I just dusted my bookshelf of and found 2 books by Jan Soelberg called AE80, came to read about this AE 500 Amplifier, and then i wondered if anyone have any experience with this ?
I know it's old but at the time it should be a very good and expensive amplifier build on mosfets, with 4 securing circuits build in.(mostly for securing mosfets - they were expensive at the time).
Have any of you guys ever heard this amplifier, and could it be a possible DIY project ? or isn't it worth spending time on ?
Please give me your opinion on this.
I know it's old but at the time it should be a very good and expensive amplifier build on mosfets, with 4 securing circuits build in.(mostly for securing mosfets - they were expensive at the time).
Have any of you guys ever heard this amplifier, and could it be a possible DIY project ? or isn't it worth spending time on ?
Please give me your opinion on this.
Hello Frandsen.
Very nive finding I suppose. I did search local libraries and the internet several times to find the AE500 amplifier, but could not find the book or any hints on the internet.
Can you possibly scan the diagram and post it here. I would also like to compare with newer designs.
PS! Jostykit is closed and Jan Soelberg is not with us any more, dont think anyone would mind posting here.
Søren
Very nive finding I suppose. I did search local libraries and the internet several times to find the AE500 amplifier, but could not find the book or any hints on the internet.
Can you possibly scan the diagram and post it here. I would also like to compare with newer designs.
PS! Jostykit is closed and Jan Soelberg is not with us any more, dont think anyone would mind posting here.
Søren
I will visit you tomorrow steenoe and bring the book, problem is that the schematic is very "small" in the book, the book also includes BOM, and schematics fore the psu used at the time named NT500 it included 4 trafoes, but there must be an easyer way to make this today.
by the way the Amplifiers right name is AF500 and not AE500 as i wrote in the header.
There is also Smaller amplifier constructions in the book.
Could be fun to make one of this - if its worth spending time on.
by the way the Amplifiers right name is AF500 and not AE500 as i wrote in the header.
There is also Smaller amplifier constructions in the book.
Could be fun to make one of this - if its worth spending time on.
Hi again Rovsing
It is mainly the AF500 (and the powersupply) I have been looking fore as I am planning on building a DIY power amplifier.
I am living in Sønderborg. In the weekend, probably sunday, I am going to visit Odense anyway. Maybe we can meet, so there would be no need to pay for posting copies.
You are welcome to email further details.
Yours Søren
It is mainly the AF500 (and the powersupply) I have been looking fore as I am planning on building a DIY power amplifier.
I am living in Sønderborg. In the weekend, probably sunday, I am going to visit Odense anyway. Maybe we can meet, so there would be no need to pay for posting copies.
You are welcome to email further details.
Yours Søren
Short about the securing circuits
Output current limiter
2 zeners over gate/source in this case 2 10v zeners and 2 insulationdiodes
limits output current to 20 A
DC fault relays
R33, R35, R34, C16, C19, T2, T3, T4, T6
are the securing circuit it measures continously if the DC comes out of the amplifier fore longer than 0,3 sec. and if - it shuts down the relay in the loudspeaker output, it is also coupled together with T1 on the fet output if idlecurrent is to high it will also shut down.
Actually the relay is shut down by turning on the amplifier, and when everything is in order and the circuits are stabilized and calmed down it will turn on.
Overheating relay
by 80 degrees C pulls one relay and inputsignal will go down with 20 DB or 10 times
100 degrees C pulls second relay and inputsignal will go further 20 DB down or totally 40 DB - 100 times down.
sound will be so weak that it can't damage output no matter how much you turn up volume.
I have translated this from Danish i hope it's understandable current, voltage, bias is not exactly my favorit words, i might have used them on wrong places
Output current limiter
2 zeners over gate/source in this case 2 10v zeners and 2 insulationdiodes
limits output current to 20 A
DC fault relays
R33, R35, R34, C16, C19, T2, T3, T4, T6
are the securing circuit it measures continously if the DC comes out of the amplifier fore longer than 0,3 sec. and if - it shuts down the relay in the loudspeaker output, it is also coupled together with T1 on the fet output if idlecurrent is to high it will also shut down.
Actually the relay is shut down by turning on the amplifier, and when everything is in order and the circuits are stabilized and calmed down it will turn on.
Overheating relay
by 80 degrees C pulls one relay and inputsignal will go down with 20 DB or 10 times
100 degrees C pulls second relay and inputsignal will go further 20 DB down or totally 40 DB - 100 times down.
sound will be so weak that it can't damage output no matter how much you turn up volume.
I have translated this from Danish i hope it's understandable current, voltage, bias is not exactly my favorit words, i might have used them on wrong places
Hi Rovsing,
yes I did recieve the full pdf file. Thanks very much.
I have only had a brief look at it, but I can share my first impression (IMHO):
1)Did hope it was an all-fet amplifier, but it is not.
2) The design is quite straight forward by todays standards.
3) Like the use of cascoded gain stages(if designed and tested properly).
4) Dont think the output current limiting works with new MOSFETs because of higher forward transconductance.
5) Think the CSS's and cascode transistors would benefit from some local decoupling capacitors.
6) Think the MOSFETs and temperature supervisor IC is obsolete now.
In another article by Soelberg he wrote something like: "amplifiers do not need stabilized powersupply at all, because the high amount for negative feedback does compensate for it and give high PSRR."
That is basically correct, but I dont think poor powersupply and lots of global negative feedback is the way to go for high performance amplifiers today.
yours Søren
yes I did recieve the full pdf file. Thanks very much.
I have only had a brief look at it, but I can share my first impression (IMHO):
1)Did hope it was an all-fet amplifier, but it is not.
2) The design is quite straight forward by todays standards.
3) Like the use of cascoded gain stages(if designed and tested properly).
4) Dont think the output current limiting works with new MOSFETs because of higher forward transconductance.
5) Think the CSS's and cascode transistors would benefit from some local decoupling capacitors.
6) Think the MOSFETs and temperature supervisor IC is obsolete now.
In another article by Soelberg he wrote something like: "amplifiers do not need stabilized powersupply at all, because the high amount for negative feedback does compensate for it and give high PSRR."
That is basically correct, but I dont think poor powersupply and lots of global negative feedback is the way to go for high performance amplifiers today.
yours Søren
Well i don,t have that much knowledge in electronics that i,m able to see if it,s worth building and now you have given me the opinion that i have asked fore, i'll continue with my other partly finished projects - Krellklone - Aleph x - Zen v4 - BZLS - LM3886 klone - VSPS - etc. etc. maybe i should take all those very nice PCB's put them in a big frame and hang them as a picture on the wall to remind me that theres a lot of unfinished DIY to make
Now I got interrested here.
I believe I have both Jan Soelbergs books here too.
Along with several of the Kits described in them.
Perhaps I should look it up and see what there is in the AE-box of my electronic universe?
Any of You Danes who know where all Josty-Kit and Josti Electronics went?
(I believe there was two Brothers owning each of the two companies?)
I believe I have both Jan Soelbergs books here too.
Along with several of the Kits described in them.
Perhaps I should look it up and see what there is in the AE-box of my electronic universe?
Any of You Danes who know where all Josty-Kit and Josti Electronics went?
(I believe there was two Brothers owning each of the two companies?)
I usually say that evereything is for sale at all times.
But unfortunately for You aren theese books not for sale.
They represent a period in my life where nearly all electronic interrest and understanding was built among all other things, theese books.
Actually there was an earlier book he wrote, in 1974 i think, that started my interrest all over.
But if I find them I would be glad to share some scans I could make?
Some day, Gerdmuellerdk, someday.
Hopefully You will be there when I decide to let the youngsters get their share.
Just don't give in yet.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.