DIY guitar amp recommendations

[rob_gould]

Evening all.

I recently had a lucky find and picked up a knackered old 4x12 guitar speaker cabinet which was about to be trashed. The cabinet looked like it was home made and had suffered a long life being kicked about on the road.

The good bit - inside were four celestion Vintage 30 speakers which look like they're in excellent condition. The 8 ohm model.

I've got the speakers out and ditched the cabinet.

I'd like to make a 1x12 or possibly 2x12 combo amp. I played a lot 20 years ago but I'm now *really* out of the loop of all things guitar.

I'd like it to be as versatile as possible - clean sounds wood be good but I'd like Stevie Ray type crunch and also proper distorted tones for more metal stuff.

I would like to be able to have crunchy / distorted tones while playing at home volumes - I will not be gigging or playing with a band.

Tubes would be fun.

I'm no opposed to a kit, but getting jus the PCB / turret board and souring parts myself is also ok

The woodwork bit I can handle - that's my day job.

1 - What are people's recommendations for a nice DIY amp project?

2 - Can anyone recommend a forum dedicated to guitar amp projects?

Cheers

 

[Matador]

AX84 is a classic for low wattage. Rob Robinette's "Blackvibe" is also excellent.

DIY Audio has an amp section in their forum.

 

[rob_gould]

AX84 is a classic for low wattage. Rob Robinette's "Blackvibe" is also excellent.

Thanks Matador, I'll look them up!

DIY Audio has an amp section in their forum.

Christ - eye test needed. I checked diyaudio on my phone before and somehow missed that. I will investigate now. Thanks.

 

[pucho812]

one of my favorite DIY amps was a supro inspired amp that used 6973 power tubes. it maxed out at about 18 watts or so. Used a single 10, but could easily do it with a single 12. It's a great bit of kit for the studio.

I got schematics and layouts If interested

 

[mhelin]

This kit is a 18W amplifier and comes with good quality components:
https://en.uraltone.com/kits/british-amp-kits/uraltone-18w.html

 

[CJ]

Princeton Reverb

They sell about everything so you don't have to do all the fab work which takes 90 percent of your time.

 

[groselicain]

I guess my answer depends on a couple of things. One, are you looking to DIY it or purchase a kit? Two, is output wattage a variable in decision making?

I built an amp running 6973s like Pucho mentioned and I love it. It's distinctive, though—I specifically built it to try and achieve Led Zeppelin I and Led Zeppelin II sounds. It can be clean, and it can be dirty. Can it do SRV? Not really. I put a 12" speaker in mine.

I've spent hours compiling documents and notes on building a Bluesbreaker. I'll admit, I'm coming from a certain point of view. I'm a guitar player by trade, and I have a fair number of amplifiers. It's worth noting that I have a handful of Fender amps of different eras, so I'm not really looking for that specific sound. That said, the Bluesbreaker has always seemed like the most well-rounded amp to me for building. The EQ section is flexible enough, the gain structure is fairly variable when you take jumpering channels into account, and it has tremolo if that's something you're interested in. Is it clean? Eh, I guess. Can it do dirty? Absolutely. Can it do SRV? I feel like it can with the right guitars.

If cleans are what you're after and you're not afraid to use pedals for a certain degree of dirt, just build a Princeton. The Bluesbreaker is a rock and roll machine, but the Princeton will always suffice.

As an aside, I always notice Vox amps don't get much love when people start talking about DIY amps. I have one of the Anniversary handwired AC-15s and that's my gigging amp. I've worked on it a couple of times and never saw anything too wild. What's with the fear?

 

[CJ]

One consideration might be your budget, ,NOS tubes make a big difference in sound and durability, so which. NOS tubes are cheapest? I just paid 250 for amperex bugle boy el84 pair, rca 6l6 black plates are even worse, 6v6gt are reasonable, 6973 are also reasonable, 7591 is another cool option. NOS is going up as ruskies are busy killing for reasons unknown.

 

[Heikki]

Princeton Reverb.

Couple years ago I shared gerber files for Princeton Reverb for any who wants to build one
https://groupdiy.com/threads/what-have-you-built-recently.75052/page-4#post-958131
Gerber files for princeton reverb
https://ghr.fi/guitaramps/trinceton/princetonreverbo350x110.zip
https://ghr.fi/guitaramps/trinceton/princeton.pdfhttps://ghr.fi/guitaramps/trinceton/layoutprinceton.pdf
https://ghr.fi/guitaramps/trinceton/trinceton.jpghttps://ghr.fi/guitaramps/trinceton/trinceton-sisu.jpg
Here you can find gerber files to 5E3 and 5F6A bassman that my brother made
https://ghr.fi/amps/5e3/https://ghr.fi/amps/5f6a/

 

[shabtek]

+1 for rob robinette s projects

I built a bassman micro that is fun and runs a 12_ _7 output tube. It sounds great and gets almost loud enough. Eventually it might get married to an optional class d output stage

 

[hodad]

I had a 5E3 clone that I bought years ago from a list member here--very cool and fun amp. Rob Robinette appears to have a mod for switchable negative feedback for the 5E3 that would likely make it a much more versatile amp. I foolishly sold the 5E3 to the son of a friend--poor decision on my part.

 

[pucho812]

I guess my answer depends on a couple of things. One, are you looking to DIY it or purchase a kit? Two, is output wattage a variable in decision making?

I built an amp running 6973s like Pucho mentioned and I love it. It's distinctive, though—I specifically built it to try and achieve Led Zeppelin I and Led Zeppelin II sounds. It can be clean, and it can be dirty. Can it do SRV? Not really. I put a 12" speaker in mine.

I've spent hours compiling documents and notes on building a Bluesbreaker. I'll admit, I'm coming from a certain point of view. I'm a guitar player by trade, and I have a fair number of amplifiers. It's worth noting that I have a handful of Fender amps of different eras, so I'm not really looking for that specific sound. That said, the Bluesbreaker has always seemed like the most well-rounded amp to me for building. The EQ section is flexible enough, the gain structure is fairly variable when you take jumpering channels into account, and it has tremolo if that's something you're interested in. Is it clean? Eh, I guess. Can it do dirty? Absolutely. Can it do SRV? I feel like it can with the right guitars.

If cleans are what you're after and you're not afraid to use pedals for a certain degree of dirt, just build a Princeton. The Bluesbreaker is a rock and roll machine, but the Princeton will always suffice.

As an aside, I always notice Vox amps don't get much love when people start talking about DIY amps. I have one of the Anniversary handwired AC-15s and that's my gigging amp. I've worked on it a couple of times and never saw anything too wild. What's with the fear?

Yes.... that's why i did an amp with 6973's too, Led zeppelin I and II. While it doesn't have a built in reverb and reverb tank, it does vibrato and sounds awesome.

 

[AnalogPackrat]

Depends on what "home volume" means in your situation. V30s are pretty efficient with 100dB/W SPL rating, so even a few watts will be fairly loud in a decent cab. I like 5W vibrochamps into bigger cabs with pedals for distortion/crunch. Depending on your loudness requirement 5W may be plenty with a single or pair of V30s.

I found a semi-beat Fender knockoff "empty" 2x12 closed back cab for $55 a few years ago. When I got it home and popped the back off I found a couple of surprises. First it had the original baffle poorly hacked out and replaced with a 1x10 + 1x12 baffle made from particle board. Second, there was still an Eminence 1x12 ceramic in it that had come out of an early DRRI. That speaker went into my '77 SFDR and I replaced the crappy particle board baffle with a 2x12 plywood one and made a 2-piece open back with black tolex for it. Put Eminence 16 ohm Red Fang and 16 ohm Wizard in it, both rated 103dB/W. It's pretty loud when driven by 5W. Also sounds good with a Mesa TA-15 on any setting.

A former work colleague amp builder lent me his ~1-2W 12AU7 P-P output micro-head during the lock down. I forget which circuit it was, but it had little clean headroom. Some variant of a Firefly, IIRC. Pretty cool dirty tone. Through my 2x12 it was about the perfect solo practice volume for me.

The tweed deluxe would be a great option if you can take the volume and could use pedals for heavier crunch.

 

[AnalogPackrat]

I had a 5E3 clone that I bought years ago from a list member here--very cool and fun amp. Rob Robinette appears to have a mod for switchable negative feedback for the 5E3 that would likely make it a much more versatile amp. I foolishly sold the 5E3 to the son of a friend--poor decision on my part.

I repurposed the 3-pos power polarity switch on my '77 DR as a negative feedback switch: Blackface, open (tweed), and ~ Brown deluxe. Really worthwhile mod, in my opinion. It becomes apparent exactly what negative feedback is doing when you can switch it live and feel the dynamic response and overall frequency response change.

 

[rob_gould]

Thanks to everyone who replied. I've spent a very enjoyable few days going through all the suggestions.

I'm probably going to get a kit from the Uraltone shop first, just for the sake of simplicity. Following that, I'd like to do something from the Rob Robinette site. The SLO Micro projects look really nice.

 

[midwayfair]

With a 1x12, my favorite 5W amp that I built is loud enough to stand up to drums played respectfully. A princeton or deluxe already in hearing damage range. An awful lot of really great sounding high gain sounds come from pedals. Not played at conversation levels but also not loud enough to really rattle the tubes.

This won't do what you want (it's designed to mimic a Tone King Imperial at low wattage, so it's pretty clean sounding), but it has an example of the feedback switch packrat's talking about. It does make a big difference.

https://www.dropbox.com/s/jeuuh3wc71h287h/Woodchipper.png

 

[AnalogPackrat]

Yes, that's the idea. If you use an on-off-on switch you can have no feedback and two different feedback settings.

 

[Whoops]

I would like to be able to have crunchy / distorted tones while playing at home volumes - I will not be gigging or playing with a band.

Maybe you will need to use guitar pedals for that (distortion at home volumes), which is no big deal as there are a lot of good sounding pedals.
Tube amps can have great Crunch but normally they need to be pretty loud.

1 - What are people's recommendations for a nice DIY amp project?

For home playing you should go for a Lower Wattage amplifier.
I highly recommend a Fender Deluxe Reverb type project, it's 22Watts, has a great tone and very good clean sounds.
Sound also good with pedals in front of it

2 - Can anyone recommend a forum dedicated to guitar amp projects?

Best forum for guitar amp projects by far is in my opinion is EL34World from hoffman amplifiers:
https://el34world.com/Forum/index.php
In Hoffamn website you will also find all the info to do a Turret board based Deluxe Reverb amp (Turret layout, Schematics, BOM), search for AB763 which is the board and circuit that the Deluxe Reverb uses:

https://el34world.com/schematics.htm#Hoffman_AB763_One_Channel_

You can also buy a Deluxe Reverb complete DIY KIT from Mojotone:

https://www.mojotone.com/amp-shop/amp-kits/blackface-amp-kits?page=1

 

[groselicain]

...Rob Robinette's "Blackvibe" is also excellent.

+1 for rob robinette s projects

I built a bassman micro that is fun and runs a 12_ _7 output tube. It sounds great and gets almost loud enough. Eventually it might get married to an optional class d output stage

I have to admit, even after being a TDPRI member for years I had never really looked into Rob's stuff. Man, that Bassman Micro looks incredible. Bought turret board supplies today to build one. Thanks for mentioning it @Matador and @shabtek!

 

[murrayatuptown]

2nd vote for EL34world.
Also like ampgarage site

Some of the same wise, helpful, experienced people frequent both (and others that elude my memory at the moment).

For some reason I enjoy searching for tube amp schematics from Japan & Taiwan, maybe because some really odd things appear when one goes further down the Google finds list and pick thru the non-English results.

If I need to I roll the dice with Google Translate.

I have found some really odd things I would never dream up on my own (like a 5687 cascode power amp (~ 1 W) in multiple configurations.