BobL wrote: ↑Thu Apr 22, 2021 3:45 pm
The good news is that I don't plan on playing the amp with the volume off.
Took this to band practice last night, and it did really well. Does particularly well with certain drive pedals - super rich, harmonic overdrive.
My main kinda 'base' drives are a Bondi Sick As (modified Klone), and a Seymour Duncan Forza - the Sick As didn't sound that great, but the Forza sounded outstanding (total sleeper pedal people overlook).
I have an RYRA Klone that I use for a lead boost, and that did pretty well too. The amp has a pretty different and kind of pronounced midrange vs the Fender style amps I usually play, so having a drive with a mid control (like the Forza) was really useful. Cool shimmer on the cleans, and seems like way more volume on tap as built now vs. as built previously. I really didn't have it turned up much at all. Tight low end vs. my Fenders.
Overall, feeling pretty happy with it, though I still don't care for the voicing of the reverb. Too splashy.
Hah, yeah I hadn't realized the bleed over until you mentioned it. Why play a tube amp with the volume turned way down?
I agree there are so many great tones in this amp and it kills with pedals. Really, really loves boost pedals.
BobL wrote: ↑Thu Apr 22, 2021 3:45 pm
The good news is that I don't plan on playing the amp with the volume off.
Took this to band practice last night, and it did really well. Does particularly well with certain drive pedals - super rich, harmonic overdrive.
My main kinda 'base' drives are a Bondi Sick As (modified Klone), and a Seymour Duncan Forza - the Sick As didn't sound that great, but the Forza sounded outstanding (total sleeper pedal people overlook).
I have an RYRA Klone that I use for a lead boost, and that did pretty well too. The amp has a pretty different and kind of pronounced midrange vs the Fender style amps I usually play, so having a drive with a mid control (like the Forza) was really useful. Cool shimmer on the cleans, and seems like way more volume on tap as built now vs. as built previously. I really didn't have it turned up much at all. Tight low end vs. my Fenders.
Overall, feeling pretty happy with it, though I still don't care for the voicing of the reverb. Too splashy.
Hah, yeah I hadn't realized the bleed over until you mentioned it. Why play a tube amp with the volume turned way down?
I agree there are so many great tones in this amp and it kills with pedals. Really, really loves boost pedals.
Mike
If I wasn't searching for hum, I might never have noticed it - I just had the volume all the way down to confirm no hum, then plugged the guitar in before I turned it up and realized I could hear it.
mojotom wrote: ↑Thu Apr 22, 2021 8:24 am
I read somewhere Benson uses .02 on the whole power amp on his production Monarch amps but his personal amps still uses .1.
From his 1st post here...
chasbenson wrote: ↑Wed Nov 18, 2020 12:29 am
I'm bored on a plane and came across this. I must say I'm flattered to join the ranks of traced stuff on here...I've used this forum as a resource many times over the years, especially when I was doing repair work. Hopefully it is helpful of me to point out at first glance of the shared schematics that the power supply for the Monarch is not correct and will probably hum as drawn, the Tall Bird output buffer will not work as drawn, and the Vinny power tube grid stopper should be 27k, not 2.7k. bonus note: we use all .02 for the PI caps in the Monarch these days since gets rid of a bit of tubbiness but I haven't switched my personal amps over because it really doesn't change much.
Regards,
Chris
Thanks for digging that out of this now 17 (!) page thread. I changed all 3 of the .1 uF coupling caps to .02uF. Solid bass is still there, but toned down just a bit. I like it.
I played a bit. The signal is being picked up somewhere in the PI -> power tube circuit, on the half that is feeding the trim pot. If I disconnected the grid on that half of the phase inverter I got no sound with the volume turned off, and normal (quieter as it's single ended now) behavior with the volume up. I tried shielding the lead. Didn't help.
I played a bit. The signal is being picked up somewhere in the PI -> power tube circuit, on the half that is feeding the trim pot. If I disconnected the grid on that half of the phase inverter I got no sound with the volume turned off, and normal (quieter as it's single ended now) behavior with the volume up. I tried shielding the lead. Didn't help.
Anyone have any thoughts?
Mike
Not that I figured this out on my own, but I think what you are hearing may be similar to what is mentioned in the Guitar Magazine add-on reverb write up. https://guitar.com/guides/diy-workshop/ ... amplifier/
Like the circuit in the article, the Monarch reverb taps off after V1A and gets mixed back in after the volume control.
The author comments
"This makes the Swart reverb design fully independent, and the amp’s volume control operates only on the dry signal. You can even turn the volume right down and listen to the reverb effect on its own"
I played a bit. The signal is being picked up somewhere in the PI -> power tube circuit, on the half that is feeding the trim pot. If I disconnected the grid on that half of the phase inverter I got no sound with the volume turned off, and normal (quieter as it's single ended now) behavior with the volume up. I tried shielding the lead. Didn't help.
Anyone have any thoughts?
Mike
Not that I figured this out on my own, but I think what you are hearing may be similar to what is mentioned in the Guitar Magazine add-on reverb write up. https://guitar.com/guides/diy-workshop/ ... amplifier/
Like the circuit in the article, the Monarch reverb taps off after V1A and gets mixed back in after the volume control.
The author comments
"This makes the Swart reverb design fully independent, and the amp’s volume control operates only on the dry signal. You can even turn the volume right down and listen to the reverb effect on its own"
Great thought. I just checked and the bleed through signal is dry. The reverb knob has no effect on the bleed through sound. The tone knob does, however. It must be jumping over pre tone knob to the phase inverter.
mikeywoll wrote: ↑Fri Apr 23, 2021 10:06 pm
Great thought. I just checked and the bleed through signal is dry. The reverb knob has no effect on the bleed through sound. The tone knob does, however. It must be jumping over pre tone knob to the phase inverter.
Getting closer...
Mike
If the tone knob affects it, doesn't that mean that it's jumping from post the tone circuit not pre?
Have you checked that the Volume pot wiper goes zero resistance to ground?
I spent some time today trying to figure out where the signal is bleeding through....
The volume pot does go to 0 ohms to ground when it's out of the circuit. When it's in circuit it stops at 1.8 ohms. Directly grounding the signal on the volume pot does not eliminate the bleed through.
The tone knob affects the bleed through signal
The voicing switch does not affect the bleed through signal
There is no reverb on the signal
The signal is only on one half of the phase inverter
I'm stumped. There must be a subtle difference in the turret board layout vs the point to point layout. Chalking this up to cool feature. The amp sounds great otherwise and the signal doesn't seem to be causing any negative effect.
Tried separating the plate power supply of V2a and V2b, no help.
Tried shielding and rearranging the leads from the 0.022 tone caps to the tone pot/voicing switch, no help.
Tried bypassing the D node filter cap with a small ceramic cap, no help.
I have reflowed all ground points. Changed filter caps.
Tried rolling tubes, no difference across Russian, Chinese, JJ, EHX, Tung Sol.
Ultimately, I have no measurable AC voltage post volume control into the second stage of the V1 tube, but can measure a small AC voltage on the plate of the second stage of V2 and beyond the coupling cap heading to the PI. The magnitude is similar to the unamplified guitar signal.
It's either jumping up by the pots, in the tube, or via ground?
Very interesting. I tried disconnecting the volume pot from the second stage and grounding the grid of the tube directly to ground. Signal still bleeds through. It must be happening up at the control pots. In the point to point layout, the controls are pretty far from the circuit and the layout physically separates the various stages. In the turret board layout as I built it, the controls are close to the circuit and different stages are near each other. Plenty of high impedance points near strong signals that allow the opportunity for bleed.
The amp sounds amazing, plays great, and is stable at all volumes. I may rebuild this one in the future, point to point next time
