Getting started building tube preamps

[aaronlowther1993]

Hi guys, first post here, so sorry if I'm out of line. I've been building pedals and guitars for a while now. I'd like to be able to build amps too. To start with, I'd like to build a couple of tube preamps, to kind of learn the ropes. I'd like to do one like a 70's Marshall and one like a Blackface Fender. Could you guys maybe help me out with some direction to find diagrams or instructions? I'm the kind of guy that typically do something once I've seen someone do it, or had some decent instructions.

Any help you can toss me us much appreciated. Thanks in advance.

 

[JeffBlue]

Aaron, I wish I could help. I recently built a Mojotone Studio One amp kit and it still doesn't work correctly. I want to build a triple channel tube preamp with blackface clean, tweed and Marshall tones. Alas, if I cannot even get a kit to work, I'm afraid to even try something scratch built. My specialty is building guitars. Good luck.

 

[mefgames]

Got me curious, googled 3 channel tube preamp. This was amongst the sites returned.

https://www.musikding.de/Anvil-Tube-Preamp-Kit

There a few projects here as well

http://www.londonpower.com/tube-preamp-kits

 

[richa]

Google rob robinettes amp stuff. Active on this forum as robrob.

 

[robrob]

Aaron, I recommend you start with a basic tube amp kit like a Fender 5F1 Champ or 5E3 Deluxe. There are hundreds of people on this forum that can help you get it built right and up and running. Building an obscure preamp could be a challenge because troubleshooting it will be much more difficult since few will be familiar with the circuit.

 

[aaronlowther1993]

Aaron, I recommend you start with a basic tube amp kit like a Fender 5F1 Champ or 5E3 Deluxe. There are hundreds of people on this forum that can help you get it built right and up and running. Building an obscure preamp could be a challenge because troubleshooting it will be much more difficult since few will be familiar with the circuit.

Would you recommend a good place to purchase a kit from? I know I'm still trying to get my feet wet, so I want to start with something simple. I'd love to build something that typifies the classic Fender Clean sound. Someday, far down the road I'm sure, I'd like to experiment with Hybrid Amps. The new Milkman Half & Half 300 is what prompted me to go down the whole rabbit hole with amps, though I'm sure it'll be a few years before that idea can ever be acted on.

 

[richa]

Alot folks here have done the boothill 5e3. That might fit the bill.

 

[mitchfinck]

Pick up an old tube manual/text book.
A lot of them had instructions on how to build simple preamp and power amp circuits and also explain a lot of tube theory.
Many an older amp is taken almost directly from these.

 

[aaronlowther1993]

Pick up an old tube manual/text book.
A lot of them had instructions on how to build simple preamp and power amp circuits and also explain a lot of tube theory.
Many an older amp is taken almost directly from these.

Any recommendations on what book/books to buy?

 

[mitchfinck]

I'll check which one I have when I get back to the house. It's just an old textbook of my dad's (tubes weren't quite obsolete when he went through school)... It's old as ****.
Maybe one of the other guys knows a more modern/accessible text?

 

[steve v]

I second the idea of building a 5f1. It's a pretty simple layout and will be easy to troubleshoot. I also see some value in having an amp that will be easy (and not too expensive) to mess around with.

I built an amp from a kit that was somewhat more complicated and I can honestly say that I hardly learned anything from the process. I was able to follow the instructions, and it worked, but I did not gain any great insights into the workings of the amp. I have the often recommended Dave Hunter Guitar Amp Handbook which has some good basic info.

 

[aaronlowther1993]

I second the idea of building a 5f1. It's a pretty simple layout and will be easy to troubleshoot. I also see some value in having an amp that will be easy (and not too expensive) to mess around with.

I built an amp from a kit that was somewhat more complicated and I can honestly say that I hardly learned anything from the process. I was able to follow the instructions, and it worked, but I did not gain any great insights into the workings of the amp. I have the often recommended Dave Hunter Guitar Amp Handbook which has some good basic info.

I have just never been a fan of the Champ. I know in the right hands it sounds amazing, but not in mine. Would the 5E3 be too complicated to lend itself to learning? It doesn't look (says the total novice) that much more complex.

 

[robrob]

Since you are a pedal builder a 5E3 Deluxe is doable and it's a real amp that you can gig with. I'm a fan of BootHillAmps.com and Mojotone.com's kits. They both sell a 5E3 kit.

Start here for an intro into how tube amps work:
https://robrobinette.com/How_Amps_Work.htm

 

[aaronlowther1993]

I've been looking over your website all day. It's got me pretty excited to give this a try. Are there any mods you normally suggest for the 5E3 circuit?

 

[richa]

Talkin' mods already.

 

[Commodore 64]

http://members.iinet.net.au/~jamesrr/UniversalPCB/Circuits/Universal PCB - Base Circuit layouts.pdf

http://www.wattkins.com/projects/universal-pcb

There's also universal chassis, too for the PCBS.

If you start with a UPCB, then you can try all kinds of preamps with the building blocks above. There's schematics AND layouts available for dozens of amp topologies at ppwatt.com

That's how I started building amps, at least. So I'm biased.

 

[robrob]

Are there any mods you normally suggest for the 5E3 circuit?

The 3-Way NFB Switch and the Lead Channel Mod are two that I recommend for almost all 5E3 builds. The negative feedback switch in the off position is the unchanged 5E3 circuit but the other two switch positions make the 5E3 a much more versatile amps and less of a one trick pony.

The lead channel mod turns the typically unused normal channel into something you can use. It cuts the excess bass so you can run boost and overdrive pedals and get a more modern, clean overdrive tone.

These are the only two mods I recommend being built into a new build because they don't complicate amp startup and troubleshooting. Just make sure the NFB switch is off on first startup.

P.S. I'm not a fan of PCB amps because they make repair and mods more difficult.

 

[aaronlowther1993]

The 3-Way NFB Switch and the Lead Channel Mod are two that I recommend for almost all 5E3 builds. The negative feedback switch in the off position is the unchanged 5E3 circuit but the other two switch positions make the 5E3 a much more versatile amps and less of a one trick pony.

The lead channel mod turns the typically unused normal channel into something you can use. It cuts the excess bass so you can run boost and overdrive pedals and get a more modern, clean overdrive tone.

These are the only two mods I recommend being built into a new build because they don't complicate amp startup and troubleshooting. Just make sure the NFB switch is off on first startup.

P.S. I'm not a fan of PCB amps because they make repair and mods more difficult.

To avoid abusing your kindness any further I'd like to ask two more things and thank all of you for the help. First off, is the 5e3 an amp that can get a good clean tone at a gigable volume? Second, if not, is there an amp build of similar difficulty that you'd recommend?

Thank you all so much for the advice. I cannot wait to get started.

 

[robrob]

You can gig with a 5E3 but in stock form but there's not a whole lot of clean headroom. It depends on the venue and your drummer. The NFB switch adds clean but does reduce max volume.

The Proluxe (Weber & BootHillAmps.com) is a fixed bias 6L6 version of the 5E3 and adds a lot of volume and clean headroom. It's only slightly more complex than a normal 5E3 and is a good first build.

 

[aaronlowther1993]

You can gig with a 5E3 but in stock form but there's not a whole lot of clean headroom. It depends on the venue and your drummer. The NFB switch adds clean but does reduce max volume.

The Proluxe (Weber & BootHillAmps.com) is a fixed bias 6L6 version of the 5E3 and adds a lot of volume and clean headroom. It's only slightly more complex than a normal 5E3 and is a good first build.

Damn, it doesn't seem that either of them carry the proluxe any longer. Any other suggestions?