SemiSouth power Jfets .......... FW J2

[Tea-Bag]

off topic now..Looking at this.http://www.keith-snook.info/QUAD-405-2-Mods.htmlIt seems it wouldn't trigger until 8-10volts DC. That seems high to me.

[Zen Mod]

in our forum(s) everything is off ..... and on topic :buehehe:8Vdc means 1A across 8R coil means 8Wit's negligible even for silver Lowther

[generg]

T2 is a 8A Triac with low gate current requirement and a gate trigger voltage about 1V to 2V so a d.c. voltage of about 9V across C17 will cause T1 to breakover and trigger Triac T2 which will short the output blowing a fuse but saving the speaker

Dear Zen Mod but we have no fuse that can break when the output is shorted...... :sarcastic_hand:And Semis are expensive..... But my speaker of course more...

[Zen Mod]

put 10A fuses in both lines when crowbar is functional - it's anyway something wrong with teuer semis:rofl:

[generg]

I understand!

[Tea-Bag]

Well, The SemiSouth's don't seem to blow if you don't short them. That's been my problem on my channel 2 escapades. But hopefully troubles are settled.I've been using F5 without protection for a couple of years, and have been lucky I guess.I am looking into part substutes for this contraption you speak of.

[sp300b]

Nelson P. is not using protection circuit in any of his amplifiers, and seems it's not needed.My Babel was playing for more than 2 years, connected to FR Sonido SFR144. Never had any problem - Offset was set at the very beginning of the game, and never reset again.J2 is the same structure, so set J2 after 30min working without speaker (+In, -In and Gnd together) and You've done. Conect whatever You want then.

[generg]

........ we only got a bit nervous because of the "cone excursion" of tea-bag ------- and it was interesting to hear what Zen Mod suggested what you can do if you want......

[Zen Mod]

.... I'm here ....... to serve and protect !

[sp300b]

.... I'm here ....... to serve and protect !

Zen, a question.Papa seems to made J2 with 1,4A current and output resistors as parallel of 0,47Ohms. Here we have slightly different approach. Personally, I don't think that running SemiSouths on 2A will make any problem, but on contrary, but Source Degeneration resistors could probably be good to be tested with some other values like 0,22 or 0,33 Ohms?Your Serve (Djokovic)

[Zen Mod]

I need to find table with CNY LED voltages vs. currentI remember I made it and maybe even post it in thread that will tell us what's lowest voltage we can have across middle resistors

[sp300b]

I need to find table with CNY LED voltages vs. currentI remember I made it and maybe even post it in thread that will tell us what's lowest voltage we can have across middle resistors

Here LED comesDegeneration Question is about what would be the best solution to have in circuit - 0,5 Ohms or lower

[Zen Mod]

naaah ....... I don't really care if you can cope with loss of power , then you can cope with even more triode transfer function :buehehe:at 4mA ( sweet spot for LED in CNY) there is ~1V1 across LEDso - 1A4 ...... 1V1 ..... demands overall ( two MOX in series) 0R785Papa obviously have few Rabbits more in his sleeve

[Tea-Bag]

Okay dudes,Trying to get the ball rolling to get this boxed up. I don't have all the parts, so was thinking about how to do this.. So, if I get .6v across R23 - What's the benefit of going from 12k to 4.7k, is this a safer parameter, or a performance parameter? Tjat conversation was a bit lost on me. I was also thinking about a shunt Power Supply, supplying about 4A total I guess using a 22V transformer, or a traditional CRC like ZM used in his setup.

[Zen Mod]

.........So, if I get .6v across R23 - What's the benefit of going from 12k to 4.7k, is this a safer parameter, or a performance parameter? Tjat conversation was a bit lost on me. .........

performance/safer ; it will give firmer base current to programming transistor in both CCS-es ;

........I was also thinking about a shunt Power Supply, supplying about 4A total I guess using a 22V transformer, or a traditional CRC like ZM used in his setup.

reeeeeeeeeaaaaaaaaaaaalllllly non-economic ;cap multiplier is OK ( I almost like them for power stages ) ........ maybe even sort of series reg ( I don't like them for power stages ) but shunt reg will result in insane vaste of energy/heat

[Tea-Bag]

thanks. I will stick with a CRC for now, and get some 4.7k resistors in route.

[hifish]

evo pa kome treba logo

Ovo zvuci kao da je za mene! :happy64:Al' kad ih nema vise...

[Zen Mod]

Paint rulez!

edit : schm deleted by ZM

[Magura]

Do note the file name :rofl:Magura

[Zen Mod]

[sp300b]

Do the same with PCB

[Zen Mod]