How To Build A Tube Amp, or Burn down A house.. Phase 1 the Research.

Tuckstir · 2019-02-14T07:24:49+00:00

This Little post is for Me to collect my thoughts, get advise and basically go out of my comfort zone by a large degree and try something different, and hop...

How To Build A Tube Amp, or Burn down A house.. Phase 1 the Research.

Tuckstir

OK... So after having some discussions, pondering and deep thought, and some YouTube sampling, I have Narrowed the choice down..so we doing an 7 valve amp....... an have managed to source the most of elusive items, the transformers, and boy do i now know more about transformers than i ever thought id ever need to know.

but before I commit to anything I'm busy making a list of all components, pricing and links to source. and looking at the incomplete pricing... i have to ask why am i doing this again. its not cheap, and i could get a very capable amp for the cost...

thanks Yeti for those links, Uncle Doug's YouTube channel is a wealth of info, just waiting on a book order i have for designing valve amps, for some light reading.

so with the knowing that i can get the correct spec transformers this is going to be a complete scratch built project which opens up some possibilities, do i go stack or combo,
stack gives me the ability to really show off the valves.. combo means less hassle transporting storing etc.
as modulator correctly stated so much routes, choices and info, suppose one just has to look,

Yeti

Sounds like you are making some progress, do you have a circuit diagram for us to check out?
Out of interest, what transformers are you getting and where are you getting them?

Regarding price... no, this certainly isn't a cheap way of getting an amp. Some of these components are very specialised and correspondingly expensive. For me it was far more about having a project to work on... and the fact that it's easier (for me) to get project expenses past my wife than purchases. ?
Although, having a completed build that sounds great is a fantastic feeling.

Tuckstir

Yeti Chosen the Princeton AA1164 or alternatively Hoffman Princeton
as for the transformers..all acquired from TRXE
Power transformer = 290XEX ( Fender No 125P1B )
Output Transformer = 1750E ( Fender No 125A10B )
Choke Transformer = 1750A ( Fender No 125A20B )

Yeti For me it was far more about having a project to work on

agreed, I need to have something creative to keep me busy..

Yeti

Very nice!
The main signal path is very similar circuit to mine except that mine doesn't have the third preamp stage and has a long tail inverter instead.
That power tube bias tremolo looks really cool too. Are you planning to build the reverb and tremolo?

If there is one mod I'd definitely recommend it's the master volume. Push/Pull 6v6s are plenty loud and you'll battle to get anything other than clean tones at home volume without one. I went with a Post Phase Inverter MV for mine because of the inverter but with the cathodyne phase inverter I think you can get away with the simpler pre-phase inverter. I'm sure that Rob Rob has plenty to say on the subject.

Tuckstir

YEAH, I want it all lol.. Reverb and Trem I am definitely going to do.. Its one of the many things that attracted me to the Princeton

Thanks for the heads up on the master, was wondering where/what to look for,
Quick question, I was originally going to go for something like a 1/4 power switch or 10% power-switch for bedroom playing, is the Master volume better?

Yeti

Awesome, looking forward to watching this build. Out of interest, where are planning to get your reverb tank?

So I put in the master volume And a switchable attenuator.

Attenuator has 3 levels, -3, -6 and -10. I didn't use his exact design but it's the same idea... And honestly I'm underwhelmed, even -10 is a surprisingly small reduction and I never use the other two.

Master volume on the other hand gives you a massive range and I seldom turn it up above half way, even at the garage days jams. Almost all of the clips I've posted on the group have the master set to less than 20% with kids sleeping in the next room.

That said, the 10% attenuator is an easy mod and does give an extra option if you want to drive those output tubes a little harder. Just remember that those 25W resistors need a heat sink (chassis works well), I completely missed that at first.

Tuckstir

Yeti Awesome, looking forward to watching this build. Out of interest, where are planning to get your reverb tank?

from Tonetube.co.za
as well as all the Valves and Valve sockets.

and my speaker from Musicmadness

That is so far what I've sourced..

also going to need to do the Pedal for it, which should be fairly simple from what i understand, basically just 2 switches.

Yeti

While I was working on my amp last night I remembered this excellent article on grounding and thought you might be interested. Unfortunately I don't have a link for it and don't even know where it is from because I'd love to read the rest of the book. I followed it's advice and used a star grounding scheme and I'm pretty sure that it is a major reason that my amp is nice and quiet... or at least was before my mod... holding thumbs it remains that way.

https://www.dropbox.com/s/0jee3ba0nbwinlh/Grounding.pdf?dl=0

Yeti

Yeti Unfortunately I don't have a link for it and don't even know where it is from because I'd love to read the rest of the book.

I’ve found it! Turns out it’s one of the sites I linked to in an earlier post (although that isn’t where I got it). Trying to get hold of the book but it doesn’t seem to be available as an ebook.
http://www.valvewizard.co.uk/Book1.html

Tuckstir

Thanks
will definitely give it a read.

since we are sharing, here are a few i have collected.
Amps

Tuckstir

So today my books arrived..

so the one is as I predicted, just a book filled with marshall amp schematics..
the other.. Build a tube amp... I thought was HOW to Build a tube amp.. so another book filled with schematics.. :facepalm

Yeti

So yeah... shielded wire (big jump in this thread but it makes sense in the context of mine ?). Useful for longer runs and early stages that are going to be heavily amplified. Your google foo may be better than mine but this is the only place I could find it. https://raru.co.za/musical-instruments/6749035-allparts-7-5m-single-conductor-shielded-wire-silver
Long lead time though.

Tuckstir

Yeti
thanks will definetly keep that in mind..
pity its 22ga.. My Bom Calls For 18ga and 20ga so will try my hand at google foo

RobbieZ

@Tuckstir Drop me a email. brj217@gmail.com. I might have something for you that will interest you.

Tuckstir

RobbieZ

Thanks RobbieZ , I have added the 2 books to the Google drive folder above, also have a few others if you want to browse

Yeti

Tuckstir Fair enough, let me know what you find.
I'm only planning on using this right at the very front end of the amp where there is almost no current so 22ga should be ample for my needs.

Tuckstir

Yeti

Thanks , will try to source one digital copy. but looks like a difficult Google-foo battle from what I Tried this morning

In the meantime I see Takelot has a copy for sale..which I might just get next month..

Yeti

Tuckstir Thanks for the link, I hadn't tried that.
My google foo failed spectacularly. Just pages and pages of SEO sites with no real content. I did find one on scribd but I cancelled my subscription a few months ago. Incidentally, I contacted the author directly and he confirmed that there isn't an official electronic version. He did send me this link however and told me that I'd find most of it there.
https://www.google.com/search?tbm=bks&q=merlin+blencowe

Johnny-B

Hi, Tedibear. I have a full 18W Plexi schematic and a copy of the book Electronics for Guitarists, which has a chapter on tube power amp design, if you are interested.

Tuckstir

Johnny-B
I wont say No..
I have A google drive that can be accessed if you want any Books and stuff.