I have an old weber 5e3x2 chasis that the PT died on me and there are few parts from the original build (this was the first thing I built several years ago) that are really worth saving.
I'm pretty much looking at a complete new build on this one and just want some ideas. The chassis has space for 5 x 8 pin sockets (1 recto + 4 output tubes) and 3 x 9 pin preamps. The controls are just standard 5E3 Vol, Vol, Tone. but it would be easy enough to drill a few more holes if required.
I'm pretty open to any suggestions but I'm thinking I want something on the lower power side ie 2 6V6.
What to build in weber 5E3x2 chassis
Moderators: pompeiisneaks, Colossal
Re: What to build in weber 5E3x2 chassis
My first thought would be to build the 5F4 Super, a 5E5, or a 5E7 all of which I think would be great in a 2 x 12 format and all of which are nearly identical circuit and layout. You could even go with a JTM45, 5F6-A, or 5F8-A, which also share nearly identical circuit/layout. There are just so many options if you just want to drill out your existing chassis for the extra controls and not worry about trying to fit another. It looks like you have room for two more control pots, so you might have to choose between a variable Presence with fixed Mid, or v.v.
Re: What to build in weber 5E3x2 chassis
If you want to work with just 3 knobs, I suggest you have a look at this 2 knob tone stack: http://www.freewebs.com/balijukka/roybeanstack.htm
Although a bit counter-intuitive to use compared with the type to which we've grown accustomed, this one really does do it all. Additionally, it is lossless, which is a huge advantage. It means your 2 hole preamp configuration is more than adequate. I'm assuming you need the third noval tube for the PI. If you use a concertina, you can get another half triode gain stage to compensate for the zero gain of the concertina and you might think about doing that with a 12AU7.
That leaves just about anything you want for the back end PA. Here's a wild hair idea that will give you a ton of clean headroom. Use 4 6SN7's, cathode biased. This is 8 tridoes and should give you about 20W. 8 triode sections (4 tubes) should work well with your typical 18W 8K primary. Triodes will tolerate a wide range for the OT primary. That 2x5E3, though, is probably ~3.3K and I'd say it's too low.
Here's what I did with a pair of 6SN7's http://home.comcast.net/~psymonds/6SN7amp.htm If I had known about that Roy Bean tone stack at the time, I would have used it.
Well, maybe this doesn't float your boat, but it sure is off the beaten path.
Although a bit counter-intuitive to use compared with the type to which we've grown accustomed, this one really does do it all. Additionally, it is lossless, which is a huge advantage. It means your 2 hole preamp configuration is more than adequate. I'm assuming you need the third noval tube for the PI. If you use a concertina, you can get another half triode gain stage to compensate for the zero gain of the concertina and you might think about doing that with a 12AU7.
That leaves just about anything you want for the back end PA. Here's a wild hair idea that will give you a ton of clean headroom. Use 4 6SN7's, cathode biased. This is 8 tridoes and should give you about 20W. 8 triode sections (4 tubes) should work well with your typical 18W 8K primary. Triodes will tolerate a wide range for the OT primary. That 2x5E3, though, is probably ~3.3K and I'd say it's too low.
Here's what I did with a pair of 6SN7's http://home.comcast.net/~psymonds/6SN7amp.htm If I had known about that Roy Bean tone stack at the time, I would have used it.
Well, maybe this doesn't float your boat, but it sure is off the beaten path.
Re: What to build in weber 5E3x2 chassis
Cool thanks guys.
I was half looking at all the fender tweed stuff and think I could do something along those lines but I really like the idea of something a little different, as I have played with this style of build a fair bit now.
Both the Roy Been tone stack and the 6SN7 power section are things I would love to look into. I have mostly only seen the 6Sn7 as a preamp tube though but the more I dig this looks like a very cool option. Do you have any other examples of using the 6SN7 in the front end
http://www.ax84.com/4-4-0.html this has peaked my interest
I was half looking at all the fender tweed stuff and think I could do something along those lines but I really like the idea of something a little different, as I have played with this style of build a fair bit now.
Both the Roy Been tone stack and the 6SN7 power section are things I would love to look into. I have mostly only seen the 6Sn7 as a preamp tube though but the more I dig this looks like a very cool option. Do you have any other examples of using the 6SN7 in the front end
http://www.ax84.com/4-4-0.html this has peaked my interest
Re: What to build in weber 5E3x2 chassis
As I understand it, the 6SN7 works well as a power triode for two reasons. One is the large plate area, and the other is its maximum plate voltage is 450v. I believe these two things are inter-related and the reasons why this is a better choice than a 12AU7, it's noval equivalent.
As a pre-amp tube, it is essentially the same as a 12AU7. Aside from its ability to run at a higher voltage, I'm not sure you get much other benefit.
If you are simply enamored with the idea of an all octal build, then drill out those noval sockets with a step bit and put in octal sockets. Then you can use 6SL7's. Be forewarned, that I've been told new production 6SL7 tubes can be noisy and microphonic. I have had good success sourcing "almost new" USA made from eBay. With patience, look for multiples of 2 or more to keep shipping cost under control, and don't pay more than $10/tube including shipping cost. 6SN7 tubes go a bit cheaper on eBay. There is also the very inexpensive 6AQ7, which is half of a 6SL7 with a couple of diodes in the bottle that aren't particularly useful. Really, though, there's not much to be gained from going all octal.
One note on my the 6SN7 amp I built is that I tried two different PI's. Instinct told me the concertina was the way to go and that's what I tried last. I tried a floating paraphase first (a la Ampeg B-15) and it was driving the finals much too hard. I figured I'd get the same from a standard LTP.
With the concertina and 3 noval sockets, you get input (try two sections in parallel or use each section for 2 channel input) > tone stack > tone stack recovery > concertina.
C'mon, go for it! If you don't like it, you can always put something else in there. You'll learn something new.
As a pre-amp tube, it is essentially the same as a 12AU7. Aside from its ability to run at a higher voltage, I'm not sure you get much other benefit.
If you are simply enamored with the idea of an all octal build, then drill out those noval sockets with a step bit and put in octal sockets. Then you can use 6SL7's. Be forewarned, that I've been told new production 6SL7 tubes can be noisy and microphonic. I have had good success sourcing "almost new" USA made from eBay. With patience, look for multiples of 2 or more to keep shipping cost under control, and don't pay more than $10/tube including shipping cost. 6SN7 tubes go a bit cheaper on eBay. There is also the very inexpensive 6AQ7, which is half of a 6SL7 with a couple of diodes in the bottle that aren't particularly useful. Really, though, there's not much to be gained from going all octal.
One note on my the 6SN7 amp I built is that I tried two different PI's. Instinct told me the concertina was the way to go and that's what I tried last. I tried a floating paraphase first (a la Ampeg B-15) and it was driving the finals much too hard. I figured I'd get the same from a standard LTP.
With the concertina and 3 noval sockets, you get input (try two sections in parallel or use each section for 2 channel input) > tone stack > tone stack recovery > concertina.
C'mon, go for it! If you don't like it, you can always put something else in there. You'll learn something new.
Re: What to build in weber 5E3x2 chassis
I think if I do something a bit different with the power section, I might do something more traditional with the preamp.
That being said, I have also thought about doing something with an EF86, similar to the Route 66 schematic that is floating around, not sure how well this will work though. (I thought I better add that I only want to do this to try something different and learn something new, rather than clone a DR Z amp)
Learning is fun
I wish I had of been this interested at learning new stuff when I was actually in school
That being said, I have also thought about doing something with an EF86, similar to the Route 66 schematic that is floating around, not sure how well this will work though. (I thought I better add that I only want to do this to try something different and learn something new, rather than clone a DR Z amp)
Learning is fun
I wish I had of been this interested at learning new stuff when I was actually in school
Re: What to build in weber 5E3x2 chassis
I've read the EF86 can be microphonic and you might go through several until you get one you like. I had some luck with glass 6SJ7 pentodes, but these are octal. The pentode input is "rich" but think about whether it's worth the trouble. With pentode input, I'd go for a traditional tone stack.
At the risk of sounding pushy (not meaning to be), I'd try the RB stack over the triode power section. IMO, power sections are a dime a dozen -- nothing all that special about them. The stack is where you shape tone. I believe you won't be disappointed with the RB. After I built it, I wondered if I'd ever build another kind. Everything is "in there". You just have to twiddle the knobs to find it. The pots are interactive.
At the risk of sounding pushy (not meaning to be), I'd try the RB stack over the triode power section. IMO, power sections are a dime a dozen -- nothing all that special about them. The stack is where you shape tone. I believe you won't be disappointed with the RB. After I built it, I wondered if I'd ever build another kind. Everything is "in there". You just have to twiddle the knobs to find it. The pots are interactive.
Re: What to build in weber 5E3x2 chassis
your not being pushy at all, and what you say is pretty true that the tone stack is where a lot of the tone shaping goes on.
I really do appreciate any advice given.
I really do appreciate any advice given.