Just another topic with 8W Monster. I hesitate to put my 2 Monsters into encasings because they will be very large and heavy. So I tried, just for fun, to use SMP's. Each chanal 2x14V/5A (put me back 20 Euro for all of them). Surprisingly it sounds really good, the music losts a little bit of weight in the bottom but is clearer. For me the most importat things: the amplifiers are still dead silent (speaker 8Ohm, 94 dB/Wm), I use a little filter, and the palpability is still the same like befor with more than 3 F of capacitors each chanal. Now its going to be very cheap to have a extremly good sounding amplifier.
The PCB's are from Jims Audio, all fets and transistors are original, resistors Tantal film, 0.6 A quiescent current.
The PCB's are from Jims Audio, all fets and transistors are original, resistors Tantal film, 0.6 A quiescent current.
We tried Smps from Meanwell. The charming of the voices was gone. My Monster PSU is 470000uF with 35 year old Frako caps.
Recently I ve did excessive damping of the amp case with car matts. Even the caps were placed on matts. Was surprised of the details of music that came out, and never heard before.
Recently I ve did excessive damping of the amp case with car matts. Even the caps were placed on matts. Was surprised of the details of music that came out, and never heard before.
How do you describe the sound difference? Which one is better? I'm using a modern output transistor of the same code with the original. It was from 20 years ago, Panasonic brand.
@ aubmar
If you want to build up and test a pair if boards and share your experience with us,
I will send you a pair of boards.
Regards from Reimund
If you want to build up and test a pair if boards and share your experience with us,
I will send you a pair of boards.
Regards from Reimund
There is much more depth and clarity, almost an airiness or transparency in the music that was not there with the transistors that came with the Jims Audio Hiraga kit - The bottom end seems lower and cleaner too.
I use it with a Salas DCG3 pre and a pair of Altec 604-8G's in 9cu ft cabs, and the combo is absolutely amazing, full credit to Salas and Teabag for the GB's.
A few years ago I asked Jims Audio if he could get the original transistors and after some months he got 20 and traced them all to make up two pairs, and thats what I am using now.
He also has it as an item on his ebay listing and quite cheap, it was a very worthwhile upgrade.
I use it with a Salas DCG3 pre and a pair of Altec 604-8G's in 9cu ft cabs, and the combo is absolutely amazing, full credit to Salas and Teabag for the GB's.
A few years ago I asked Jims Audio if he could get the original transistors and after some months he got 20 and traced them all to make up two pairs, and thats what I am using now.
He also has it as an item on his ebay listing and quite cheap, it was a very worthwhile upgrade.
Thank you Reimund,
I am in the middle of a house move right now and won't get at any of this stuff for a while, but when settled and audio room set up I will certainly take you up on the offer and drop you a line.
Thank you again,
Aubrey
If measured I'd suspect you'd find clear difference in 3 characteristics namely :
1. output impedance
2. harmonic spectrum
3. phase of 2nd harmonic
Most of which can be fine tuned using 3 potentiometers P1-P3 described by Nelson Pass in his F5 Turbo article and ratio of the feedback resistors. Not easy, mind you, but doable.
Wasn't there a Carver guy that "tuned" amps to imitate the characteristics of some of the big names. He probably did it the way you outlined above.
I think throwing in another two pairs of trannys is simpler and closer to the original designers intention, plus less items/paths to go wrong.
Reminds me of a story where, in the 70's, the Japanese car manufacturers decided they wanted to build a "classic" automobile but they couldn't understand that a classic happens in time.
So they sent engineers to Germany to get the merc door clunk, jaguar to get the scent of the leather interior and to the US to get the purr of the V8 power house and many more.
When they returned they added adjustable pads to the inside of the doors that changed the clunk when tensioned, and each door was tensioned by a trained ear, they impregnated the leatherette upholstery with a man-made leather smelling fragrance, and then redesigned the silencer/muffler to get them to "bark" a bit more. There were many more design mods including shapes and colours, but all of that still didn't make a Classic Car.
These days they probably do have some though!
I'll probably get in trouble for off-topic rambling - sorry about that!
I think throwing in another two pairs of trannys is simpler and closer to the original designers intention, plus less items/paths to go wrong.
Reminds me of a story where, in the 70's, the Japanese car manufacturers decided they wanted to build a "classic" automobile but they couldn't understand that a classic happens in time.
So they sent engineers to Germany to get the merc door clunk, jaguar to get the scent of the leather interior and to the US to get the purr of the V8 power house and many more.
When they returned they added adjustable pads to the inside of the doors that changed the clunk when tensioned, and each door was tensioned by a trained ear, they impregnated the leatherette upholstery with a man-made leather smelling fragrance, and then redesigned the silencer/muffler to get them to "bark" a bit more. There were many more design mods including shapes and colours, but all of that still didn't make a Classic Car.
These days they probably do have some though!
I'll probably get in trouble for off-topic rambling - sorry about that!
Hello,
Everyone talking about a le monstre with a completely different circuit and transistors is also off topic because it will be different amp. Could be good.
Greetings, eduard
Everyone talking about a le monstre with a completely different circuit and transistors is also off topic because it will be different amp. Could be good.
Greetings, eduard
Thanks Aubmar. I will try to design my own version soon (using modern transistor).
Have a look here, it is well worth 16 bucks - you can use the modern equivalent to get it up and running, and it will be a simple switch to change them later and you can hear the differences for yourself.
There is the matter of Y grade K170/J74 pair that new builders need. Klaus Scherm solution won't produce the same sonic signature. 🙂
Yes, currently I'm using something similar from Panasonic. But I have never used the original small package transistors.
When I change the output transistor, everything else will change too. It's not going to be Le Monstre anymore. But I think the most critical one or the limitation will be the driver. I have almost complete collection of Sanyo video transistors to choose from.
masag1
Very interesting project. Can I buy (do you sell I mean) 2 pcs for a stereo system ?
Elias
Very interesting project. Can I buy (do you sell I mean) 2 pcs for a stereo system ?
Elias
Bob Carver's "tuned" amplifier
Bob Carver has designed and sold several generations of power amps with selectable Voltage mode (low impedance) and Current mode (high impedance) outputs. The high impedance configuration is meant to emulate a vacuum tube, especially a Tetrode, Beam Power or Pentode output.
Many years ago, Fisher, when it was still an American company, had a continuously variable pot that had high impedance output Current feedback at one end and low impedance output Voltage feedback at the other. You could always dial something in-between.
I believe there was a console or system called the "Integrand" that servo'd its SPL and frequency response to optimize for room characteristics, carpeting, draperies and the number of sound-absorbent listeners.
I wonder if anyone ever bought or tried to mimic one. It goes far beyond second voice coil, accelerometer, optical or enclosure pressure feedback. MEMs pressure sensors were too noisy for my taste and I was too cheap to try a piezoelectric sensor. I've even tried a 10 GHz Doppler radar module for velocity feedback, with mixed results.
Ron
Bob Carver has designed and sold several generations of power amps with selectable Voltage mode (low impedance) and Current mode (high impedance) outputs. The high impedance configuration is meant to emulate a vacuum tube, especially a Tetrode, Beam Power or Pentode output.
Many years ago, Fisher, when it was still an American company, had a continuously variable pot that had high impedance output Current feedback at one end and low impedance output Voltage feedback at the other. You could always dial something in-between.
I believe there was a console or system called the "Integrand" that servo'd its SPL and frequency response to optimize for room characteristics, carpeting, draperies and the number of sound-absorbent listeners.
I wonder if anyone ever bought or tried to mimic one. It goes far beyond second voice coil, accelerometer, optical or enclosure pressure feedback. MEMs pressure sensors were too noisy for my taste and I was too cheap to try a piezoelectric sensor. I've even tried a 10 GHz Doppler radar module for velocity feedback, with mixed results.
Ron
masag1 any possibility to buy a pair of pcb
Instead of the above I like to buy a 2pcs set. By the way in Greece-Athens I only can find "BY" grade FET.
I'm very curious...... does this amplifier sounds more accurate than JLH's ? (No I haven't build till now neither of them and I don't have any experience with "class A". My builds are only class AB )
Elias
Instead of the above I like to buy a 2pcs set. By the way in Greece-Athens I only can find "BY" grade FET.
I'm very curious...... does this amplifier sounds more accurate than JLH's ? (No I haven't build till now neither of them and I don't have any experience with "class A". My builds are only class AB )
Elias
