Benson Monarch

[dorrisant]

Can you post the Kicad files?

[mikeywoll]

I’ve lost track...
Is there an updated schematic for these current successful builds?

I created this in Kicad and I think its accurate but maybe someone else can put a second set of eyes on it and verify?

There are only 3 significant changes from the original schematic
1. the power supply nodes
2 the US/UK switch wiring
3 the plate resistor on reverb return triode to 220K

I have that plate resistor as 470k (yellow,purple,yellow) to pull down the voltage to 75ish volts from 260 volts with a 2.2k (red,red red) cathode resistor.

Per the photo of the original amp...

Screenshot_20210504-190743.png

Mike

[T Wilcox]

Can you post the Kicad files?

Sure thing! Let me know if that works EDIT: Didn't work
I didn't have a rectifier object and just made this so I would stop working off the wrong schem when I built mine
I will edit my last post to reflect the 470k instead of 220k

Thanks

[T Wilcox]

I’ve lost track...
Is there an updated schematic for these current successful builds?

I created this in Kicad and I think its accurate but maybe someone else can put a second set of eyes on it and verify?

There are only 3 significant changes from the original schematic
1. the power supply nodes
2 the US/UK switch wiring
3 the plate resistor on reverb return triode to 220K

I have that plate resistor as 470k (yellow,purple,yellow) to pull down the voltage to 75ish volts from 260 volts with a 2.2k (red,red red) cathode resistor.

Per the photo of the original amp...
Screenshot_20210504-190743.png

Mike

Got it ! Not sure why I have 220K, and yes my voltage there was higher than it should be. Still sounds great so I'm wondering if I'll hear much difference

Thanks Mike

[dorrisant]

Can you post the Kicad files?

Sure thing! Let me know if that works
I didn't have a rectifier object and just made this so I would stop working off the wrong schem when I built mine
I will edit my last post to reflect the 470k instead of 220k

Thanks

Come up as a blank...

[T Wilcox]

Can you post the Kicad files?

Sure thing! Let me know if that works
I didn't have a rectifier object and just made this so I would stop working off the wrong schem when I built mine
I will edit my last post to reflect the 470k instead of 220k

Thanks

Come up as a blank...

It says invalid file on every one but that one when I try to post
PM'd you

[mikeywoll]

I created this in Kicad and I think its accurate but maybe someone else can put a second set of eyes on it and verify?

There are only 3 significant changes from the original schematic
1. the power supply nodes
2 the US/UK switch wiring
3 the plate resistor on reverb return triode to 220K

I have that plate resistor as 470k (yellow,purple,yellow) to pull down the voltage to 75ish volts from 260 volts with a 2.2k (red,red red) cathode resistor.

Per the photo of the original amp...
Screenshot_20210504-190743.png

Mike

Got it ! Not sure why I have 220K, and yes my voltage there was higher than it should be. Still sounds great so I'm wondering if I'll hear much difference

Thanks Mike

I wouldn't think there would be too much difference, maybe a little high frequency rolloff? The rp/rk ratio is similar, so I would think otherwise the stage should behave similar with regards to gain?

Thank you for sharing your files!

[T Wilcox]

I have that plate resistor as 470k (yellow,purple,yellow) to pull down the voltage to 75ish volts from 260 volts with a 2.2k (red,red red) cathode resistor.

Per the photo of the original amp...
Screenshot_20210504-190743.png

Mike

Got it ! Not sure why I have 220K, and yes my voltage there was higher than it should be. Still sounds great so I'm wondering if I'll hear much difference

Thanks Mike

I wouldn't think there would be too much difference, maybe a little high frequency rolloff? The rp/rk ratio is similar, so I would think otherwise the stage should behave similar with regards to gain?

Thank you for sharing your files!

I didn't get to the footswitch tonight but when I get a chance I'll swap that resistor too
As far as the files, anytime man. The Kicad files dont seem to upload properly though so if you or anyone else reading this wants them PM me

[pompeiisneaks]

Sure thing! Let me know if that works
I didn't have a rectifier object and just made this so I would stop working off the wrong schem when I built mine
I will edit my last post to reflect the 470k instead of 220k

Thanks

Come up as a blank...

It says invalid file on every one but that one when I try to post
PM'd you

There's a limited number of file types it allows. The KiCad files could be zipped as I think that .zip is... if you can give me the extension of the kicad files I can add them as an option.

~Phil

[didit]

The KiCad files could be zipped as I think that .zip is...

Suggest KiCad files probably always ought to just be zipped as several file types comprise each "project" directory.

Best .. Ian

[T Wilcox]

Come up as a blank...

It says invalid file on every one but that one when I try to post
PM'd you

There's a limited number of file types it allows. The KiCad files could be zipped as I think that .zip is... if you can give me the extension of the kicad files I can add them as an option.

~Phil

Thanks Phil, didn't think of that. I'll do the same with DIYLC files next time as well
Ian is right there are about 4-5 files anyways

[dorrisant]

I went ahead and put a new OT in today... I left the mill marks. I don't think that will hurt.

I put the bottom on as well. Now for the headshell.

[mikeywoll]

Made the pilgrimage across town to Benson Amps and picked up my speaker today. Super friendly crew there. Even threw in a free hat.

PXL_20210506_030521609.jpg

Mike

[T Wilcox]

Its a little squeaky at first, I threw my looper on in the garage for a few hours and it started breaking in nicely
Let me know know if you have similar observation

[mikeywoll]

I went ahead and put a new OT in today... I left the mill marks. I don't think that will hurt.

I put the bottom on as well. Now for the headshell.

That's beautiful. I'm curious, did you try the variation on the power supply reported by Alex in his non-reverb monarch head? Did you run into any hum with the single PS ground?

Its a little squeaky at first, I threw my looper on in the garage for a few hours and it started breaking in nicely
Let me know know if you have similar observation

Squeaky is relative, I guess. It definitely has less high end than the Jensen that was in there. It's a great match for the amp and a part of the sound I hear on recordings/videos of the real thing. I like the speaker with my other amps as well. If it gets better with break in, I'm only going to be happier.

Mike