Finally started building

[rlyach]

I spent the whole day on the cabinet / box. I wanted to make it look a little more standard, so I used tolex, corners, and feet. I also got a leather handle. Now I can start on the electronics... Yeah. I like the way the cabinet turned out, but tolex glue is really messy to work with. Also, if anyone is interested in using tolex, I did have to deepen the rabbet to make room for the tolex.

 

[DoS]

I found when cutting wire for on the front plate it is cleaner with a touch shorter than the measurement except for the coaxial and shielded twisted pair. Wires that follow along down to the output transformer are better to be a bit longer than the measurement and the ones that go to the back panel were a good length. I found stripping a hair less for the 6mm stripping instructions was cleaner too. However for the power transformer I recommend concentrating on wire lengths that allow you to make as much room around the 10w resistor as you can (because its hot, and nothing should touch it). In fact I ended up mounting the capacitor that connects to 4U and 5U off to the side (towards center of the plate, not over the transforme). The big reason is when you close the amplifier up, its easy to smash that capacitor into the 10w resister if the wires are not where you want them to be perfectly (they have to be long enough to have a little bit of slack so they can move around some).

I say this all because you are making yours so neat a tidy that I assume the wiring will be so as well.

Overall the instructions are very good. They are the perfect type of instructions for any DIY project. Showing people how with pictures and what not is so much better than just a schematic or something like that. I commend Bottlehead for doing such an awesome job at this aspect. I've experienced nightmarish DIY projects before that take 3 pdfs and one website to work on... The only wish I have is that similar looking tiny resistors were labeled.

Words of advice *DO NOT SOLDER ANY THING THAT IT SPECIFICALLY DOES NOT SAY TO SOLDER, EVEN WHEN THE NEXT FEW PAGES DON'T TELL YOU TO DO SO! I checked on this wondering if anything was just forgotten on accident but, some things you don't solder on until like 20 pages later. It is, however, complete in that way. It never misses a beat of when to solder and when to just attach.

I'm sure you'll have a working amplifier shortly.

 

[rlyach]

I finally finished the Tode. Everything worked first try. My voltages were a few volts lower on all readings but otherwise everything checked out. I played it with my Martin acoustical guitar that has a pickup and it sounded good. I really like the controls. The variable feedback has much more latitude that any guitar amp I have used to date. I also liked the output break as well. The mid scoup was interesting, although with my acoustical, the M******* tone was too dark. The only thing that is not quite right is that there needs to be better shielding somewhere. Like DoS I am also getting radio stations quite clearly. My house ground is good so I don't think that has much to do with it. I even get it with no guitar plugged in, although it is diminished. I will have to poke around and see what I can do. It is a little distracting. I spent a lot of time on the lead dress and tried to make it as clean as possible. The hum is not too bad, although I have worked on quieter amps. All-in-all a fun project.

 

[Doc B]

If you are picking up hum with no cable plugged in you have a unique problem. Every one we have built has been dead quiet. I also don't hear any extraneous noise unless a cable is plugged in the amp. Any hum I have heard on any of the Todes I have used has come from the guitar or the cable. The one exception is that the tubes will pick up a nearby cell phone searching for a cell. The 10 meg input impedance may create a more sensitive input than some folks have used before, and amplify the hum pickup of a given guitar more than other amps. But it's not the amp, or at least it shouldn't be.

 

[DoS]

My eF and eM settings are significantly quieter than flat. I haven't found that the feedback is as versatile as I thought it would be. The problem is that with my guitar's volume high it'll overdrive the pre on E6, maybe A. But to get feedback on the crunch I have to turn it up into this range. The crunch is much stronger in the bass notes. Maybe this has something to do with my guitar, but I'm not convinced for sure. Perhaps putting in a 250k tone control will fix this a little bit. (volume is 250k, tone is 20k atm).

Mine is dead quiet with nothing plugged in. To combat RF I put a ferrite bead on my guitar cord. It works. Luckily it didn't utterly destroy the sound like it does with audiophile powercords and RCA's.

The funny thing about the capacitor choices for the input and scoops, is that they are almost the same size as I would of thought appropriate for a to ground capacitor at the input to eliminate RF.

 

[Paul Birkeland]

You could try popping a 47pF cap across the 10M resistor on the EF86.  This never presented itself as an issue on our end, but the mod is easy enough to try.

-PB

 

[Doc B]

My eF and eM settings are significantly quieter than flat. I haven't found that the feedback is as versatile as I thought it would be. The problem is that with my guitar's volume high it'll overdrive the pre on E6, maybe A. But to get feedback on the crunch I have to turn it up into this range. The crunch is much stronger in the bass notes. Maybe this has something to do with my guitar, but I'm not convinced for sure. Perhaps putting in a 250k tone control will fix this a little bit. (volume is 250k, tone is 20k atm).

Yes a 15dB scoop will make the midband more quiet. It's a subtractive control, like most amp tone controls.

The amp's response is pretty flat on the flat setting, maybe a variation of +1 dB or so through the midband. So if the lower notes are distorting before the upper notes there is more energy in those notes coming into the amp. I would suggest adjusting your pickups - get the treble end closer to the strings, the bass end farther away. And try a few other guitars. Guitar setup is a whole nother complex subject, and tweaking it as well as amp setup seems to help get the best performance out of the guitar/amp system as a whole.

Bear in mind that just like audio any standards for output levels were thrown out by many manufacturers years ago. The Tode has more range of overdrive control than most two stage guitar amps because of the variable feedback. But there are limits to what can be compensated for in the amp. In some cases one might need more gain from a boost pedal ahead of the amp, for example if you are trying to get a lot of distortion from a lower output single coil pickup. My jazz box with a Johnny Smith style mini humbucker set well away from the strings can distort with some work, so it's right on the edge, about as far as the typical jazz player ever wants to go. My Strat with sort of low/medium output single coils will just get into some snarly bite with the feedback cranked down. A little more would be nice, but the vintage sounding pickups would sound different if wound for more output. My 335 with classic 57 humbuckers will go into really fat bluesy distortion easily. To get that metal full on distortion with unending sustain a boost pedal ahead of the amp works best.

It's interesting to me that a lot of the comments about the Tode's sound are by folks using acoustic electrics or homebrew experimenter setups or ukeleles or whatnot. I would like also to hear from someone who uses a LP or a 335 or Strat or Tele - something a little more typical. And also from folks who may have access to several different guitars. One thing I will say is that selling a guitar amp creates a nice excuse to get a new axe now and then...

 

[rlyach]

I worked on trying to find the source of the hum. I moved the heater wires between the tubes away from all other tube pins and that made a difference. Secondly, I moved the speaker wire closer to the back plate when the system was together and it improved it a little more. The big improvement happened by accident. I moved the power cord and the hum disappeared. The radio signals are also gone if I place the power cord along grounded metal conduit. I think I will try a shielded power cord. I was amazed at this discovery. I am not sure why the power cord makes such a difference. I went over the entire circuit and checked all solder connections and everything is fine. The only thing that has a major effect is the power cord.

Update: I tried the power cord I built for the Stereomour and if it is looped once the hum is gone. I think a shielded, twisted power cord is in order.

 

[Grainger49]

Randy,

I suppose you have thought of this, is your AC circuit properly grounded?

 

[rlyach]

Yes, the grounds are correct but I suspect they used 50' runs of 14 gauge wire. I plugged the amp into an outlet on the same wall where the electric service enters the house and the amp was dead quiet. In our bedroom, about 40' away and on the second story, I can still hear a small amount of hum. The internal routing changes I made eliminated the radio station issue, even with the guitar chord plugged in. If the shielded power cord helps that is one way to overcome a resistive ground in the house wiring. Now I can start really playing the amp. I have a shecter dual humbucker guitar that I will try next.

 

[Doc B]

Schecter's gonna Rock. 

 

[rlyach]

Here is the Schecter... Also, I think the amp is quieting down the more I play it. Does the EF86 have a noticeable break-in period, or is it just my imagination?

 

[Grainger49]

Randy,

Then check and see that the terminations where you want to use the Tode are tight and under the screw.  Of course, kill the breaker first, check for voltage.  I am not posting that for you, you probably know this, but for anyone reading this thread afterward.  Tightening up the grounds and neutrals at the service panel might help too.

 

[rlyach]

Grainger,

Good call on the screw torque at the panel. Several of my commons and grounds were loose and all needed an additional tightening. Our house was built in '94 so it has been a while since they were checked. A friend of mine lost several appliances when her common became loose and a large voltage developed on the common circuit in her kitchen. It is always a good idea to have the panel serviced once in a while.

Randy

 

[Doc B]

Yeah, typically the cathodes of the EF86s need to form with some burn in time before they get to their lowest noise level.

 

[rlyach]

Success!!! I removed all the hum and static from the amp. I had the amp running without the box and probed around for sensitive areas. Using an antenna wire I discovered that the front chassis plate near the input was the source. If I touched the wire to the chassis plate near the input the static signal was much much worse. Further, touching the antenna wire to the shield terminal on the input was like listening to a radio at loud volumes. It was one station in particular. Looking at the mid-scoop circuit I found a loop antenna from one of the small capacitors. I removed that and wired it to the switch instead of the input and 90% of the noise went away. Secondly, I added an additional ground wire from the shield on the input to terminal 18 to make sure the chassis near the input was well grounded, and voila.... the noise was gone. I know my house ground is not that great but this makes me feel much better.

 

[rlyach]

My son finally brought his Schecter over and wow... I did not expect what I heard out of the Tode. It really has a nice growl, especially when I used all the pickups. I find that I really like the EFish setting for the Schecter. The flat is nice too but it really sounds nice on EFish. I will now pack up the Tode and send it to Nashville to my other son (who is the assistant audio engineer at myrmidon studios and really plays). He is anxious to hear it and try different recording techniques with it. I will keep you updated on his evaluation. Also, the bands that record at the studio use a lot of the studio equipment including the amps that we have built together. It is likely that someone my want to use the Tode because of its unique sound. Plus it just looks good, especially covered in black tolex