"sometimes we do what works, rather than what we prefer to do". i work with software with code mostly inherited from 'original team'. This is a truth in a lot of my decisions too.
Fiddling with working code to make it personally more palatable is a great way to introduce bugs that can result in uncomfortable conversations with your manager - and possibly a stroll out of the building with your personal possessions in a bankers box. :)
Thanks Lyle! I have one of the JCM900’s a dual reverb in my case. Thanks to you and this video I will be doing some preventative mods with the rectifiers and resistors. And some preemptive re-soldering and hardware tightening. Appreciate as always that you share your knowledge and experience! Thanks! BTW can you link your Part 1 vid?
generally a bridge rectifiers current rating is based on how much heat they can dissipate, so a higher current-rated one will likely run cooler. Still always a good idea to mount them off the board though!
I will defend the accounts on this one . The PCB designer is to blame 100% the increase for larger pads with thru holes is little to nothing . Standing off the bridges is just in the details on the stuffing the boards. Look rather undersized to generate that much heat. That you could blame the accountant for . Complete cost analysis of parts is far above the pay grade of many of Fenders upper management .
And the component layout of the PCB (components in neat lines) unfortunately very often means that in fact the signal path is far from ideal. Of course the same mistake is very often done in the case of turret boards as well because some people still believe that if component layout looks like a military parade, and because of that the wires are usually much longer than they should be, and component leads are very strictly bent in 90 degrees angle etc., it will sound good as well. But it is BS. Apparently for some idiots it does not matter if the amp hums and oscillates because the most important thing seems to be that the components and wires are in military order. I have seen amps where for example grid stoppers have been placed far from grids to be side by side with plate resistors or screen resistors etc. to form a neat looking layout which only makes the amp prone to severe parasitic oscillations etc.
@@johnwilliamson467 Yes. And the same thing with grounding. For example those thick ground rails in many tube amps are just ridiculous. Tube amps are high voltage, low current devices, it is a fact, and thick wires are needed only for paralleled tube heater circuits and OT secondary wiring. If you want to avoid hum problems, you don't need thick ground wires à la railway track because you only need to understand how to control B+ ripple currents. In practice it means understanding how star grounding works and just mainly keeping main filter capacitor ripple currents away from preamp stage ground circuit. I have learned my lessons in early 90's when my work was to design very sensitive industrial analog instrumentation amps for very challenging environments and sometimes a very strict pure 100% star grounding was the only option to get any useful signal out of that hostile environment. So when I talk about star grounding, I know what I am talking about because I have learned my lessons in a hard way more than 30 years ago. And star grounding is a really a very simple way to tackle hum and especially ground loop problems because star grounding simply eliminates ground loops. But it does not look as nice and neat as one 1/10" thick ground rail made of silver. 😁
@@jutukka I dislike the whole ground term thing as it misdirects the thinking of the designer. If one looks at it as the referenced to zero volt return leg then the use of star grounding would be more common . Reducing the multi path problem a big bus bar grounding system can cause with . RF is view as black magic because stray element i.e inductance and capacitance that are too small at low frequencies become real at higher frequencies. The bandwidth of tube amps is greater or should be said to be effected by more than people choose to see as you have pointed out .
"sometimes we do what works, rather than what we prefer to do". i work with software with code mostly inherited from 'original team'. This is a truth in a lot of my decisions too.
Fiddling with working code to make it personally more palatable is a great way to introduce bugs that can result in uncomfortable conversations with your manager - and possibly a stroll out of the building with your personal possessions in a bankers box. :)
I like the SL-X. Once BR3 is dealt with they make good meat and potatoes rock amps.
thanks forsharing with us youre knowledge
Always great.
"Burnt Rectifier 3"
Thanks Lyle! I have one of the JCM900’s a dual reverb in my case. Thanks to you and this video I will be doing some preventative mods with the rectifiers and resistors. And some preemptive re-soldering and hardware tightening. Appreciate as always that you share your knowledge and experience! Thanks!
BTW can you link your Part 1 vid?
Just scroll down. First part is not called Part 1, just something with JCM900
It sounds good. Would larger value bridge rectifiers run cooler?
generally a bridge rectifiers current rating is based on how much heat they can dissipate, so a higher current-rated one will likely run cooler. Still always a good idea to mount them off the board though!
Getting there. Crunched my ears Sir. I was wearing earbuds when you cranked it up and demonstrated the oscillation. Thank you very much.
Maybe the LAST decent Marshall that isn't priced too high..
Ouch. Yeah. I could hear the humming.
😎👍
I will defend the accounts on this one . The PCB designer is to blame 100% the increase for larger pads with thru holes is little to nothing . Standing off the bridges is just in the details on the stuffing the boards. Look rather undersized to generate that much heat. That you could blame the accountant for . Complete cost analysis of parts is far above the pay grade of many of Fenders upper management .
And the component layout of the PCB (components in neat lines) unfortunately very often means that in fact the signal path is far from ideal. Of course the same mistake is very often done in the case of turret boards as well because some people still believe that if component layout looks like a military parade, and because of that the wires are usually much longer than they should be, and component leads are very strictly bent in 90 degrees angle etc., it will sound good as well. But it is BS. Apparently for some idiots it does not matter if the amp hums and oscillates because the most important thing seems to be that the components and wires are in military order. I have seen amps where for example grid stoppers have been placed far from grids to be side by side with plate resistors or screen resistors etc. to form a neat looking layout which only makes the amp prone to severe parasitic oscillations etc.
@@jutukka I would agree that the understanding of how the unit is operating rather than how it looks is missing to most "designer" .
@@johnwilliamson467 Yes. And the same thing with grounding. For example those thick ground rails in many tube amps are just ridiculous. Tube amps are high voltage, low current devices, it is a fact, and thick wires are needed only for paralleled tube heater circuits and OT secondary wiring. If you want to avoid hum problems, you don't need thick ground wires à la railway track because you only need to understand how to control B+ ripple currents. In practice it means understanding how star grounding works and just mainly keeping main filter capacitor ripple currents away from preamp stage ground circuit. I have learned my lessons in early 90's when my work was to design very sensitive industrial analog instrumentation amps for very challenging environments and sometimes a very strict pure 100% star grounding was the only option to get any useful signal out of that hostile environment. So when I talk about star grounding, I know what I am talking about because I have learned my lessons in a hard way more than 30 years ago. And star grounding is a really a very simple way to tackle hum and especially ground loop problems because star grounding simply eliminates ground loops. But it does not look as nice and neat as one 1/10" thick ground rail made of silver. 😁
@@jutukka I dislike the whole ground term thing as it misdirects the thinking of the designer. If one looks at it as the referenced to zero volt return leg then the use of star grounding would be more common . Reducing the multi path problem a big bus bar grounding system can cause with . RF is view as black magic because stray element i.e inductance and capacitance that are too small at low frequencies become real at higher frequencies. The bandwidth of tube amps is greater or should be said to be effected by more than people choose to see as you have pointed out .