uses a wall wart and I
> just don't want to mess around with pedals and boxes that require an
> external power supply on stage. Does anyone here have any knowledge
> of/experience with this sort of thing? Google has not been all that
> helpful.

AI is always helpful, just call or email.

My guess is that the preamp's current draw will be too high for the AI,
but you could ask. Or look at the current requirement of the preamp and
at the current capability of your AI head.

Steve "very happy owner of a Series III Ten2, a Series III Ten2-EX, and
an original series head" Freides

[Tim McNamara]

Cool to know. I don't have any reverb on the 5E3 and had thought about
getting one of those for that as they can be had at a good price used.
ISTR Ben Monder uses one.

[Tim McNamara]

On Tue, 11 Feb 2014 20:12:19 -0500, Steve Freides <st...@kbnj.com> wrote:
> Tim McNamara wrote:
>
>> ... That got me wondering about whether there is a tube preamp that
>> runs off of 48V phantom power, since the AI can provide that; the ART
>> Tube MP uses a wall wart and I just don't want to mess around with
>> pedals and boxes that require an external power supply on stage.
>> Does anyone here have any knowledge of/experience with this sort of
>> thing? Google has not been all that helpful.
>
> AI is always helpful, just call or email.

They are, I have had some contact by e-mail with them in the past and
their replies were prompt and helpful- even though they didn't sell me
my Clarus (I bought it used. Ditto, BTW, the folks at Redstone, very
helpful to me even though I was not a direct customer. There are some
companies with excellent customer service).

> My guess is that the preamp's current draw will be too high for the
> AI, but you could ask. Or look at the current requirement of the
> preamp and at the current capability of your AI head.

Having done some reading since then, it appears this is exactly the
issue. The ART mic preamp uses a starved plate design, which lets it
run from a wall wart. Demeter's Tube Direct has a built-in power supply
but I am guessing from the one photo I have seen of the circuit board
that it too runs on low voltage. But running preamp tubes at full
voltage would be beyond what phantom power could provide.

[Steve Freides]

Tim McNamara wrote:
> On Tue, 11 Feb 2014 20:12:19 -0500, Steve Freides <st...@kbnj.com>
> wrote:
>> Tim McNamara wrote:
>>
>>> ... That got me wondering about whether there is a tube preamp that
>>> runs off of 48V phantom power, since the AI can provide that; the
>>> ART Tube MP uses a wall wart and I just don't want to mess around
>>> with pedals and boxes that require an external power supply on
>>> stage. Does anyone here have any knowledge of/experience with this
>>> sort of thing? Google has not been all that helpful.
>>
>> AI is always helpful, just call or email.
>
> They are, I have had some contact by e-mail with them in the past and
> their replies were prompt and helpful- even though they didn't sell me
> my Clarus (I bought it used. Ditto, BTW, the folks at Redstone, very
> helpful to me even though I was not a direct customer. There are some
> companies with excellent customer service).
>
>> My guess is that the preamp's current draw will be too high for the
>> AI, but you could ask. Or look at the current requirement of the
>> preamp and at the current capability of your AI head.
>
> Having done some reading since then, it appears this is exactly the
> issue.

Do I get a prize or somethin'? :)

> The ART mic preamp uses a starved plate design, which lets it
> run from a wall wart. Demeter's Tube Direct has a built-in power
> supply but I am guessing from the one photo I have seen of the
> circuit board that it too runs on low voltage. But running preamp
> tubes at full voltage would be beyond what phantom power could
> provide.

An interesting question for AI, and your preamp maker, would be if
there's any potential harm to either side by trying this. I say this
because I recall reading in AI's literature that their phantom power
would be OK with mics that called for a different voltage (I think it
was voltage) than 48 - I think I was considering a mic at the time that
required 13 v or something like that so I asked, and they said it would
be fine although I confess I don't understand why it would have been
fine. (I never bought that mic.). The impression I was left with what
that their phantom power had at least some ability to sense what it was
connected to and respond accordingly.

-S-

[Tim McNamara]

On Fri, 14 Feb 2014 12:28:57 -0500, Steve Freides <st...@kbnj.com>

Looking at the voltages on the V1 and V2 of my home-built Deluxe, I find
that the highest DC voltages (pins 1 and 6 of each of the two preamp
tubes) are between 118 and 195. That's well above the 48V available via
phantom power. The wall wart for the ART TubeMP puts out 9.45VAC; I
don't know what the voltages on the pins of the 12AX7 in the TubeMP are.

[jaz]

you may have noticed but that's a bit up from the 120 line too.

[Tim McNamara]

On Fri, 14 Feb 2014 18:24:26 -0800 (PST), jaz <jackz...@gmail.com>
wrote:

Yeah, although the 5E3 has two fairly massive piles of iron in the power
transformer and the output transformer, especially the former, which I
think accounts for that. The TubeMP and the wall wart together weigh
less than half of what the 5E3's power transformer weighs. I don't know
enough about electronics to understand how that all works. It's quite
possibly that a preamp running on 48V phantom power would still be a
starved plate design but a less-starved one.

I have been experimenting with several options. The TubeMP puts out
line level, so running 1/4" cable from the preamp to the input of the
Clarus is noisy and provokes some clipping unless I dial the gain down a
lot. Running XLR from the preamp to the Clarus is much better,
presumably the amp is wired for line level through the XLR pins on the
input. I have a reamp box that I can put between the preamp and the
Clarus, which quiets things down by dropping the level from line to
instrument. Right now I have the preamp in the effects loop.

The sound chracteristics are slightly different with each of those
setups. It's quite interesting.

The Demeter tube DI apparently puts out instrument level via the
buffered 1/4" jack and can run into the front end of an amp directly; it
can also go straight to the desk via XLR at line level. That'd be nice
flexibility if the sound is good.

[Nate Najar]

the tube mp is junk. It's really just a cheap, noisy ic preamp with a "tube" distortion circuit.

jack's alembic in front of a clarus gives you the sound you guys seem to be after.

the thing about tube gear that we seem to love so well when we are not talking about intentional overdrive, is instead the really high headroom clean signal we get. That's what made the old tube pro audio gear so good sounding. That's why we like a fender amp with jbl's.

the demeter tube DI sounds good not because it's a tube design but because it is a good design.

Another fantastic box- my favorite in fact- is the fire eye red eye preamp/DI. www.fire-eye.com And it will run on 48v from your acoustic image. No tubes but a good sounding transformer. I use this box all the time. For local dates I plug my guitar into it and then use the send to go to my walter woods and then buscarino chameleon speaker. On the road I just take the red eye and I play into the FOH at the hall and get them to stick a wedge upright behind me like an amp.

I also use the redeye in the studio with magnetic pickups- i'l play a solid body electric or my arch top or use it for fender bass. It is the best input stage I have ever encountered. I have a regular wednesday gig at a local saloon with an electric keyboard player and upright bass. No drums. It's the piano player's gig. I just use this box into his PA system with my archtop. It sounds terrific.

but please stay away from the ART thing. It's another box and it's just junk. I have a feeling when you plug it in the enhanced volume and slight distortion you hear is what is pleasing over the extremely linear sound of the acoustic image. but you can do better!

[John A]

On Saturday, February 15, 2014 12:45:33 AM UTC-5, Nate Najar wrote:
> On Saturday, February 15, 2014 12:20:53 AM UTC-5, Tim McNamara wrote:
>

>
> the tube mp is junk. It's really just a cheap, noisy ic preamp with a "tube" distortion circuit.
>

One man's trash is another's treasure ... I wouldn't use it as a pre-amp in front of a guitar amp (I've tried and it doesn't sound good, and I hate wall warts in any sort of live setting), but it has its uses in recording. I've used it as a mic pre and an instrument DI, and it has worked well for me. I didn't find it any noisier than the rest of my crappy stuff (you want to talk noisy and crappy? Premier tube reverb in an aux send. That's noisy and crappy). I have a an old Silvertone short scale bass with a lipstick tube pickup, and it has proven to be the secret for getting a good sound down with that. I also like it for adding a bit of color to an SM57 as a vocal mic, but I record a lot of gritty blues-y stuff. I agree, though, that if you're trying to make a modern SS rig sound like an old Ampeg Gemini, that's not the tool.

> the thing about tube gear that we seem to love so well when we are not talking about intentional overdrive, is instead the really high headroom clean signal we get. That's what made the old tube pro audio gear so good sounding. That's why we like a fender amp with jbl's.

That's what I also found most frustrating about my Fender Pro with a JBL -- very hard to warm it up.

John

[Tim McNamara]

On Fri, 14 Feb 2014 21:45:33 -0800 (PST), Nate Najar
<na...@natenajar.com> wrote:
>
> the tube mp is junk. It's really just a cheap, noisy ic preamp with a
> "tube" distortion circuit.

Well, it was $20 used compared to about 20 times that much to buy a used
Demeter tube DI. ;-)

> Another fantastic box- my favorite in fact- is the fire eye red eye
> preamp/DI. www.fire-eye.com And it will run on 48v from your acoustic
> image. No tubes but a good sounding transformer. I use this box all
> the time. For local dates I plug my guitar into it and then use the
> send to go to my walter woods and then buscarino chameleon speaker.
> On the road I just take the red eye and I play into the FOH at the
> hall and get them to stick a wedge upright behind me like an amp.
>
> I also use the redeye in the studio with magnetic pickups- i'l play a
> solid body electric or my arch top or use it for fender bass. It is
> the best input stage I have ever encountered. I have a regular
> wednesday gig at a local saloon with an electric keyboard player and
> upright bass. No drums. It's the piano player's gig. I just use
> this box into his PA system with my archtop. It sounds terrific.

This is a new product to me. Thanks for the information, Nate, I will
check into this. Even nicer if it will help with both my archtop and my
nylon string (usually my Rick Turner RN-6).

> but please stay away from the ART thing. It's another box and it's
> just junk. I have a feeling when you plug it in the enhanced volume
> and slight distortion you hear is what is pleasing over the extremely
> linear sound of the acoustic image. but you can do better!

The ART seems to selectively boost some frequencies that are helpful
with my archtop, pushing my carvetop floater a bit towards the Jim Hall
sort of tone by providing a smidge of tube saturation. I don't push the
tube to the point where distortion is audible but no doubt there is a
bit there that gives the effect of fattening the tone. The circuit is
slightly noisy at home, but my home wiring seems to be slightly noisy
for some reason- I get less noise at most gigs!

At the $20 price point I paid for the ART TubeMP, I've got pretty much
zero risk with it- which also makes it easy to replace with something
beter. I've got my eye on a couple of Demeter auctions and will check
into the Red-Eye further. Thanks for the tip!

[Steve Freides]

Nate Najar wrote:

> Another fantastic box- my favorite in fact- is the fire eye red eye
> preamp/DI. www.fire-eye.com And it will run on 48v from your
> acoustic image.

Nate, I want to make sure I follow this. You go 1/4" from guitar out to
red-eye instrument in, then XLR out of the red eye into the AI also via
XLR and you turn on the AI's phantom power, and this lets you not use a
battery in the red eye - did I get that right?

-S-

[Nate Najar]

1/4" guitar out to red eye in. Red eye xlr out to FOH and 1/4" to my amp (either Clarus SLR or Walter woods)

[Steve Freides]

Nate Najar wrote:
> 1/4" guitar out to red eye in. Red eye xlr out to FOH and 1/4" to my
> amp (either Clarus SLR or Walter woods)

I must have misunderstood - I thought you said the AI could power the
red-eye but that would mean it would have to somehow be connected to the
XLR input on the AI.

-S-

[Nate Najar]

It can but it isn't how I use it. I prefer to send a clean, uneqd signal to the FOH but be able to EQ on the amp, so I do it this way. If there was no FOH and just the amp, then it would be the way you describe and works just fine.

[Steve Freides]

OK, thanks, Nate.

-S-