Untitled Document

The philosofy behind the Mario series of amplifiers

Most REASONABLE people want a high quality amp , but practical considerations limits them from realising theire dreams ,

hence the DEMAND for a high quality stereo integrated tube amp , I forgot to mention that the demand was also for a COMMERCAIL pricing .

Being what I am , I am sorry but I cant change that .
My demands are purely on how can we obtain the best compromise for this .

Stereo integrated :

powersupply for all

high quality and SE design , well only the 300B fills the bill since it works at a normal voltage and delivers a decent power output and is easy to drive .

no general feedback , negative powersupply , and minimum of stages .

simple chassis , good looks and easy to build .

AND FULLY upgradable with many options .

There are different versions of this amp , as I build the kit to suit the customers :
The different versions are in chronological appearance :

Mario std :

he wanted a high quality amp with krone tubes , good solid engineering
this was the first version : rocksolid powersupply using my diode damper rectifier ( simulates tube rectifier ) and simple gain stages RC coupled 2C51 to 300B running at very conservative voltages and currents 430volts 90mA for 12 watts outputpower .

I believe this customer is very satisfied , all pictures are from him and he ordered the Daniella speakers to partner his design and currently he also ordered our non oversampling dac + CD player .

Franck M. :

This customer read all about tube amps , and desperately wanted the best deal on the planet but with a few of his own ideas implemented ,

like all beginners he was most afraid at having only 10 watts , so he demanded Krone valves for an estimated 20 watts , alltough I told him that the advertised 25 watts is a load of

Bullshit he insisted on having the KR52BX tube and a high voltage supply capable of delivering the necessary power .And all of this for a budget price .
I agreed because I was toying with this idea and needed a test person for this project so I designed the power supply ,

rocksolid and capable of holding 800 volts . from experience I know that 565 volts and 140mA would be a minimum for 20 watts and so it was done ,

I used the same 2C51 but thanks to the higher voltage I was able to increase plate resistors which is allways better .
The result :

Too much power was the complaint of mr Franck , and after a month 1 tube blew
And the KR guys refused to honor the guarantee they give for the tubes , this put me offcourse in a bad situation , so I offered another KR52BX at half price

( cut the apple in 2 ).
Since anyway he had to much power we lowered the high voltage to 535volts and then even to 460 volts running at 125mA , there is still ample power

( estimated 9-10 watts )
PLEASE NOTE that with regular 300B you would have more power !!!!!!!!!!

Again the customer is very happy with his amp , had me redesign his Audax kit filters to get a decent sound ( I told him the kit is good for the garbage , he is considering his options )
And I proposed him the Fabricio's kit with an added tweeter , but although it is in his budget he wants better value for his money

( which I can understand it looks cheap but I and Fabricio know it is far better then his old speakers ) .

The C3m version : ( design by Aquablue Benny Glass )

This started after Paulo asked for a chassis and all components for a Legacy amp by Thorsten.So I supplied the components for the driver and outputstage according to the schematic supplied to me from Paulo .
Paulo had massive hum problems , I helped him reduce most of them but it is allways the same ,

you need a quiet high voltage supply to achieve low hum levels , carefull wiring of you're AC wires ( used for the filaments on Paulos request , i allways use DC on filaments )or you can reinject hum to the driver for hum cancellation .

The original Legacy amp uses DC on the filaments and this may be the cause so
Paulo tried DC on filaments , then regulated DC LM337 , then LT1086 and It clearly improved the hum a lot , know he too is happy .

His version uses the SV83 as the original Legacy but as Thorsten mentions it is a massive improvement to use the C3m .
That's how the MARIO C3m version came to life .( designed by Aquablue)

As it happened 2 new customers came along with each there specific demands so I made 2 versions to please both of them .

The George C3m interstage version using 50 DHT triodes in the outputstage .

This version is tube rectified , uses nice meters on the topplate and excellent powersupply .
It is a simple amp , using negative bias for the outputtube and autobias for the driver .
The interstage provides optimum performance ( no coupling cap , and better tube loading )

George made a simple mistake in the construction of the amp , and had to drive all the way from Stuttgart ( 500Km) to my shop to cure the problem ,

he had inverted the grid and anode connections of the output tubes ,but no damage done .

His wife's comment on the amp when first listening ( they have a std 300B commercial amp )
IT SOUNDS CLEARER , BETTER .

The 2nd C3m version JOE's amp .

He has not build it yet , he went on a long holiday so just schematics , but it is the same as the C3m interstage without the interstage and with

krone 300B tubes using a special output tranny from Lundahl that can handle 120mA in the case he wants KR valves like to draw more current .