Benson Monarch build

[CanadianDave]

Yo,

I’m finally getting around to trying my hand at building my first amp, a Benson Monarch.

Thanks again to demetris who was able to get me a layout and schematic.

It’s still a work in progress, but here’s where I’m at so far…

I measured the components, created a chassis template on Apple pages, and printed it to scale.

By covering the chassis in painters tape and gluing the template down, I could use it as a drill template.

Please ignore the fact that I originally had heater wires running to the rectifier tube.

I also screwed up and cut the template for the wrong power transformer, so I made an adapter plate for the correct transformer.

 

[CanadianDave]

The front and back are water slide decals, and those preppy stripes are hiding a seam between the two transfer sheets.

I’m also just realizing that PedalPCB beat me to the punch with the “Viceroy” reference.

 

[CanadianDave]

Now, here’s where I could use a little help.

I made a change to the original layout and flipped the output transformer so the leads that go to the power tubes and the output jack (which I also moved from the original) would be closer to each other and the output jack leads wouldn’t be running past the tubes.

I attached a gut shot of the original for reference.

Before things go to far, does this seem like a bad idea to anyone?

 

[Quirkey]

Where'd you find the schematic/layout for this? I just started building amps as well and this looks like a great build.

 

[CanadianDave]

It lives!

After a few rookie mistakes, it fired up and it’s fully functional with the exception of a bad tone control.

To minimize my financial risk, I used cheap alpha pots and Mallory caps. Now that I know I haven’t thrown my money down the toilet and electrocuted myself in the process, I’m going to swap the pots for CTS and the caps for Jensons.

 

[CanadianDave]

Simultaneously, I’m working on the cabinet.

Solid pine. The plan is to go with tweed fabric, and shellac it to give it a nice amber. Then an Oxblood and gold grill cloth.

I’ve never upholstered anything, so wish me luck.

 

[ThatDude]

Where'd you find the schematic/layout for this? I just started building amps as well and this looks like a great build.

+1 on what Quirkey asked. Can you point us to the schematic you used? Thanks in advance.

 

[CanadianDave]

Hit me up on a private message and I’ll send the layout and schematic I used.

 

[ThatDude]

Hit me up on a private message and I’ll send the layout and schematic I used.

Ooof, I haven’t posted enough to be allowed to PM someone. It says I can only PM staff. Are you able to PM me?

 

[ThatDude]

@CanadianDave, how does it sound? It looks awesome.

 

[CanadianDave]

@CanadianDave, how does it sound? It looks awesome.

I hooked it up to a Celestion greenback that’s mounted in a Fender cabinet, and it sounded awesome. The description of the Monarch being somewhere in the middle between Fender/Marshall/Supro is accurate.

I briefly plugged in my PedalPCB Pillion overdrive, and it was magical.

In the meantime, the caps are being swapped out for Jensens and the cabinet is covered in tweed. The tweed has been shellacked with an amber, and I’ll probably give it a couple coats of clear, just in case.

A Mojotone British Vintage 25 watt speaker should arrive tomorrow to give this thing some pre-rola greenback vibes.

 

[ThatDude]

I hooked it up to a Celestion greenback that’s mounted in a Fender cabinet, and it sounded awesome. The description of the Monarch being somewhere in the middle between Fender/Marshall/Supro is accurate.

I briefly plugged in my PedalPCB Pillion overdrive, and it was magical.

In the meantime, the caps are being swapped out for Jensens and the cabinet is covered in tweed. The tweed has been shellacked with an amber, and I’ll probably give it a couple coats of clear, just in case.

A Mojotone British Vintage 25 watt speaker should arrive tomorrow to give this thing some pre-rola greenback vibes.

View attachment 70029

are you planning in using the send and return loop for a reverb tank, or just as an optional effects loop?

 

[CanadianDave]

are you planning in using the send and return loop for a reverb tank, or just as an optional effects loop?

The send and return is for the reverb tank. It’s a accutronics 8EB2C1B.

In my brief test, the reverb was great too. Very usable and not over saturated. Hidden back in the cabinet is a jack for a reverb foot switch.

 

[Dan0h]

This is amazing. I appreciate your attention to detail on all the little things.

I’ve been trying to find a legit schematic for a while. Also was surprised to hear that Mr. Benson is open to selling his company. Surprised Gibson hasn’t scooped it up.

 

[CanadianDave]

This is amazing. I appreciate your attention to detail on all the little things.

I’ve been trying to find a legit schematic for a while. Also was surprised to hear that Mr. Benson is open to selling his company. Surprised Gibson hasn’t scooped it up.

I’ve got a few of those details to wrap up this weekend before I can say it’s finished.

I saw an interview with Mr Benson where he said that he wants to build things, not run a company. I can respect that. The financial freedom to focus on being creative and building, without having to worry about meetings and spreadsheets. Sign me up.

 

[airbud]

this looks amazing, i'm very eager to get into amps (and eventually studio gear) so this is good inspiration. thanks for sharing!

 

[CanadianDave]

this looks amazing, i'm very eager to get into amps (and eventually studio gear) so this is good inspiration. thanks for sharing!

I will say this, when I started building pedals, I didn’t know my ass from a hole in the ground. In some ways, I still don’t.

But the knowledge I was able to gain from the experience, from online, and from lurking on this forum, ended up being great preparation for an amp build.

The biggest thing this forum has taught me is the value of doing quality work, clean layouts, and being thoughtful and meticulous about things that nobody but you will ever see. As I understand it, those factors play a huge part with the success of an amp build.

 

[CanadianDave]

I recapped (with the exception of the reverb circuit) with Jensen caps. I also swapped out the pots for CTS.

I did get a little creative with mounting the chassis. Rather than holes through the top, I used L brackets mounted inside. Four 4mm bolts with lock nuts mounting the chassis, and four 1-1/4 screws to the cabinet.

I also used foam tape between the chassis and cabinet to compensate for the unevenness of the tweed, and maybe it will help dampen vibrations.

 

[CanadianDave]

Another mod, which was probably me going overboard in an effort to mechanically isolate the reverb tank, I made a little box to house the tank, and lined it with more of that foam. Probably overkill, but at the very least, it looks clean.

I did swap out the tank to a Ruby brand. Somewhere along the line, I must have damaged one of those fragile leads in the tank. The ruby seems like a much better build quality.

I also made a little aluminum clip on the inside of the back cabinet panel that will clip under the chassis. It hugs the chassis and cabinet panel and makes for a tighter fit

 

[CanadianDave]

Final product…

I did all my testing with Chinese Genalex 12ax7’s that I bought on sale. I was honestly a little worried, because there was way too much headroom and output.

I swapped V1 with a Mullard, and V2 with a Tung Sol, and now sounds like the amp it’s supposed to be.

Over the next few weekends, I’ll be running a looper pedal to break everything in. But as it stands, I’m really stoked and happy with the outcome.