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-   -   TUBE/MOSFET/BJT hibrid amp need help with mosfet/bjt section (http://www.diyaudio.com/forums/solid-state/226892-tube-mosfet-bjt-hibrid-amp-need-help-mosfet-bjt-section.html)

MINER 2nd January 2013 02:38 PM

TUBE/MOSFET/BJT hibrid amp need help with mosfet/bjt section
 
Because i cant get help with this in tubes/valves section, i`m opening thread here with HOPE , that SOMEONE whould be able to HELP ME. :o:)
I need help with the current/transistor section of the amp :wchair::cool::)
Sorry -___- looks like dont know how to post smaller pics with the enlargement option.................
I`ve put just links for the second, and third picture
I`ve read thru part of the moskido thread, and few others, and there are some good:p:D ideas, and some not so good:p:D but i would like help for some of the designes, i havent seen in those threads :) I`ve made a few modifications to some projects, i have found., but i`m not experienced designer, nor so knowledgeable about suitable elements for the design, i want to achive/make:) So i want to present, design idea by design idea, and to finish it:) with your help :):D
I`ll upload the original design(s) that inspired me, and the resulting one, to polish&finish it without blunders of type "ooooupss i didnt know that":rolleyes::cool::D with your help ^___^
I`m new to spice, so i`ll TRY:rolleyes::D to do something on my own, but dont hold your hopes to much for that XDDD :p


I will start with the design i saw/found in Elektor 1997 september :p:D
This is the tube section of the amp
http://img707.imageshack.us/img707/3207/11uz.png


this is the original current section

http://imageshack.us/a/img203/3061/hibrid1.jpg

and this is the modified current section

http://imageshack.us/a/img96/5227/en...hibridpr1s.jpg

For cheaper version up to +47/0/-47V i consider BD912 T6-T13 / BD911 T14-T21 with R20-R35=100ohms, and R36-R51=0,27ohm

For better option(and higher voltages), i consider 2SC2992/2SA1216 pairs and MJL15024/MJL15025 , MJL21193/MJL21194, 2SC5200/2SA1943 as other options :)

Quote:

Originally Posted by MINER (Post 3306801)
I started this thread because i didnt want to bury my posts under 200+ pages of posts in the moskido thread .......
Also i`m gona post some other moskido, and non moskido designs that i have modified, and in need of help for finishing them.
Can someone help me with sugestion about usable BJT-s, R20-R35 best values for the sugested BJT-s, and with boucherot-s network values, because i supose the old ones are not suitable for new design.
And how much smaller values can i use for resistors R18&R19???
Or should i open a new thread i solid state part of the forum???

@kenpeter: - CCS is not a junk, and has a good role i CMRR, and preventing the oscilation in mosfets.


TANDBERGEREN 2nd January 2013 05:07 PM

DAMNED, those pics came out big on my computer.

44250 2nd January 2013 06:42 PM

2 Attachment(s)
yes,he should learn how to use "manage attachments" button...

wasnīt it possible to use two drain- and two sors- resistors at driver fets instead each bp output transistor having itīs own? simmilar output stage could been seen at boraomegaīs (Borivoje Jagodić) "Lambda" and "CroSer" amplifiers. The description about those two amplifiers you can find at :::Borina Amaterska Svastara::: under AUDIO/POJAČALA/... boraomega said there that it was Andrej Laknerīs idea wich he used in those two ampīs,here are the schemes:

MINER 2nd January 2013 07:39 PM

THANK YOUUU 44250 ! XD
Finaly, someone with something useful :D
I`ll try to learn manage atachements :-) Those pics half of time pop-out in normal size, sometimes big, until then i`ll try for some pics to post just links for them :-)

I`ve had a quick look at the pics of schematics you posted(realy realy nicely engineered amps, i`ll look in details later for shure) Yeah , i know its posible to put just one(like in compaund output stages) but if its like this i dont have to calculate the ohms, and the wattage is evenly distributed on every resistor, and any inductivity if i use cheaper resistors is lessen. Using both NPN and PNP on both upper, and down output stage parts should maximally cut down the crossover distortion+ the configuration allows puting double number of output transistors(in the drawing i`ve put 8(up)+8(down) because there was no place on paper for 4 more, for using BD911/BD912). In the MPA amp from elector(where they used BD-s, they used separate resistors for every transistor), and it has its advantages, also in that i wont have to hunt odd values of resistors for adding, or subtracting aditional transistors. But there is a catch, idealy all four transistors should be maximaly matched(quadruple matching), the minimum should be like in normal(matching upper, and downer device) npn/pnp matching(thanks to you 44250 i now have more transistors as an option for output devices :D )

Can you tell me something about R18/R19 in schematics, can i, and how smaller values can i put infront of mosfets ????

MINER 2nd January 2013 08:13 PM

Can someone do the simulation of the modified circuit, because i still know my way around SPICE, and dont have simulation models for the most of the output BJT-s i consider to use ???
PLS? :-)

MINER 7th January 2013 02:27 AM

Is there anyone ???

MINER 20th January 2013 07:54 PM

The link in previous post is invalid now. Here is the new one, and new three more schemmatics :-)
All schenatics in this post are UNFINISHED designes for which i need help with, from the people on this forum :-)
These is the original starting point design for the schematics after this one.
http://imageshack.us/a/img11/7320/hybridschem.jpg



http://imageshack.us/a/img13/8572/24372437.jpg

hibrid project 2
http://imageshack.us/a/img560/1467/hibridpr21.jpg

hibrid project 3
http://imageshack.us/a/img407/1474/hibridpr3.jpg

hibrid project 4
http://imageshack.us/a/img90/3663/hibridpr4.jpg

hibrid project 5
http://imageshack.us/a/img266/1162/hibridpr5.jpg

ilimzn 20th January 2013 10:26 PM

Quote:

Originally Posted by MINER (Post 3334892)
The link in previous post is invalid now. Here is the new one, and new three more schemmatics :-)

All of the above haave fatal errors in the circuitry which will at least make it non-functional but in most cases instantly explode some transistors on power up. Which is what you get with simulator designs where someone has forgotten to simulate real world situations.

MINER 21st January 2013 09:00 AM

Quote:

Originally Posted by MINER (Post 3307986)
:) I`ve made a few modifications to some projects, i have found., but i`m not experienced designer, nor so knowledgeable about suitable elements for the design, i want to achive/make:) So i want to present, design idea by design idea, and to finish it:) with your help :):D
I`ll upload the original design(s) that inspired me, and the resulting one, to polish&finish it without blunders of type "ooooupss i didnt know that":rolleyes::cool::D with your help ^___^
I`m new to spice, so i`ll TRY:rolleyes::D to do something on my own, but dont hold your hopes to much for that XDDD :p


I will start with the design i saw/found in Elektor 1997 september :p:D
This is the tube section of the amp
http://img707.imageshack.us/img707/3207/11uz.png


this is the original current section

http://imageshack.us/a/img203/3061/hibrid1.jpg

and this is the modified current section

http://imageshack.us/a/img96/5227/en...hibridpr1s.jpg

For cheaper version up to +47/0/-47V i consider BD912 T6-T13 / BD911 T14-T21 with R20-R35=100ohms, and R36-R51=0,27ohm

For better option(and higher voltages), i consider 2SC2992/2SA1216 pairs and MJL15024/MJL15025 , MJL21193/MJL21194, 2SC5200/2SA1943 as other options :)

It says in the very first post (as you can see from the quote) that i`m not experienced circuit designer, or that knowledgeable, the other thing is that i started from the WORKING, and already proven circuits, NOT simulations. And know for a fact that modification of elektor hibrid DOESNT have errors(so it means your lying), but i think it could use a little optimisation/improvment.
Third thing is that i stated that other 4 projects are NOT FINISHED designes, and NEED adjusting/finishing.
So, from your post i can only conclude that you are very rude, and with bad intentions.

For those with good intention, and will/knowladge to help, i think maybe 2SK2221/2SJ352 pair could be used without any pains of adjusting/modificating the tube section. Any thoughts on that ?

MINER 21st January 2013 10:12 AM

And one corection,because of the desire, and speed to show the ideas wrong version of schematic is posted, the hibrid project 3 is reuploaded.

http://img191.imageshack.us/img191/328/hibridpr31.jpg


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