I design all my "Home brew" amps to enhance bass as much as possible, and carry 2nd order harmonics. That for me is the rich tube sound I look for. almost none of my amps have negative feedback. All I do is to try to control high frequency oscillations.
Perfect! - Just what I’ve been looking for … and it’s also super simple in build terms as well as a great learning tool for understanding the impact of certain components and how to tune the output to your liking 👍
i think these tubes are among the most expensive of the interconnect tubes!,it could also be a good preamp for a hybrid!,thanks to Skunkie and thanks to Matt!
@@SkunkieDesignsElectronics Haha. Well said! Guess there is a first for everything. 🤣🤣. Cheers, and keep up the great work!! Just got the caps for my R8 as I move through your series of upgrades. 😍😍
Ah, geez…the simulator zombies and forum trolls. 🙄 Cool for getting a somewhat general idea, but not helpful in knowing how something will sound. Looking forward to this build. I’ve got a rather big stash of NOS 12AU7’s, so this is perfect. Thanks, Steph! 🔊😊🎶
Yes indeed ! They who don't understand amplification are those who spew critisism..... PP amplification ( the mosr common amplification mode )....cancels second harmonics and by doing so they cancel out the harmonic relation between pair and odd harmonics , reinjecting some second harmonics ( and other pair harmonics ) the hamony of harmonic content of music is restored ... To create second harmonic distortion onr brings the tube in an operation point to produce some second harmonic distortion , therefor the potentiometer is shifted to the back of the circuit. One can adjust eventualy the sensitivity ( or overloading ) of the input by a resistive divider ( switch or multiple selector ) ....the bass ( hi pass filter output ) can indeed be adjusted by choosing other values of capacitors or and a higher impedance potentiometer (example ...20K )... Best is to double the output capacitors , 2µF by two 1µF in // , or higher values. The inductance is lowered and the ESR of the capsis half.... I don'targue anymore withthose audiophile discussions , the less they know the stubbern they are , .........believers instead of reel experience and reel facts ...you can't argue with a belief. Have a nice day , and yes Steph is right to build and explore this concept from MATT.
I just finished same project for connecting to project #72 of Rod Elliott and result was wonderful. You probably know that cathode voltage is 7V with B+ 300V. mentioned 5.8V on Mat drawing is for B+ 250V which was first attempt. thanks and waiting to see if any hint can make mine better.
Yeah someone brought that up on the forum and tried to make some huge deal out of it. I'm like "Whatever, I'm sure Matt just overlooked this when he rewrote some notes." I'm more of a build it, adjust till it sounds good and then write down the voltages kind of person anyway :)
Hi, I really love the content. I wanted to mention that I got the analog discovery working with the audio analyzer and it’s a great tool, However when looking at low distortion preamps it has too much noise and distortion itself to get measurements that I could reIy on. I then tested this on an audio precision analyzer and was able to determine that the analog discover can add some of its own distortion which isn’t huge but for preamp levels did make it difficult to use. It seems to especially add odd order harmonics in my setup. I would be happy to run anything on the APX 515 if you ever needed or wanted that.
That's why I build a small amp with no driver stage to test pre-amps. But I know even that isn't perfect. Mainly I just make sure stuff isn't crazy bad :) I honestly have no idea what a APX 515 is.
@@SkunkieDesignsElectronics Thanks for the reply, I think the audio analyzer suite is a great tool and the only alternative I could find under 10K. The APX 515 is one of Audio Precison's two channel analyzers. I only mentioned it because I kept hitting a wall while trying to test differences between in tubes in a Freya Preamp. I kept getting these harmonics that dominated the distortion numbers and were common between all the tubes I tested. I felt like that couldn't be correct so I finally bit the bullet and got the APX 515 (only because I needed it for another purpose) and confirmed that. To be clear these are like -70db so I don't think it would matter when looking at 1% distortion type things. I was able to finally determine that Electro-harmoix 6SN7 tubes had 10dB less noise and greatly reduced distortion than some triode matched JJ tubes. 0.002% vs 0.1% type differences which is quite crazy. I hope to publish those results soon. I really love your work and hope to build the KT120 SE amp when you do that one. In the mean time I hope to be able to learn more about the performance of new production tubes. I would love to look at old tubes but don't have any and can't really practically do that at this point.
I don't see what's so hard to understand..the explanation makes sense. This project looks like something I'm truly interested in. I love how certain tube preamps sound with a very transparent DAC and extremely transparent solid state Class D and Class G amps. Just a touch of warmth or roundness while remaining transparent and losing no or minimal clarity. One of the best pairings I've come across is with an older Chinese preamp, the Dared SL2000a (which I'd give me left foot for the 2012 board schematic) I've been able to change some parts in it but I really need the schematic. I've emailed many places/people looking for it. Wish I knew someone I could send it to and let them figure out the schematic for it. Anyway...this build could work for me, very interested to see how it turns out. Good luck, hope it goes well. Amir's forum is all about transparency from point A to point B. Tubes are not what that group is about. I go to ASR for other types of information.
I did run a quick calculation with with the 6.8µf output capacitor. The 1.0µf cap in the schematic sets the output -3dB point at ≈15Hz. This is what accounts for the ≈ -2dB response at 20Hz as I reported on the web page. With a 6.8µf cap in that position, the -3dB point goes down to ≈2.2Hz. This will result in very minimal loss at 20Hz as the 0.1µf coupling cap after the gain stage is already overly large given the input impedance of the cathode follower. This change will support the low frequency response much more. However, if the downstream amplifier is susceptible to overdrive conditions (i.e. grid current) then this large capacitor could lead to blocking distortion in overdrive conditions. Since this was mostly conceived as a circuit to drive class-D amps (which seldom suffer from input current during overdrive) this may not be a real issue. I'm interested to see how your build comes out. Matt CascaedTubes.com
Thanks Matt. I do want to test the frequency response and see if that larger cap is really needed, but I left space inside in case I go that route. And yeah I don't see this as a pre-amp for a tube amp, but more for a SS and especially a class D one. In the final video I discuss possibly adding a voltage divider to elevate the tube heaters to about 45VDC. It's not absolutely needed and I wanna see how quiet it is with grounded center tap heaters first.
I’m looking forward to seeing how this comes together and what your thoughts are on how it sounds. First thing I noticed when looking at the schematic was the volume pot being at the output of the pre as opposed on the input. Was wondering why this was being done. Your explanation makes perfect sense! A pre like this should have a constant sonic signature. No point in building something like this if the specific sound quality is only heard when the neighbors are calling the police with a noise complaint :) Be interesting to see how the coupling cap value changes the bass response. I would imagine the input impedance of the SS power amp would have an impact on what value is ideal? I recently built a SS Hiraga 30 watt class A amp that has speaker protection on the output. Because my preamp had too up DC on the output, which was triggering the protection circuit, I had to add a coupling cap in the power amp. Figured it was better to put it there, than on the pre, as I didn’t want the pre cutting low frequencies on other amps which would have different input impedances.
Yes, changing the 1.0uF capacitor to a 6.8uF capacitor will change the frequency response and the phase shifts. The output is a simple single pole high-pass filter, so the variable potentiometer will also affect the frequency response and the phase shifts. Running the numbers (assuming a low impedance on the output (i.e., R_v >> R_output)): (a) with a 1.0uF capacitor f_c (corner frequency or 3dB down frequency) will be about 16 Hz to 159 Hz with the variable potentiometer from 10K to 1K, respectively; and (b) with a 6.8uF capacitor f_c will be about 2.3 Hz to 23.3 Hz with the variable potentiometer from 10K to 1K, respectively. At the corner frequencies, there will be some distortion introduced by phase shifts in the waveforms. It looks like distortion is (also) being introduced via the 1M ohm feedback resistor in the second stage, since that is positive feedback (i.e., regeneration). It might be fun to add a variable resistor in series or parallel to that resistor to hear how that affects the sound, assuming that you don't put too much positive feedback in and create a screeching oscillator. I also might be fun to play around with a tuned or tunable filter in the place of the 1M resistor to hear how that sounds 😉
@@SkunkieDesignsElectronics Yeah, if modifying the feedback works out well, perhaps a set of controls could be added to allow someone to set various feedback to get a sound he or she likes 🤩 Just make sure that he or she cannot make an oscillator 😉
Thanks for the video and the info! Now....about the output cap and the 10k pot.... If there was a spec for the unit, this would be a less muddy subject. If the pot is all the way up (out of the circuit) and you are driving a 1 ohm load, you would have one result. If the minimum allowable impedance on the power amp's input was 600 ohms (or 10k), the response would be vastly different. With the advent of cheap ($65) spectrum analyzers, making frequency response measurements is a snap.
Nope, you are still driving across a 10K pot unless for some reason you decide to short the output, which would be a bad idea! Also this was never intended to drive a 600R input impedance amp, if such a thing even exists. Most amps have around a 50-100K input impedance. Yes the pot does vary the output load across this 10K pot, but in use, you never go past 1/2 volume. The output cap is large enough to deal with this, unless you are trying to drive a ridiculous load. To drive this theoretical 600 ohm load without impacting the low frequency response, you would need a 130uf cap!
@@SkunkieDesignsElectronics I have never designed anything without having some kind of specification in mind. The last amp that I designed and built had an FX loop output using a standard cathode follower. The input had a level control. The output went into a transformer with a balanced 600 Ohm output (XLR) with a single ended output (1/4") with ground lift. The other pre-amp output was derived from a lead off the speaker output transformer with a level control to a 1/4" jack. 600 Ohms is a typical load value in professional gear. I apologize for accidentally falling into a hobbyist webspace. Keep up the great tutorials. Oh...one little thing about ground strips. Look inside any older Fender amp and you will find a nice brass ground strap under the controls.
Yeah, it's such a shame most of us here are just "hobbyists" using mere consumer, hobby webspace gear, and we aren't using pro spec gear like you. And yes I have a spec in mind for everything I build, you just assumed it was something else.
@@SkunkieDesignsElectronics So much sadness in your postings. I am full of sorrow that I missed the electrical specification for your project. I am sure that I would had different thoughts had I read it first. I also do hobby projects. One on the back burner, although I have most of the parts is for one of those trendy little cutsie mini micro Class-D amps. I have a 2.1, which I will use with a couple of thrift store subs and a pair of Realistic speakers. Remember the little black metal ones? I'll power the kit with some rechargeable Li-On batteries. It's for a sound system on-the-go. Out in the woods kind of thing - jamming with friends. I won't have the full spec until I have squeezed the batteries dry of charge. The math says I'll get well over 150 Watts of sound power out of this for a couple of hours. For normal use, it would be much longer than that. Hey! There's the first part of my spec! "Much Longer". I swear - I should be in marketing!!! FYI - I am a design engineer by trade and have (on the side) built, modified and designed quite a few tube amps. Only one went into production. I cannot say who the most famous customer is, but he is currently on tour with Mr. Vai. Have an amazingly amazing Mothers Day!
That's the problem with the forums, everybody is blind to the goal and just go on a mad tangent trying to outdo one another.🤦🤣 Looks like a super interesting bit of kit. I'm catching up on your videos fast, absolutely incredible stuff, even watching stuff more than once, not anything aside from music videos on TH-cam that has me do that.👍🙂
Have enjoyed all your tube projects so far... and your thoughts about keeping things pure and simple! But I have been waiting for you to do this type of color tube preamp project ...as I have been using a cheap and cheerful but modded FX audio tube preamp to add some tube magic(😂) in my streaming/class D system....and even hough the FX is a great entry point and does add some nice colour, musicality and dimensionality...the circuit design apparently doesn't drive the tube to their best operational parameters ...so I have been looking around for something better, new or DIY to try! So I'm looking forwards to seeing how this turns out Equally I am curious if you managed to try out that little inline Nobsound (Douk) E6 preamp yet? ....as there has been a little bit of a buzz about it on the net -.but using modded Russian tubes..as,the chinese tubes are said to really bad and very microphonic. Anyway thanks again for doing what you're doing
This iscool. I already have all the parts on hand! Could this design (with some variation) become a guitar distortion/“drive” pedal (feeding a SS guitar amp)? Also, I am converting a Bogen tube PA amp into a guitar amp (as seen in yt video). Roughly speaking, could a circuit like this, with tweaks, be added at earlier stage for similar purpose of this video? Any thoughts? If I just wanted to play around with distortion, tone, gain…, could I safely add pots at various points to see how they do. If so, where would you place these? Any other suggestions on how to mess around to understand possibilities for experiment? I’m a self-taught hobbyist and have learned a lot from you. Love your channel!
While I understand the concept here, I have to say that my experience of putting a level pot at the output of a preamp driving the cable to a solid state power amp sounded awful. But every component combination will have its own sound, so maybe you'll get better results.....good luck!....
I look at the schematic and I had to keep reminding myself it was meant to be a distortion device. But saturator or not, I don't design or build anything that the signal leaves the output 180 degrees flipped. The input and output signal must remain in phase!
having the volume pot on the output defeats the whole purpose of the pre IMO. you had the voltage gain cascaded to the next triode to lower the impedance then you bring it back back by making it go through the volume pot. might as well just put a volume pot between dac and power amp. because thats the last touch. putting the volume pot at the input side of the pre will lower the noise floor and still maximize the sound and gain from the tubes. it will be more tube colored if thats what youre after. ive tried it both ways.
Putting the volume pot on the input defeats the whole purpose of preserving the second order harmonics from the input tube being driven hard, which is the SOLE purpose of this device. Installing the pot on the input, the amount of "Color" will vary with the volume setting. I'm really not sure what else I can do to try to explain why this pre-amp isn't wired that way. Myself and the designer totally understand why someone looking for a super clean, low distortion pre-amp would install it on the input, that is not the design goal here. "To preserve the harmonic character of the preamp, the gain stage is followed by the buffer which is then followed by the volume control. This means there is no attenuation of the color provided by the gain stage at any volume setting." www.cascadetubes.com/the-12au7-cathode-follower-color-preamp/
Thanks for donating the parts Dan!
Adding 0.5-1% 2nd-order harmonic distortion makes the sound richer without harshness. SE amp lovers get this.
I design all my "Home brew" amps to enhance bass as much as possible, and carry 2nd order harmonics. That for me is the rich tube sound I look for. almost none of my amps have negative feedback. All I do is to try to control high frequency oscillations.
Perfect! - Just what I’ve been looking for … and it’s also super simple in build terms as well as a great learning tool for understanding the impact of certain components and how to tune the output to your liking 👍
Glad you like it!
Adding a Bass and Treble controls to this pre-amp would make it interesting. With this simple design to add the controls would be easy.
Feel free to send me a schematic, I'm interested in trying that.
This is the build I've been waiting for. I do plan to build a preamp and this may be the one. Can't wait!
I'm thrilled with this preamp, I'm building one now😜
Everyone who has heard it loves it!
Nice chassis. I would buy one every time for my builds. That is exactly the style that I like, and I can't get in the uk..
Yeah he hand built that for me!
i think these tubes are among the most expensive of the interconnect tubes!,it could also be a good preamp for a hybrid!,thanks to Skunkie and thanks to Matt!
As Paul from PS Audio said - “A tube pre amp and SS amp, can be a Holy Grail pairing”. 😍
That may be the first thing Paul has said I agree with lol
@@SkunkieDesignsElectronics Haha. Well said! Guess there is a first for everything. 🤣🤣. Cheers, and keep up the great work!! Just got the caps for my R8 as I move through your series of upgrades. 😍😍
Ah, geez…the simulator zombies and forum trolls. 🙄 Cool for getting a somewhat general idea, but not helpful in knowing how something will sound. Looking forward to this build. I’ve got a rather big stash of NOS 12AU7’s, so this is perfect. Thanks, Steph! 🔊😊🎶
Yes indeed !
They who don't understand amplification are those who spew critisism.....
PP amplification ( the mosr common amplification mode )....cancels second harmonics and by doing so they cancel out the harmonic relation between pair and odd harmonics , reinjecting some second harmonics ( and other pair harmonics ) the hamony of harmonic content of music is restored ...
To create second harmonic distortion onr brings the tube in an operation point to produce some second harmonic distortion , therefor the potentiometer is shifted to the back of the circuit.
One can adjust eventualy the sensitivity ( or overloading ) of the input by a resistive divider ( switch or multiple selector ) ....the bass ( hi pass filter output ) can indeed be adjusted by choosing other values of capacitors or and a higher impedance potentiometer (example ...20K )...
Best is to double the output capacitors , 2µF by two 1µF in // , or higher values.
The inductance is lowered and the ESR of the capsis half....
I don'targue anymore withthose audiophile discussions , the less they know the stubbern they are , .........believers instead of reel experience and reel facts ...you can't argue with a belief.
Have a nice day , and yes Steph is right to build and explore this concept from MATT.
I just finished same project for connecting to project #72 of Rod Elliott and result was wonderful. You probably know that cathode voltage is 7V with B+ 300V. mentioned 5.8V on Mat drawing is for B+ 250V which was first attempt. thanks and waiting to see if any hint can make mine better.
Yeah someone brought that up on the forum and tried to make some huge deal out of it. I'm like "Whatever, I'm sure Matt just overlooked this when he rewrote some notes." I'm more of a build it, adjust till it sounds good and then write down the voltages kind of person anyway :)
Hi, I really love the content. I wanted to mention that I got the analog discovery working with the audio analyzer and it’s a great tool, However when looking at low distortion preamps it has too much noise and distortion itself to get measurements that I could reIy on. I then tested this on an audio precision analyzer and was able to determine that the analog discover can add some of its own distortion which isn’t huge but for preamp levels did make it difficult to use. It seems to especially add odd order harmonics in my setup. I would be happy to run anything on the APX 515 if you ever needed or wanted that.
That's why I build a small amp with no driver stage to test pre-amps. But I know even that isn't perfect. Mainly I just make sure stuff isn't crazy bad :) I honestly have no idea what a APX 515 is.
@@SkunkieDesignsElectronics Thanks for the reply, I think the audio analyzer suite is a great tool and the only alternative I could find under 10K. The APX 515 is one of Audio Precison's two channel analyzers. I only mentioned it because I kept hitting a wall while trying to test differences between in tubes in a Freya Preamp. I kept getting these harmonics that dominated the distortion numbers and were common between all the tubes I tested. I felt like that couldn't be correct so I finally bit the bullet and got the APX 515 (only because I needed it for another purpose) and confirmed that. To be clear these are like -70db so I don't think it would matter when looking at 1% distortion type things. I was able to finally determine that Electro-harmoix 6SN7 tubes had 10dB less noise and greatly reduced distortion than some triode matched JJ tubes. 0.002% vs 0.1% type differences which is quite crazy. I hope to publish those results soon. I really love your work and hope to build the KT120 SE amp when you do that one. In the mean time I hope to be able to learn more about the performance of new production tubes. I would love to look at old tubes but don't have any and can't really practically do that at this point.
I don't see what's so hard to understand..the explanation makes sense. This project looks like something I'm truly interested in. I love how certain tube preamps sound with a very transparent DAC and extremely transparent solid state Class D and Class G amps. Just a touch of warmth or roundness while remaining transparent and losing no or minimal clarity. One of the best pairings I've come across is with an older Chinese preamp, the Dared SL2000a (which I'd give me left foot for the 2012 board schematic) I've been able to change some parts in it but I really need the schematic. I've emailed many places/people looking for it. Wish I knew someone I could send it to and let them figure out the schematic for it. Anyway...this build could work for me, very interested to see how it turns out. Good luck, hope it goes well. Amir's forum is all about transparency from point A to point B. Tubes are not what that group is about. I go to ASR for other types of information.
very cool 12au7 is good musical tube
It's funny, the online forums all repeat these are horrible for hifi use...
I did run a quick calculation with with the 6.8µf output capacitor. The 1.0µf cap in the schematic sets the output -3dB point at ≈15Hz. This is what accounts for the ≈ -2dB response at 20Hz as I reported on the web page. With a 6.8µf cap in that position, the -3dB point goes down to ≈2.2Hz. This will result in very minimal loss at 20Hz as the 0.1µf coupling cap after the gain stage is already overly large given the input impedance of the cathode follower.
This change will support the low frequency response much more. However, if the downstream amplifier is susceptible to overdrive conditions (i.e. grid current) then this large capacitor could lead to blocking distortion in overdrive conditions. Since this was mostly conceived as a circuit to drive class-D amps (which seldom suffer from input current during overdrive) this may not be a real issue.
I'm interested to see how your build comes out.
Matt
CascaedTubes.com
Thanks Matt. I do want to test the frequency response and see if that larger cap is really needed, but I left space inside in case I go that route. And yeah I don't see this as a pre-amp for a tube amp, but more for a SS and especially a class D one.
In the final video I discuss possibly adding a voltage divider to elevate the tube heaters to about 45VDC. It's not absolutely needed and I wanna see how quiet it is with grounded center tap heaters first.
I’m looking forward to seeing how this comes together and what your thoughts are on how it sounds. First thing I noticed when looking at the schematic was the volume pot being at the output of the pre as opposed on the input. Was wondering why this was being done. Your explanation makes perfect sense! A pre like this should have a constant sonic signature. No point in building something like this if the specific sound quality is only heard when the neighbors are calling the police with a noise complaint :) Be interesting to see how the coupling cap value changes the bass response. I would imagine the input impedance of the SS power amp would have an impact on what value is ideal? I recently built a SS Hiraga 30 watt class A amp that has speaker protection on the output. Because my preamp had too up DC on the output, which was triggering the protection circuit, I had to add a coupling cap in the power amp. Figured it was better to put it there, than on the pre, as I didn’t want the pre cutting low frequencies on other amps which would have different input impedances.
hi id like to know the output impedance value of this preamp .thanks
We will cover that in a future video.
Yes, changing the 1.0uF capacitor to a 6.8uF capacitor will change the frequency response and the phase shifts. The output is a simple single pole high-pass filter, so the variable potentiometer will also affect the frequency response and the phase shifts.
Running the numbers (assuming a low impedance on the output (i.e., R_v >> R_output)): (a) with a 1.0uF capacitor f_c (corner frequency or 3dB down frequency) will be about 16 Hz to 159 Hz with the variable potentiometer from 10K to 1K, respectively; and (b) with a 6.8uF capacitor f_c will be about 2.3 Hz to 23.3 Hz with the variable potentiometer from 10K to 1K, respectively. At the corner frequencies, there will be some distortion introduced by phase shifts in the waveforms.
It looks like distortion is (also) being introduced via the 1M ohm feedback resistor in the second stage, since that is positive feedback (i.e., regeneration). It might be fun to add a variable resistor in series or parallel to that resistor to hear how that affects the sound, assuming that you don't put too much positive feedback in and create a screeching oscillator. I also might be fun to play around with a tuned or tunable filter in the place of the 1M resistor to hear how that sounds 😉
Thanks, it will be fun to see what the audio analyzer tests show.
@@SkunkieDesignsElectronics Yeah, if modifying the feedback works out well, perhaps a set of controls could be added to allow someone to set various feedback to get a sound he or she likes 🤩 Just make sure that he or she cannot make an oscillator 😉
Thanks for the video and the info! Now....about the output cap and the 10k pot.... If there was a spec for the unit, this would be a less muddy subject. If the pot is all the way up (out of the circuit) and you are driving a 1 ohm load, you would have one result. If the minimum allowable impedance on the power amp's input was 600 ohms (or 10k), the response would be vastly different. With the advent of cheap ($65) spectrum analyzers, making frequency response measurements is a snap.
Nope, you are still driving across a 10K pot unless for some reason you decide to short the output, which would be a bad idea!
Also this was never intended to drive a 600R input impedance amp, if such a thing even exists. Most amps have around a 50-100K input impedance. Yes the pot does vary the output load across this 10K pot, but in use, you never go past 1/2 volume.
The output cap is large enough to deal with this, unless you are trying to drive a ridiculous load. To drive this theoretical 600 ohm load without impacting the low frequency response, you would need a 130uf cap!
@@SkunkieDesignsElectronics I have never designed anything without having some kind of specification in mind. The last amp that I designed and built had an FX loop output using a standard cathode follower. The input had a level control. The output went into a transformer with a balanced 600 Ohm output (XLR) with a single ended output (1/4") with ground lift. The other pre-amp output was derived from a lead off the speaker output transformer with a level control to a 1/4" jack. 600 Ohms is a typical load value in professional gear. I apologize for accidentally falling into a hobbyist webspace. Keep up the great tutorials.
Oh...one little thing about ground strips. Look inside any older Fender amp and you will find a nice brass ground strap under the controls.
Yeah, it's such a shame most of us here are just "hobbyists" using mere consumer, hobby webspace gear, and we aren't using pro spec gear like you. And yes I have a spec in mind for everything I build, you just assumed it was something else.
@@SkunkieDesignsElectronics So much sadness in your postings. I am full of sorrow that I missed the electrical specification for your project. I am sure that I would had different thoughts had I read it first.
I also do hobby projects. One on the back burner, although I have most of the parts is for one of those trendy little cutsie mini micro Class-D amps. I have a 2.1, which I will use with a couple of thrift store subs and a pair of Realistic speakers. Remember the little black metal ones? I'll power the kit with some rechargeable Li-On batteries. It's for a sound system on-the-go. Out in the woods kind of thing - jamming with friends. I won't have the full spec until I have squeezed the batteries dry of charge. The math says I'll get well over 150 Watts of sound power out of this for a couple of hours. For normal use, it would be much longer than that. Hey! There's the first part of my spec! "Much Longer". I swear - I should be in marketing!!!
FYI - I am a design engineer by trade and have (on the side) built, modified and designed quite a few tube amps. Only one went into production. I cannot say who the most famous customer is, but he is currently on tour with Mr. Vai.
Have an amazingly amazing Mothers Day!
This one is a great project!
Thanks!
That's the problem with the forums, everybody is blind to the goal and just go on a mad tangent trying to outdo one another.🤦🤣
Looks like a super interesting bit of kit. I'm catching up on your videos fast, absolutely incredible stuff, even watching stuff more than once, not anything aside from music videos on TH-cam that has me do that.👍🙂
Yeah, people drag it off topic trying to outdo each other. Turns into a _____ measuring contest...
This exactly what Ill like to get ;-)
Becaause I am running class D amp
My best to Y all from Denmark DK
Have enjoyed all your tube projects so far... and your thoughts about keeping things pure and simple!
But I have been waiting for you to do this type of color tube preamp project ...as I have been using a cheap and cheerful but modded FX audio tube preamp to add some tube magic(😂) in my streaming/class D system....and even hough the FX is a great entry point and does add some nice colour, musicality and dimensionality...the circuit design apparently doesn't drive the tube to their best operational parameters ...so I have been looking around for something better, new or DIY to try!
So I'm looking forwards to seeing how this turns out
Equally I am curious if you managed to try out that little inline Nobsound (Douk) E6 preamp yet? ....as there has been a little bit of a buzz about it on the net -.but using modded Russian tubes..as,the chinese tubes are said to really bad and very microphonic.
Anyway thanks again for doing what you're doing
I plan to do a "shootout" with an OG FX audio, that nobsound and this color pre-amp when I am finished.
@@SkunkieDesignsElectronics The shootout idea is perfect for me 😊 ...thanks again!
This iscool. I already have all the parts on hand! Could this design (with some variation) become a guitar distortion/“drive” pedal (feeding a SS guitar amp)?
Also, I am converting a Bogen tube PA amp into a guitar amp (as seen in yt video). Roughly speaking, could a circuit like this, with tweaks, be added at earlier stage for similar purpose of this video? Any thoughts?
If I just wanted to play around with distortion, tone, gain…, could I safely add pots at various points to see how they do. If so, where would you place these? Any other suggestions on how to mess around to understand possibilities for experiment?
I’m a self-taught hobbyist and have learned a lot from you. Love your channel!
I would maybe play with lowing the bias voltage on the input tube to make it easier to overdrive?
good job 😊
I wonder how this would fare in an effects loop of a solid state guitar amp?
Might be fun, I've never messed with guitar amps.
@SkunkieDesignsElectronics ive built a few amps.
Its a rare thing that i ever leave a design alone, as i guess you call me a tone chaser.
Thanks 😁
While I understand the concept here, I have to say that my experience of putting a level pot at the output of a preamp driving the cable to a solid state power amp sounded awful. But every component combination will have its own sound, so maybe you'll get better results.....good luck!....
We will see! I'm not the first person to build this one and the guy who designed it put a lot of design and engineering into this.
I look at the schematic and I had to keep reminding myself it was meant to be a distortion device. But saturator or not, I don't design or build anything that the signal leaves the output 180 degrees flipped. The input and output signal must remain in phase!
having the volume pot on the output defeats the whole purpose of the pre IMO. you had the voltage gain cascaded to the next triode to lower the impedance then you bring it back back by making it go through the volume pot. might as well just put a volume pot between dac and power amp. because thats the last touch. putting the volume pot at the input side of the pre will lower the noise floor and still maximize the sound and gain from the tubes. it will be more tube colored if thats what youre after. ive tried it both ways.
Putting the volume pot on the input defeats the whole purpose of preserving the second order harmonics from the input tube being driven hard, which is the SOLE purpose of this device.
Installing the pot on the input, the amount of "Color" will vary with the volume setting. I'm really not sure what else I can do to try to explain why this pre-amp isn't wired that way. Myself and the designer totally understand why someone looking for a super clean, low distortion pre-amp would install it on the input, that is not the design goal here.
"To preserve the harmonic character of the preamp, the gain stage is followed by the buffer which is then followed by the volume control. This means there is no attenuation of the color provided by the gain stage at any volume setting."
www.cascadetubes.com/the-12au7-cathode-follower-color-preamp/