Now we gonna have special speakers by Lira.... hand made, glued with special 24 hours epoxi glue.... special soft spider... rubber soft suspension to reduce the resonance frequency, special enammeled wire, two coils over a kapton material (do not burn till 400 degrées celsius), special high power double Alnico magnets, special diafragm that cannot be twisted into operation, long complicance, high power and high quality.
I have closed my forum...too much spammer entering publishing porno images..also advertisers entering publishing medicine drugs...the man that was taking care of my forum could not filter that...then i decide to block the forum not to be helping people to publish dirty things to the whole world using my name for that.
We continue working...Juan Vargas from Puerto Rico has sold all his pcboards...was 32 USD the kit i think including shipment...all them sold.
Now we have developed the Dx Supply... a voltage regulator... a vintage series pass regulator, a circuit using error amplifier and several series pass transistors in a darlington connection..adjustable and stabilized within 0.25%..... capacitance multiplier filtering of ripple...something good to the Dx Super A amplifier.
I have assembled and i am using the supply... several videos published in my channel about that..you can go and see..type Carlos Mergulhão and then you will be directed to uncle charlie lovely channel (hehehehehehe)
Zimmer, a Brazilian Kraut (German from Brasil) that lives in the South of my country, Rio Grande do Sul State (South big river) is producing layout for the second Dx Supply, this one much more huged, able to withstand 2 channels of the Dx Super A operating at 2 ohms and full power (340 plus 340 watts RMS).
He is making the layout now a days...he will manufacture and will supply pcboards of the supply and also the Dx Super A with pcboards made in Brasil....price will be almost the same as Juan made....something around 32 USD for a kit including shipment .... some places may be more expensive because some distant countries have higher shipment cost..this is the average value for Europe, Africa and North America... i do think Asia, Mid east and Australia may be more expensive.
Power supply, the Dx Power Supply, may look this way
It gonna be good to feed two channels pumping 350 watts RMS each channel, distortion of 5 percent THD, 2 ohms loads.
This amplifier is 80/150/330 watts RMS with low levels of distortion...8/4/2 ohms.
Supply is to reduce cost of electrolitic filters, because it uses capacitance multiplier effect, has error amplifier, stability full power of 0.25% and adjustable from plus and minus 15 volts to the maximum input voltage of 48 volts DC symetrical, aproximately 800 watts of power.
Here you have the schematic from the Dx Super A and also the Dx linear supply
I suggest you to use them together..the supply must receive 46 to 48 volts DC in it's input and should be adjusted to 42 volts and nothing more because the BD139/140 cannot hold more than that...they can be damaged...so.... you can reduce your supply voltage..but cannot increase.
The Dx Supply has trimpots and you can adjust your output voltage...the best sittuation is when you adjust 4.6 volts measure from coletor and emitter into the series pass transistor from the Dx Supply...this means you put one multimeter probe point to measure DC voltage into the colector and the other multimeter proble point goes to the emitter.
Stand by current to the Dx Super A is 250 miliamperes.
I was busy because my sons where here visiting me in Recife - Pernambuco - Brazil...now i am more free and on vacations from my daily job.
A Brazilian friend...half German (we have thousands in Brazil... descendents), wich name is Zimmer, is producing a SMPS and he will send me to test together my amplifiers..if approved, then he will be the SMPS supplier to go together my power amplifiers...for a while i am using an old style series pass regulator, with darlington output and transistor error amplifier...very simple and reliable.... designed by Ampex (Video Tape Open Reel Recorders) down the seventies.
This supply was tested for years long..i have build almost 2 dozen of them and distributed to Radio Amateurs....since the seventies and no one complained till today..rock stable, excellent filtering...i was avoiding to publish details because your forum is dedicated to SMPS..but, this may be a curiosity...some ancient circuit for you to see.
We have distributed 70 kits to the international comunitty , distributed by Juan Vargas Diaz from Puerto Rico...and now the white boards, to the Brazilian group, also distributed more 100 kits...these ones includes power supply..one power supply to two channels....
Dx Super A is able to put out 80 watts RMS at 8 ohms with 0.001% THD.... aproximatelly 150 watts at 4 ohms and almost 300 watts RMS at 2 ohms...distortion is 0.018% THD in the worst case scenario
Input impedance 56K
Sensitivity 700 milivolts to full power
Supply is 42 plus 42 volts (cannot be a little bit more because BD139/140 will be fried by excess of voltage)
And supply needs 1.2 Kilowatt to operate full power at 2 ohms.
It uses a simplified Super A circuit..that injects high current in low volumes, to operate in Class A mode, having none crossover distortions by transistor switching...and then when you increase the volume it switches automatically to Class AB...this joins together both worlds...the Class A world and the Class AB world..circuit is simple, based on a single zener and couple of other passive componentes.... very, very very simple..ridiculously simple.
Zimmer knows more than i know about SMPS...but even this way he is not that good...he is learning about.
He made one self oscilating but i have asked him to put a chip to control, a feedback.... now i have asked him to reduce the size because it was too much be...he is on troubles, FETs are burning..... sadly he does not speak english.... so,..... your help will not be possible.
Well...i will be waiting his progress..because as i told you, i have to test it in my home...and Zimmer supply can be sent as he lives in the south of my country and distance is less than 3 thousand kilometers...so...he can assemble and can ship it to me for testing purposes.
Because of that he is the one elected...because he can ship to me, also he can order manufacturer, also he can distribute....so... a good helping hand.
Zimmer does not speak good english, so...use simple words...he will use google translator..... if he face problems, then he will forward the message to me..then i gonna help him.
I am working for Brazilian Government, this is for life long job, result of a competition in my country and i was selected together 237 other guys in a few million guys in competition ..... i do not earn money because of pcboards..... when they sell 40 kits i have one kit for free to me... only that.
This may change in the future...for a while the price is low because we are using cost price (almost)
Final price is 37.5 USD that includes two audio amplifiers pcboards and one supply
pcboard.... the price does not include shipment.
They are new pcboards...re designed.... we have removed the "L" shape adaptor to allow better heat transference to the heatsink..these power amplifiers can put out 300 watts RMS at 2 ohms...this demmands direct contact of the power transistor to the heatsink.
Zimmer will provide White and Black pcboards to Brazilians.....pcboards made in Brazil.
Juan Vargas will provide Blue pcboards to the international comunitty...pcboards made in China.
Pcboards to Juan Vargas already shipped from China to Puerto Rico...when arrive he will assemble one unit for testing, will ship one unit to Brasil and i gonna test it too, then he will make good photos and will publish...at same time he will open a group buy in www.diyaudio.com, solid state.
He is collecting reservations...this is needed because he have only ordered 50 kits...or 150 pcboards....and 20 percent of that already sold in one day.
Go to Juan Vargas Diaz, collect price with shipment included and make your reservation if you want these pcboards... each one 12.5 USD, no matter if amplifier of supply pcboard.
I see that no layout for home etching..... for DIY etching...i will manage to post for you to make it at your home.... i am sorry for that..my mistake..will post them here tomorrow... also updated schematic.
Pcboards are going to Puerto Rico.... departure from China already happened...in more 15 days they gonna be available for shipment.... Juan Vargas can ship from US using UPS system that is something we can trust... registrated with numbers that may allow you to track them using internet....payment is paypal money transference in advance of shipment...payment confirmed in 24 hours the pcboards gonna be travelling to your home.
About Zimmer pcboards.... we do not trust in Brazilian postal system to send you pcboards.....better is to order from Juan...but not forbidden to order to Zimmer if you want to take the risk for yourself...happened in the past that two shipments were lost...Zimmer pcboards will be available in October.