Hello and thank you for stopping by. I need to throw this out there, and start getingt to it.
I'm gearing up for my 3rd tube amp build, but, this one may stand to be something different from my previous builds - I've built a Fender 40 watt and a 20 watt 6V6 Marshall plexi. I'm an electronic technician pretty much by trade so fortunately, these builds went well and I use the Fender as my gigging amp.
I need to build a third amp for an instrument I made. On first sight, this intrument looks like a walnut Stratocaster with elaborate brass inlays and one single pickup, a humbucker in the neck position. This "guitar" will never be picked, plucked nor strummed. It is a fretless that I made strictly for use with an ebow (electronic bow). It is a pure, singing melody instrument who's lyrical expression is far close to a cello or violin than any guitar you would ever hear. It is my big, 10 pound electric violin/cello that looks oddly like a Fender Stratocaster. Primarily I've been using it straight through my DI - micpreamps - stereo FX processor - D/A converter into recording software. I'm fairly convinced that it would benifit from an amp that has a strong Hi Fi element(s) to it. It can sound good through a typical clean guitar tube amp but sounds a bit strident or mushy. a little of that is OK but it lacks a more pristine quality that is heard though my relatively hi-end home studio front end.
I'd like to use a pair of KT88's for the power section. The idea of having good headroom at moderate stage volume is attractive, and plus, I just like something about those tubes, even the way they look.
The option for UL also is something that interest me for this project. and if for some reason, I preferred straight pentode, I'd still have the option.
I build a "tube designed station" out of an old Bogner amp so, I'm in a good place to try different topologies as I go.
Strangly enough, this "guitar" used with the Ebow, volume pot full up yields an output of nearly 3 volts at maximum. This is just about line level and a very high output compared to the typical 250mV of a typical electric guitar. So right there, It would be easy to push every stage of a typical guitar tube amp into saturation (which is the opposite of what this will need).
In my recent looking around for alternatives I found those Dynaco Hi Fi amps interesting, that perhaps they may be a good start to hear what this strange instrument would sound like though a more Hi Fi tube amp.
What would your first inclination be for an instrument with 15k ohm @ 2-3volt output be if you wanted it big, rich and clean?
I figured it wouldn't be too much to ask for 60-70 watts from a pair of KT88's in UL.
Thanks muchly for your time,
Phil D
I'm gearing up for my 3rd tube amp build, but, this one may stand to be something different from my previous builds - I've built a Fender 40 watt and a 20 watt 6V6 Marshall plexi. I'm an electronic technician pretty much by trade so fortunately, these builds went well and I use the Fender as my gigging amp.
I need to build a third amp for an instrument I made. On first sight, this intrument looks like a walnut Stratocaster with elaborate brass inlays and one single pickup, a humbucker in the neck position. This "guitar" will never be picked, plucked nor strummed. It is a fretless that I made strictly for use with an ebow (electronic bow). It is a pure, singing melody instrument who's lyrical expression is far close to a cello or violin than any guitar you would ever hear. It is my big, 10 pound electric violin/cello that looks oddly like a Fender Stratocaster. Primarily I've been using it straight through my DI - micpreamps - stereo FX processor - D/A converter into recording software. I'm fairly convinced that it would benifit from an amp that has a strong Hi Fi element(s) to it. It can sound good through a typical clean guitar tube amp but sounds a bit strident or mushy. a little of that is OK but it lacks a more pristine quality that is heard though my relatively hi-end home studio front end.
I'd like to use a pair of KT88's for the power section. The idea of having good headroom at moderate stage volume is attractive, and plus, I just like something about those tubes, even the way they look.
The option for UL also is something that interest me for this project. and if for some reason, I preferred straight pentode, I'd still have the option.
I build a "tube designed station" out of an old Bogner amp so, I'm in a good place to try different topologies as I go.
Strangly enough, this "guitar" used with the Ebow, volume pot full up yields an output of nearly 3 volts at maximum. This is just about line level and a very high output compared to the typical 250mV of a typical electric guitar. So right there, It would be easy to push every stage of a typical guitar tube amp into saturation (which is the opposite of what this will need).
In my recent looking around for alternatives I found those Dynaco Hi Fi amps interesting, that perhaps they may be a good start to hear what this strange instrument would sound like though a more Hi Fi tube amp.
What would your first inclination be for an instrument with 15k ohm @ 2-3volt output be if you wanted it big, rich and clean?
I figured it wouldn't be too much to ask for 60-70 watts from a pair of KT88's in UL.
Thanks muchly for your time,
Phil D
3 volts is "just about" line level? That is a hot signal. SOunds like you really want something with line level inputs...like a keyboard amp. SUch amps often if not usually have horns or tweeters, to get you the high end sparkle you seem to lack.
Guitar amps have guitar amp speakers, and they generally roll off after about 3kHz. DO you need that much power?
As an experiment, play your guitar amp chassis through a PA speaker cab. (a full range cab) That will let you know what the amp actually creates.
I am not experienced with e-bow, but it gives me the impression that there would not be a lot of large transients. Contrast a bass guitar, where plucks, slaps, and even picks can result in huge transients. SO I wonder how much headroom would be challenged.
If your existing setup lacks headroom, I think it would serve to find out where the shortage lies. I know in a Classic 30 Peavey, the phase inverter clips way before the power tubes do.
Guitar amps have guitar amp speakers, and they generally roll off after about 3kHz. DO you need that much power?
As an experiment, play your guitar amp chassis through a PA speaker cab. (a full range cab) That will let you know what the amp actually creates.
I am not experienced with e-bow, but it gives me the impression that there would not be a lot of large transients. Contrast a bass guitar, where plucks, slaps, and even picks can result in huge transients. SO I wonder how much headroom would be challenged.
If your existing setup lacks headroom, I think it would serve to find out where the shortage lies. I know in a Classic 30 Peavey, the phase inverter clips way before the power tubes do.
Thanks Enzo, I don't have an existing set up for this instrument. Thats why I'm building one, so I can do some experimenting and find topologies that suit the instrument. Plus, I just want to build it for fun and experience.
Not only would this have an amp for the instrument itself, the plan is to do something like tap off the speaker for a line level and process that through a stereo FX processor for stereo reverb, delays, ambience, etc... And this would be all-in-one, 2 speaker cabs each with the main tone and the stereo processed sound. But for now, its looking at circuits to see whats there in HI FI and guitar tube amps, which I've already done a bit of.
Generally, I think of this instrument as having a slow attack and legato sustain, not getting too much into any transients, unless I wanted to smack the Ebow into the pickups which is a technique one can use. I pretty much will be using it as the slow attack and sustain envelope.
This instrument definitely doesn't lack any high frequency content on its own. as a matter of fact, there is a menacing hive of angry hornets around 8.5Kh that a bit of low pass helps to serve. The pickup I use in series humbucker has a very extended top which is surprising for a humbucker with such high dcr (15K ohms in series - 5.2Kh resonant freq).
Those Dynaco tube amps are catching my eye as a starter point - ST70, MKiii, those amps. Some of them use KT88's in UL with those 6SN7 tubes which as I understand are alot like the 12AU7's. I'll definately want to see how a Hi Fi circuit renders the sound and it its too clean, I can always do other things, play with NFB, gain stages, no UL. But I'm at the stage of just collection components, tube and such to start buiding and experimenting with this thing. And of course, looking forward to the whole process. Otherwise, I'd just go buy someone elses amp!
thanks and best!
Phil D.
Not only would this have an amp for the instrument itself, the plan is to do something like tap off the speaker for a line level and process that through a stereo FX processor for stereo reverb, delays, ambience, etc... And this would be all-in-one, 2 speaker cabs each with the main tone and the stereo processed sound. But for now, its looking at circuits to see whats there in HI FI and guitar tube amps, which I've already done a bit of.
Generally, I think of this instrument as having a slow attack and legato sustain, not getting too much into any transients, unless I wanted to smack the Ebow into the pickups which is a technique one can use. I pretty much will be using it as the slow attack and sustain envelope.
This instrument definitely doesn't lack any high frequency content on its own. as a matter of fact, there is a menacing hive of angry hornets around 8.5Kh that a bit of low pass helps to serve. The pickup I use in series humbucker has a very extended top which is surprising for a humbucker with such high dcr (15K ohms in series - 5.2Kh resonant freq).
Those Dynaco tube amps are catching my eye as a starter point - ST70, MKiii, those amps. Some of them use KT88's in UL with those 6SN7 tubes which as I understand are alot like the 12AU7's. I'll definately want to see how a Hi Fi circuit renders the sound and it its too clean, I can always do other things, play with NFB, gain stages, no UL. But I'm at the stage of just collection components, tube and such to start buiding and experimenting with this thing. And of course, looking forward to the whole process. Otherwise, I'd just go buy someone elses amp!
thanks and best!
Phil D.
Great project, have you tested ‘the instrument’ with a PA amp or something normal used for both pa and hifi (crown, hafler, etc)? This should help establish range and power requirements. this is a unique instrument right? how about something completely different? Consider atmosphere’s m60 otl balanced monoblock design. You would lose the kt88s on the output stage but the m60 circuit has very nice (complicated?) 6sn7 driver stage and as much power as you need (it’s a circlotron design so you could add pairs of tubes for more power if needed.) While this might fly in the face of instrument tube amp conventions it could sound amazing.
Finally a Mr. Claypool called and he would like his ebow back...no seriously Les Claypool has been slapping bows on strange e-cello type instruments for decades, have a looked into how he is driving them?
Finally a Mr. Claypool called and he would like his ebow back...no seriously Les Claypool has been slapping bows on strange e-cello type instruments for decades, have a looked into how he is driving them?
Thanks for stopping by Indegent.
I will certainly take a look at the system you mentioned. I havent heard of it.
And yes, this amp will be an opportunity to try out all kinds of things, UL vs Pentode vs Triode, adjustable NFB, # of gain stages, tube types, cathode followers and EQ's. The final amp could be anything, even somewhere lost between a HI FI and a guitar amp. It doesn't matter as long as I did enough trials to land on a great tone for the instrument. I want to get the thing in action but, yes it is a strange new instrument, at least to me. When I built it, I didn't even know if it was going to work but, it surpassed my expectations and gave me a challenge I may never master.
The resultant sound to me is somewhere between an electric guitar feedback, an Irish flute, and a Cello. Its not what I expected but then again, how would I have known what to expect? a few guys in Turkey play Ebow fretless's pretty well but, the style is of their culture where I want this for playing romantic European melodies, like a classical cello or violin. It really does offer you many of the melodic lyrical qualities of a bowed string instrument. Since it is a very unique outcome, I feel it deserves or require a unique playback system.
I have not used this live through a true PA system, not in the way you would say, plug a synth into a mixing board. However, I've spent 200 hours playing it through a studio front end, which I take as fairly non-distorted and accurate to the output of the instrument. It actually is quite fine that way, even though I would normally never use a standard 6 string electric exept for a couple of exceptions. Plus, I'm hooked on building tube amps right now. That will wear off someday I'm sure but, its time to catch it while its hot. And now is the time!
Thanks! I'll look into that amp you told me about. Alot of amps I've looked at used the preamp tubes you mentioned. Seems like a popular one that was used often in older hi fi amps. Sounds like one I should definately try. And I'm not totally committed to KT88's, its just with their 42 watt max, I figured they would offer some good clean dynamic range if desired at moderate stage volume. This Fretless Ebow guitar has a huge dynamic range, from nicely humming at very low volume, very filtered, to screaming at 2.5 volts with tons of harmonics in the 5K to 9K range, really too much for me. But, perhaps a nice low pass tube stage could help contend with that. The harmonics really open up as it is "bowed" more, theres even something of a formant going on in there. Strange, but nice in its own way.
Thanks again for your input - sure appreciate that.
Best, Phil Donovan
I will certainly take a look at the system you mentioned. I havent heard of it.
And yes, this amp will be an opportunity to try out all kinds of things, UL vs Pentode vs Triode, adjustable NFB, # of gain stages, tube types, cathode followers and EQ's. The final amp could be anything, even somewhere lost between a HI FI and a guitar amp. It doesn't matter as long as I did enough trials to land on a great tone for the instrument. I want to get the thing in action but, yes it is a strange new instrument, at least to me. When I built it, I didn't even know if it was going to work but, it surpassed my expectations and gave me a challenge I may never master.
The resultant sound to me is somewhere between an electric guitar feedback, an Irish flute, and a Cello. Its not what I expected but then again, how would I have known what to expect? a few guys in Turkey play Ebow fretless's pretty well but, the style is of their culture where I want this for playing romantic European melodies, like a classical cello or violin. It really does offer you many of the melodic lyrical qualities of a bowed string instrument. Since it is a very unique outcome, I feel it deserves or require a unique playback system.
I have not used this live through a true PA system, not in the way you would say, plug a synth into a mixing board. However, I've spent 200 hours playing it through a studio front end, which I take as fairly non-distorted and accurate to the output of the instrument. It actually is quite fine that way, even though I would normally never use a standard 6 string electric exept for a couple of exceptions. Plus, I'm hooked on building tube amps right now. That will wear off someday I'm sure but, its time to catch it while its hot. And now is the time!
Thanks! I'll look into that amp you told me about. Alot of amps I've looked at used the preamp tubes you mentioned. Seems like a popular one that was used often in older hi fi amps. Sounds like one I should definately try. And I'm not totally committed to KT88's, its just with their 42 watt max, I figured they would offer some good clean dynamic range if desired at moderate stage volume. This Fretless Ebow guitar has a huge dynamic range, from nicely humming at very low volume, very filtered, to screaming at 2.5 volts with tons of harmonics in the 5K to 9K range, really too much for me. But, perhaps a nice low pass tube stage could help contend with that. The harmonics really open up as it is "bowed" more, theres even something of a formant going on in there. Strange, but nice in its own way.
Thanks again for your input - sure appreciate that.
Best, Phil Donovan
For those who haven't played with an Ebow, watch this 12 year old video by a 9 finger guitar player. Bagpipes from an ES335 stype guitar, yes. Phil Keaggy is an amazing guitar player, who is better now than in this video. I saw him live in 2017 and his "pedalboard" has grown into a small rack with three loopers that he can play at the same time.
YouTube
I haven't seen my Ebow since I packed up and moved out of Florida 6 years ago, but I often just plugged the guitar (a cheap Squier Strat) straight into the audio interface on my PC and used the effects and amp sims in TH2 (now TH3) from Overloud. A volume pedal like Keaggy uses is great for those swells and slow attacks.
YouTube
I haven't seen my Ebow since I packed up and moved out of Florida 6 years ago, but I often just plugged the guitar (a cheap Squier Strat) straight into the audio interface on my PC and used the effects and amp sims in TH2 (now TH3) from Overloud. A volume pedal like Keaggy uses is great for those swells and slow attacks.
Fretless Ebow guitar vid clip
I have watched and been thouroughly impressed with Phil Keaggies use of an Ebow and sound, FX in general. He knows how to create great sonic canvas's with that thing. I could (and hopefully will) learn an ocean of techniques from watching more of him.
My aim is to have a live set up using two 2 x 10" cabs that provide 2 things.
1. to have a nice tube monoblock feed the direct unaffected sound of the Ebow fretless to a 10" speaker in each cab.
2. to create a line out that goes into a high quality stereo reverb/ambience processor, into a Crown or QSC 2 channel PA amp out to the remaining 2 10" speakers for stereo effects. So, best of each world -dedicated direct sound, dedicated stereo effects, all contained within one easy to set up, easy to move system. Like having a little beautiful stereo stage monitor(s). Then the cabs can be miced up and panned left and right through the house PA system.
Thats what would float my boat and I've got to have it! Now! Well, later.
But thats the plan and I'm sticking to it. First step is to build an tube monoblock that provides complimentary gain stages and adjustments. That can be determinded by experimentation on my tube designed board station. I'm glad that Bogner Alchemist will still serve a good purpose after the good 12 years of gigging service it gave. What I did was rip everything out of the Bogner chassis and build a 20 watt Plexi from scratch. the Bogner boards were populated with 5 9-pin tube sockets and 2 octal sockets, with all the 6.3 volt filaments on one buss. Great. Perfect raw material for a tube amp design platform. And so far, those old Dynaco hi-fi tube amps and kits look like a decent place to start. KT88's, UL OT's and 6SN7 preamp tubes (or I can use 12AU7's, maybe.
Thanks for stopping by - back to work at home,
Phil D.
I have watched and been thouroughly impressed with Phil Keaggies use of an Ebow and sound, FX in general. He knows how to create great sonic canvas's with that thing. I could (and hopefully will) learn an ocean of techniques from watching more of him.
My aim is to have a live set up using two 2 x 10" cabs that provide 2 things.
1. to have a nice tube monoblock feed the direct unaffected sound of the Ebow fretless to a 10" speaker in each cab.
2. to create a line out that goes into a high quality stereo reverb/ambience processor, into a Crown or QSC 2 channel PA amp out to the remaining 2 10" speakers for stereo effects. So, best of each world -dedicated direct sound, dedicated stereo effects, all contained within one easy to set up, easy to move system. Like having a little beautiful stereo stage monitor(s). Then the cabs can be miced up and panned left and right through the house PA system.
Thats what would float my boat and I've got to have it! Now! Well, later.
But thats the plan and I'm sticking to it. First step is to build an tube monoblock that provides complimentary gain stages and adjustments. That can be determinded by experimentation on my tube designed board station. I'm glad that Bogner Alchemist will still serve a good purpose after the good 12 years of gigging service it gave. What I did was rip everything out of the Bogner chassis and build a 20 watt Plexi from scratch. the Bogner boards were populated with 5 9-pin tube sockets and 2 octal sockets, with all the 6.3 volt filaments on one buss. Great. Perfect raw material for a tube amp design platform. And so far, those old Dynaco hi-fi tube amps and kits look like a decent place to start. KT88's, UL OT's and 6SN7 preamp tubes (or I can use 12AU7's, maybe.
Thanks for stopping by - back to work at home,
Phil D.
You know, to me, everything that you've written above says "What you want is a solid-state amp." Literally all the qualities you list above are hard to get from a tube amp, but easy to get from a solid-state one.
Seventy watts of clean Hi-Fi audio is very easy to get from a modern class-D power amplifier module, and it will be a lot more manageable in every way than the huge, hot, heavy, expensive, monstrous beast of a tube amp you'd need to achieve the same thing.
This $30 (!!!) class D board will do what you want easily, use with a power supply with about +/- 35 volts to get your target 70 watts into 8 ohms: Amazon.com: Digital Power Amplifier Board,IRS2092S 500W Mono Channel Digital Amplifier Board Class D HiFi Power Amp Board: Electronics
If you're planning to use two speakers to share the output power, 35 watts each, then there are lots of affordable stereo class D amps that will do the job for you, like this handsome one for $74, which includes the power supply. Plug in your guitar, speakers, and go! Link: Amazon.com: SMSL SA50 50Wx2 TDA7492 Class D Amplifier + Power Adapter (Black): Electronics
Just saying...to me, this is one of those cases where the right tool for the job is not a tube amp, but a solid-state one!
-Gnobuddy
Thanks Gnobuddy, and what you say definately has occurred to me.
I'm sure it would work well.
I'm basing my decision on where I am right now. I just got done with 2 tube amps and have a level of comfort in the building and understanding of how they work. Plus, it still isn't known what will work the best with this instrument. I can only make assumptions at this point. For all I know, a Marshall Major might be the ticket. Or, it could be that I'm not satisfied unless I can switch out some gain stages for different levels of distortion/gainyness or cleanliness. I feel much more closer in my head to accomplishing this from tube topology although I'm certainly no expert in that but thats part of it. I'm just ready to try a hand at designing a tube system for this since my feet are already wet in it. And, I have a number of good NOS tubes that can use a home.
So, I have no interest in trying something totally different. Maybe after this I'll try a hand at something solid state. I would need to spend some time getting familiar with the type of solid state circuits that are game for the job.
Thanks!
Phil D.
I'm sure it would work well.
I'm basing my decision on where I am right now. I just got done with 2 tube amps and have a level of comfort in the building and understanding of how they work. Plus, it still isn't known what will work the best with this instrument. I can only make assumptions at this point. For all I know, a Marshall Major might be the ticket. Or, it could be that I'm not satisfied unless I can switch out some gain stages for different levels of distortion/gainyness or cleanliness. I feel much more closer in my head to accomplishing this from tube topology although I'm certainly no expert in that but thats part of it. I'm just ready to try a hand at designing a tube system for this since my feet are already wet in it. And, I have a number of good NOS tubes that can use a home.
So, I have no interest in trying something totally different. Maybe after this I'll try a hand at something solid state. I would need to spend some time getting familiar with the type of solid state circuits that are game for the job.
Thanks!
Phil D.
Understood!
There's the middle path to consider as well - a hybrid amp, with a tube preamp (to get any distortion you might want), and a solid-state power amp (to deliver a clean 70 W from a small, light, affordable box.)
The two links I posted are to pre-built SS amplifiers. The second one is complete and needs no work. The first one needs a power supply and an enclosure (and maybe an input level control.)
Good luck with the project!
-Gnobuddy
There's the middle path to consider as well - a hybrid amp, with a tube preamp (to get any distortion you might want), and a solid-state power amp (to deliver a clean 70 W from a small, light, affordable box.)
The two links I posted are to pre-built SS amplifiers. The second one is complete and needs no work. The first one needs a power supply and an enclosure (and maybe an input level control.)
Good luck with the project!
-Gnobuddy
Hybrid amp
A hybrid amp.
Now that sounds interesting. My bass player uses an amp (Ampeg?) that has a few 12ax7s in the preamp and it looks like 4 power Mosfets for each side of a push-pull output. He needed some solder joints re-flowed and that's when I noticed. I have to say, that amps has plenty of power, tone, and adjustability tone wise.
I really should take a look at that.
Thanks Gnobuddy,
Phil D
A hybrid amp.
Now that sounds interesting. My bass player uses an amp (Ampeg?) that has a few 12ax7s in the preamp and it looks like 4 power Mosfets for each side of a push-pull output. He needed some solder joints re-flowed and that's when I noticed. I have to say, that amps has plenty of power, tone, and adjustability tone wise.
I really should take a look at that.
Thanks Gnobuddy,
Phil D