SET12
Super Member
Good morning everyone!
I thought I might discuss a different approach to power design. :scratch2:
Some may regard the following opinions as very controversial :nono: others may find it very enlightening :yes:
So I thought I might post this thread in the DIY section, but I often see 3 times more people on line here and since I see people talking about console amps and mods to them along with Dyna mods I thought I'd post my thread here
I have discussed some of my views with a few people but never in a dedicated thread. I started writing about these views in another thread but there is a lot to say so I thought its about time for a little discussion.
So I'd like to start out small sort to speak about a very easy mod to a Pilot 240 integrated that I converted to a power amp with a modification to its supply along with a few other goodies. Some on this forum may have already seen it. But its a good start and a simple one at that.
Heres the amp, and the story begins by this statement
The 100 Ohm power resistor is power supply restricting
Since the amp is Push-Pull it naturally cancels noise. Since it does this you might consider removing the resistor and just tying the two cap sections together that are connected to the rectifier and the output transformers.
You should be pleasantly surprised at just how much more dynamic the amp will be.
This was my first experience with my buddy who is a former musician yet loves music enough to go see Jazz and Classical concerts several nights a week.
When I first did this I just put a Radio Shack jumper across it to listen to it. I knew the worst that might happen is I might hear an increase in noise. But I had a couple hundred uf's there which was double of the stock supply. And as I said we listened to it and our jaws were on the floor from the dynamics alone and of course the was sweet and even more informative. The whole amp was so much more involving like toe tapping instead of slow weakish and to some extent a little boring in contrast to the 100 ohm being in the circuit!
Some would say, oh! that's hard on the rectifier! Well the amp uses a 5AR4 slow turn rectifier as it is. The amp above has been running on 3-400uf that I can remember now for 10yrs plus and has had no issues at all in fact all of the tubes are still 100%
There are other amplifiers that do this, such as the legendary EICO HF81 an EL84 Integrated amp as the Pilot.
The EICO will very likely run circles around a stock Pilot 240 IMO. But! with the Pilot's supply set up like the EICO the Pilot likely would pull ahead IMO as it has very,very good output iron even better than the Pilot console amps that many people have on this forum. My buddy who owns the above amp owns two Pilot console amps and their iron is not in the same league IHO, but the consoles are still nice IHO. I haven't heard the HF81 but I have its schematic, and I don't think the HF81 output iron is quite in the same class as the Pilot 240.
My buddy bought his Pilot for maybe $150 brought it home fired it up and was severely disappointed. It had what is referred to as knob disease meaning the controls were noisy and not tracking well for left-right balance along with selector switch issues not to mention all the switches and lengthy signal paths. I had a schematic and saw a simple and sensitive power amp. I wired it direct in the chassis and called him to listen to it! He was thrilled! though his wife did not like its looks so we made it look good by pulling the iron repainting the iron gloss piano black he got some brass and had a metal shop cut the holes. He made a simple walnut wood skirt and copper bottom plate. I redesigned the layout which made the amp substantially quieter. It was one of my favorite projects that I ever under took. Some say the EL84 is the best of all Pentodes and it wasn't until hearing the amp drive my buddy's $6000 Dunlevy 4's that I understood literally the legend of the EL84 or the Pilot for that matter.
Cheers
SET12
I thought I might discuss a different approach to power design. :scratch2:
Some may regard the following opinions as very controversial :nono: others may find it very enlightening :yes:
So I thought I might post this thread in the DIY section, but I often see 3 times more people on line here and since I see people talking about console amps and mods to them along with Dyna mods I thought I'd post my thread here
I have discussed some of my views with a few people but never in a dedicated thread. I started writing about these views in another thread but there is a lot to say so I thought its about time for a little discussion.
So I'd like to start out small sort to speak about a very easy mod to a Pilot 240 integrated that I converted to a power amp with a modification to its supply along with a few other goodies. Some on this forum may have already seen it. But its a good start and a simple one at that.
Heres the amp, and the story begins by this statement
The 100 Ohm power resistor is power supply restricting
Since the amp is Push-Pull it naturally cancels noise. Since it does this you might consider removing the resistor and just tying the two cap sections together that are connected to the rectifier and the output transformers.
You should be pleasantly surprised at just how much more dynamic the amp will be.
This was my first experience with my buddy who is a former musician yet loves music enough to go see Jazz and Classical concerts several nights a week.
When I first did this I just put a Radio Shack jumper across it to listen to it. I knew the worst that might happen is I might hear an increase in noise. But I had a couple hundred uf's there which was double of the stock supply. And as I said we listened to it and our jaws were on the floor from the dynamics alone and of course the was sweet and even more informative. The whole amp was so much more involving like toe tapping instead of slow weakish and to some extent a little boring in contrast to the 100 ohm being in the circuit!
Some would say, oh! that's hard on the rectifier! Well the amp uses a 5AR4 slow turn rectifier as it is. The amp above has been running on 3-400uf that I can remember now for 10yrs plus and has had no issues at all in fact all of the tubes are still 100%
There are other amplifiers that do this, such as the legendary EICO HF81 an EL84 Integrated amp as the Pilot.
The EICO will very likely run circles around a stock Pilot 240 IMO. But! with the Pilot's supply set up like the EICO the Pilot likely would pull ahead IMO as it has very,very good output iron even better than the Pilot console amps that many people have on this forum. My buddy who owns the above amp owns two Pilot console amps and their iron is not in the same league IHO, but the consoles are still nice IHO. I haven't heard the HF81 but I have its schematic, and I don't think the HF81 output iron is quite in the same class as the Pilot 240.
My buddy bought his Pilot for maybe $150 brought it home fired it up and was severely disappointed. It had what is referred to as knob disease meaning the controls were noisy and not tracking well for left-right balance along with selector switch issues not to mention all the switches and lengthy signal paths. I had a schematic and saw a simple and sensitive power amp. I wired it direct in the chassis and called him to listen to it! He was thrilled! though his wife did not like its looks so we made it look good by pulling the iron repainting the iron gloss piano black he got some brass and had a metal shop cut the holes. He made a simple walnut wood skirt and copper bottom plate. I redesigned the layout which made the amp substantially quieter. It was one of my favorite projects that I ever under took. Some say the EL84 is the best of all Pentodes and it wasn't until hearing the amp drive my buddy's $6000 Dunlevy 4's that I understood literally the legend of the EL84 or the Pilot for that matter.
Cheers
SET12
