Tube preamp (do I dare bring up modelers!?!?!?)

Mike McLane

Mike McLane

Active member
The whole Ukraine thing has brought up the tube sourcing saga and suggests the eventual death of tube amps as the predominant force in the guitardom. I wonder about a tube driven preamp as a front end to a modeler setup to impart some "tubiness". Not an OD pedal, but something along the line of a mic preamp. 1) Would it really help the situation? . . and. . . . 2) could you basically get the same thing from a well designed FET circuit (which might suggest that there are already a couple of candidates in the PPCB stable)?
 
Tube preamps are kind of my thing, and putting a clean tube preamp in front of a modeler is probably the #2 most common way people seem to use the ones I make. #1 is skipping the modeler and going straight from the tube preamp into an IR loader over to FOH.

Could this be done just as well with a FET circuit? To some degree sure, but if you're looking for tube tone, you'll be hard-pressed to get something satisfying without a tube.
 
I’m not sure if you watch That pedal show, but they did an episode on preamp pedals. Though they used a power amp and speaker cab opposed to direct in or an ir loader. They used the d&m drive, gladio, broadcast, and benson preamp. And they put them against Kingsley pedals that are designed to be a preamp. It’s worth a watch or at least jump around to the pedals you may be curious about.

@vigilante398 I’ve never owned a tube pedal. Though I have been interested in them. and keeping with the theme of the discussion, how often do tubes in preamp pedals have to be replaced? While I don’t love the idea of not having an amp, I also know that if I want to play live many places are demanding a silent stage. So this seems like a good alternative.
 
Funnel said:
@vigilante398 I’ve never owned a tube pedal. Though I have been interested in them. and keeping with the theme of the discussion, how often do tubes in preamp pedals have to be replaced? While I don’t love the idea of not having an amp, I also know that if I want to play live many places are demanding a silent stage. So this seems like a good alternative.
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I mean if you run them constantly and never unplug them you may have a tube fail in 10 years or so, but I feel like the general answer I can give is "almost never". Preamps are not generally super hard on the tubes, so a preamp tube in a typical preamp pedal should last just about forever. If someone tells you that you need to "change them regularly for best results" they're probably trying to sell you tubes.
 
vigilante398 said:
Tube preamps are kind of my thing, and putting a clean tube preamp in front of a modeler is probably the #2 most common way people seem to use the ones I make. #1 is skipping the modeler and going straight from the tube preamp into an IR loader over to FOH.

Could this be done just as well with a FET circuit? To some degree sure, but if you're looking for tube tone, you'll be hard-pressed to get something satisfying without a tube.
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Silicon can sound just like germanium
 
Yeah, I know about the Kinglsey pedals. Saw the TPS vid and the Kingsley is a thing of beauty. Would LOVE PPCB to design a Squire look alike. As to my application, I was thinking about the Page which is an OD type thing, but not a full bore preamp with EQ, etc. Pretty much just a gain and volume control with a (hopefully) flat response simply to sweeten the sound. Something akin to the Six String Stinger except tube driven. As to Vig398's point, if PPCB would uncork a TPA3118 unit I'd put that with a Squire type pedal and walk away a happy man! Hey Vig398, where can I see your stuff??
 
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Seems somebody did that a few years back, as I recall it was a collaboration between line 6 and another amp builder, it may have been modeler in front of tube power section, been too many years and beers
 
Mike McLane said:
Yeah, I know about the Kinglsey pedals. Saw the TPS vid and the Kingsley is a thing of beauty. Would LOVE PPCB to design a Squire look alike. As to my application, I was thinking about the Page which is an OD type thing, but not a full bore preamp with EQ, etc. Pretty much just a gain and volume control with a (hopefully) flat response simply to sweeten the sound. Something akin to the Six String Stinger except tube driven. As to Vig398's point, if PPCB would uncork a TPA3118 unit I'd put that with a Squire type pedal and walk away a happy man! Hey Vig398, where can I see your stuff??
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You can see my current stuff on my website https://www.sushiboxfx.com/product-category/pedals/ I also have a dedicated thread on Talkbass where I spend WAY too much time because 99% of my customers are bassists. It turns out if you find a group that's largely been neglected by pedal makers and do something specifically for them they react positively :p

JamieJ said:
We definitely need a @vigilante398 and @PedalPCB tube driven preamp collab!

Is all this tube shortage talk just a temporary issue like we have seen with ICs or is this going to be a permanent issue?
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I used to do a Kingsley Harlot (v2) clone, but I discontinued it as I'm trying to focus more on original circuits and less on clones. I would be more than happy to share schematics and ideas if @PedalPCB wanted to pick up the Harlot or something similar. My design fit in a 125B but it was all surface mount. If you use a PCB-mounted tube socket and have the tube stick out the top of the enclosure it would free up enough space that you should be able to fit the rest of the circuit in there though. Just a thought.

As for tubes, I expect it to be temporary. It smelled to me like an EHX cash grab from the beginning, create demand while using the excuse to drive up prices at the same time, then yesterday EHX announced that they worked everything out and will be getting more tubes, and urged everyone not to cancel their backorders. I didn't buy Russian tubes before this, I don't plan to buy them after. JJ has always been good for me, and I plan to stick with them.

One of the main reasons no new companies are coming up to build tubes is equipment. Psvane is the newest tube company I'm aware of, they make expensive hi-fi tubes, but they were able to set up shop by buying out an old retired factory and using the equipment that was already there. JJ is the newest common tube manufacturer, and they set up shop with the old Tesla manufacturing equipment (thus JJ/Tesla). Nobody makes the machines to make tubes anymore, so if you want to start from scratch you're going to have to design and manufacture the machines that do the building. HUGE up front cost for a niche market.

Another frequently cited reason is environmental regulations. Manufacturing tubes is not a super environmentally friendly process due to the materials and processes involved, so they're currently only made in countries that don't have strict environmental regulations. This is, in my understanding, one of the big contributing reasons for the USA tube factories shutting down.

Anyway, my $0.02.
 
vigilante398 said:
My design fit in a 125B but it was all surface mount. If you use a PCB-mounted tube socket and have the tube stick out the top of the enclosure it would free up enough space that you should be able to fit the rest of the circuit in there though. Just a thought.
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Personally, I hate* tube-pedal designs that stand the tube upright in the enclosure, exposing the tube to potential eventual harm.

One of the reasons for your Sushibox’s success, I’m sure, is the properly-packaged tubes — and may you have continued success, sir.


There are others on this forum that have no problem with pointing tubes at the sky, that is their prerogative.
I’d rather go to 1590BB and secure tube inside than have a 1590N1 with a sacrificial tube-altar.



* (“hate” may not be strong enough… “loath”, “despise”, “vehemently oppose”, “disgusted by”, “#%*^@”… hmmm 😼)
 
Funny this came up. I recently met up with a guy who has a Fuchs ODS and we A/B tested the ODS submini tube preamp pedal I made using the Fuch's loop return.
We both thought the pedal preamp actually sounded just as good, if not a bit better! I'm suspicious the depletion mode, high -voltage Mosfet buffer output on the pedal had something to do with it.

I run it into a Two Notes Cab M+ for headphone playing and going direct and it's a great setup.

The only downside is now I want to do a 4-tube design with a Dumble clean channel on one side and an SLO preamp on the other, lol.
 
So if the nutube technology performs as well as a 12AX7. . . . GREAT! Otherwise stay with 12AX7 technology. That said. . . . when do we get the PCB?? I vote for simple straightforward Fender BF-like pedal (AB763). Now you have a great pedal platform for all your PPCB gear.
 
Mike McLane said:
I ran across this "nutube" thing in relation to the Vox MV50's (which I had never heard about). I Googled Noritake (the developer) and discovered that its not a Vox proprietary thing. In fact if you go here . . . . http://nutube.us/ . . . . or here . . . . https://diyaudiostore.com/products/korg-nutube . . . . they're making it available to DIY'ers for discovering alternate uses. VERY INTERESTING.
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I have a Vox MV50 Clean which I love. I have the matching 8-inch and 12-inch speaker boxes, too. If I was doing serious gigging I'd probably buy another one and run them in stereo.
 
Barry said:
Seems somebody did that a few years back, as I recall it was a collaboration between line 6 and another amp builder, it may have been modeler in front of tube power section, been too many years and beers
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It was Bogner Amplification who collaborated with line 6. One day I randomly saw that on reverb while I was looking for another amp.
 
Feral Feline said:
Personally, I hate* tube-pedal designs that stand the tube upright in the enclosure, exposing the tube to potential eventual harm.

One of the reasons for your Sushibox’s success, I’m sure, is the properly-packaged tubes — and may you have continued success, sir.


There are others on this forum that have no problem with pointing tubes at the sky, that is their prerogative.
I’d rather go to 1590BB and secure tube inside than have a 1590N1 with a sacrificial tube-altar.



* (“hate” may not be strong enough… “loath”, “despise”, “vehemently oppose”, “disgusted by”, “#%*^@”… hmmm 😼)
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Yeah I don't like the tubes up top either. I appreciate the space savings, and it can be a neat look with glowing tubes sticking up like a hot-rodded Camaro, but they belong safely tucked inside the pedal in my opinion. My typical mounting method is a bit of a pain, though I do have one other mounting method I tried out and it works fine, I've considered throwing together a project with that method, but my regular builds (and my day job, and my wife, and my kids, etc) have kept me busy enough that I haven't gotten around to casual PCBs for the DIY-ers.

Mike McLane said:
So if the nutube technology performs as well as a 12AX7. . . . GREAT! Otherwise stay with 12AX7 technology. That said. . . . when do we get the PCB?? I vote for simple straightforward Fender BF-like pedal (AB763). Now you have a great pedal platform for all your PPCB gear.
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Nutubes are okay, I'm not a fan. If you look through the Nutube-based schematics on the internet you'll be hard-pressed to find one with 100% tube signal path, they always have something solid-state in front of them pushing them. This is because Nutubes have a ridiculously low amplification factor (mu), They don't drive very well on their own. The extremely low power requirement is awesome, but the sound makes it not worth it in my opinion.

TubeAmplification Factor (µ)
12AX7100
12AT760
12AU720
Nutube 6P114.5
 
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