Dx Blame ST - Builder's thread - post pictures, reviews and comments here please.

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I am spreading the Dx Blame amplifier all over the world

all them in diy foruns...all them for free..all them offering boards in group buy... each forum has their own board to offer their people at cost price.

This way, i am developing other boards...we have already:

Todd Johnson boards
Metal and Rudi red and gold boards
Rudi and Metal new board to come
Mitchel brazilian green board
Mitchel brazilian blue Supercharged boards
Zharmo boards

and we can have Alexmm boards too..his style is long strip..these other ones prefer square the same i prefer... Alex is one of the best layout designers we have to produce boards.... the only one seems to be a real professional.

I have already offered and files sent to forum management about Zharmo and also Mitchel blue boards...so...these things are inside forum management files.... Mark Cronander should have them and may do something with them in the future i hope.

I am spreading and having several foruns to increase my amplifier safety.... i can be banished or kicked out from this or other forum and others will take the responsability to continue to spread Dx Blame amplifier all over the world....why this?...because it is the best and i want to share this with people.

Genius design from Doctor Self...i made my personnal touch too...result great..the best...just the best i have ever listened too.... i have built and listen more than 6300 amplifiers...i have bougth other 100 along my life....this is the best..no doubts.

You should build several forum designs... i am sure you will like this one the most...Symassym will offer you more bass..only that...maybe more dinamics too..but has not all that magic..you should try both.

regards,

Carlos
 
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Boys, i am increasing rail resistors wattage...these 33 or 39 ohm ones

you have connected to rail diodes.

Some monsters have connected pre amplifier with several volts and smoked the series resistances because they have saturated VAS transistors.

They were already substituted, both VAS, by MJE15032 transistors..they are using heatsinks and i feel that these resistances should be bigger... 1 watt may be nice there..even 2 watts will be interesting..depends on the room you have in your board.... this is for safety to face monsters..and their criminal connections.

This amplifier is able to reach full power when you input 750 milivolts peak.... some guys connects 8 volts preamplifiers and turn the volume all the way up.

ahahahahahah!

regards,

Carlos
 

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Use back to back diodes at input...

Single diodes... as shown here :
An externally hosted image should be here but it was not working when we last tested it.


link: Analog Devices : Analog Dialogue : Input Protection

This will limit the input to +/- .8V (1.6v p-p)
For our "super amps" , to have a good amount of headroom , double (2 pairs in series) "back to back" diodes to get 3.2V p-p input limit. Good "fix" for those who "nuke" thier amps with preamps on steriods (10v p-p OP :smash: )

OS
 
But this clips the signal Ostripper

and this is not a very good idea as have sonic issues on that.

I would prefer an AGC style circuit, draining signal to ground without clip it... a fet receiving DC audio rectified captured in the output..adjusted to enter only when people overdrive the amplifier (not to kill dinamics...not to avoid distortions...just to avoid BIG distortions)

This is something you could cooperate and would be welcome..to develop the circuit... see AGC in the internet if this is not something that belongs your age...AGC is old and simple circuit, and can be highly developed.

This can be a "monster audiophile controller".....if they plug high level preamplifier, then signal will be controled without mess with the power amplifier.

I have made it once but was not good..... problems with hold and release time.

I was thinking to ask Hugh Dean...but the man is too much busy...he will not do it for me as he has his own personnal targets.

Monster audiophiles exists and they are not just few.... these powerholic guys does whatever they can to play loud...they increase signal in the input and also they install several speaker in parallel...hehehehehe... terrible these guys, they need a really heavy duty amplifier, something made to a hummer war vehicle....i have visited some and i perceived they do not perceive distortions....clipping and distorting at 5 percent is normal for them.....bass clipping and sinus transformed in square waves is what they listen...another world.... the "monster world"

regards,

Carlos
 
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Under normal conditions (under 3.2v p-p) the diodes would never clip and would offer a stiff upper limit to the input. AGC is known to me (basically a compressor).

Here is that circuit you mentioned (pix-below 1) link: http://www.arrl.org/files/file/QEX_Next_Issue/Sep-Oct_2010/Anderson%20Sept-Oct.pdf

This would be better put at the output of the preamp , one must note that either clipping or compression DOES alter the signal . Clipping sets a "hard limit" , but compression (AGC) might affect the sound otherwise. 🙁

OS
 

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Hi, I'm trying to put the final transistors (2SC5200 and 2SA1943) with HFE similar but they have very different HFE. The 5200 are below 50 and 1943 are above 100, what happens by placing the transistors so different?
I've tried more than 5 pnp and 5 npn but they are all with those values.
 
There's no problems, this is normal to happens

Sometimes this produces an interesting effect in sonics..do not worry about that.

the gain is the multiplication of the drivers and the output...so..sometimes these errors are compensated there.

Usually PNPs have more gain than NPNs...it is not easy to match them.... your results will not be different from the majority of folks..... this happens a lot.

Of course matched can be even better..but sonically i have tested and i did not find detectable differences.

What is your country dear Larry?.... we have not this information under your name.

regards,

Carlos
 
The NPN will draw approximately 1/100 of it's Ic into the base from the driver stage.
The PNP will input approximately 1/50 of it's Ic from it's base to the driver stage.

If the quiescent Ic is 100mA then the PNP injects ~ 1mA more into the lower driver than the NPN sucks out of the upper driver. What is the driver quiescent current? Will a 1mA difference in output base currents significantly alter the driver loads and thus it's sound performance.

Now consider peak currents to the speaker load.
Let's guess at ~5Apk to your speaker.
The NPN will draw ~ 50mApk from the upper driver.
The PNP will inject ~ 100mApk into the lower driver.
Will this imbalance in driver loadings affect performance?

I will be honest: I don't know how this will affect the sound performance.
 
What is Dr Bora's preamplifier output level and impedance?

What is the maximum output undistorted volts?...please inform if your numbers will be peak, RMS or Peak to Peak...also inform THD...this is needed because you should adjust your power amplifier to match it.

Bora is great....this amplifier may be excellent.

Dx amplifiers does not need preamplifier....here you have a video where it is explained why uncle Charlie does not use preamplifiers:

http://www.youtube.com/watch?v=VOJ4S9aTCPY

regards,

Carlos
 
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I would like to suggest dear friends to open a special thread about your personnal

interest and subject... we are running Dx Blame ST, post pictures and comments here....use some more posts to arrange another thread to go dear friends, and return soon to talk about Dx amplifiers too.

You know..not to deviate the subject..some posts can be OK!..but please do not continue too long.

Build a Dx amplifier boys.... already made?... build the second and then you will have two... and he third can be a Supercharged to use it for bass.

Each one that build my amplifier helps me to climb on more step in heaven's direction, as this drives me very happy... a Paradisiac feeling of gladness to cooperate with the community.

Grazie fratelli.

Carlo di Danesi (nona Italiana di Firenze)

Arrivederci.
 

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