This is the DHR.... Dx High Resolution Turbo - diyAudio
Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 16th June 2008, 09:07 PM   #1
diyAudio Member
 
destroyer X's Avatar
 
Join Date: Feb 2004
Location: Recife - Brasil Northeast
Default This is the DHR.... Dx High Resolution Turbo


Made for Brazilian powerholic.... it is the "marriage" of the Dx Standard, Dx HRII and Dx Precision 1 amplifiers.

The idea was to use the good points of those amplifier, to use the same supply (two 27 AC transformer coils installed in series) to allow you to have simetrical 70 plus 70 volts DC.

Effort was applied not only in sonics, but in special to obtain power into 2 ohms and 1.5 ohms loads.... and i could reach 650 watts RMS, continuous, sinusoidal, undistorted (unclipped) into 1 Kilohertz and flat from 5 hertz to 100 Kilohertz... sensitivity of 750 milivolts to full power.

Into 8 ohms power is not special....only 260 watts RMS.

Supply needs 20000uf each rail, and to each amplifier if you gonna use it into 4 ohms speakers (8 amperes) ... twice of that will be needed if you decide to use lower impedance speakers.

Off set is lower than 1 milivolt and bias is around 100 miliamps (force output to conduct)... zener is 1 watt for safety reasons.

500 miliwatts of more to the bootstrapp resistances

3 watts or more to the output emitter resistances

I have assembled this one last year, into December... and i found it great....have not show to you (the early basic schematic, the one i have made modifications today)... i was silent about this one because of Precision 1..... it was under development last year(board).

Diodes must go to the heatsink...they must be insulated using thermal tubes and attached into the heatsink using glue and thermal compound into the places the diode touches the heatsink...glue goes to the resistance series extreme points.

Avoid too much long wires to this one.... despite it is not too much sensitive into those points (not a tripple darlington) it can result a problem if you use long wires...make it shortest as possible.

There's nothing absolutelly different, just a retuning and a marriage fo those amplifiers i have told you..... adjusted to produce power into lower impedance loads...just that.... reliable, good in sonics (alike HRII).... powerfull as the Precision 1 (more powerfull into low impedance loads)

To use into 4 ohms... i suggest you to use 6 pairs of transistors... will be more safe than the 4 pairs you see into the schematic...was problem of space into the simulator to draw the sketch.....of course, to use into 8 ohms only...you can use 3 pairs... and even into 4 ohms...but better to increase if you gonna plug it into crazy loads.

Well, i do not know if there are someone interested..... if you need something, just post here and i will supply you the needed informations you may need.... transistors are 2SC4793 and 2SA1837...into the output use 2SC5200 and 2SA1943 or other unit with the same, or better, specifications of voltage,current, power dissipation and gain.

Enjoy another Dx amplifier...they are all very nice.... this one has controled thunder bass...huge power...excelent dinamics and special treble too... voice is normal.... about sound stage i have not idea about..have not tested this one in stereo.

regards,

Carlos
Attached Files
File Type: pdf dhr.pdf (14.1 KB, 3095 views)
__________________
Brazilian Airways Christmas Message to all of you!
https://www.youtube.com/watch?v=HFGM5K-WWnY#t=135; Unbeatable!; https://www.youtube.com/watch?v=u4tGBiqMnzQ
  Reply With Quote
Old 17th June 2008, 12:24 AM   #2
quoydoy is offline quoydoy  United States
diyAudio Member
 
Join Date: Apr 2008
It's so good to see another amp here fired off by your never resting neuronians!

I just picked up the bridge rectifiers for the HRII power supply, and I'll make my electronic debut by building that amp first.

This amp looks intriguing for a speaker I have, but I have a lot a catching up to do.

I just wanted to thank you for being such a generous and giving person. I continue to read the HRII and Precision threads, and have learned what little (extreamly little) I know from those.

So, very best wishes with this new amp Carlos.

Brian
  Reply With Quote
Old 17th June 2008, 12:32 AM   #3
diyAudio Member
 
destroyer X's Avatar
 
Join Date: Feb 2004
Location: Recife - Brasil Northeast
Default Thank you very much.... your happyness is what moves me


The Dx Amplifier thread.... Dx amplifier, my amplifier, teaches a lot, because we have studied a lot of things since the early begining...there you have descriptions and how to force an amplifier to work.... a simplified design method or Dc biasing into transistor audio amplifier stages....there you may learn something.

I am happy you have appreciated this one...it has something about the others inside....the good points...the good sounding circuits put all together.

Enjoy and be happy, i am sure the amplifier will cooperate with your joy.

Carlos
__________________
Brazilian Airways Christmas Message to all of you!
https://www.youtube.com/watch?v=HFGM5K-WWnY#t=135; Unbeatable!; https://www.youtube.com/watch?v=u4tGBiqMnzQ
  Reply With Quote
Old 17th June 2008, 12:46 AM   #4
AKSA is offline AKSA  Australia
diyAudio Member
 
Join Date: Sep 2001
Location: Melbourne, Australia
Carlos,

Very nice amp - highly refined, congratulations, and thank you!

I suspect the emitter resistors for the output NPNs are in the wrong place; should be under the transistors, not at the rails.

Apart from that this would be an extremely clean, dynamic amp.

Ciao,

Hugh
__________________
Aspen Amplifiers P/L (Australia)
www.aksaonline.com
  Reply With Quote
Old 17th June 2008, 01:08 AM   #5
diyAudio Member
 
Join Date: Mar 2008
Default wow, monstar amp

hi DX,

wow, monstar amp. how about the watts into 8ohms? its like more easy to build then Pre-I. is this more sweeter then prc-I?


waiting waiting......tick tak...tick tak.....

best regards
micahel
  Reply With Quote
Old 17th June 2008, 02:36 AM   #6
jaycee is offline jaycee  United Kingdom
diyAudio Member
 
Join Date: Apr 2004
Location: Norwich, UK
I have the same comment about the resistors on the NPN outputs.. surely they should be at the emitters...

Oh, i'm also wondering why the zener-resistor arrangement for the LTP, instead of a transistor-LED or transistor-transistor based current source? Just curious - i've read so often that zeners are noisy and should be avoided at such places
  Reply With Quote
Old 17th June 2008, 04:43 AM   #7
diyAudio Member
 
Join Date: Nov 2004
Location: Florida
Also, I'm wondering, is that VAS/47uf bootstrap & 3.3K+3.3K setup strong enough to drive the transistors into 2 ohm loads? On an amp I built similar to yours (75V rails) I used 2.2k+2.2K and 470uf bootstrap for 4 ohm loads (even though 2 ohms tested fine)

And yea, to enable current sharing, you have to use the resistors in the emitters. The gain is based from b-e voltage, not b-c, so you want emitter resistors to even out the b-e voltage and gain of all the transistors. This keeps one transistor from running hotter than the rest.
  Reply With Quote
Old 17th June 2008, 10:17 AM   #8
diyAudio Member
 
destroyer X's Avatar
 
Join Date: Feb 2004
Location: Recife - Brasil Northeast
Default Will fix the emitter resistance mistake..sorry folks


Yes.... zener produces noises.... the capacitor there hold the job to kill those noises.

Space:

"This one eat the Precision into the breakfast... easy!...laughing"

The best one comparing the three amplifiers made.... better than Dx Standard, better than HRII and better than Precision 1.

You can go to it.... will be very happy and i am sure will thank me a lot by this suggestion.

I could not create anything better...so, i have decided, the way i have done in the past, to join the best points of each one of my amplifiers... the wonderfull bootstrapp is there, and something from HRII and from Precision 1....I have tried Precision II VAS too...i have not the Precision II schematic, i have lost my Hard drive.... and it belongs to Nordic.

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

Yep

I have tried bigger current to the VAS dear Workshop.... and found even better (sligthly better) to hold lower impedance loads...but had problems of temperature....i turn myself afraid to have problems into the master VAS, because of heat and the consequences you have into transistors... also, i have tried to avoid to place the VAS into the heatsink, because of capacitance effects...i found that big heatsinks mounted into that transistors may damage the transistor leads.... because of that i have decided to that current (lower than 10 miliamps).... also i feel afraid to use bigger current there as i have decided to take the risk and to avoid the overcurrent control...that small transistor youc an see into the Precision 1.... aaaagh!.... the problematic one!

I have tried CCS into the drivers... have forced 20 miliamps, 30 miliamps, 40 miliamps and 50 miliamps into them, using two CCS, one to each driver, a transistor/zener/resistances arrangement feeding the VAS...but i have found compressing audio and mufflying the high frequencies too..... the CCS was removed and i have increased the current into the VAS...now bigger than the other amplifiers i have made.

Decisions was made listening....and i remember i found the heat..ahahahahah...the emitter resistances wrong place..ahahahaha.

Carlos

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

To the ones appreciate big condensers into the board...this one, as uses rail resistances, may need big condensers...or at least, will not be any problem to use them but how they will look.

regards,

Carlos
__________________
Brazilian Airways Christmas Message to all of you!
https://www.youtube.com/watch?v=HFGM5K-WWnY#t=135; Unbeatable!; https://www.youtube.com/watch?v=u4tGBiqMnzQ
  Reply With Quote
Old 17th June 2008, 11:55 AM   #9
diyAudio Member
 
Join Date: Mar 2008
hi DX,

oh my god.......when i saw it, i was thinking it might be great to listen then prec-1....anyway i just saw on the circuit design that you didn't write some transistors part number. can i have complete diagram pls?
also about the heat sink and other info.

thanks for great amp you are contb to all of us. many thanks to you.

i am still listing your prec-1, sound great. can't wait to make this....ha...ha..

best regards
michael
  Reply With Quote
Old 17th June 2008, 01:52 PM   #10
diyAudio Member
 
destroyer X's Avatar
 
Join Date: Feb 2004
Location: Recife - Brasil Northeast
Default Here is the corrected schematic..sorry folks


Dear Space.... let me know in advance your supply voltage.

Also your speaker impedance.... your music style and if you will really use it into the maximum power for long time.

Then i will give you AC transformer voltage, current, electrolitic condenser values to your load and type of work.

I will be glad to enter you informs into the simulator to give you better informations about bias resistance value to be pre adjusted, voltages and currents to help you to debugg the circuit if needed.

Thank you by the confidence and preference into Dx Corporation Products (just a dream...we do not pay to dream folks!)

I am sure you gonna be satisfied!... 200 % more guarantee of satisfaction compared to my other amplifiers.

- "Give to the heaven spirits the chance to enter your home to listen paradisiac sounds"

Carlos
Attached Files
File Type: pdf dhr turbo.pdf (14.1 KB, 1447 views)
__________________
Brazilian Airways Christmas Message to all of you!
https://www.youtube.com/watch?v=HFGM5K-WWnY#t=135; Unbeatable!; https://www.youtube.com/watch?v=u4tGBiqMnzQ
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 11:41 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2