Need PA amp conversion help

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Gnobuddy said:
Fortunately, our friend the difficult-to-locate-extremely-large-member-of-the-deer-family has already progressed well past that point. :)


-Gnobuddy

There's a story to the name you might appreciate considering your current location... Years ago I spent 4-5 Days hiking around the Canadian Rocky Mountains in Alberta. Our small group was told by multiple park employees and locals to keep an eye out for moose as they we're typically very active in the area that time of year. The bull moose would be especially feisty and possibly dangerous as mating season was approaching. I was keen to see one and maybe capture some photos, but the days passed and neither I or any of my companions ever saw a single moose lol. By the end of the trip we took to making jokes about the elusive moose (ie, "Keep your eyes peeled for a bigfoot and we may see one! But as for the elusive moose... save your energy, I don't think they even exist.") Shortly after the trip I began using the moniker for different usernames as it was usually unique and not taken. Still brings back fond memories of a good trip even though the moose went unspotted lol.:)
 
That is interesting, quite a bigger sweep than I thought even!
Me, too. But I notice the "hump" flattens and widens out as the frequency goes up (the "Q" of the peak falls.) So it's not much of a hump by the time the "Tone" knob is at max. I think it's going to be most noticeable at lower settings of the tone knob.

If you have a favourite setting (half-rotation, for instance) for the "Tone" knob that you use most of the time, I can plug that into the simulation and maybe get us a little closer. I think the 800 Hz I mentioned earlier was with the tone pot at half-rotation in the simulation.
...they do a thing with that mid hump and treble boost that can be very usable in certain situations...
I'm still working on how to use mine best. I don't gig, but I go to a weekly jam. Over the years, the rest of the members have gravitated towards mostly folk, cowboy, and country music, with one member who plays acoustic fingerstyle versions of some classic rock and pop songs.

So there's not much call for distorted electric guitar from me. I usually take along either an acoustic-electric, or my semi-hollow electric guitar, and use just the tiniest bit of overdrive for solos, more to increase sustain than to actually sound distorted.

I keep bouncing around between an EHX Glove overdrive, the EHX Soul Food, and a Boss Blues Driver. I've tried stacking two of them too, and there are some nice David Gilmourish sounds lurking there to play with, though they're not really suited to the jams, so I tend to just use them for fun when I'm playing alone.

But I still yearn for some real valve distortion. I really should get off my behind and get to tinkering with valve guitar preamps again soon. But I better finish the cat-feeder first!


-Gnobuddy
 

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> the moose went unspotted

Didn't see it, but found the tracks in my front yard.
 

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There's a story to the name...
I did wonder about your username a few times, but figured it was your business, and you would share if you wanted to.

At least you had fun on the hiking trip! :)

I too have yet to see a moose in real life. Considering their size, strength, and reputation, I don't really want to get too close to one. But it would definitely be a thrill to see one (or more) from a safe distance!


-Gnobuddy
 
We better spot 'em quickly, or it may be too late: Half of Canada'''s wildlife species are in decline, WWF finds | CBC News
Sadly that seems to be the truth in quite a few places. While moose can cause trouble when interacting in human environments, it's a shame that there aren't more places for them to roam and graze in the wild without human interference.

On a lighter note here's a great story I heard about on NPR once where a whole town embraced a moose and his urban shenanigans as he would get drunk on fermented crab apples and cause unintended mischief around town. :)

Recalling Alaska's most notorious drunken moose, the street-smart Buzzwinkle - Anchorage Daily News
 
If you have a favourite setting (half-rotation, for instance) for the "Tone" knob that you use most of the time, I can plug that into the simulation and maybe get us a little closer. I think the 800 Hz I mentioned earlier was with the tone pot at half-rotation in the simulation.
Thank you, but that's probably not necessary now. I put in some more time yesterday playing with the amps tone stack and the treble/tone knobs on my drive pedals. Now I have a better idea how to manipulate the mid scoop notch in the amp where I want it using the treble and bass controls. Also normally I play with the klone tone knobs somewhere between noon - 2o'clock, But upon seeing how much the sweep of that knob can effect the mid hump I started boosting and cutting more drastically than I normally would. I think everything may actually be more usable than I realized. The only trouble now is switching between single coils and humbuckers requires drastically different settings. I might just end up with 2 klones on my board so I can set one for each kind of pick up.

I'm still working on how to use mine best. I don't gig, but I go to a weekly jam. Over the years, the rest of the members have gravitated towards mostly folk, cowboy, and country music, with one member who plays acoustic fingerstyle versions of some classic rock and pop songs.

So there's not much call for distorted electric guitar from me. I usually take along either an acoustic-electric, or my semi-hollow electric guitar, and use just the tiniest bit of overdrive for solos, more to increase sustain than to actually sound distorted.

I keep bouncing around between an EHX Glove overdrive, the EHX Soul Food, and a Boss Blues Driver. I've tried stacking two of them too, and there are some nice David Gilmourish sounds lurking there to play with, though they're not really suited to the jams, so I tend to just use them for fun when I'm playing alone.
I haven't used the Glove Drive, but I do have plenty of experience with blues drivers and klones. As you mentioned the klone is good as a solo boost (drive all the down and tone and level to taste). Have you tried adding a compression pedal to that as well? An MXR dynacomp (or just about any other compressor of your choosing) and a klone set this way is a great recipe for a twangy country/folk rock/americana vibe. Sustain for days! Otherwise I tend to just use my klones to boost a solo or lead line with a little extra grit (drive around 10o'clock - noon).
 
Thanks for the story of Buzzwinkle. That was pretty funny!

I remember watching a film about moose invading a city in, I think, Colorado. The moose did start to become aggressive, chasing civilians and threatening to gore or smash them. Apparently the local police force finally found a solution: the moose hated Segway transporters! So they had a few cops riding Segways around the town to chase off the moose whenever they became dangerous to the human population.
I think everything may actually be more usable than I realized. The only trouble now is switching between single coils and humbuckers requires drastically different settings. I might just end up with 2 klones on my board so I can set one for each kind of pick up.
You have a "loop switch" pedal (a sort of A/B switch designed to switch between one chain of FX pedals and another with a single stomp)? I have been tempted to make myself one.
Have you tried adding a compression pedal to that as well?
Thanks for the suggestion!

My only compressor is a Joyo, which seems to be a clone or near-clone of a Ross, which seems to be a clone or near-clone of an MXR Dyna Comp. (I compared the PCB of the Joyo with a Ross schematic, and the circuitry seemed about 99% the same.)

Virtually all my guitars have humbuckers. To my shock, I found out that the one I use most, an Agile AS-820 ( Agile AS-820 Natural at RondoMusic.com ), has pickups strong enough to overdrive the Joyo compressor!

This makes some rather nasty distortion. The Joyo also has some tone-suck issues - it definitely dulled the sound of the guitar.

I built a simple JFET buffer to put between the guitar and compressor, which solved the "tone suck" problem, but the Joyo still got overdriven.

Since then I built another JFET "unbooster", a buffer with a switch and a pot so you can knock down the guitar volume by a pre-set amount when you step on the pedal. I haven't tried it out with the Joyo compressor yet, though - I use the Unbooster as a rhythm / solo switch, and had kinda forgotten about the compressor until you mentioned it just now. I should really try it again!

Probably the real fix is to set-up my Squier Standard Stratocaster again and use that instead of the AS-820. The Standard has really low-output (read: cheap!) pickups, though.

I think both the Agile and the Squier could benefit from better pickups, but the budget won't stretch that far at the moment. One of these days! (Trying to re-wire the semi-hollow guitar through the f-holes won't be fun, either!)


-Gnobuddy
 
My only compressor is a Joyo...
...pickups strong enough to overdrive the Joyo compressor!
Is that the green one with the scorpion on it? I've seen those around but never tried one. Haven't played a Ross Compressor but I do own a Dynacomp. I've never had issues overdriving the Dynacomp, but I really only play it with single coils. I find humbuckers compress a bit already on their own and don't really like the sound of them through the Dynacomp at all, everything becomes too squished very quickly. Your strat may indeed be a better choice to try with your Joyo compressor. Also on the overdrive issue, I think I remember reading that some people modding the old Dyanacomp and Ross pedals found that the CA3080 OTA chip was the culprit in overdrive problems. I believe some of them had success swapping CA3080 variants for newer CA3280 chips which can handle higher input signals from humbuckers and other very hot pickups without distorting. I've never done that mod so I don't know how easy or difficult it is, but it may be worth looking at if your Joyo is using the same old OTA chip design.
(See link for CA3080 - CA3280 data comparison CA3280 Distortion )

Probably the real fix is to set-up my Squier Standard Stratocaster again and use that instead of the AS-820. The Standard has really low-output (read: cheap!) pickups, though.

I think both the Agile and the Squier could benefit from better pickups, but the budget won't stretch that far at the moment. One of these days! (Trying to re-wire the semi-hollow guitar through the f-holes won't be fun, either!)
Now there's an area where I actually do have some expertise lol. I have a good bit of experience maintaining, modifying, and repairing guitars for myself and others, so if you ever want any guitar set up/modification advice to make sure you're optimizing the potential of those guitars I'd be glad to assist. I could also make some cost effective pick-up upgrade suggestions for your Squier or Agile when the time comes.:)
 
You have a "loop switch" pedal (a sort of A/B switch designed to switch between one chain of FX pedals and another with a single stomp)? I have been tempted to make myself one.
Nope haha, I wouldn't be against it at all except that I'm currently running moderately sized board to keep things smaller and lighter right now and most of those loop switchers tend to take up a good bit of space and add some serious weight.
For a low tech solution I think I have just enough room on my board to squeeze that Soul Food pedal we we're talking about on there just after the other klone I'm currently using. The Soul Food can be internally set to true bypass so my signal will only be seeing the buffer on the first klone pedal. Then I'll optimize one klone for single coils and the other one for humbuckers. Not ideal, but free, easy, and it only adds the weight of one additional pedal lol.
 
Is that the green one with the scorpion on it?
That's the one! I opened it up once to try fiddling with the bias pot (the OTA only works in a narrow range, and the bias pot sets it to the middle of that range.) I found the factory had already got it right. Moving the bias pot either way made the compressor overdrive more easily.

I thought I remembered the OTA was a 3080, and this morning I found a Youtube demo video of this compressor complete with gut-shots. Yup, a CA3080E.

When I wrote my last post, I forgot that I do have another compressor (three, actually!) Not a guitar compressor per se, but three ART tube MP/C preamp / compressor / limiters ( Access to this page has been denied. ).

I've used these with 4 and 5 string electric bass, also with vocal mics, and they are excellent at almost perfectly transparent compression. I don't know if that's actually what we want from a guitar compressor, though these are quite versatile and I've never explored extreme control settings. I guess I'll have to try it to find out. But they are really far too big and beefy to put on a pedalboard.
I find humbuckers compress a bit already on their own and don't really like the sound of them through the Dynacomp at all, everything becomes too squished very quickly.
I've heard the same thing from some of my guitars, and I think it is the input stage of the guitar amp that compresses (not the guitar itself) when hit with the hot signal from a humbucker.

Fender biased his half-12AX7 triodes to only -1.5 volts Vgk, and we know that appreciable grid current is already flowing at something like -0.9 volts, so that leaves only about 0.6 volts peak (or 1.2 V pp) for the guitar signal before some soft-clipping and compression starts. I don't think this is enough for hot ceramic humbuckers, though it was probably plenty for early 'Strats with much weaker Alnico magnets and fewer pickup windings.

The funny thing about my guitars with cheap pickups is that the cheap single coils in my Squier Standard is wound with too few turns, presumably to save copper. Meantime, the cheap humbuckers in my semi-hollow guitar are wound with too many turns for some reason, making them sound duller and more muted than I like (and really too hot for Fender Blackface inputs and pedals like the Joyo compressor)!
I could also make some cost effective pick-up upgrade suggestions for your Squier or Agile when the time comes.:)
I've been thinking about the Stewmac Golden Age Parsons Street humbuckers ( Golden Age Parsons Street Humbuckers | stewmac.com ). I can tell from a few You Tube clips that they are definitely brighter than the stock pickups in the AS-820, but I've never heard them in person, so I don't really know any more than that. (Even these are over $100 CAD each, not counting shipping and maybe import duties depending on the mood of the customs inspector.)

If you have an opinion on the Parsons Street pickups, or suggestions about other affordable PAF-type humbuckers, I'd be glad to hear them!

There are many very wonderful things about life in Canada, but easy access to cheap consumer toys is not one of them! :)


-Gnobuddy
 
I do have another compressor (three, actually!)...
... But they are really far too big and beefy to put on a pedalboard.
Those do look like they'd take up quite a bit of real estate on a board, unless... :scratch2: you got crafty and installed one underneath a board and used it as a subtle always on compressor. Sounds like the "transparent" compression it provides could be great for that extra bit of sustain and dynamics without excessive overdrive and color. And it takes a standard 9V power supply input as well so it would be perfect for an under board install if your board has room or can be modified to make room underneath. For a slightly more expensive solution, I've never used one but have a few friends who own and are very happy with this pedal for humbucker use:
Keeley Compressor Plus - Keeley Electronics
They can be had for $130US new here in the US and around $90US on the used market. They're designed with a switch for single coil or humbucker pickups that somehow changes the compression dynamics to be optimized for one or the other.
 
If you have an opinion on the Parsons Street pickups, or suggestions about other affordable PAF-type humbuckers, I'd be glad to hear them!
I haven't come across any Parsons Street pickups yet, but the ratings do look favorable. Here are some PAF style pickups that I have installed for some friends and was impressed by for the price (pretty much all can be had as a set for under $200US + shipping/fees):

Humbuckers, PAF | the buzztone

Stigma | Organic Pickups (I think they're out of the UK)

The Camelot – Geppetto Guitars

Deacons P.A.F. Set – Tyson Tone Lab Guitar Pickups

The only other advice I can give on that one is make sure your guitar's pick up height is optimized for the pickups you have in there before you change anything, and also after you install any new ones for that matter. I can't tell you how many guitars I've seen where someone put new expensive pickups in and they're not happy with the sound so they blame the new pickups. Then I spend a little time with a screwdriver dialing in the right pickup height and all the sudden they find the clarity and definition they thought were missing. It sounds like a simple thing, but so many people do it wrong. Ceramic magnet humbuckers especially can be tricky, I find there is a very, very, very small window where the higher frequencies and little harmonics are clearly audible but the depth of the low mid-range is still there. Like 1/2-3/4 of a screw turn too far one way or the other and things start getting either muddy in the low mid-range, or brittle on the high end even, pretty quickly.

For your Agile I'd start somewhere close to the recommended pickup height for 335 style guitars: While fretting at 22nd fret measure from the top of the pickup to the underside of low and high E strings. Look for 1/16" (1.6 mm) for the bridge pickup and 3/32" (2.4 mm) for the neck on the bass side. 1/16" (1.6 mm) on the treble side for both bridge and neck humbuckers. Then adjust each pick up separately a half turn at a time for both scews. Go up and down a good ways in both directions playing a little after each turn until you hear what you want, the most articulation and clarity possible. You may end up pretty far off spec and that's okay as long as you're hearing the clearest articulation that you can.

That trick won't make cheap pickups sound like PAF's but it may make them a little more enjoyable to play until you can upgrade ;)

Also as a side tangent on the "PAF style" pickup trend. "PAF" is a buzzword that has caught on with resurgence in popularity and value for late 50's early 60's era Gibson guitars, but sometimes people are just referring to brighter livelier sounding humbuckers and not necessarily direct copies of the original Patent Applied For 2 wire design. If an exact PAF copy is what you want then your Parson Street pickups or something like one of my suggestions above is the way to go. But if you're just looking for brighter sound and more high end definition then there are a lot of other options out there that won't be priced higher just because they're modeled after PAF's.
For example: There are a lot of very good alnico magnet Filtertron Style pickups that can be had on the used market for pretty cheap right now ($40US-$60US in my area). People are buying midpriced Gretsch guitars and changing out the stock pickups for "upgrades" and letting the perfectly fine stock ones go for nothing.
Or if you want something full frequency that's clear and dynamic across the board I've installed these on one of my Les Paul style guitars and really enjoyed them. Alumitone Humbucker Gold/Chrome
– Lace Music Products

They are the most full frequency guitar pickup I've ever heard, almost too much so in fact. But they are something different for sure and I've liked what they bring to the table in clarity and touch sensitive dynamics.

... Look at me, you asked for one bit of input and I've written a short novel lol, sorry if this is more info than you wanted, but I hope at least some of it helps! :D
 
Here are some PAF style pickups...
Thank you for the list! I looked them up, and found one or two demo videos. Unfortunately it's really difficult to tell how these are going to sound, and I think all of them end up costing more than the Stewmac pickups (which are something like $70-ish each in US dollars.)

Eventually I stumbled across this: YouTube

And this: YouTube

And this: YouTube

Seymour Duncan does a really good job of providing good quality sound clips and other information on their pickups, and they are available at one of the local music stores, meaning I don't have to deal with customs duties, shipping, and credit card currency exchange fees. I'm now beginning to think the '59 neck and bridge humbuckers might be what I was looking for; the Jazz neck PU (SH-2) is, I think, a little too trebly for me, sounding almost like the low-ouput single coils in my Squier Standard 'Strat.
...make sure your guitar's pick up height is optimized...
Thanks for that reminder / set of tips! I'll definitely re-visit that.
...If an exact PAF copy is what you want...
Nah, I'm utterly uninterested in what sort of insulating tape or wire enamel was used in a pickup. :D And some of the PAF "mystique" is certainly total nonsense, like the claims that maple coil spacers are the only way to recreate the original PAF sound, and plastic will sound different. Brother. :rolleyes:

I looked for used Filtertrons on the local Craigslist and Kijiji sites, and found nothing remotely reasonable. Canada has one-tenth of the population of the US, and some cultural attitudes are quite different. So sometimes you find surprisingly big differences when you cross that two-inch-wide stripe of white paint that separates Washington from British Columbia. For instance, old Pentium computers that people set out on the curb with their recycling in Los Angeles years ago, still have considerable value here - I couldn't find a cheap one at all, after much Craigslist-scouring.
... Alumitone...full frequency...almost too much so...
For me, definitely too much so! They sound like the Shadow nanomag pickups that are fitted to some acoustic-electric guitars and some Epiphone Les Paul Ultra models, where they're supposed to produce plugged-in acoustic guitar sounds.

The first electric guitar I owned sounded a lot like that. That's because I made it myself in the mid 1980's, and in those pre-Internet days, guessed wrong about how many turns my home-brewed pickups needed. I ended up with pickups that were very low output, very clean, and a guitar that sounded almost like an acoustic-electric, though it was a solid-body!
... Look at me, you asked for one bit of input and I've written a short novel lol,
Not at all, thank you for taking the time to give me such a detailed response!

As I'm sure you've already noticed, my forte is not brevity. In middle school, I was the only kid who got in trouble with my English teacher because my compositions and written reports were too long!


-Gnobuddy
 
Seymour Duncan does a really good job of providing good quality sound clips and other information on their pickups, and they are available at one of the local music stores, meaning I don't have to deal with customs duties, shipping, and credit card currency exchange fees. I'm now beginning to think the '59 neck and bridge humbuckers might be what I was looking for; the Jazz neck PU (SH-2) is, I think, a little too trebly for me, sounding almost like the low-ouput single coils in my Squier Standard 'Strat.
Hard to go wrong with any Seymour Duncan products, that man knows how to make quality products and hire people that will uphold his high standards for products and service. The only downside is that you'll usually end up paying more for the familiar brand name, though I don't think they price gouge at all. They just ask what the market has set for their long tradition of quality and the customer service is excellent in my experience.:up: I agree they do a good job of demoing the products on their website as well.

I looked for used Filtertrons on the local Craigslist and Kijiji sites, and found nothing remotely reasonable.
Are you using Reverb.com for used product searches? If not then I recommend it. They have options to only search for sellers in Canada. The new products being sold there by music stores are not always the cheapest, but if you're looking for used products deals can be found, especially from private sellers. There were only 4 results in used filtertrons in Canada, but here's a quick search on new and used PAF style pickups in Canada alone
"paf pickups" Gear | Reverb

I've had some luck there buying pedals, pickups, and other odds and ends. Even sold a guitar once myself.:)
 
Quote:
Originally Posted by ElusiveMoose22 View Post
... Alumitone...full frequency...almost too much so...
For me, definitely too much so! They sound like the Shadow nanomag pickups that are fitted to some acoustic-electric guitars and some Epiphone Les Paul Ultra models, where they're supposed to produce plugged-in acoustic guitar sounds.
Haha :rofl: I can see how you'd make that connection, they're definitely not for everyone and Lace has some of the worst product demos I've ever seen/heard :(. I've let two friends borrow my guitar with the alumitones and one loved it and the other absolutely hated it lol. Though they can be used to very good effect in the right context, say a late 80's kinda vibe... Just another tool to have when needed, definitely not for every project :).

Neck and bridge samples from my guitar:

YouTube

YouTube

Certainly not what you're going for though, I'd say stick with more traditional pick ups if you like those Duncan '59s. Those have a great sound :up:
 
Going back to subject matter more related to this thread, I've been thinking more on what to do with the 2 unused inputs and pentodes in the circuit. I still like the idea of using one as a mic input, but the other unused one has me thinking :scratch2:...

Lately I've been weighing the merits of a pentode driven tremolo circuit. I've only started research and collected a few resources below and attached. Does anyone have a favorite pentode trem circuit they've had success building or enjoyed playing in another amp? The two schematics I found attached both use 6AU6's which is the exact tube I have in place with my EF86 adapters already, so I think building off something like these schematics might be prudent, though I've never played those specific amps and I'm not sure how much I would or wouldn't like their tremolo effect.

And just to really make things difficult (added difficulty, the only way I do my projects lol :rolleyes:), if I'm using the second channel for mic input and the third for trem that means I only have the 1 volume pot on the third channel free to control trem oscillation. Anyone have success designing a 1 control knob trem system? Should I somehow tie oscillation speed and depth to 1 pot, or should I try to put in some kind of single knob dual pot control / push pull pot or something cute like that?

The Valve Wizard- Tremolo Oscillator
 

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they (Alumitones) can be used to very good effect in the right context, say a late 80's kinda vibe...
I think good artists - people who are really creative - find ways to use anything in the cause of art. I'm sure a more creative musician than myself - someone like you - would find good ways to use the sound of those Alumitones!

I agree about the 80's sound, your Alumitone sample with chorus / flanging also gave me flashbacks to Cindy Lauper and the soundtrack from John Hughes' "Sixteen Candles" and other movies of that period.

I remember a stingingly bright guitar tone somewhere in the soundtrack of "Sixteen Candles", that sounded like a 'Strat through a treble booster into a perfectly clean and piercingly sharp solid-state guitar amp. Thin, cold, bright, harsh, with no body or warmth at all. It was a strange time in American culture!
The two schematics I found attached both use 6AU6's which is the exact tube I have in place
I know little about tremolo, but a pentode should make a nice trem oscillator (it has plenty of voltage gain, while some triodes have barely enough for this type of oscillator to work.)

Both the tremolo circuits you attached use what is sometimes called "bias wiggle" tremolo, where the tremolo oscillator varies the grid bias voltage on the output valves, which in turn varies their gain, causing the tremolo effect. I suspect this may only work well when the output stage is running clean (not distorting), otherwise it will sound like wiggling the gain knob on your distortion pedal.

Now that I think about it, I'm not sure I've heard many examples where tremolo was used along with a distorted guitar sound.

There is at least one other very different (and slightly less ancient) approach to tremolo, which is to insert some sort of circuit element in the signal chain, and vary its value cyclically. Often the variable element was an LDR, a light dependent resistor (now becoming scarce, and never famous for reliability). A small light bulb or LED positioned right against the LDR is driven by the tremolo oscillator, and the fluctuating light varies the LDR resistance, causing the tremolo effect as the guitar signal goes through it.

Because of the high signal voltages in valve guitar amps, I'm not sure there are a lot of other suitable variable-gain elements to choose from. (In low-voltage designs, FETs can also be used as variable resistors.)

Incidentally, the way the Silvertone tremolo "depth" pot is wired is a classic case of thoughtless design. When that pot wears out and the wiper loses contact with the carbon track inside the pot, the grids of the output valves have nothing to tie them to ground, and will float to some arbitrary voltage. This could result in destroyed output valves, maybe also a destroyed output transformer, and if you're really unlucky, maybe also the power transformer and rectifier valve if any.

This is easily fixed by adding a resistor from pot wiper to ground to guarantee a ground reference for the output valve control grids. To keep that resistance value from being too high to save the valves, it would be better to also reduce the 1M pot to, say, 250k, and the 1M series resistor to, say, 220k. The attached schematic shows my suggested changes in red.

To allow for the reduced pot resistance, the 0.02uF pot across the 1M "depth" control might need tweaking too. If so, 0.047 uF or 0.1 uF should do it.
Should I somehow tie oscillation speed and depth to 1 pot, or should I try to put in some kind of single knob dual pot control / push pull pot or something cute like that?
My two cents is that you will be happier with two knobs, by whatever method possible. I think there will be times when you want the tremolo slow and deep, or slow and shallow, or fast and deep, or fast and shallow, and a single pot won't allow you this sort of creative freedom.

In the past, I've seen dual pots with concentric shafts (an outer hollow shaft controlling one pot, a solid inner shaft controlling the other), and corresponding stacked concentric knobs. This seems like an elegant solution to your conundrum, but potentiometers as a component category have been gradually going extinct for the last twenty-odd years, and I don't know if this sort of exotic concentric pot and matching special knobs are available these days.


-Gnobuddy
 

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