MP3 tracks (won't upload)
Here are some MP3s of the amp.
Some tracks are dry, some are wet using a MOD reverb tank from CE (AES).
The dry acoustic track for House of the Rising Sun includes two short clips: dry and then wet bar chord strums in advance of two phrases of the song's riff.
The Acoustic tracks were made using a custom-built Martin 0018 Vintage reissue with under saddle piezo pickup and soundhole capacitor mic in Martin's patented "tone blend" system.
The electric tracks were made with an MIA Fender Stratocaster.
All of these tracks were recorded using an Audio-Technica AT 3031 condensor mic through a MOTU 896HD A/D into SONAR (plain, no effects or filtering) of the 12-inch speaker (picture to be uploaded later) attached to the Amp documented by the posted circuit diagrams.
It's just before midnight in California now.
But the DIY Audio website won't let me upload the MP3 tracks. I get an "invalid file" error. Seems the extension .mp3 is not supported. Only picture formats seem to be supported.
Here are some MP3s of the amp.
Some tracks are dry, some are wet using a MOD reverb tank from CE (AES).
The dry acoustic track for House of the Rising Sun includes two short clips: dry and then wet bar chord strums in advance of two phrases of the song's riff.
The Acoustic tracks were made using a custom-built Martin 0018 Vintage reissue with under saddle piezo pickup and soundhole capacitor mic in Martin's patented "tone blend" system.
The electric tracks were made with an MIA Fender Stratocaster.
All of these tracks were recorded using an Audio-Technica AT 3031 condensor mic through a MOTU 896HD A/D into SONAR (plain, no effects or filtering) of the 12-inch speaker (picture to be uploaded later) attached to the Amp documented by the posted circuit diagrams.
It's just before midnight in California now.
But the DIY Audio website won't let me upload the MP3 tracks. I get an "invalid file" error. Seems the extension .mp3 is not supported. Only picture formats seem to be supported.
Never give up . . .
Okay, I see that a zip file is supported. So I made one containing the mp3 files. However, the filesize limit is less than one megabyte. It still won't go.
Let's try another method.
One at a time.
Okay, it took the clean tracks. Let's see if they get to the forum now when I submit this post.
Okay, I see that a zip file is supported. So I made one containing the mp3 files. However, the filesize limit is less than one megabyte. It still won't go.
Let's try another method.
One at a time.
Okay, it took the clean tracks. Let's see if they get to the forum now when I submit this post.
Success! Zippity doo dat! Zippity DID dat!
Now for some crunch and fuzz.
The Johnny B. Goode tracks use a moderate amount of gain, just past the point where it begins to break up just to show that side of things. There wasn't time to get into the super mid-range boost that works so well on modestly distorted single note blues licks which this amp can do. Perhaps later.
The Watchtower track uses full gain with cathode resistor and screen resistor switched over to the "tighter overhead" narrow input window position. The tone controls are also set to carve out the middle, leaving only maxxed out bass topped off with crisp treble, a mix that lends itself to this kind of track.
I know the heavy distortion on this amp leaves much to be desired. That's why there is a five-tube version of this amp.
But that amp will break the price ceiling, so I'll wait a day or so before adding its specs and samples to the mix here. (I've got some better sounding Watchtower tracks already on the drive.)
The high frequency (treble) is very pronounced in this three-tube version. That was deliberate. I can always shunt some of it to ground later. But having it there without generating screeching shrieks means I can use a cheaper output transformer in an economy version while still keeping some of the ka-chinga-ching at the speaker.
These tracks are awfully sloppy and not representative of what I believe I'm capable of. I'm woefully out of practice. When I began testing this amp a few weeks ago, I had no callouses remaining on my left hand at all. It had been years since I had picked up the guitar on a daily basis.
Even now it's only been about this last week that I've had the guitar in my hands every day.
Now that this amp is built (more or less) and the deadline has come and gone (for me, anyway) I intend to not let my guitar skills ever get this sloppy again if I can but put PLAYING IT at a higher priority than any other optional daily task. This little amp will make that task much easier, too, because--if I do say so myself--it makes playing so easy and so much FUN.
I now have some callouses and am not blistering my fingers every time I get serious about rehearsing the Watchtower piece (even if it is still full of sloppy trainwrecks and messy clams). I have this "challenge" to thank for that. Had it not been for the need to actually play the thing to showcase this amp, I don't know how I might ever have gotten past the frustration inertia in order to get seriously back into playing the guitar.
This week--just yesterday, as a matter of fact--for the first time in AGES I found myself going up and down the neck improvising on a theme without running out of steam or losing interest. And the fingers were actually going into many of the places I was trying to send them.
I have you and your encouragements to thank for this.
This is from one who's greatest pleasure in life has been playing the guitar. Again, thanks.
I believe I may well still have some interesting things to do at the guitar end of a tube amp.
If you don't hear anything so wildly ambitious when you listen to these tracks, please keep in mind that it's been YEARS since I picked up a guitar more often than two or three times a month. Sometimes the guitar cases sat for MONTHS without being opened.
I can assure you that I'm well aware that these tracks sound downright nasty. But compared to where I was a month ago, it's a glorious start, believe me.
Once again, I hope you enjoy listening to these little takes.
Now for some crunch and fuzz.
The Johnny B. Goode tracks use a moderate amount of gain, just past the point where it begins to break up just to show that side of things. There wasn't time to get into the super mid-range boost that works so well on modestly distorted single note blues licks which this amp can do. Perhaps later.
The Watchtower track uses full gain with cathode resistor and screen resistor switched over to the "tighter overhead" narrow input window position. The tone controls are also set to carve out the middle, leaving only maxxed out bass topped off with crisp treble, a mix that lends itself to this kind of track.
I know the heavy distortion on this amp leaves much to be desired. That's why there is a five-tube version of this amp.
But that amp will break the price ceiling, so I'll wait a day or so before adding its specs and samples to the mix here. (I've got some better sounding Watchtower tracks already on the drive.)
The high frequency (treble) is very pronounced in this three-tube version. That was deliberate. I can always shunt some of it to ground later. But having it there without generating screeching shrieks means I can use a cheaper output transformer in an economy version while still keeping some of the ka-chinga-ching at the speaker.
These tracks are awfully sloppy and not representative of what I believe I'm capable of. I'm woefully out of practice. When I began testing this amp a few weeks ago, I had no callouses remaining on my left hand at all. It had been years since I had picked up the guitar on a daily basis.
Even now it's only been about this last week that I've had the guitar in my hands every day.
Now that this amp is built (more or less) and the deadline has come and gone (for me, anyway) I intend to not let my guitar skills ever get this sloppy again if I can but put PLAYING IT at a higher priority than any other optional daily task. This little amp will make that task much easier, too, because--if I do say so myself--it makes playing so easy and so much FUN.
I now have some callouses and am not blistering my fingers every time I get serious about rehearsing the Watchtower piece (even if it is still full of sloppy trainwrecks and messy clams). I have this "challenge" to thank for that. Had it not been for the need to actually play the thing to showcase this amp, I don't know how I might ever have gotten past the frustration inertia in order to get seriously back into playing the guitar.
This week--just yesterday, as a matter of fact--for the first time in AGES I found myself going up and down the neck improvising on a theme without running out of steam or losing interest. And the fingers were actually going into many of the places I was trying to send them.
I have you and your encouragements to thank for this.
This is from one who's greatest pleasure in life has been playing the guitar. Again, thanks.
I believe I may well still have some interesting things to do at the guitar end of a tube amp.
If you don't hear anything so wildly ambitious when you listen to these tracks, please keep in mind that it's been YEARS since I picked up a guitar more often than two or three times a month. Sometimes the guitar cases sat for MONTHS without being opened.
I can assure you that I'm well aware that these tracks sound downright nasty. But compared to where I was a month ago, it's a glorious start, believe me.
Once again, I hope you enjoy listening to these little takes.
Dilemma time. Actually way past that but something just occurred to me and I do not know if I should change things or not. I wanted to do my best to get the different flavors of Fender amplifier sections, with different PI configurations. I was looking at the paraphase config and I noticed that Fender did not use a blocking capacitor between the voltage divider from the output of the first stage to the grid of the second stage. My thinking tells me that the cathode biased voltage from the output stage will offset the operating point of the second triode.
Not having much time to experiment (I really wanted to get this done this week) do I stick in a capacitor to block the dc or do I go vintage correct and take the warts in all to get the sound of the amp as Fender built them at the time?
http://ampwares.com/schematics/deluxe_5d3.pdf
Not having much time to experiment (I really wanted to get this done this week) do I stick in a capacitor to block the dc or do I go vintage correct and take the warts in all to get the sound of the amp as Fender built them at the time?
http://ampwares.com/schematics/deluxe_5d3.pdf
The little critter making all that sound
Here's a look at the little critter making all that sound.
Ain't much to look at, I agree. More an experiment than a prototype. The unused tube socket is for the 5-tube version of the amp. (Where's the fifth one go? In the sidecar.)
Not all of the shafts poking through the front panel represent connected pots. Some of them were just for finding out what values to assign to the fixed resistors of a voltage divider and at least one of them is for a control that isn't relevant to the three-tube version of the amp. Even so, not all of the connected pots will necessarily be needed. For example, some people might not feel the need for the reverb mix pot, saving its cost, since the send pot can also be used to control the reverb level at the output. The mid control could conceivably be replaced by a simple switch for someone with only a limited this/that need and a tighter budget.
Likewise, two of the front panel jacks don't connect to anything, which is why they're not in the BOM either. One is for optional footswitches that are not yet been designed into the circuit, but could control both reverb and gain using a stereo (TRS) connection. The other is for an optional headphones circuit.
Knobs? We don't need no gumfounded knobs. Just the one that controls the GAIN.
(But if we did need knobs, we could still find a way to fit them in the budget.)
The MOD reverb tank in the picture is a 4FB3D1B. There are others that will work with the amp, too.
I don't know what kind of 12-inch speaker this is. I've never opened the box to find out.
The point-to-point wiring is positively frightening to look at. Next task: find a way to lay out chassis and wiring that makes it less intimidating. Maybe use a tag board instead of terminal strips? I've seen some on eBay.
Here's a look at the little critter making all that sound.
Ain't much to look at, I agree. More an experiment than a prototype. The unused tube socket is for the 5-tube version of the amp. (Where's the fifth one go? In the sidecar.)
Not all of the shafts poking through the front panel represent connected pots. Some of them were just for finding out what values to assign to the fixed resistors of a voltage divider and at least one of them is for a control that isn't relevant to the three-tube version of the amp. Even so, not all of the connected pots will necessarily be needed. For example, some people might not feel the need for the reverb mix pot, saving its cost, since the send pot can also be used to control the reverb level at the output. The mid control could conceivably be replaced by a simple switch for someone with only a limited this/that need and a tighter budget.
Likewise, two of the front panel jacks don't connect to anything, which is why they're not in the BOM either. One is for optional footswitches that are not yet been designed into the circuit, but could control both reverb and gain using a stereo (TRS) connection. The other is for an optional headphones circuit.
Knobs? We don't need no gumfounded knobs. Just the one that controls the GAIN.
(But if we did need knobs, we could still find a way to fit them in the budget.)The MOD reverb tank in the picture is a 4FB3D1B. There are others that will work with the amp, too.
I don't know what kind of 12-inch speaker this is. I've never opened the box to find out.
The point-to-point wiring is positively frightening to look at. Next task: find a way to lay out chassis and wiring that makes it less intimidating. Maybe use a tag board instead of terminal strips? I've seen some on eBay.
Attachments
Revised BOM
Okay, who's the wiseguy that moved the "zero" key on my keyboard?
That came about after a hasty edit when I couldn't clearly see the total cell for the line of the spreadsheet which added the cost of R29 and R30. It truncated the $3.10 into 3.1 and it didn't look right to me, so I moved R30 to its own line. There are still two resistors named on the R29 line, but only one is added into the tally.
Okay, now it's fixed. Two item prices added correctly on the line with R29 and R30 and that naughty 259K pot has been deleted.
What the?
Okay, who's the wiseguy that moved the "zero" key on my keyboard?
That came about after a hasty edit when I couldn't clearly see the total cell for the line of the spreadsheet which added the cost of R29 and R30. It truncated the $3.10 into 3.1 and it didn't look right to me, so I moved R30 to its own line. There are still two resistors named on the R29 line, but only one is added into the tally.
Okay, now it's fixed. Two item prices added correctly on the line with R29 and R30 and that naughty 259K pot has been deleted.
Step by step.
Don't miss out these values, they will lead you to mojo, gorgeous toneland. Actually, I'm kidding because I have no idea why this amp sounds so good. Yeah, not pretty good anymore; last night this one went to another level, it went to and stayed into dreamland territory. A level only achieved by the chosen ones.
Maybe it's because of the Mullard '84 or the 'Mullard' coupling cap or because of the crappy looking vintage OT. I'm afraid I will never know and it really doesn't matter: when you hit the jackpot you don't ask yourself questions. Well, maybe I do..... I have an inquisitive mind, a mind with a disorder.
* Hey Tubekit, didn't check out your amp yet, just woke up. But I will and I'm happy for you. You did it!
Don't miss out these values, they will lead you to mojo, gorgeous toneland. Actually, I'm kidding because I have no idea why this amp sounds so good. Yeah, not pretty good anymore; last night this one went to another level, it went to and stayed into dreamland territory. A level only achieved by the chosen ones.
Maybe it's because of the Mullard '84 or the 'Mullard' coupling cap or because of the crappy looking vintage OT. I'm afraid I will never know and it really doesn't matter: when you hit the jackpot you don't ask yourself questions. Well, maybe I do..... I have an inquisitive mind, a mind with a disorder.
* Hey Tubekit, didn't check out your amp yet, just woke up. But I will and I'm happy for you. You did it!
Attachments
Hey Tubekit, your amp sounds pretty good. Some clips sound a tad too bright for my taste, anyway Tubelab has a real competitor. That is, until I post my sound clips, then it's game over for all of you.
Printer, there are many types of paraphase splitters, I'm not sure which one are you talking about. Anyway, if Fender didn't have a problem why would you?
Printer, there are many types of paraphase splitters, I'm not sure which one are you talking about. Anyway, if Fender didn't have a problem why would you?
Hear, here, my good man! (Men.) (Ladies and gentlemen.)
See one of my previous posts. This was deliberate, since it's relatively trivial to shunt the highs to ground with a cap. But GETTING the highs without creating a squealing screaming pig is the tricky part.
Also, with this kind of high frequency response, there will still be a good bit of the ka-chinga-ching left after replacing the quality Edcor OPT with a back-wired filament tranny that's notoriously lacking in high frequency response for the economy version of the amp.
Plus, there's a "bright" switch in the circuit. It was ON during the "tad too bright" takes. Simple solution: turn it off or back down on the treble control. Or both.
Wait until I post the "bass only" and "mid only" tracks and hold your final opinion in reserve until after you hear these.
My "dreamland" tracks haven't been posted yet. Just so you know.
But I'm confident that yours will all but certainly be nearly as good.
Who knows? They might even be just possibly a qualified almost arguably better, perhaps.
To the listening tests!
Noted. And for mine.
See one of my previous posts. This was deliberate, since it's relatively trivial to shunt the highs to ground with a cap. But GETTING the highs without creating a squealing screaming pig is the tricky part.
Also, with this kind of high frequency response, there will still be a good bit of the ka-chinga-ching left after replacing the quality Edcor OPT with a back-wired filament tranny that's notoriously lacking in high frequency response for the economy version of the amp.
Plus, there's a "bright" switch in the circuit. It was ON during the "tad too bright" takes. Simple solution: turn it off or back down on the treble control. Or both.
Wait until I post the "bass only" and "mid only" tracks and hold your final opinion in reserve until after you hear these.
My "dreamland" tracks haven't been posted yet. Just so you know.
But I'm confident that yours will all but certainly be nearly as good.
Who knows? They might even be just possibly a qualified almost arguably better, perhaps.
To the listening tests!
"Nice suit. Same tailor, too. So how much do you owe?" (--Groucho)
Hi again, Cassiel:
I just checked out your circuits.
The simple elegance of that amp circuit is jaw-dropping.
(And the price ceiling of this challenge is therefore clearly moot.)
I liked your voltage quad solution when I first saw it a week ago, as I said back then.
That 15-Ohm / 5W resistor in the filament circuit is pure genius.
Either things are very expensive in Madrid, or one of us is going to be abjectly shamed by your total cost of materials.
Hi again, Cassiel:
I just checked out your circuits.
The simple elegance of that amp circuit is jaw-dropping.
(And the price ceiling of this challenge is therefore clearly moot.)
I liked your voltage quad solution when I first saw it a week ago, as I said back then.
That 15-Ohm / 5W resistor in the filament circuit is pure genius.
Either things are very expensive in Madrid, or one of us is going to be abjectly shamed by your total cost of materials.
They went away from that style of inverter, maybe they had a problem. Just doing a back of napkin calculation it looks like the 12A*7 triode will be biased close to -4 volts but I could be wrong.
Thanks for your kind words Tubekit.
According to the rules I'm out not in. Vintage, unobtainable parts aren't allowed. I expect to be allowed to participate in the poll but that's it. I don't really mind, this challenge is between you and Tubelab, and the ironic thing is that it was so from the very beginning. The rest are mere decorators. Again, I don't mind being a decorator. Maybe Printer does mind but I doubt it. He's having fun just like me, same happens with all the people who are still following this thread. As a bonus, we got one amp we didn't have at the start of this challenge.
Printer, I've experimented with paraphase splitters more than once. I love in particular that phase splitter you posted but I would only use one resistor. Tie the cathodes. Download the Ampeg B15N schematic to know what I'm talking about.
According to the rules I'm out not in. Vintage, unobtainable parts aren't allowed. I expect to be allowed to participate in the poll but that's it. I don't really mind, this challenge is between you and Tubelab, and the ironic thing is that it was so from the very beginning. The rest are mere decorators. Again, I don't mind being a decorator. Maybe Printer does mind but I doubt it. He's having fun just like me, same happens with all the people who are still following this thread. As a bonus, we got one amp we didn't have at the start of this challenge.
Printer, I've experimented with paraphase splitters more than once. I love in particular that phase splitter you posted but I would only use one resistor. Tie the cathodes. Download the Ampeg B15N schematic to know what I'm talking about.
I'll look the Ampeg up. And you are right I am just in it for the fun. That may be why I took the last turn and decided to add features that would price me out of the running. In the end I went for the amp that I was most curious about. Hopefully I can get it to work well, if so I have some ideas to take it even further. What I am also hoping for is to get an idea on the sound of the different configurations of the parts I am using. If I decide one or the other is worthy of others building I will suggest it using the part which should come under the $100 limit. Something a little simpler that anyone can build. I hope to see more from others after the dust is settled, even one of's that use hard to get parts. I just like to see what is possible.
Well technically I didn't "have my papers in order" or have sound files by the deadline, but I am still working on it. The rules and deadline have changed several times but the original words were something like the first one with the goods wins. By that yardstick Tubekit is already the winner. I'm OK with that, but it is BST's dime, and we haven't heard from him in a while.
I lost my mother, and my mother in law this year. I can also state that the B.S. that follows is almost as hard as the event itself, in a different way. In my case it still isn't over. Neither estate has been settled. BST is likely rather busy right now.
My wife, Sherri has been away for most of this year helping her mother through her final days, and now dealing with the B.S. She will be home for 9 days starting on Monday. This puts me at work until late every night getting ahead so that I can take next week off.
I should be able to finish the speaker cabinet at wood shop class tomorrow night. After that I don't know how much time I'll have to work on this. I am updating the spreadsheet tonight. The amp head isn't mechanically finished yet, but I can and have, powered it up with clip leads.
Attempts to record my lousy guitar playing with a cell phone sounded worse than a $2 radio. I'll try the Sony still camera next. It does 640 X 480 video but I don't know how good the sound is. The only videos I have made were drag races, machine guns, and grandkids. None require good sound.
I have a good sound card and Cakewalk Sonar, but NO microphones!!!!!
Either way, this little amp is nearly done, and will be finished. It was done because the original gauntlet was thrown down over an amp that could be sold in kit form for $69. This amp is my representation of that goal from the vantage point that I had when I started down this road. The little guy rocks, and that's what I wanted. Today, I might choose a different path.
Amp 2.2 has been sitting in the corner lonely and neglected. I came to the realization that I wouldn't have have time to finish both of them. It was in working condition last time I plugged it in. I was still tinkering with it because I believe it still has more sounds locked inside it, and I want them to come out! It will be finished also, but I can't say when. This one will fit in the $100 budget and it has the widest tonal pallette of anything I have recently played with. I don't expect anyone to wait around, but if I find a way to make good sound files, I will make some with this amp too, because you just gotta hear this thing. Even with my crummy playing it can go from clean to cranked just by flipping the pickup switch on the guitar.
After that.....screw the budget, I want it LOUD, 120 db kind of loud. I think 2 channels, about 100 to 150 watts each and a pair of 100db 12 inch speakers ought to do it. SO......say $200???????? OK, maybe $250. This is hard right? NO the hard part is already done. Several builders have already build Petes magic red board according to my 125 WPC upgrade and none have seen any issues. YES, I have plugged my guitar into it using the preamp of amp 2.2 and it is deadly!
I updated the schematic to include component values. They are lifted right from the board that is used in the amp. Some capacitors may have a higher voltage rating in the spreadsheet because the price is often better on 350 and 400 volt caps. I used surplus 200 volt parts to build the amp, which runs on 160 volts. The spreadsheet will be posted late tomorrow or more likely Friday.
Anyone still experimenting should try this tone control circuit. Cranked one way it's a high pass filter. Cranked the other way its a high cut filter. In between it seems to affect everything. It gives the widest range of sound I have heard from a single knob.
Anyone still experimenting should try this tone control circuit. Cranked one way it's a high pass filter. Cranked the other way its a high cut filter. In between it seems to affect everything. It gives the widest range of sound I have heard from a single knob.
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Microphone recommendation for the frugal gourmet
For my money, you couldn't beat the sound of this little mic without spending twenty-five times its price somewhere else. It's called "omni-directional" but it likes the sound better when it's in front of the mic, and close. You might need to place it relatively near your speaker, but that shouldn't be a problem for a guitar amp. I don't know what its max SPL rating is. Getting too close is probably a bigger concern than too far when micing a speaker with this little mic, but you can always place it across the room if the amp is especially loud.
Use it. If you don't overdrive it you'll think your using a high-end Neuman for the clarity of its reproduction. Response is amazingly flat, considering its price.
It needs a phantom power voltage (or a 9v battery) but most sound cards have that. It uses a TRS mini-phone plug, so if your sound card doesn't have a phantom power voltage you can jury rig something to feed it with.
I say "most" because any microphonic issues that are too tame to bother the bedroom version may turn into unmanageable snarling beasts onstage.
In general, though, a modest PI, a quad of xxL6s, and a couple of boatanchors are all it takes to turn a bedroom amp into a stage amp.
Anyone with a box full of sweep tubes and a CE catalog should be able to do it in his sleep.
Radio Shack (please don't laugh, this is a very serious suggestion!) sells a little clip-on condenser mic that has absolutely impeccable sound! It's in the under $15 range if I remember correctly. They have more than one clip-on mic, so be sure to get the right one. It comes with a round mounting stand about as big in diameter as a half dollar with a stick-on pad on the back and has a push-on/push-off switch. Model # 33-3026. (Update: it appears that my favorite cheap mic is not currently available. I have no experience with their current model 33-3013, which sells for about $33. NEW UPDATE: Apparently you can get the 33-3026 from Amazon for $18. GET 'EM WHILE THEY LAST!!!)
For my money, you couldn't beat the sound of this little mic without spending twenty-five times its price somewhere else. It's called "omni-directional" but it likes the sound better when it's in front of the mic, and close. You might need to place it relatively near your speaker, but that shouldn't be a problem for a guitar amp. I don't know what its max SPL rating is. Getting too close is probably a bigger concern than too far when micing a speaker with this little mic, but you can always place it across the room if the amp is especially loud.
Use it. If you don't overdrive it you'll think your using a high-end Neuman for the clarity of its reproduction. Response is amazingly flat, considering its price.
It needs a phantom power voltage (or a 9v battery) but most sound cards have that. It uses a TRS mini-phone plug, so if your sound card doesn't have a phantom power voltage you can jury rig something to feed it with.
True. Most little amps can be made into a Chuggawatt monster having all of the same controls with most of their tonal range by adding another stage or two. Some subtleties may be lost in the process. Certain not-so-subtleties will be gained.
I say "most" because any microphonic issues that are too tame to bother the bedroom version may turn into unmanageable snarling beasts onstage.
In general, though, a modest PI, a quad of xxL6s, and a couple of boatanchors are all it takes to turn a bedroom amp into a stage amp.
Anyone with a box full of sweep tubes and a CE catalog should be able to do it in his sleep.