Hello to all.
i want to make a tube pre-amp to try to integrate some tube sound into a solid state amp. And wondering if this is anything worth trying. I will be trying at my own construction of a pre amp. I plan to run it like this:
Guitar --> pre amp --> solid state head --> effects loop --> speakers
would this work at all?? and is there any benefits here??
Thanks
i want to make a tube pre-amp to try to integrate some tube sound into a solid state amp. And wondering if this is anything worth trying. I will be trying at my own construction of a pre amp. I plan to run it like this:
Guitar --> pre amp --> solid state head --> effects loop --> speakers
would this work at all?? and is there any benefits here??
Thanks
I think you want the effects loop between the pre amp and the power amp, not between the power amp and the speakers.
Lots of commercial amps (Marshall ValveState for example) have a tube preamp and a solid state power amp, so this is a very workable idea.
However, in my opinion, most of these amps fail to work as well as all-tube amps because they are usually done to keep costs down. It's cheaper to do an SS power amp than a tube one of any given wattage. The problem is that the typical SS guitar power amp is as cheaply made as can be. Small power transformers, small power-supply filter capacitors and poor attention to detail make for mediocre results. Again, this is my opinion, others may disagree.
Lots of commercial amps (Marshall ValveState for example) have a tube preamp and a solid state power amp, so this is a very workable idea.
However, in my opinion, most of these amps fail to work as well as all-tube amps because they are usually done to keep costs down. It's cheaper to do an SS power amp than a tube one of any given wattage. The problem is that the typical SS guitar power amp is as cheaply made as can be. Small power transformers, small power-supply filter capacitors and poor attention to detail make for mediocre results. Again, this is my opinion, others may disagree.
I expect a guitar tube pre to be relatively tricky, with regards to impedances and gain structure
been looking at a Summit pre
if I remember correct it has both SS and tube curcuit, and a blend fuction
no doubt a tube could give you tube sound, but not automaticly
been thinking about going the opposite route
to build a cheap tube power with EL34
and use maybe Tech 21 Sansamp bass driver
or even build my own pre too, with combined Jfet and tube gain
with commercial amps, note if it takes balanced signal only, or have multiple options
and input from guitar may need to be very high impedance, megaohm
with onboard guitar pre it may be different
the Summit has switchable input impedance, so maybe it could be a matter of simple resistors
been looking at a Summit pre
if I remember correct it has both SS and tube curcuit, and a blend fuction
no doubt a tube could give you tube sound, but not automaticly
been thinking about going the opposite route
to build a cheap tube power with EL34
and use maybe Tech 21 Sansamp bass driver
or even build my own pre too, with combined Jfet and tube gain
with commercial amps, note if it takes balanced signal only, or have multiple options
and input from guitar may need to be very high impedance, megaohm
with onboard guitar pre it may be different
the Summit has switchable input impedance, so maybe it could be a matter of simple resistors
tube pre/SS power amp hybrid
I've been considering this idea myself based on the Marshall VS100 that I have. The power amp stage of that failed and I managed to rig a Velleman K8060 power amp into the place of the failed Marshall unit. It works but is messy. Thinking I would like to make a cut-down version of the VS100, I have been pondering the building of my own tube pre/SS power Amp. I have just cut and pasted various parts of the circuits of the VS100, K8060 and Ampmaker SE5 that I built last year together and wonder if anyone with more experience than me (shouldn't be hard to find!) could pass an eye over it. I know it's not going to sound that good from the price of it and any suggestions for easy/V-cheap improvements would be gladly received. Mainly I just would like to know, Is it just going to go BANG and take me with it or does this look like it might work?
I've been considering this idea myself based on the Marshall VS100 that I have. The power amp stage of that failed and I managed to rig a Velleman K8060 power amp into the place of the failed Marshall unit. It works but is messy. Thinking I would like to make a cut-down version of the VS100, I have been pondering the building of my own tube pre/SS power Amp. I have just cut and pasted various parts of the circuits of the VS100, K8060 and Ampmaker SE5 that I built last year together and wonder if anyone with more experience than me (shouldn't be hard to find!) could pass an eye over it. I know it's not going to sound that good from the price of it and any suggestions for easy/V-cheap improvements would be gladly received. Mainly I just would like to know, Is it just going to go BANG and take me with it or does this look like it might work?
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Old thread moved to Instruments & Amplifiers since it is guitar amp related.I've had a lot of great results with tube preamp and ss power amp, as well as all-tube. Transistor front ends...are really tricky and IMHO not as versatile.
Note that my stuff is designed to be versatile, but not to switch sounds instantly during performance. I can get any sound I want but it takes some tinkering.
My favorite is two Fender preamps sections in series, with a bypass switch around the second one. Jerry Garcia did OK into an Alembic preamp that was basically the two preamp channels of just about any Fender tube amp, except Jerry put the two preamps in series, just running a cable from the output of one into the input jack of the other.
This allows you to use 4 12AX7 stages:
An input buffer for some gain. Leave out the second input jack and the series resistors. You can connect the input more directly to the grid of the first tube stage for much better sensitivity, just by leiminating the resistor netowrk at the input that provides two input jacks for each channel. Wasteful unless you have a stereo guitar. The circuit between the particular pickups and volume pot in the guitar is really critical...remember when for a few years steroes had switches to match the input to the turntable cables and cartridge? Well, for guitar all the same concerns apply.
side note: Right after the first stage and before the first tone stack I usually provide an output jack (with a second volume, on the back panel) where there is still maximum dynamic range (before any tube compression), for driving the voltage-control section of an auto-wah or trigger-filter...sense here for the control voltage, but apply the filter to the output of the preamp.
Between stage 1 & 2 is a volume and tone stack, but what matters most is the bright switch which puts a cap across the volume pot. The value of the cap determines the frequency where this "bright" treble-pass comes in and the "volume" knob setting also affects how steep the curve is.
The next stage 2 regains the output lost in the tone stack. If overdriven, it can add some post-preemphasis distortion too.
Now we're between the two channels. This is a great place to add an effects loop for additional distortion devices.
That goes right into the next stage 3 (or a bypass switch), which would have been the input to the second channel, but now in series with the output from the first channel. This is like Jerry's cable between channels...you can optionally put a volume pot between. This tube generates most of the compression and distortion. Because it is between the pre-emphasis curve from the "bright" switch and the post de-emphasis curve of the next tone stack, you can control the tone (bass/treble) of just the distortion seperately from the guitar tone. For instance, for a creamy distortion that's not irritating, you can set the first volume low with the bright switch on, then the treble turned down on the second tone stack...the guitar tone gets treble boosted and cut, and sounds about right, but the distortion generated after the first tone stack only gets its irritating treble cut.
Then there's the second channel's volume & tone stack. You don't need a bright switch in this one.
Stage 4 regains the losses of the 2nd tone stack and drives the power amp.
You need a volume control on the power amp input and/or a volume on the output from the preamp. You might also put jacks for the effects loop here, it's a great place to add reverb, echo, chorus, flange, phase-shift, pitch-shift, tremoolo, true vibrato, etc. after the real string-touch, tone, distortion etc. are established.
One more thing I should mention: If you're using a solid state power amp, you want it to faithfully reproduce the sound of the preamp, without adding any distortion of its own, as the solid-state distortion is not very "musical" to say the least. So I usually recommend 4 to 10 times more rated power than if you were using a tube power amp. And if the ss power amp has a switfhing power supply or it itself a switching-mode amp, that's great, but then double the required rating spec again. a 100-watt (continuous) rated switching-mode amp might not make a 101-watt output at all, not even for a millisecond duration.
I don't like starved-plate stages...if you want that buy a Chandler or Blue Tube or any of their ilk and stick it in the effect loop or between pre and power amps. A solid-state preamp with one starved-plate tube will not sound like I want.
Another thing worth trying it to build the preamp into a floor box with some footswitches. Shorter cable run to the guitar. Knobs are convenient if you're young enough to stoop over, without feedback problems approaching your backline.
Note that my stuff is designed to be versatile, but not to switch sounds instantly during performance. I can get any sound I want but it takes some tinkering.
My favorite is two Fender preamps sections in series, with a bypass switch around the second one. Jerry Garcia did OK into an Alembic preamp that was basically the two preamp channels of just about any Fender tube amp, except Jerry put the two preamps in series, just running a cable from the output of one into the input jack of the other.
This allows you to use 4 12AX7 stages:
An input buffer for some gain. Leave out the second input jack and the series resistors. You can connect the input more directly to the grid of the first tube stage for much better sensitivity, just by leiminating the resistor netowrk at the input that provides two input jacks for each channel. Wasteful unless you have a stereo guitar. The circuit between the particular pickups and volume pot in the guitar is really critical...remember when for a few years steroes had switches to match the input to the turntable cables and cartridge? Well, for guitar all the same concerns apply.
side note: Right after the first stage and before the first tone stack I usually provide an output jack (with a second volume, on the back panel) where there is still maximum dynamic range (before any tube compression), for driving the voltage-control section of an auto-wah or trigger-filter...sense here for the control voltage, but apply the filter to the output of the preamp.
Between stage 1 & 2 is a volume and tone stack, but what matters most is the bright switch which puts a cap across the volume pot. The value of the cap determines the frequency where this "bright" treble-pass comes in and the "volume" knob setting also affects how steep the curve is.
The next stage 2 regains the output lost in the tone stack. If overdriven, it can add some post-preemphasis distortion too.
Now we're between the two channels. This is a great place to add an effects loop for additional distortion devices.
That goes right into the next stage 3 (or a bypass switch), which would have been the input to the second channel, but now in series with the output from the first channel. This is like Jerry's cable between channels...you can optionally put a volume pot between. This tube generates most of the compression and distortion. Because it is between the pre-emphasis curve from the "bright" switch and the post de-emphasis curve of the next tone stack, you can control the tone (bass/treble) of just the distortion seperately from the guitar tone. For instance, for a creamy distortion that's not irritating, you can set the first volume low with the bright switch on, then the treble turned down on the second tone stack...the guitar tone gets treble boosted and cut, and sounds about right, but the distortion generated after the first tone stack only gets its irritating treble cut.
Then there's the second channel's volume & tone stack. You don't need a bright switch in this one.
Stage 4 regains the losses of the 2nd tone stack and drives the power amp.
You need a volume control on the power amp input and/or a volume on the output from the preamp. You might also put jacks for the effects loop here, it's a great place to add reverb, echo, chorus, flange, phase-shift, pitch-shift, tremoolo, true vibrato, etc. after the real string-touch, tone, distortion etc. are established.
One more thing I should mention: If you're using a solid state power amp, you want it to faithfully reproduce the sound of the preamp, without adding any distortion of its own, as the solid-state distortion is not very "musical" to say the least. So I usually recommend 4 to 10 times more rated power than if you were using a tube power amp. And if the ss power amp has a switfhing power supply or it itself a switching-mode amp, that's great, but then double the required rating spec again. a 100-watt (continuous) rated switching-mode amp might not make a 101-watt output at all, not even for a millisecond duration.
I don't like starved-plate stages...if you want that buy a Chandler or Blue Tube or any of their ilk and stick it in the effect loop or between pre and power amps. A solid-state preamp with one starved-plate tube will not sound like I want.
Another thing worth trying it to build the preamp into a floor box with some footswitches. Shorter cable run to the guitar. Knobs are convenient if you're young enough to stoop over, without feedback problems approaching your backline.
One other thing: If you have two tube stages in series, both driven outside their linear range and into a bit of compression and distortion, it sounds different than jsut driving one stage harder. A 'scope picture doesn't always correlate well to what you hear...but there's a theory flaoting around that the distortion is mostly to the peaks, and when you shift phase by going thru a stage, then apply more distortion, it's to a different area of the waveform. Just one thing to keep in mind. Sometimes for some sounds it's essential to have more than one tube stage adding its signature, and sometimes you don't want those sounds added in parallel.
The Fender circuit is simple and well-understood. That's why I recommend two, with a lot of volume controls between stages and at output (but not at input, I don't even like the volume controls in most guitars). Consider a volume pedal after the first tube stage (a poorly-named drive or gain pedal, it also controls distortion), and another volume pedal at the output to the power amp (like a master volume, it does not affect tone). I've had some luck with a pedal housing a dual linear pot, with some resistors and trim pots to alter the curves and ranges, wired oppositely, so at one extreme the pedal turns up the early "gain/drive" volume and the master volume down, at the other extreme the pedal turns down the early "gain/drive" and the master up. It's a pedal that allows you to fine-tune the exact guitar touch that will cross the line from clean to dirty.
Clean is clean, and two preamps is series can be adjusted to add a little gain at each stage with all stages within their linear range and have a wonderful clean tone, especially with that first bright switch. Of course you've got to decide what knd of dirty you want. I make two broad classifications: auto-correct and emotive. The distortion I call auto-correct makes every note sound the same; same attack, same tone, same compressed volume, it automatically corrects the shortcomings of your fretboard taps, hammer-ons, pull-offs, and sweep picking to make every picked note the same. As spell-check is to your computer writing, so auto-correct distortion is to your guitar playing. Transistors can do this kind of high-gain distortion, as can a hard-driven Marshall. The other kind of distortion is more emotive, and allows you to do clean single-note picking with some dynamic range, yet pick harder to get some bite like a singer's voice or sax or trumpet when over-driven for very emotive phrasing, and it adds a lot of rich complexity, beats, overtones, harmnics etc. when multiple strings are excited.
Good luck to all.
The Fender circuit is simple and well-understood. That's why I recommend two, with a lot of volume controls between stages and at output (but not at input, I don't even like the volume controls in most guitars). Consider a volume pedal after the first tube stage (a poorly-named drive or gain pedal, it also controls distortion), and another volume pedal at the output to the power amp (like a master volume, it does not affect tone). I've had some luck with a pedal housing a dual linear pot, with some resistors and trim pots to alter the curves and ranges, wired oppositely, so at one extreme the pedal turns up the early "gain/drive" volume and the master volume down, at the other extreme the pedal turns down the early "gain/drive" and the master up. It's a pedal that allows you to fine-tune the exact guitar touch that will cross the line from clean to dirty.
Clean is clean, and two preamps is series can be adjusted to add a little gain at each stage with all stages within their linear range and have a wonderful clean tone, especially with that first bright switch. Of course you've got to decide what knd of dirty you want. I make two broad classifications: auto-correct and emotive. The distortion I call auto-correct makes every note sound the same; same attack, same tone, same compressed volume, it automatically corrects the shortcomings of your fretboard taps, hammer-ons, pull-offs, and sweep picking to make every picked note the same. As spell-check is to your computer writing, so auto-correct distortion is to your guitar playing. Transistors can do this kind of high-gain distortion, as can a hard-driven Marshall. The other kind of distortion is more emotive, and allows you to do clean single-note picking with some dynamic range, yet pick harder to get some bite like a singer's voice or sax or trumpet when over-driven for very emotive phrasing, and it adds a lot of rich complexity, beats, overtones, harmnics etc. when multiple strings are excited.
Good luck to all.
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The reason for sticking with the components I have mentioned is that:
A, I have them all
B, The marshall transformer gives me 6 volts for the heaters, 35 volts + and - for the SS amp cicuit and 190 volts for the valve.
I am trying to produce a better circuit diagram with more/clearer value data on it. I don't need 200w of output and hope that by not overdriving the SS amp, I can avoid adding SS distortion just a little something from the valve. The SE5a I built sounds sweet but is not quite loud enough for the gigs I play. And I do like to tinker
A, I have them all
B, The marshall transformer gives me 6 volts for the heaters, 35 volts + and - for the SS amp cicuit and 190 volts for the valve.
I am trying to produce a better circuit diagram with more/clearer value data on it. I don't need 200w of output and hope that by not overdriving the SS amp, I can avoid adding SS distortion just a little something from the valve. The SE5a I built sounds sweet but is not quite loud enough for the gigs I play. And I do like to tinker
I disagree with the previous post saying you need many times more watts from a SS amp than a tube amp. What you need is to limit the voltage going into the SS amp to keep it out of clipping.
I would think copying a Marshall preamp and then soft clipping before the power amp would be interesting.
I would think copying a Marshall preamp and then soft clipping before the power amp would be interesting.
That's partially true, partially not, I just didn't get into it at any depth. The right compressor or peak limiter can indeed keep a SS out of trouble and make it behave more like a tube amp. But if you want the full capabilities of a tube preamp to be reproduced by a ss power amp that's a requirement the tube amp sidesteps. A tube power amp is a compressor/peak limiter but will also still operate farther outside its linear range...so in general I'd still stand by the recomendation that a ss power amp for guitar have a much higher power rating than a more conventional tube power amp for comparable usable output. That's partly because the ratings are based on some 'clean' distortion spec, and the tube amp is usable far beyond that, but the ss amp is not. Then again, the tube guitar amp "rating" may be so unflated it's unrelated to any reality...
And I would agree and yet disagree. Depending on the NFB and design of the amp the tube amp can keep clean up until clipping and no increase in voltage happens and the signal just gets more square. On the SS end I have a Lil Tiger amp that had no global NFB and it gave more distorted power than if spec'd for some arbitrary distortion figure.
An amp really needs multiple stages of tubes to get the true tube sound.
I have designed power amps with tube front ends but they sounded too clean.
So, are we saying that I should put 2 tubes in the pre-amp to get my tube amp sound? The SS amp circuit is 200w rms but I only want volume levels equivalent to about 30 to 40 watts SS (like my sons Marshall MG30DFX). So that fits with Printer2s suggestion that I need more SS power to equate to Tube power (My 5w tube amp has a similar volume output to my Vox supertwin 20w SS amp). As I said in my first post, I don't expect this to sound great, but maybe it can with a bit of thought? If anyone is interested in making this work rather than debating the merits/demerits of the principal, do come on board. below are links to the circuits I am using as a starting point and my first draught design.
1. Marshal VS100 tube HT circuit, top right corner. http://www.drtube.com/schematics/marshall/v100-60-02.pdf
2. Marshal VS100 power supply, lower right corner. http://www.drtube.com/schematics/marshall/v100-61-02.pdf
3. SE5a tube amp pre-amp circuit. http://www.ampmaker.com/images/ak01kit/ak01sc2.jpg
4. Velleman K8060 SS poweramp stage
http://www.sayalhobbies.com/images_d/K8060D.gif
5. My design. see thumb nail on thread item #6
A final thought, how about using an old PC tower case to put it all in? maybe glue some sort of material on the inside to dampen the metal from vibrating?
1. Marshal VS100 tube HT circuit, top right corner. http://www.drtube.com/schematics/marshall/v100-60-02.pdf
2. Marshal VS100 power supply, lower right corner. http://www.drtube.com/schematics/marshall/v100-61-02.pdf
3. SE5a tube amp pre-amp circuit. http://www.ampmaker.com/images/ak01kit/ak01sc2.jpg
4. Velleman K8060 SS poweramp stage
http://www.sayalhobbies.com/images_d/K8060D.gif
5. My design. see thumb nail on thread item #6
A final thought, how about using an old PC tower case to put it all in? maybe glue some sort of material on the inside to dampen the metal from vibrating?
No, actually I was saying you might only need a bit more power and to keep the amp out of clipping. Say you take your 5W tube amp and run it to its sweet spot. Take the signal off the output and feed it into a SS amp and you would get appreciatively more output coming off a higher rated SS amp given that the ratings are accurate and you are driving the same speaker.
I would get a transformer something like this and run one of the 120V windings as input power and the other as the high voltage winding and then use a voltage doubler on it. You could probably find a lower VA rating one to use that is cheaper.
229C12 - Hammond - datasheet
Or you could use a back to back transformer arrangement to step up the voltage from your amplifier power transformer.
I would consider something like this.
The Free Information Society - Marshall 2204 Preamp Electronic Circuit Schematic
Sorry, forgot you already had a HV winding.. Just rectify it and use it as is. The reason I suggest the two valve circuit is that preamp distortion with a couple more gain stages is suppose to be more pleasing than getting it all in one stage.
Printer2, did you look at my schematic on post #6? with a 2 valve preamp, will I need to run the output through an output transformer before feeding the SS amp or can I feed it through a volume pot into the SS amp. this would let me reduce the input into the SS to reduce transistor clipping. I'm still lost as to what your plan was for the hammond bobbin.
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