• Welcome to the General Discussion forum for UAD users!

    Please note that this forum is user-run, although we're thrilled to have so much contribution from Drew, Will, and other UA folks!

    Feel free to discuss both UAD and non-UAD related subjects!

    1) Please do not post technical issues here. Please use our UAD Support Forums instead.

    2) Please do not post complaints here. Use the Unrest Forum instead. They have no place in the the General Discussion forum.

    Threads posted in the wrong forum will be moved, so if you don't see your thread here anymore, please look in the correct forum.

    Lastly, please be respectful.

Tube Amp Kit for Recording Rig - Help Me Choose a First Kit

scratch17

Venerated Member
After doing a lot of research I've decided to make some additions to my recording guitar rig. I won't be gigging ever again. There are lots of reasons but they are irrelevant to this discussion. So volume is not a factor. But I am downsizing, so space is an issue. Smaller is better.

My current selection of tube amps:

Mesa Boogie Rectifier Recording Preamplifier + 20/20 Stereo Power Amp. It is in perfect condition. I am keeping this one.

Ampeg AX-70. It is a combo with a 1 x 12 open back. The speaker is a Celestion G-70M Creamback. It has a tube preamp, an effects loop and reverb tank with a solid state amp. I got it for $75. It needs work. Basically just needs pots and jacks cleaned. I will service this one first.* After it is serviced, I will likely keep it. But I may sell it to downsize.

I bought a '68 Bandmaster a few years ago which needs even more work. Certainly needs pots and jacks cleaned. Probably needs some caps replaced and maybe tubes. But it powers up and plays. No excessive hum. It's just not clean at low volumes and scratchy as hell when I move a pot. I plan on pulling it from its cabinet (head, not combo) and servicing it myself after I service the Ampeg.* I got this at a garage sale for $225. It was built in February of '68. So it has SilverFace cosmetics. But it is actually a BlackFace inside. I got really lucky.

*Before everyone screams at me I know how to drain the capacitors so I can work on a tube amp without electrocuting myself in the process. I can safely service tube amps myself.

I might sell the Bandmaster after it's serviced. I really want a BlackFace amp with reverb. So if I sell the Bandmaster, I plan on buying a MojoTone kit. Either a Princeton Reverb or better still, a Deluxe Reverb.

The thing is, the Deluxe Reverb is a much more complicated build compared to the Princeton Reverb. It's not the difference in cost, which is trivial. Nor am I intimidated by the mechanical part of the build. I've built wood cabinets in my shop lots of times.

It's that I've never scratch built an amp before. I just think servicing an amp that already works is easier to do than scratch building a kit. The Deluxe Reverb has a whole lot of extra circuitry to figure out if I get it put together and there is an electrical issue. Which is likely from what I've read.

So I think these are my options:

A. Take small steps to get experience at scratch building. Some examples: Scratch build a Catalinbread Knight School Overdrive pedal as a starter project. Next I'll try the MojoTone Princeton Reverb. If I love it, I'll keep it and I'll be done. If not, I sell it and build the Deluxe Reverb.

B. Just go for the Deluxe Reverb kit.

C. Keep the Bandmaster. Build the MojoTone 6G15 Reverb kit. This won't be nearly as difficult a build as the Deluxe Reverb amp.

The MojoTone6G15 kit doesn't indicate how to interface it with an amp. I am assuming that it would go into an effects loop. So I'd need to add a MojoTone effects loop between the AB763 preamp and the Bandmaster's phase inverter.

Adding the loop also provides me with lots of options. For example, I can use the 4 cable method with the RectoPre to add two extra channels to the Bandmaster. I'd keep the Bandmaster's preamps for clean settings, maybe putting my overdrive pedals in front of it. Then I get two more channels from the RectoPre. I can imagine setting the RectoPre's clean channel with different gain levels to set up a crunch rhythm sound, or an edge of breakup tone, and the lead channel for higher gain leads. Very cool!

The downside of adding the loop is that I will be modifying a vintage tube amp. Not that I plan to sell it. Of course the effects loop mod is easily reversible.

Having written this diatribe out, made changes as thoughts occurred, etc., I am now leaning towards building the pedal first, then doing option C.

So what do you guys and gals think?
 

MaxTwang

Active Member
Mojotone's kits are a step up from other kits as their parts are sorted in plastic parts organizers with parts clearly labeled on the inside of the lid. Mojotone's support is also really good. Sourcing all the parts, chassis and transformers is a lot of work - Mojotone kits eliminate all the hassle and use really good components. Down side is sometimes Mojotone's schematics and/or layouts have errors. Also, the Princeton kit has a detailed manual while the Deluxe does not.

I've also built a Weber 5E5A, Brown Note D'Lite and a Brown Princeton (not a kit). The D'Lite (Dumble ODS clone) was the most complex yet it went smoothly.

An easier kit is the Tweed Deluxe which also has a detailed manual. I recently built Mojo's Studio One amp which is killer and I have their new Blonde Bassman kit arriving this week!

EL34World.com and AmpGarage.com are good resources.

Now your warnings: Keep one arm behind your back when working on a live amp so you don't send 400+ volts from one hand - through your heart - to the other hand. And use chop sticks to probe wires and components in a live amp - keep your hands out!!!!!

Most importantly - keep an eye on lead dress (wire routing) as slight deviations can cause oscillations that'll give you all kinds of strange noise and behaviors. If you're getting weirdness on power up use your chop sticks to tap on components, sockets and nudge wires.

KEEP YOUR HANDS AND METAL TOOLS OUT OF A LIVE AMP.


BTW have you ever soldered before? Amps aren't really that difficult when it comes to populating the board or mounting jacks and pots to the chassis. It's running all those wires from the board to the pots, jacks and switches that will take the most time - and is prolly why the Deluxe is more difficult as each wire is an opportunity for noise and oscillations.
 

djangodeadman

Active Member
I can’t comment on anything to do with building amps, but I do know about 6G15 reverb units. In my experience they should be placed before the amp.
 

scratch17

Venerated Member
Also, the Princeton kit has a detailed manual while the Deluxe [Reverb] does not.

An easier kit is the Tweed Deluxe which also has a detailed manual. I recently built Mojo's Studio One amp which is killer and I have their new Blonde Bassman kit arriving this week!

BTW have you ever soldered before? Amps aren't really that difficult when it comes to populating the board or mounting jacks and pots to the chassis. It's running all those wires from the board to the pots, jacks and switches that will take the most time - and is prolly why the Deluxe is more difficult as each wire is an opportunity for noise and oscillations.
Thanks, @MaxTwang. I appreciate the warnings. And I have spent a lot of time analyzing the circuit the MojoTone manual for the Princeton and Tweed Deluxe. I've also watched a ton of kit building videos.

I spent a lot of time as a kid soldering my electric train set. I had to be on my back, with the soldering iron above me on the underside of the train set surface. I still have a long scar on the side of my left thumb from carelessly picking up the iron. I learned my lesson there.

I haven't done any soldering since then, so I am really out of practice. I plan on using a breadboard with some components as a practice tool. I will be taking my time on this. And I've decided to start by building a few pedal kits.

I'd really like to attend one of MojoTone's amp building classes. I just can't afford that luxury right now. So I'm leaning toward the Tweed Deluxe kit and go from there.

One of the reasons that I want to try a kit is that I have a wood shop so I can make my own head and combo cabs. That saves me a lot of money. I easily found the original cabinet plans on line for free. I'd love to make a Tweed Deluxe in a combo cab made of walnut and maple with a matching extension cab. I have a box joint template for my dovetailing jig. But I'm thinking of doing dovetail joints to really dress up the cab.

I've also looked at the Studio One. It does look sweet! And let me know how you like the Blonde Bassman.
 

scratch17

Venerated Member
I can’t comment on anything to do with building amps, but I do know about 6G15 reverb units. In my experience they should be placed before the amp.
Now that I think of it, that is the way Fender did their reverb circuits. I actually hadn't considered putting it in front of the amp. Thanks for the advice.
 

David MacNeill

Established Member
You may want to talk to my friend and former bandmate Chris Murray, a brilliant amp designer here in Boise. Both of my studio amps (I don't gig any more either) are custom Murrays and they are perfect for me in every way. One is an 18-watt Plexi with all the roar but none of the cop visits/divorces and the other is a '57 tweed Champ circuit with a mid-scoop Framus knob that sounds incredible and is my daily recording amp now.

His flagship amp these days is his Masterverb, a Fender 6G15 external reverb built into a tweed Bassman circuit in either head or combo format. If I still gigged, this would be my amp.
 

Eric Dahlberg

Purveyor of musical dreams fullfilled.
After doing a lot of research I've decided to make some additions to my recording guitar rig. I won't be gigging ever again. There are lots of reasons but they are irrelevant to this discussion.
I hope all is well!

Ampeg AX-70.
Sell

I bought a '68 Bandmaster a few years ago which needs even more work. Certainly needs pots and jacks cleaned. Probably needs some caps replaced and maybe tubes. But it powers up and plays. No excessive hum. It's just not clean at low volumes and scratchy as hell when I move a pot.
Drool. Easy fix.

I might sell the Bandmaster after it's serviced. I really want a BlackFace amp with reverb. So if I sell the Bandmaster, I plan on buying a MojoTone kit. Either a Princeton Reverb or better still, a Deluxe Reverb.
Original drool-worthy Bandmaster > Deluxe Reverb kit. Only reason to sell the Bandmaster is if you're concerned about slipping on all the drool it induces.

The thing is, the Deluxe Reverb is a much more complicated build compared to the Princeton Reverb.
Do the Princeton Reverb. You'll lose the worthless Normal channel, who cares. If you did a Deluxe Reverb and turned the Normal channel into a brownface preamp, that would be a different story.

C. Keep the Bandmaster. Build the MojoTone 6G15 Reverb kit. This won't be nearly as difficult a build as the Deluxe Reverb amp.
By all means yes. We built a 6G15 with a 6G6B. PHE-NO-ME-NAL. Plus, you'll be able to use the reverb with your other amps. The only thing I'd warn about is that the vintage schematic has too little filtering and the Mojotone kit has even less. I recommend changing them to 40uF or higher to reduce noise.

The MojoTone6G15 kit doesn't indicate how to interface it with an amp. I am assuming that it would go into an effects loop. So I'd need to add a MojoTone effects loop between the AB763 preamp and the Bandmaster's phase inverter.
It plugs straight into the input of the amp.

Adding the loop also provides me with lots of options.
Meh
 

Eric Dahlberg

Purveyor of musical dreams fullfilled.
An easier kit is the Tweed Deluxe which also has a detailed manual.
Mojotone sells nice pre-wired Tweed Deluxe boards, too.
 

MaxTwang

Active Member
Here's a couple resources with items that will help your build.

Check out the "Simple Light Bulb Current Limiter" and Variac on this page. Rob Robinette is a great resource and often uses a 5E3 Deluxe layout for instruction.

Here's a page on safely discharging filter capacitors using a 2k 5 watt resistor.

Mojotone sells a Chassis Stand that is really helpful if you think you'll be building or working on more than 1 amp - I just got one after building 7 or 8 amps over 15 years. I wish I had one all along as it makes life so much easier. Here's a DIY amp chassis stand (you'll see Slukey on AmpGarage.com and his posts are really helpful).

I spliced one of these onto a power cord and use it between a variac and amp to monitor volts and current while testing amps. It's redundant with the light bulb limiter and variac, but I like a lot of info when I work.
Electricity Usage Monitor
 

MaxTwang

Active Member
If you build the 5E3 Deluxe then check out the Dumble Tweedle Dee mods


But if you're leaning towards the Princeton, which may be more appropriate than a Deluxe Reverb for home use, the check out this video with Tom Bukovac discussing eq pedals with his Princeton before he heads to a gig at the Ryman Auditorium with his Princeton Reverb. It looks like he's using a UAD OX in this video.

 

scratch17

Venerated Member
Wow! Great advice. Thanks.

I will build an amp stand before I do anything else. It’s a simple jig. In fact, I want to improve on it by adding a soldering clamp like the one StewMac sells.

I am now leaning hard towards the MojoTone Princeton Reverb kit. It looks relatively easy to build and no, I don’t need the extra channel.

Just so happens that Lyle Caldwell of Psionic Audio just did two videos on a Princeton which was a treat. Then I watched him join Jeff on 5 Watt World on a two way conversation about their 5 favorite practice / home amps. They both picked the Princeton as their number 1 choices.

I checked out combo plans and I and a buddy are going to build two cabs: a combo with a 10” and a 12” extension.

Probably with solid mahogany or walnut with maple accents and Baltic birch for the back parts and baffle. If the lumber is too expensive, I’ll use solid pine. It’s been a while since I bought hardwood.

As for adding an effects loop to the Bandmaster, I’ve decided to just get a Freyette PS-2 which adds a loop after both the pre and power amp. The loop in the PS-2 does’t have the flexibility of mixing and matching different preamps and power amps.

But it will allow me to keep the preamp clean with the power amp cranked while still having time based effects after the Bandmaster. And it won’t require a mod.
 

MaxTwang

Active Member
@scratch17 when you get your Mojotone kit be sure to verify the parts are included and correct - including transformers. You'll receive the small parts in organizers like the pic below - verify the quantity and component value (the quantity is the number in parenthesis). Mojotone has been known to occasionally make mistakes but they're great about getting missing parts to you. Mojotone likes to save on shipping by including any additional parts you might order in your amp kit or cabinet box, but I've had them forget to include the additional parts a couple times.

For a one-time or occasional building having the parts pre-sorted and ready to go is a huge time saver as sourcing parts while working from a schematic can take hours and hours and hours (I just spent more time sourcing parts for a '66 Bassman re-cap and bias repair than it'll take to do the actual work).

I also included a pic of my Studio One which runs shockingly quiet (no hum, very little noise) and is true bedroom volume. I installed the Mojotone FX Loop yesterday and it's also very good. Ignore the soldering iron marks on the first yellow cap - I soldered this before I got a chassis cradle and had the chassis propped up on boxes at a funny angle, the chassis cradle makes life so much easier.

IMG_4839.jpeg IMG_4836.jpeg
 
Last edited:

MakerDP

Hall of Fame Member
Man it's really too bad the old AX84 forums are defunct. That was an absolutely FANTASTIC resource for amp building.

You can still get to the schematics developed by the community though. If you want a great amp and you don't mind sourcing the parts yourself and drilling your own chassis, then an easy and great sounding amp to build can be found in the "Building Blocks" section of the archived website: https://web.archive.org/web/20210916204733/https://ax84.com/archive/ax84.com/buildingblocks.html Combine the Simple Preamp with the 20 Watt Push Pull power amp. They are so good I've built two of these! There is no reverb, but whatever that's easy to get outboard or with a pedal. I modified mine with the variable negative feedback adjust from the October amp found there. I also put it on a push-pull pot to defeat the negative feedback altogether. Geez what a versatile amp. The Blues Preamp is great too... it's a Tweed Bassman/JTM45 preamp. Sounds great with the 20 Watt Push Pull also (basically an AX84 October found on the site.)

My first amp build was the TC15 kit from Trinity Amps which is a Matchless HC30 but with only 15 watts (I highly recommend their kits - I've done three of them). My second build was my first AX84 Simple/20 Watt combo. I've since done a lot of self-designed/modified builds. It can be a VERY addictive hobby!

Anyways... all something to consider. I do recommend you start with a kit of some kind though. The "conventional" path is to start with a simple Fender Tweed kit and move up from there. A Deluxe Reverb is quite an undertaking, even in kit form with great documentation, so I really do suggest starting smaller.
 

MaxTwang

Active Member
Man it's really too bad the old AX84 forums are defunct. That was an absolutely FANTASTIC resource for amp building.

You can still get to the schematics developed by the community though. If you want a great amp and you don't mind sourcing the parts yourself and drilling your own chassis, then an easy and great sounding amp to build can be found in the "Building Blocks" section of the archived website: https://web.archive.org/web/20210916204733/https://ax84.com/archive/ax84.com/buildingblocks.html Combine the Simple Preamp with the 20 Watt Push Pull power amp. They are so good I've built two of these! There is no reverb, but whatever that's easy to get outboard or with a pedal. I modified mine with the variable negative feedback adjust from the October amp found there. I also put it on a push-pull pot to defeat the negative feedback altogether. Geez what a versatile amp. The Blues Preamp is great too... it's a Tweed Bassman/JTM45 preamp. Sounds great with the 20 Watt Push Pull also (basically an AX84 October found on the site.)

My first amp build was the TC15 kit from Trinity Amps which is a Matchless HC30 but with only 15 watts (I highly recommend their kits - I've done three of them). My second build was my first AX84 Simple/20 Watt combo. I've since done a lot of self-designed/modified builds. It can be a VERY addictive hobby!

Anyways... all something to consider. I do recommend you start with a kit of some kind though. The "conventional" path is to start with a simple Fender Tweed kit and move up from there. A Deluxe Reverb is quite an undertaking, even in kit form with great documentation, so I really do suggest starting smaller.
Trinity’s Ampeg and Dumble kits looks interesting, but haven’t been in stock for quite a while. I’m leaning towards the TripTop (Ampeg) for a future build as I like old Ampegs with 6SL7 octal preamp tubes.
 

MakerDP

Hall of Fame Member
Trinity’s Ampeg and Dumble kits looks interesting, but haven’t been in stock for quite a while. I’m leaning towards the TripTop (Ampeg) for a future build as I like old Ampegs with 6SL7 octal preamp tubes.
Yeah I've built the Dumble. Not an easy build so beginners beware! But it does sound great. Looked at the TriTop for some time now. That would be a cool build. But I've also wanted to build the HiWatt.

I've done the TC15, the OSD, and the 6V6 Plexi. He built a really nice head cabinet for my OSD in wine red tolex as well. My review of the OSD was featured on his site for a while - don't know if it's still there.

He is a really nice guy so you might want to contact him directly to check on availability of the amps not in stock.
 

scratch17

Venerated Member
The Trinity OSD has me salivating. Maybe after I've built three or four easier kits.

I've decided I am going to start my kit building journey with the MojoTone Princeton Reverb. I think it's in my wheelhouse.
 

MakerDP

Hall of Fame Member
That's a solid choice for your first build. Take your time. Highlight the layout AND the schematic as you go. Double then triple check before you go to the next step. Patience and good solder flows will ensure you have a successful startup the first time out.

There is a first startup guide somewhere that I follow... ruby something... let me see if I can find it.

EDIT: Here it is... https://paulrubyamplifiers.com/info.html#FirstPowerUp This one is well-written and has never failed me yet.
 
UAD Bundle Month
Top