Benson Monarch

[rasc117]

Update,
removed my tone circuit and went straight to the master volume from the first plate
still weird RF noise

used shielded cable on both the input grids and now we're cooking w/ gas. Amp is MUCH quieter. I'll begin to re-add the tone controls and see where i get.
Thanks y'all

[joeboo88]

Hiya. I built this 2 weeks ago and it sounds great. I have never bought a store bought amp before, but this one would be one I would buy.
I used iron from RJ (these were for a cathode biased 6v6 Express ~ 18watts) but I already have an Express, so I had these sitting for a couple of years.
this was my first point to point and I was leery about using 6 ground points. One for IEC one for power and cathode and OT ground. One for pre amp/pots.... but 3 for each of the tube grounds.
The amp is very quiet and no weird noises. I also just laid the heater wires on top of each other and didn't twist them.
I really like this amp, and it sounds great with the couple of pedals I used. I'm using a Greenback speaker that I use with my 5e3 amp.
sounds really good. The reverb also works like its supposed to.
I haven't decided how I'll house this, maybe a combo

thanks guys for creating the schematic and doing all the hard work.
Joe

[Colossal]

Nice work and a good looking build! Is that PT 290-0-290?

[joeboo88]

Thanks. Dave... 280 0 280 - my voltages are almost identical to some of the others who posted.
Yeah I'm almost out of RJ's stuff, I had bought a box of stuff from him a couple of years ago. He's the best, he's busy with his house Reno's now and doesn't have much amp time anymore.... I'm gonna build his Rocket Reverb with kt66’s next.

[cgharrison]

Hey everybody-

First off, thanks to all who have put their time and effort into this thread - I built the Monarch circuit, and it turned out absolutely great. Now, I'm trying to put together a Tall Bird Reverb (based on the Dizzy Bird schematic posted early on here). The issue I'm having is that the tubes aren't labeled on the schematic. I know the Tall Bird is 2 12AX7's and 1 12AU7, and that one half of the 12AU7 will be driving the reverb tank (just like the 12DW7 in the Monarch). My question is if anyone has any ideas which triode on the schematic is the other half of the 12AU7. Any thoughts are appreciated!

[cgharrison]

And also- any ideas on Chris Benson's comment that "the output buffer will not work as drawn"?

[TUBEDUDE]

The output cathode follower would be the best use of it. A 12AU7 there will work well.

[CraigGa]

I'm well into my build now but I've come across a discrepancy between the various layouts and schematics in this thread regarding the voice switch.

Basically when the circuit is distilled a bit (mounting components on the switch makes it look more complicated), it comes down to switching a capacitor across a resistor or switching a resistor across a capacitor - see attached diagram.

So which one is correct?

Craig

[CraigGa]

Thinking about it a bit more,
adding 470K in parallel with 250pF isn't going to do much but bypassing a 470K resistor with 250pF is going to pass more high frequencies.

Craig

[mikeywoll]

Thinking about it a bit more,
adding 470K in parallel with 250pF isn't going to do much but bypassing a 470K resistor with 250pF is going to pass more high frequencies.

Craig

The cap is always in circuit and the resistor is switched. It seems counter intuitive, but you are creating 2 different tone stacks this way, vs just switching in or out a treble peak by switching the capacitor.

We discussed it back here:
https://ampgarage.com/forum/viewtopic.p ... &start=150

About halfway down the page.

Mike

[CraigGa]

Thanks Mike,
I must have read that before but failed to process it

Craig

[mhat]

Finished my build. Really fun but I need to build a cab. A few questions came up...

1. Volume on 0 and still audible guitar - bedroom level volume. I read through the tread, so this is what everyone has with this build?
2. No ground loop buzz, but some amp hiss. I'm assuming it's due to the fact there's no NFB circuit and I DID use carbon comp resistors. My Princeton Reverb build has CC resistors but quieter when comparing both without guitars plugged in.
3. I do get some pop on switching between USA/British voicing, anyone else?

Edit:
3. Fixed the popping. Accidentally used 470 vs 470k on the switch. Whoops!

[cgharrison]

Bumping this again - thoughts on the idea "the output buffer will not work as drawn" in the reverb section of the dizzy bird schematic, per Benson?

[Aaron]

Hi everyone,

Thanks Tom for the reminder about this amp. I got the amp back and took some pics.
Hope this helps.

Thanks,
Aaron

[Aaron]

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