Destroyer x Amplifier...Dx amp...my amplifier

[destroyer X]

YouTube - Antonov boards factory & Marcisium Labs.mpg

regards,

Carlos

[destroyer X]

where aborted.

I am producing another filter, this one entirelly discrete, and the active filter from Marcisium Laboratories will be fixed...well...i do not like chips anyway..let's see what gonna happens....for a while, the TriAmp project wil be in stand by mode.

regards,

Carlos

[destroyer X]

is a 100 watts unit...... was inspected in the waveform and was fine too..also simulator it is fine too..distortion is around 0.023% (thd)

Sound is nice and respectable.... the Dx Blame ST beat this one in many things, but this one continues to be very pleasant, having super interesting huge loosen bass (looooonger than normal, also more intense).

Treble appear fine if we increase equalizer in 6 dB to the treble range...the amplifier is flat...but this does not mean it will be acoustically flat..depends several factors.

Braveheart soundtrack reproduced using the Dx Amplifier shows the drums much better than the Dx Blame ST.

Waveform is 20 kilohertz, 10 volts per division

I am having fun.... dinamics is interesting too.

regards,

Carlos

[destroyer X]

YouTube - Dx amplifier, camera mic saturates

Camera mic saturates with huge bass.. and anything more is recorded than the bass.

The Dx active crossover is under construction..here you have the treble unit..all discrete this one.

regards,

Carlos

[destroyer X]

Listen this recording i have made today:

http://www.youtube.com/watch?v=8sTbEfpnXzw

regards,

Carlos

[destroyer X]

A lovely "generic" amplifier from the seventies and beginning of eigthies, almost all factories have used this schematic, now a days Chip amplifiers uses, also some big STK chips use this schematic..they use because it is good...internally, the LM3875 chips, and others, are not too much different too.

regards,

Carlos

[destroyer X]

Greg's Web Site

regards,

Carlos

[destroyer X]

will be in stand by for comparison...here is a short video:

YouTube - Dx amplifier... mine one!

regards,

Carlos

[tinitus]

Are you now using BD139/140 as drivers, instead of TIP41/42 ?

[destroyer X]

I have mentioned we could use BD139/140 too..... the amplifier is more reliable, more resistant to oscilations when using TIP41/42..... these former ones are not oscilation addicted because their maximum operational frequency is low.

I have received a bunch of nice BD139/140 from Anonimous, our forum friend.... he sent me matched pairs, high quality ones, also insulated, the ones have not the metal tab in it's back face...... so, i am using them..... despite they are finishing and i have 7 pairs remaining only.

BD139 and BD140 can work up to 100 volts (be carefull, some can work till 80V)...this means i can use supplies up to plus and minus 50 volts without burn them... current and dissipation are not so good for drivers, reason why in some amplifiers, alike DHR Turbo and some others that operates with higher supply voltage, i am using 2SC4793 and 2SA1837.... the maximum supply voltage, without the need to change parts in this amplifier is plus and minus 42 volts.

There are several possibilities for replacement, we have just to respect the main parameters to have the transistor operating within the linear portion of it's graphic....maximum current, maximum VCE voltage, gain.... well, the very basic parameters that let us free to choice several others, there are hundreds or pair we can use, not only as Differential, also as VAS and Drivers....... also to output we have several options.... depending what i have, then i go using.

For the differential i love to use BC556, while the 2N5401 is the original transistor.

For the VAS the BD139 was always the selected one, to the output we can use several types, as the big Sankens, and some medium sized Sankens too, the 2SC3281.... or the evolution, the 2SC5200..... the FJL4215/4315... also MJL21193/21194...and several others, including 2N3055 and 2N2955 when using 8 ohms loads only.... depending the supply voltage, you can even use TIP41C and TIP42C.

I use what i have at hand...because made several tests and have built several and i could not perceive difference in sonics when substituting transistors...as no replacement one is wrong...maybe a wrong replacement, out from the linearity region, will show sonic differences.

Builders have not used the TIP41C and TIP42C..... the big majority have used other transistors..since the early beginning we had people giving their "personnal touch" in this amplifier...one from the very first ones was Klaas Veenstra..que used different transistors as drivers, some BD prefixed transistor.

Some transistors are sensitive to oscilations, in special the ones have higher gain and the possibility to operate under high frequencies..... 2N5401 was a problem several times.... also MJE340/350..... reason why, at least the MJE340 and MJE350 i use to ask people to avoid to use...... 2N5401 belongs to the first schematic, the first board...too late to change that..but i would prefer BC556.

regards,

Carlos