Today I tore a 1966 (or '67 :-\) Fender "Deluxe Amp" to pieces, doing all sorts of mods to it. I was too preoccupied to take a picture of the finished product; nevertheless, here's a photo I took after removing a bunch of components, so you can at least get an idea of the extent of the mods:
(http://i244.photobucket.com/albums/gg29/cactuskeeb/2010-10-24124418.jpg)
OK, I just opened it back up to give a shot of the inside. Essentially, I added two mid controls (two 10k pots where the second inputs used to be on both channels), changed several component values in the first tone stack, and removed the vibrato circuit and used that tube as an extra stage for the normal channel (I took the idea from Gerald Weber's book, _Tube Guitar Amplifier Essentials_, in which he describes how to do this to larger Fender amps).
I'll have audio later in the week...
(http://i244.photobucket.com/albums/gg29/cactuskeeb/2010-10-26010649.jpg)
Now that looks fun! Thanks for sharing. It's like working on an old car where all the parts actually have some breathing room and you can get your tools in there. Looking forward to the audio man.
That's all reversible right? Right? Keep the parts Keeb.... What's your favorite way to drain caps?
Keeb, that looks great man! So when are you sending it up to me so I can play this bitch out? ;D
Quote from: Happyorange27 on October 26, 2010, 07:01:51 AM
Now that looks fun! Thanks for sharing. It's like working on an old car where all the parts actually have some breathing room and you can get your tools in there. Looking forward to the audio man.
It's not a lot of fun, really. It's incredibly nerve-wracking to work on an old amp like that because there are so many random variables that can totally ruin the project if you don't pay attention to every single little detail. And if it doesn't work, you're f*cked because you have no idea where the problem is 99 percent of the time.
Quote from: Walker done done on October 26, 2010, 01:29:57 PM
Keeb, that looks great man! So when are you sending it up to me so I can play this bitch out? ;D
Mail me a round trip ticket and book me a hotel room and you can play it for as long as I have a free vacation.
Nice man! I've got a couple clones that I've been tweaking on for a while. Getting ready to install a London Power Best Tube EFX Loop in one. I was curious about the second gain stage. I can see the connection of the pre to power section but why is the lead coming from the 20K resistor going to the bias splitter.........nevermind I see it's the output coupler. I've been meaning to get Weber's book along with some of TUT vol.'s. I'm sure you already know this but you can increase the PI input cap value to pronounce more mids also. I've been curious about how to install a mid boost of some sort where the vibrato section used to be as well. And you're right it's more like work than fun! Can't wait to here some clips.
I have TUT volume 3. There's so much packed into it you can actually read between the lines and get ideas. What I mean to say is, the author clearly has his agenda and wants to impart certain wisdom but he writes in a way that makes the thrust of what he's talking about entirely theoretical, and allows for you to see things a different way.
So I know I promised to have audio by this point but I have been trying different things in/with the circuit to see what I like best. I have to say that, today, I'm pretty damn satisfied with how it sounds. I'm a novice at recording and a crappy guitar player, so bear with me a few more days until I can get an audio clip worthy of the amp itself. I never thought it would sound so different from the original...wow. And I can tell you, with 100 percent certainty, that every little change makes a difference in the sound. If you change the type of cap, you can hear the difference. There are so many dr. know-it-alls on the interwebs who like to sound off on every forum thread dealing with the differences between paper in oil, polypropylene, etc. These guys always say the same thing: it doesn't matter what kind of capacitor (or resistor) you're using, as long as the electrical value (e.g., .022, .01, .1, etc.) is the same, everything will still "sound" the same. But I no longer believe this to be true.
Anyway, here's another shot of the inside in the midst of my last (and, for now, final) revision during the component population process, and before I had finished everything I would ultimately do to the circuit:
(http://i244.photobucket.com/albums/gg29/cactuskeeb/2010-11-04195252.jpg)
http://yourlisten.com/channel/content/69394/Dirt
And
http://yourlisten.com/channel/content/69391/Swept_Away
Sorry, I don't know enough about mastering to make these sound even halfway listenable on laptop speakers -- perhaps other speakers as well. I used headphones to monitor the mix. The difference between my headphones and laptop speakers in terms of detail is frustrating, to say the least. Although, it's spurring me to learn how those famous sound engineers are able to make their final product sound good on every kind of sound system.
SETUP:
- Guitar set to low volume
- "Normal" channel on Fender amp (Mid: 10; Vol: 4; Treble: 7; Bass: 4)
- Effects: one TS9 w/ full level, 12 o'clock drive --> Ross comp
- One AKG 414 mic on amp
- Shure SM58 mic for vocal (*please excuse the pitch problems; I'm rather new at this whole singing thing!*)
---> 2 channel mic preamp --> Audacity.
Some musings:
V1 seems to be extremely microphonic no matter what tube I put in there. The slot seems to be very loose, so perhaps that is the problem. I'll try putting in a new tube socket... Also, I blew out a power tube minutes after recording the above sound byte. I had set the bias (way too high) at about 31ma per tube, just to see what would happen :P. I'll record some more of just the amp and open it up a little bit, tomorrow, at around noon (when my neighbors won't care).
(http://i244.photobucket.com/albums/gg29/cactuskeeb/2010-11-07005647.jpg)
Quote from: cactuskeeb on November 05, 2010, 02:31:27 PM
....... And I can tell you, with 100 percent certainty, that every little change makes a difference in the sound. If you change the type of cap, you can hear the difference. There are so many dr. know-it-alls on the interwebs who like to sound off on every forum thread dealing with the differences between paper in oil, polypropylene, etc. These guys always say the same thing: it doesn't matter what kind of capacitor (or resistor) you're using, as long as the electrical value (e.g., .022, .01, .1, etc.) is the same, everything will still "sound" the same. But I no longer believe this to be true.
I agree infinity %. The type of cap has just as much to do with it as the value itself. I have tried just about everything out there as well and it makes a BIG difference. It all boils back down to player preference. Enough of my "dr. know-it-alls " spill! :D
I do have a couple questions keeb. I may be crazy but is there no treble cap in channel 1's tone stack? Since you ditched the 2nd input on both channels did you divide the input resistors value in half or go with some other value? I have the same value that Boogie uses on their input on channel 1 of my amp which slams the 1st gain stage a lot harder than stock Fender. Because of that I have to be carefull about volume setting or I can get microphonic as well. You may be hitting V1 to hard. I know this is a basic question but did you ditch the aluminum cans as well? Sometimes the tube covers can induce microphonics. I notice no silver mica's as well. I've been thinking about swapping all mine out for ceramics as well. I really love the tone you're getting. Everything sounds great. 8)
There is a treble cap in channel one; it's a 500pf/630vdc polystyrene I took it out, today, because the temperature inside the amp proved too much for anything polystyrene, which does not maintain it's value in high temp situations, and the frequencies were all over the place. I think I'm explaining that right. Anyway, now it's a 500pf ceramic.
I guess you could say I divided the input resistors in half, because now there's only one 68K feeding the input wire.
I fixed the microphonic mess by replacing the tube socket in V1, which was the most fucking annoying thing I've done in a while, because the individual sockets kept closing up with solder (at the bottom, where the preamp tube pins go in) every time I would solder a wire to the pins on the reverse side.
Today I realized that I didn't blow a tube, my rectifier was just bad. Now I wish I hadn't thrown away that RCA 6v6gt/g. That's, like, 80 dollars I just threw away with the garbage.
Also today, I changed the phase inverter cap from a .001 to a .02, which I didn't like (too much bass), and then to a .01, which I really like but it still seems to have just a tad too much bass. Sounds great when I'm sitting right in front of it but it's hard to get rid of that all-encompassing, low-frequency boominess when recording.
I don't know, today is just one of those days wherein I got tired of all this shit and started asking myself, what the hell am I doing? And, 'Why am I even doing all this shit? Shouldn't I be doing something else I can actually manage to do well?'
EDIT: Also, today I learned that if you have an actual vintage Fender and not a reissue, you simply MUST remove the bright cap on the vibrato channel. It makes that channel inexplicably better sounding. I remember removing this on my reissue years ago and it made the amp sound anemic. Not so, this time. Not sure why this is the case.
Just learned my rectifier wasn't bad...
I finally realized I forgot to solder the heater wires going from one power tube to the other. That's why one power tube was losing power, along with all the preamp tubes (I hadn't noticed this last fact before, because I had the tube covers on). Moreover, when I went to fix this (the first time) I accidentally just (re)soldered the functioning heater wires, instead of the ones that actually needed it. Finally, I realized my mistake and fixed the problem. Just goes to show you: if something is wrong with your amp (that you built or modified), the first thing to do is check the solder joints. And certainly not do what I did first, which was to throw away a perfectly good power tube from a matched set.
Wasn't happy with the over-the-top trebly sound of the amp and was really tired of the boomy, pressure on your eardrum, bass. I decided to put 1w carbon comps in all the plate load positions (these are the upside-down "V" spots on the circuit board, which in the deluxe and DR are composed of two 100k resistors). I also changed the. 01, at the phase inverter input cap position, back to the original .001
Also, rebiased the tubes from the mid-twenties, down to 18.6 and 17.8ma, respectively -- closer to the matching current of 18ma.
Drastic change in tone. The amp is now so quiet and the tone is settled in and musical. Audio to follow, soon.