I've tried adjustable negative feedback.
No negative feedback is nice for getting a 'broad' sound in a duo or trio setting, for instance.
I dialed in more negative feedback for louder settings, where the amp needed to stay cleaner at louder volumes.
However the negative feedback is in the output stage from speaker output to phase splitter 'tail'.
Incorporating adjustable NFB into a preamp would take more work.
No negative feedback is nice for getting a 'broad' sound in a duo or trio setting, for instance.
I dialed in more negative feedback for louder settings, where the amp needed to stay cleaner at louder volumes.
However the negative feedback is in the output stage from speaker output to phase splitter 'tail'.
Incorporating adjustable NFB into a preamp would take more work.
What I suggested with respect to bracing a cab doesn't get in the way of anything you like. It just gets rid of the stuff that when its gone you suddenly realize was giving you a muddy, boomy, out of control sound. Also, I always preferred open back until I fixed the damping of my cabs. The cab I use most has three removable back panels so it can be used in multiple different open cab configurations. Once I got control of some of the worst of sound radiating off the back and and sides of the cab, then it started to sound more like my actual guitar, only better. At that point I tried the different open and closed cab configurations and found at that point the close cab sounded best. My daughter came came over to visit for a week and she also plays guitar. She started playing it for hours because it sounds so good she just didn't want to stop playing. It was quite a revelation for me. I didn't expect that much benefit from fixing cab resonances. Later a friend who is a full time pro high end audio designer who has done work for a number of well known name companies. I told him about what I found and he said he has another friend who has been doing about the same type of thing. My friend emphasized that not overdoing the damping is key. You want some musical sound from the cab, just like you do from a semi-hollow body guitar body vibration. Over damping that is bad. But if you do it right to the cab it sounds great. Only downside is the time and effort to do it, and the final weight of the cab.I tend to dislike a hi-fi like, damped sound for my guitar sound. I like some fur in the notes.
However, there comes a point where there's just too much fur, and that's not good.
On the other hand, for me, if the sound gets too damped like a Polytone Mini-Brute, or bright and super-clean (to the point of harshness) like a Roland Jazz Chorus, then that's not good for me either.
That does make total sense. It sounds like you've put a lot of thought, time and effort into figuring that out, so I should listen!
The weight from extra bracing does worry me, but it does always seem that a heavier cab sounds better than one of these overly resonant, lightweight cabs you see nowadays.
You're also right that the speaker (cab + driver) you use has a lot more to do with the sound than the amp circuit you use. I once took a nice, big old cabinet with a 12" and an 8" and drove that with a dinky little solid state practice amp. The combination sounded GOOD!
However, in this case I'm thinking of a direct-to-computer kind of thing. I guess I could use a speaker emulator or something. I don't really want to spend the money on that, though.
I eventually want to put together a smaller gigging rig, with something like a simple 25 to 35 watt head (just volume and tone controls would probably be enough) and a good sounding 1-12" cabinet of some kind.
What kind of speaker driver do you use in your sealed cab? Is it a standard 'guitar speaker' with a thin paper cone, paper surround and smallish magnet , meant for open back or reflex loading? (think vintage Jensen or Celestion.) Or is it a more modern kind of speaker with lower sensitivity, a bigger magnet, and a more even frequency response, more like a good sound reinforcement mid-woofer? (Think JBL, Altec Lansing, or a beefy Eminence driver.)
The weight from extra bracing does worry me, but it does always seem that a heavier cab sounds better than one of these overly resonant, lightweight cabs you see nowadays.
You're also right that the speaker (cab + driver) you use has a lot more to do with the sound than the amp circuit you use. I once took a nice, big old cabinet with a 12" and an 8" and drove that with a dinky little solid state practice amp. The combination sounded GOOD!
However, in this case I'm thinking of a direct-to-computer kind of thing. I guess I could use a speaker emulator or something. I don't really want to spend the money on that, though.
I eventually want to put together a smaller gigging rig, with something like a simple 25 to 35 watt head (just volume and tone controls would probably be enough) and a good sounding 1-12" cabinet of some kind.
What kind of speaker driver do you use in your sealed cab? Is it a standard 'guitar speaker' with a thin paper cone, paper surround and smallish magnet , meant for open back or reflex loading? (think vintage Jensen or Celestion.) Or is it a more modern kind of speaker with lower sensitivity, a bigger magnet, and a more even frequency response, more like a good sound reinforcement mid-woofer? (Think JBL, Altec Lansing, or a beefy Eminence driver.)
Celestion Gold, 8 ohms, 12", 50W, alnico magnet. A great vintage sound. To be clear, have other speakers I could have used; just happen to like this one best for guitar.
Also for moving the amp and speaker around comfortably, still using an old version of folding truck something like this (300lbs rating):
https://www.bhphotovideo.com/c/product/43600-REG/Remin_S600_Super_600_Cart.html/?ap=y&ap=y&smp=y&smp=y&store=420&smpm=ba_f2_lar&lsft=BI:514&gad_source=1&gclid=Cj0KCQiA7NO7BhDsARIsADg_hIZ0lhGrtwHLxzPF4qzz4wH8svWueTNCcs3DWi6v5YbQgF-B0dkuKWYaAsqcEALw_wcB
https://www.bhphotovideo.com/c/product/43600-REG/Remin_S600_Super_600_Cart.html/?ap=y&ap=y&smp=y&smp=y&store=420&smpm=ba_f2_lar&lsft=BI:514&gad_source=1&gclid=Cj0KCQiA7NO7BhDsARIsADg_hIZ0lhGrtwHLxzPF4qzz4wH8svWueTNCcs3DWi6v5YbQgF-B0dkuKWYaAsqcEALw_wcB
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Oh does that ever bring back memories! Back when I lived in NYC, I used to use one of those to get to gigs.
Back then the cabs had huge trunks (Checker and Crown Vic) so I could fold down the cart and fit my combo amp in the trunk. But man... those NYC potholes! I'm amazed the amp made it through those years (it still works fine).
I think now that I'm older, I'd want to go a lighter...
Some players use two small amps, or a small amp head with two small speaker cabs, placed a few feet apart. Better coverage negates the need for a high sensitivity single speaker. Two 10" cabs would probably work well. Or a 2x8" cab with large-ish dimensions?
But I definitely want to go light...
Back then the cabs had huge trunks (Checker and Crown Vic) so I could fold down the cart and fit my combo amp in the trunk. But man... those NYC potholes! I'm amazed the amp made it through those years (it still works fine).
I think now that I'm older, I'd want to go a lighter...
Some players use two small amps, or a small amp head with two small speaker cabs, placed a few feet apart. Better coverage negates the need for a high sensitivity single speaker. Two 10" cabs would probably work well. Or a 2x8" cab with large-ish dimensions?
But I definitely want to go light...
I went through that as a bass player in the 80's 90's and 2000
Specially in the 2000 era is where you see small cabs.
And guys thought it would be easier to carry 2 cabinets.
Either 1x12 or 1x15
They didnt seem to get a small low cabinet is hard to roll on wheels.
Basically impossible without bending over.
Now you have to lift and carry 2 cabs 2 trips 2 things to get through a car opening.
I could slide and drop a 8x10 and roll it in before they made it back for
the second cab.
I never carried a cabinet. Rolled it.
Why you see dented grills, they carry them wrong.
3/4 inch wood is the standard basically.
You just use 1/2 inch wood and it gets lighter.
I dont have any magic insight on wood species.
At the wood store they might have 2 or 3 different sheets of 1/2 inch.
I slide and pick up all the choices. Whatever is lighter. There will be one with big difference.
That one ...Buy it, lol Science
With guitar the size of a 1x12 or 2x12 really wont change much.
But I have built some very light cabinets the same way with 1/2 inch.
And going open back does really lighten it up a little more. less wood
Or go 10" for 2x10 Eminence Legend 1028k is about the lightest speaker
you can get and sound ok. The neos kinda suck
I would look at Orange Micro Terror 20 watts.
It is basically a lunch box and light enough to light up a 2x10 or 2x12
Many moons ago Traynor made a bassman like combo.
Was 4x8 not 4x10 so it is small but can get loud if you need it.
Do the same with a light 1/2 inch ply cab, open back
Specially in the 2000 era is where you see small cabs.
And guys thought it would be easier to carry 2 cabinets.
Either 1x12 or 1x15
They didnt seem to get a small low cabinet is hard to roll on wheels.
Basically impossible without bending over.
Now you have to lift and carry 2 cabs 2 trips 2 things to get through a car opening.
I could slide and drop a 8x10 and roll it in before they made it back for
the second cab.
I never carried a cabinet. Rolled it.
Why you see dented grills, they carry them wrong.
3/4 inch wood is the standard basically.
You just use 1/2 inch wood and it gets lighter.
I dont have any magic insight on wood species.
At the wood store they might have 2 or 3 different sheets of 1/2 inch.
I slide and pick up all the choices. Whatever is lighter. There will be one with big difference.
That one ...Buy it, lol Science
With guitar the size of a 1x12 or 2x12 really wont change much.
But I have built some very light cabinets the same way with 1/2 inch.
And going open back does really lighten it up a little more. less wood
Or go 10" for 2x10 Eminence Legend 1028k is about the lightest speaker
you can get and sound ok. The neos kinda suck
I would look at Orange Micro Terror 20 watts.
It is basically a lunch box and light enough to light up a 2x10 or 2x12
Many moons ago Traynor made a bassman like combo.
Was 4x8 not 4x10 so it is small but can get loud if you need it.
Do the same with a light 1/2 inch ply cab, open back
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Going with neodymium magnet speakers can lighten the load considerably over the usual ferrite slab with the same magnetic force. Neo magnets are even more powerful per weight than Alnico.Two 10" cabs would probably work well. Or a 2x8" cab with large-ish dimensions?
But I definitely want to go light...
As a general rule, doubling the cone area gains +3dB sensitivity, the equivalent of doubling amplifier power.
2x8" will "outgun" one 10", but is a little shy of 1x12".
A 100dB 1watt/1meter sensitive speaker would require a 10watt amp to do 110dB, 100 watts for 120dB- about the level of a loud(ish) snare drum
A 15" guitar speaker has around 136 square inches (890 sq.cm.), sensitivity ~103dB.
A 12" ~ 84 sq. in. (545 sq.cm.) sensitivity ~101dB
A 10" ~ 57 sq. in. (366 sq.cm.) sensitivity ~98dB
An 8" ~ 36 sq. in. (231 sq.cm.) sensitivity ~96dB
A 6" ~ 22 sq. in. (140 sq.cm.) sensitivity ~94dB
Drivers with more bass tend to be less sensitive than the above.
Art
Maybe good to get two cabs. One for casual gigging where most of the audience is beyond the critical distance anyway. Mostly those people are hearing room reflected sound.
The other cab would be for recording and for important gigs where maybe there is a high quality PA for mic'ing up the guitar cab.
The other cab would be for recording and for important gigs where maybe there is a high quality PA for mic'ing up the guitar cab.
Thanks for the suggestions everyone.
- I am set on the mid-1960s Jensen C12N speaker I have. There are copies of it made nowadays, but I have an original. So I'll use it (and it sounds great to me).
- I think the point I'm having trouble getting across is that there is such a thing as an 'enriched' clean sound, with non-hifi levels of THD that don't destroy your ability to play chords with minor and major second intervals in them.
- I like the sound of a 1x12 cab with open back, but it needs to have a large baffle to keep the back wave from cancelling frequencies too high up. A ported cab might be a good idea, but I have no idea what tuning I would end up liking.
- I think the primary purpose for a tube preamp would be to 'warm up' the sound and send its output to some kind of solid state power amp driving the above-mentioned 1x12 cab.
The problem is now:
1. I want the sound of the Vibrato channel of a Fender Deluxe Reverb (blackface or silverface - they're the exact same preamp circuit). I could copy that circuit and put a follower on its output to drive the low impedance of the solid state power amp. I might also add a filter on the output to roll off lows below 100 Hz and highs above about 5k Hz, and possibly a line level output transformer from Edcor or the like.
2. Solid state power amp -- If class D is completely out, would an old Hafler P1000 do? That's not too big and heavy, delivers about 50W/ch, and is class AB. It can be bridged mono. It could actually be mounted in the speaker cabinet. I am not looking for power amp distortion at this point. That would be nice, but I'm not willing to carry around a big thing with a high voltage power transformer and an OPT.
3. Is this tube preamp thing a complete waste of time? Perhaps all I really need is to spend about $350 on a Universal Audio amp modeler and from that to a power amp and authentic '60s speaker of my choosing.
Here's a video about the UA Dream '65 amp modelling pedal, with a Gibson jazzbox. The guy demonstrating the box isn't really a jazz player, but I think it sounds reasonably close to a clean Deluxe kind of sound, just too bright and not 'enriched' enough.
Again, this is the kind of sound I like...
Notice how Berns plays major and minor seconds in his chord voicings, and they break up just a little, but his single note lines sing with some extra sustain, not too far below breakup territory. That's what I mean by an 'enriched' clean sound. The amp he uses is an original mid-60s blackface Fender Vibrolux Reverb (with the reverb turned off). I wish I could play like Peter... I mean... He's the greatest at what he does, and a lot of the sound he gets is in his hands and in his mind's ear. He's so melodic and relaxed at every tempo, too.
- I am set on the mid-1960s Jensen C12N speaker I have. There are copies of it made nowadays, but I have an original. So I'll use it (and it sounds great to me).
- I think the point I'm having trouble getting across is that there is such a thing as an 'enriched' clean sound, with non-hifi levels of THD that don't destroy your ability to play chords with minor and major second intervals in them.
- I like the sound of a 1x12 cab with open back, but it needs to have a large baffle to keep the back wave from cancelling frequencies too high up. A ported cab might be a good idea, but I have no idea what tuning I would end up liking.
- I think the primary purpose for a tube preamp would be to 'warm up' the sound and send its output to some kind of solid state power amp driving the above-mentioned 1x12 cab.
The problem is now:
1. I want the sound of the Vibrato channel of a Fender Deluxe Reverb (blackface or silverface - they're the exact same preamp circuit). I could copy that circuit and put a follower on its output to drive the low impedance of the solid state power amp. I might also add a filter on the output to roll off lows below 100 Hz and highs above about 5k Hz, and possibly a line level output transformer from Edcor or the like.
2. Solid state power amp -- If class D is completely out, would an old Hafler P1000 do? That's not too big and heavy, delivers about 50W/ch, and is class AB. It can be bridged mono. It could actually be mounted in the speaker cabinet. I am not looking for power amp distortion at this point. That would be nice, but I'm not willing to carry around a big thing with a high voltage power transformer and an OPT.
3. Is this tube preamp thing a complete waste of time? Perhaps all I really need is to spend about $350 on a Universal Audio amp modeler and from that to a power amp and authentic '60s speaker of my choosing.
Here's a video about the UA Dream '65 amp modelling pedal, with a Gibson jazzbox. The guy demonstrating the box isn't really a jazz player, but I think it sounds reasonably close to a clean Deluxe kind of sound, just too bright and not 'enriched' enough.
Again, this is the kind of sound I like...
Notice how Berns plays major and minor seconds in his chord voicings, and they break up just a little, but his single note lines sing with some extra sustain, not too far below breakup territory. That's what I mean by an 'enriched' clean sound. The amp he uses is an original mid-60s blackface Fender Vibrolux Reverb (with the reverb turned off). I wish I could play like Peter... I mean... He's the greatest at what he does, and a lot of the sound he gets is in his hands and in his mind's ear. He's so melodic and relaxed at every tempo, too.
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If you have a good tube amp, one that has the potential to sound good, here is how I find works pretty well to adjust the guitar and amp controls to get close to the sound you want.
Set guitar volume and tone controls to 5. Set amp tone controls to minimum. Adjust amp gain so you just start to get some breakup when playing two notes at once. Start increasing amp tone controls until you get a sound you like, but go for a midrange sound, not too much bass nor too much treble. Tweak amp gain as necessary to maintain breakup point at two strings at once moderately picked. Once amp is iteratively adjusted for breakup point and tone, then use the guitar volume and tone controls to fine tune the sound and breakup point.
Regarding open back versus closed back cabinets, for stock cabs open back usually sounds better, but if you take the time to brace the inside of the cab to keep it from vibrating too much, then its likely you can get a better tone with closed back, but the cabinet needs to be fairly stiff, with the sound pretty much only coming from the speaker, not from the cab vibrating. For my cabs, I used 1x2 maple strips on edge glued and screwed to the inside walls and to the removeable back. Don't over brace it to the point its dead, but brace it enough to dampen vibration in all the spots are where the cab will ring too much if you tap on it with your hand. Expect it to be heavier to carry around when you are done.
Set guitar volume and tone controls to 5. Set amp tone controls to minimum. Adjust amp gain so you just start to get some breakup when playing two notes at once. Start increasing amp tone controls until you get a sound you like, but go for a midrange sound, not too much bass nor too much treble. Tweak amp gain as necessary to maintain breakup point at two strings at once moderately picked. Once amp is iteratively adjusted for breakup point and tone, then use the guitar volume and tone controls to fine tune the sound and breakup point.
Regarding open back versus closed back cabinets, for stock cabs open back usually sounds better, but if you take the time to brace the inside of the cab to keep it from vibrating too much, then its likely you can get a better tone with closed back, but the cabinet needs to be fairly stiff, with the sound pretty much only coming from the speaker, not from the cab vibrating. For my cabs, I used 1x2 maple strips on edge glued and screwed to the inside walls and to the removeable back. Don't over brace it to the point its dead, but brace it enough to dampen vibration in all the spots are where the cab will ring too much if you tap on it with your hand. Expect it to be heavier to carry around when you are done.
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Set guitar volume and tone controls to 5. Set amp tone controls to minimum. Adjust amp gain so you just start to get some breakup when playing two notes at once. Start increasing amp tone controls until you get a sound you like, but go for a midrange sound, not too much bass nor too much treble. Tweak amp gain as necessary to maintain breakup point at two strings at once moderately picked. Once amp is iteratively adjusted for breakup point and tone, then use the guitar volume and tone controls to fine tune the sound and breakup point.
Re: setting controls...
I used to gig regularly with the following setup. That was something like 25 to 30 years ago. I've just started to hit jam sessions again, which is why I'm looking for a much lighter weight rig.
1. My guitar is a hollowbody Gibson, with a PAF-style neck pickup (pretty standard stuff). I have it strung with LaBella Medium flatwounds (livelier than D'Addario Chromes, GHS, etc.), gauges are .013 to .054 (very heavy by today's standards).
2. I set the guitar Tone control to about 7 or 8.
3. I set the guitar Volume control to 8 or so. That's going to be my 'as loud as it goes' setting.
4. I then go to the amp. With a stock Fender blackface tone stack, I set the Treble control to very close to 0. I set the Bass control to very close to 0. This gives as close to an electrically flat frequency response as possible. It does not have the scooped out mids of a standard Fender tone stack with its Bass and Treble controls set to 5. I don't like the mid-scoop, at least not from the preamp ('electrical EQ'). Here this is with the Bass and Treble controls just barely up, and the Mid control set to about 7, simulating the stock 6.8k R4 in the tone stack. Notice that the frequency response is close to flat.
In the stock Fender blackface tone stack, setting the Bass and Treble controls to 5 (with the Mid set to 7 as above) results in a lot of Bass and Treble boost (at 30 Hz and 5k Hz respectively) leaving a large midrange 'suckout' at about 500 Hz.
That's fine, but that's not the sound I want to hear. Too 'jangly' and 'Fender-y'. Sometimes I'd need a bit of extra Treble for louder groups, organ trios, etc.
4. I typically set the Volume control to only about 3 or 4. Maybe as high as 5. Anything more and I'd get too much grit and breakup, especially on full chords.
5. I never touched the amp's controls after that, except to make fine adjustments (which I typically wouldn't need to do).
In use...
For slow ballads I'd lower the setting of the guitar Tone control, and often lower the guitar Volume too. My guitar is a full hollowbody that has some acoustic sound to it, so I could get really quiet and let the acoustic sound blend in on really quiet numbers (I learned that from watching Jim Hall). However, if the ballad was more of a bluesy one and I felt moved to play with more dynamics, I'd raise the guitar's Tone and Vol settings to suit.
For uptempo tunes, I'd raise the guitar Vol control to 8 or 9 -- almost never to 10, unless I was playing with an organ trio or something that required extra brightness to the sound. I'd also raise the Tone control setting, sometimes all the way up, again for a loud organ trio setting or trying to keep up with a trumpet/sax fronted quintet or the like. I'd take care to make sure that even with the guitar Vol control set to 10 the amp Vol control wouldn't be set any farther up than just on the edge of initial breakup.
With all that in mind, I'm thinking all I really need is a tube preamp that lets me dial in some of that 'enriched' clean sound with a simple one knob Tone control, a preamp Gain control, and a Master Volume on the preamp's output. Maybe add a bright switch. Just an input jack, 3 knobs, and one switch.
Would that be any better sounding than a good amp/cabinet modeling pedal used as the preamp?
I still like open back 1x12 cabs, but they need to be physically large enough. I don't want to lug more than about 25 lbs. The Jensen C12N speaker weighs about 7 lbs, The Hafler P1000 weighs about 12 lbs. That leaves only 6 lbs for the cab! I'll need to find a lighter power amp. I have an Alesis A800 class D amp that's supposed to make great gobs of power bridged (claimed 800W into 8 ohms, bridged mono). The idea would be to never let it clip. Would that sound horrible?
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IME, modelers don't have the magic of a good real tube amp (although it probably doesn't matter for gigging, maybe it does for recording; certainly helps with motivation to practice). But then again, most tube amps are not that great. Why there are famous amps for different sounds is for various reasons, but for the kind of sound that just starts to break up in a good way when two strings are plucked at once in some medium intensity/volume way, from the perspective of the amplifier its mostly in the preamp section, but it needs the right topology, operating voltages, and component values to give a certain sound. And then of course there is the speaker and how it interacts with the power amp stage even if the power amp isn't clipping. Part of tone shaping can be in matching or mismatching the selected output transformer impedance winding with a particular speaker. Also, I happen to like Celestion Alnico magnet models because they give a sound I like. Fairly low power amps too, so its practical to drive the output stage into distortion if the music calls for it.
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I think you could do that fine with a jfet based preamp, or combination of jfet and a dual triode tube..then use a Cab IR or an analog speaker sim circuit if you need further processing.Would that be any better sounding than a good amp/cabinet modeling pedal used as the preamp?
I have a fine JFET preamp (Bogner Ecstasy), and it just isn't as playable as a good tube circuity. The distortion always has a solid state edge to it.
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Yeah, that may be the case with running the JFETs to saturation/clipping level, but they work very well clean and with a couple of triode stages after to distort,
you will have a very good range and distortion sound.
you will have a very good range and distortion sound.
I've done some shopping for Fender Deluxe and Bassman style preamps and modeling preamps/pedals. In their demonstrations, they all spend lots of time demonstrating their various flavors of glassy/chiming clean tones, spring reverb emulations, mild overdrive, breakup, heavy breakup, etc. Too bad I'm not interested in any of that. I want just a very mild to non-existent mid-scoop and a syrupy sort of tube-enhanced 'clean' sound, like I can get from my actual 70s Deluxe Reverb.
But none of this answers the original question -- how much THD am I aiming for?
Am I aiming for a modest amount of symmetrical THD, mostly H3?
Or am I looking for a modest amount of asymmetrical H2 on the signal?
I know what I sound like through a super-squeaky clean solid state guitar amp (like Boss Katana) and I don't like it. Plinky-plink. Thin. I know what I sound like through a Polytone Mini-Brute III or similar (punchy low mids without that weird mid-scoop, but kind of 'hard' sounding like many 1970s solid state class AB amps). I also know what I sound like through any Deluxe Reverb with bass and treble knobs set close to zero (as close to flat electrical response as you can get from a Fender tone stack) and the volume set from about 3 to 5, with a nice humbucking pickup driving it. That's what I like -- especially with a mid-1960s Jensen C12N or C12.
The JFET idea might be the most practical way to try to get that sound in a more convenient (lighter!) form factor. Do the JFETs need to be super-special high hfe types (like LSK170) or can they be more generic types (like J309 or J310)? Or should I be looking at using LND-150 MOSFETs?
Or maybe I just need a plain old two-12AX7 circuit with a pre volume, treble boost/cut control, and master volume, with a cathode follower on the output.
Either way, I just found a 1x12 cabinet for cheap, into which I'll be installing a mid-1960s Jensen C12N speaker. I hope those mate well...
But none of this answers the original question -- how much THD am I aiming for?
Am I aiming for a modest amount of symmetrical THD, mostly H3?
Or am I looking for a modest amount of asymmetrical H2 on the signal?
I know what I sound like through a super-squeaky clean solid state guitar amp (like Boss Katana) and I don't like it. Plinky-plink. Thin. I know what I sound like through a Polytone Mini-Brute III or similar (punchy low mids without that weird mid-scoop, but kind of 'hard' sounding like many 1970s solid state class AB amps). I also know what I sound like through any Deluxe Reverb with bass and treble knobs set close to zero (as close to flat electrical response as you can get from a Fender tone stack) and the volume set from about 3 to 5, with a nice humbucking pickup driving it. That's what I like -- especially with a mid-1960s Jensen C12N or C12.
The JFET idea might be the most practical way to try to get that sound in a more convenient (lighter!) form factor. Do the JFETs need to be super-special high hfe types (like LSK170) or can they be more generic types (like J309 or J310)? Or should I be looking at using LND-150 MOSFETs?
Or maybe I just need a plain old two-12AX7 circuit with a pre volume, treble boost/cut control, and master volume, with a cathode follower on the output.
Either way, I just found a 1x12 cabinet for cheap, into which I'll be installing a mid-1960s Jensen C12N speaker. I hope those mate well...
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LSK 170 is a good choice particularly *** a first stage input. I have also talked about JFET/BJT in bifet arrangement on other threads, or you could look at a mu type stage with 2 jfets, will increase the gain but keep the noise flow down.. J201 is also a good one. I like the idea of the JFET stage driving two preamp triodes, and you can switch it in/out or adjust the gain depending on how much you want to sweeten the harmonic distortion through the tubes. As you are working with the preamp section only,you won`t be dealing with anything too heavy even if it`s a single 12AX7 just a small transfo for heaters and B+ supply.The JFET idea might be the most practical way to try to get that sound in a more convenient (lighter!) form factor. Do the JFETs need to be super-special high hfe types (like LSK170) or can they be more generic types (like J309 or J310)? Or should I be looking at using LND-150 MOSFETs?
Cheers!
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