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

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Re: Now a problem to build...too much pretty to my junk parts.

destroyer X said:

hummmm...... i think i will have to buy parts.

This board deserves..... it is wonderfull...quality is special.

regards,

Carlos

Hi Carlos,

Please follow the assembly instructions carefully. You might want to print the instructions off and tick each one as you go. I noticed you have done step 5, before steps 1 to 4. :D

http://users.tpg.com.au/users/gerskine/dxamp/dx amplifier-08.htm

reagrds
 
Ahahahaha...good mood Greg.

I think you turn happy because my boards arrived.

Very good friend you are.

regards,

Carlos

........................................................................................................

Nordic

Very interesting your drillpress.

Mine was mechanicall...Grrrr...i will have to buy other.

And no option....the damn plastic will be there to broke once more..... hummm... i hate that "third world character" we have here..... do things bad this way..... this explains why i use to construct so uggly boards.

Well...Greg saved me from the shame.

regards,

Carlos
 
Fine tuning your Dx amplifier... Klaas, Nordic, Greg, Inex...well, the ones

That have constructed and succeeded...and others that are already testing and adjusting, i have a suggestion:

As i am constructing more 6 channels, new boards to myself and two stereos for local friends... i realized that there are a small difference of voltages into the rails.

There's more consumption, in stand by mode (and also when listening very low power of audio.... the audio that shows details), there are a small difference of voltages into the rails.

I made tests and the amplifier turn more detailed into very low volumes, also the distortion (the sonics off the distortion), now, is not more so tube alike as it was before.

Into the positive rail, install 100 ohms resistance in the place of the 82 ohms (R15).

Into the negative rail, install a 220 ohms resistance, in the place of the 82 ohms (R18).

I have others amplifiers constructed...i will call them back to replace those resistances.

Yeah!....was my mistake.... sorry folks!

- "Dx Corporation, reserve to itself the rigth to make small modifications to provide full satisfaction to the ones listen our products"

The amplifier, as standard, works fine, sound is very good...now even better with fine tuning suggestions posted....Bias fine tuning and those rail resistances.

Dx amplifier loose in treble and mid ranges to the Magnificent Aksa 55..... but you can reduce that difference of quality, and presence including a capacitor in parallel with R10..... make this in a try and error basis...or...in an experimental basis....install 47N and listen..... and them go increasing the value till 100N.

This will change the midrange and in special, the treble level....not quality folks....level will be increased.

That wonderfull focus, sound stage and definition into woman voices...sorry...only going to Aksa 55

regards,

Carlos

.........................................................................................................

Dear Greg.

I am having problems to install my Japanese resistances (old ones) into your board's holes...they are small in diameter...i will have to buy new parts...but they will be smaller than the space provided to them.

Well, the same happened with Aksa 55 old boards.... no problem with lifeforce and no problems with Aussie amplifier boards.... they provide you perfect matched parts, but i had used different supply voltages and this created the need to substitute few resistances.

Space provided and distance between resistance holes, are bigger than my resistances and holes smaller than my need...this is my contribution to the Universality of those boards.

They are fine, boards are great...but my resistances are notso modern but i am afraid that smaller ones will be lost into the big space provided to them...but holes will fit....

Well.. other folks may face those things too, using our informations into the home page and producing boards...they may face hole dimension problems.

I strongly suggest you to check if some modification in holes diameter will be needed or not.

regards,

Carlos
 
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Joined 2002
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Re: Fine tuning your Dx amplifier... Klaas, Nordic, Greg, Inex...well, the ones

destroyer X said:
Dear Greg.

I am having problems to install my Japanese resistances (old ones) into your board's holes...they are small in diameter...i will have to buy new parts...but they will be smaller than the space provided to them.

Well, the same happened with Aksa 55 old boards.... no problem with lifeforce and no problems with Aussie amplifier boards.... they provide you perfect matched parts, but i had used different supply voltages and this created the need to substitute few resistances.

Space provided and distance between resistance holes, are bigger than my resistances and holes smaller than my need...this is my contribution to the Universality of those boards.

They are fine, boards are great...but my resistances are notso modern but i am afraid that smaller ones will be lost into the big space provided to them...but holes will fit....

Well.. other folks may face those things too, using our informations into the home page and producing boards...they may face hole dimension problems.

I strongly suggest you to check if some modification in holes diameter will be needed or not.

regards,

Carlos

Hi Carlos,

This information is only of interest to people that have manufactured boards. Please use private mail for such discussions.

Please read my email that I sent on Sat 26/05/2007 7:10 AM.

regards
 
Hi Carlos,

You wrote >>

Dx amplifier loose in treble and mid ranges to the Magnificent Aksa 55..... but you can reduce that difference of quality, and presence including a capacitor in parallel with R10..... make this in a try and error basis...or...in an experimental basis....install 47N and listen..... and them go increasing the value till 100N.

<<

What you are actually suggesting here, is like using the power amplifier as its own 'tone control' by reducing the level of high audio frequency NFB. Any capacitor used here has the potential to drive the amplifier into AF induced overload, so there should be a series resistor. Could I suggest no less the another 2k2, in series with a capacitor value of 22nF, and this be connected separately between the base of Q2 and the audio ground.

Really though, the external tone control stage you gave in an earlier post above should be better than altering the NFB of the amplifier from a nominally flat response.


Cheers ........... Graham.
 
All rigth Greg.... visit you inbox and mail will be found there.

Thank you very much Graham....was good to receive those informs from you.

Greg loves treble and mids...he do not apreciate bass...and also his speaker already produce bigger bass.... maybe this will correct his system...turning it more adequated to his home.

I do not know if Greg has tone controls.

regards,

Carlos
 
Attention please, Dx constructors modifications are welcome.

Dx constructors modifications will be welcome... to explain clear, the modifications made by Dx constructors will be specially welcome....modifications made by people that have already assembled Dx amplifier.

I have received complains from 2 of them....as they love to make experiences, and beeing already constructors that they deserve more freedom into their own thread...they are rigth.

I will not include those modifications into the "official, standard" schematic to avoid confusion.... our forum members need something stable...some circuit standard posted into the home page as a reference to construction.

Options were removed avoiding confusion...now things are under control, as everyone that wants to construct will have easy informs, working circuit, standard and fine.

Of course, Dx constructors, the ones that have already constructed and the ones are starting to construct, are the most important folks to this thread, to Dx Corporation and to me of course...those ones, that are cooperating with the thread are welcome with their modifications tested that will be posted in the forum...but i repeat that will not be included into the home page to avoid mess....only because of that.

Beeing into the forum, thougths and modifications, suggested, made by Dx constructors, and tested will be very good for all of us...this way, the one wants to construct will go to the home page, will colect data and will construct....if latter, decide to read the entire thread (i have perceived that not to many folks do that) will find updates, ugrades, tested and made by Dx constructors.

Everyone of them, Klaas, Greg, Inex, Nordic ....and others, are having good ideas and they are testing them...this is good and productive to forum thread and forum personnel.

Re-designers, re-calculators, upgraders, updaters, theorical people, figther group or theorists, discussion Squadron, Simulators, instrumentators, CCS holics, Mirror holics, Self Religious and all NON constructors are LESS welcome...because the amplifier is more than ready to go...now, it is time to construct, to diy, to hold soldering iron, to put our hands into work, to move our a... Those, above specified and other strange original freaks, despite precious and very usefull, hardly important, famous, kind, simpaticos, brilliant and incredible experienced....are not the main target...not the focus personnel...not the really wanted people to join Dx constructors squadron.

Constructors are more important, obvious, as they gave their time to try Dx amplifier, they have placed some confidence into a strange, cheap and simple amplifier...they have worked for Dx amplifier...so...they are invited to post, inform and discuss things about....and they will be extremelly welcome doing that.

Once again.... the basic schematic, the board and all stuff will keep the way they are, the exception will be errors that would need correction, but upgrades, updates, modifications and so on...from the "Constructors" will be offered, by them, into our thread.

Dx factories are working hard....you can see in this picture that 8 channels are "on the run"...at same time.

I hope it is raining your place and friends are courageous enougth to face some construction.

Be happy folks,

regards,

Carlos
 

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Hi inex,

You have an oscillation problem, possibly on the upper half of the output waveform only.

I went to e-mail you to try and figure out what is happening, but the link via your profile is turned off.

So many things can influence susceptibility to oscillation, and I would be wary of leaving a C.dom at 100pF, but much more information is necessary before other suggestions can be tried.

Cheers ............ Graham.
 
Perfect Graham...i am glad you are taking care of this subject related Inex.

Macd also constructed the amplifier...but he is a little bit distant from our forum...a pitty that.

Well...i am constructing and i made a break....all board will be ready almost the same time, as i am installing parts alike series production...R1 goes to all boards...and them R2 goes to all boards...this way.

But i am lazy during weekend...i use to stay with family.

Here is some VBE multipliers.

Yes!..of course a condenser from colector and emitter is interesting...also 2K resistance will work fine, 1K8 will work too...a matter of adjustment.

regards,

Carlos
 

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Yes..... i like this method...it is very interesting...the board is insulated, you

... can use glue and attach the board anywhere.

The transistor, beeing plastic, do not need insulation...just an screw or some PVC glue will keep it tigth against the heatsink.

The PVC glue is that old one, transparent, dry fast, used to glue plastic alike those Revell models.... covering the transistor and having leakage to the heatsink, you will fix the unit against the heatsink and the glue is resistant to temperature too.

regards,

Carlos
 

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We do not feel pain during operation Nordic

The movements inside our mouthes are not nice...but painless.

When going out from the Doctor, have a Sodium Diphirone or something alike, and you will be nice and happy during 4 hours...then...repeat again.... some coffee may help because of Cafeine.

I am feeling you a little bit scared..... fear is bigger than the reality...you will laugh because of those things soon....we gonna laugh together.

Nice construction, yeah, progress is clear, and heatsinks mounted in this position seems very professional.

I am doing some mechanical works here too Nordic...working on heatsinks, polishing them...well, those things... a rainy day this Saturday.

The heatsink i am showing you, is the better one i have....related beauty...but not able to hold 100 watts......maximum will be 80 watts...so...a fan blower will be helping it.

The Aksa, and Symassym case will be borrowed to receive my amplifier...well.... this one is mine!

Others will be waiting other case...they are in a safe place...very good amplifiers those others.

Here is an image.

regards,

Carlos
 

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E-mail is enabled now

the capacitors were 22pF, going to experiment with values later and will also try some other drivers.

the transistors i am using now are toshiba output

mje15030/31 drivers (brand unknown)

bd139 Vas (philips)

bd139 VBE (brand unknown)

bc557 input (i think they are philips but i'm not certain about that).

I still only got 1 channel so i cant compare yet. and i dont have a scope at my place.

When this channel is working fine i am going to make the two final boards for the amplifier.

here is a pic of the amplifier case, the heatsinks are small and the transformer is even smaller but i think its going to work fine.
 

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I am happy to have you back Inex

The heatsink is nice...also transformer and case.

Your amplifier will be very pretty.

You may have heatsink enougth, because of the back plate and the bottom plate...well, both of them will need cooling holes..under holes to capture air and hole in the top to start the convection current.

Air to move, to circulate, will need entrance and exit...do not close the upper cover and open holes into your bottom plate.... 15 milimeters into the top, back side panel and the same area of holes created in the internal bottom aluminium panel will allow you enougth cooling to use a stereo amplifier, in 4 ohms loads, at full power.

Make your top cover 15 milimeters shorter related the deep dimension.

Without holes made to upper and down the case...and without rubber feet to allow air entrance..your heatsink capacity will be reduced to half the maximum capacity....around 150 watts in the place of 300 watts of capacity.

Covering the case.... without good cooling..without bottom panel holes and rubber feet, you will be able to use a single channel.... having holes, then 2 channels will work fine inside your case.

regards,

Carlos
 

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Re: The Dx amplifier schematic.

destroyer X said:

attached. an special offer from my friend Greg Erskine...sorry the quality, i have to change thing and to reduce size to fit forum

regards,

Carlos
Carlos i have a legitimate querry. In this schematic, it does not appears an input terminating resistor. I mean that, before anything else in circuit. Have you attached some outboard input potentiometer?
Regards
Fotios
 
More well come constructors....less welcome modifiers

This was said, clearly and before.... also more than once.... and i am sure you understood.

If you want to know, everybody already perceived you have know how Mr Andrew T..... maybe you do not know is that you are almost the "post champion" of our forum, posting more than some famous moderators...also beeing more helpfull than our "ethernal" postings of Mr. Cordell and others.

You may have your reasons, maybe free time or some mobility problem that attached you in front of the computer....well....the subproduct of this resulted good for us, as you are always precise and competent related thougths, suggestion and ideas.

I do not love deeply theories, only the one applied to some circuit as the matching resistance you suggested.

Also i am avoiding Mr. Fótios and Mr. Sakis.... as i have perceived some problems related my own acceptance of their behavior...maybe my own misunderstandings about them...but, while not sure.... waiting some time to continue to have good relations with them..... i put them in ignore list for a while...to avoid frontal crash inside our forum.

I have to say they are the 2 guys i am avoiding, for a while, as i felt something strange about them.... i am just waiting the dust comes down to re open conversations with them.... as no one have absolutelly sure of other folks intentions... i perceive something strange that turn me annoyed....just that.

No one is blocked in spam list or forum ignore list....just those folks...and for caution purposes...also for a while.

But i have friends that knows what i am telling all forum folks now, and they perceived, once more, the strange question...too much obvious to fótios, as he is deeply experienced.

- "Everybody is free to connect any input terminating resistor into
the input terminals, for source loading purposes... the Dx Amp.
is a general purpose amplifier, and it will work either HS or SS
source equipment"

Related improvements, or modifications...or other name we can call ..... it is a matter of organize things only...to provide thread visitors, to fast obtain the needed informations to construct... standard informations....because reading the thread, very long and dense in informations, the one can be confused with many options, improvements, modifications and will not have sure if those modifications have value or not, without reading the entire thread.

So...there's something always fixed there, a reference.. the Dx Amplifier Home page prepared by Greg Erskine.

After construction, if the one wants to tweak...of course, the board owner is free to do whatever he wants with his own property.

Also, the one can read the forum thread entirelly, having many suggestions posted, including some suggestions posted by your Mr. Andrew t.

Related modifications...each one of us have different ideas about those things....for precaution...to be carefull, i tried all CCS, mirrored and exotic styled designs...and i made them in real world and tried them into Dx amplifier.... this one is the circuit that was simple, cheap, with low parts count.... good sonics..just that...no pretention, no intentions, to be the best fine piece of world jewellery...we already have those fine things in our forum, in our communitty and gems at Stern shops too.

Imagine someone that had problems with girlfriend, or wife, or something related women......he may paint Monalisa (joconde, Gioconda) this way....Nah!.....better the original!

regards all folks,

Never mind and be happy

Carlos
 

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