I'm thinking about building this amp to run my tweeters in a bi-amp configuration so I want it to run from a 15 volts power supply and have a 13 volt swing peek to peek to get about 6 watts in a 4 ohm tweeter which I'm hoping is enough to get a decent sound level.
But I didn't really see a way to get such a high swing in the original design, at least not without using a 5 watt pot
So how about this design? R5 at the bottom is used to set the idle current, I'm not that sure it will work though.
I also added some 100 nF caps, they always seem to improve lots of things wherever I use them.
But I didn't really see a way to get such a high swing in the original design, at least not without using a 5 watt pot
So how about this design? R5 at the bottom is used to set the idle current, I'm not that sure it will work though.
I also added some 100 nF caps, they always seem to improve lots of things wherever I use them.
Attachments
Well run a couple of hunderd more if you think that's the way to understand it... with and without R5 ... alternatifely, read the article or use your common sense..
I think R5 originally only servers to increase the driver-Iq a bit (more linear), or to speed up cutt-off of the lower output trans a bit... I has nothing to do with Iq, allthough you can influence Iq a bit, a more efficient way to set Iq is to increase the upper bootstrapped resistors.... like the original article shows you..
I think R5 originally only servers to increase the driver-Iq a bit (more linear), or to speed up cutt-off of the lower output trans a bit... I has nothing to do with Iq, allthough you can influence Iq a bit, a more efficient way to set Iq is to increase the upper bootstrapped resistors.... like the original article shows you..
, but now I get it .. sorry i wasn't clear... cheers m8,
I haven't tried 2n3773, but I think, these old Mot. devices would sounding excellent in your jlh amp! These NOS power transistors (2n3055, 3442, 3773, etc..) are the first choice here!
Don't think about fT!
My oppinion is that this amplifier sounds best with the old 2n3055's, whiches fT is only 800KHz(!).
(I remember that DestroyerX wrote the same. Or not?!)
sry for my bad english!...
Don't think about fT!
My oppinion is that this amplifier sounds best with the old 2n3055's, whiches fT is only 800KHz(!).
(I remember that DestroyerX wrote the same. Or not?!)
sry for my bad english!...
anyone looking for caps?
I've been offered 48 15000uF 40V capacitors for 3 quid each. They're NOS, BHC Aerovox ALS20/21 Series long life.
Date stamp is 'UK Made 9938' (Made week38 of 1999?)
50mm diameter x 70mm length. Connection 2 x M5 screw.
I won't need more than 24 of them, anyone like some or all of the remainder? I'll ship them anywhere at cost.
And while I'm here, can I get an opinion on using eight of them per channel of a 2x output pair jlh, running 22V at 4A into 4 ohm speakers?
happy new year, y'all
Chris
I've been offered 48 15000uF 40V capacitors for 3 quid each. They're NOS, BHC Aerovox ALS20/21 Series long life.
Date stamp is 'UK Made 9938' (Made week38 of 1999?)
50mm diameter x 70mm length. Connection 2 x M5 screw.
I won't need more than 24 of them, anyone like some or all of the remainder? I'll ship them anywhere at cost.
And while I'm here, can I get an opinion on using eight of them per channel of a 2x output pair jlh, running 22V at 4A into 4 ohm speakers?
happy new year, y'all
Chris
Re: anyone looking for caps?
Count me in. You should have an email from me.
Chris Ma has, IIRC, reported earlier in this thread that he built the higher power JLH using three 15000uF capacitors per rail per channel. He subsequently tried two and then one 15000uF per rail and found that two gave him the best compromise with regard to sound quality (bass weight versus mid/treble clarity).
I hope my memory is correct. If not I am sure that Chris will rectify any errors.
Geoff
Chrisbremen nacht said:
Count me in. You should have an email from me.
Chris Ma has, IIRC, reported earlier in this thread that he built the higher power JLH using three 15000uF capacitors per rail per channel. He subsequently tried two and then one 15000uF per rail and found that two gave him the best compromise with regard to sound quality (bass weight versus mid/treble clarity).
I hope my memory is correct. If not I am sure that Chris will rectify any errors.
Geoff
Re: Re: anyone looking for caps?
That's very interesting. I can see why more uF = heavier bass but I'm not sure how less uF = better mid/treble clarity.
Maybe I should bi-amp. Could do a much smaller version for the tweeters - wouldn't need to use an electrolytic for feedback cap
I just searched the thread but couldn't find Chris's report.
Geoff said:
That's very interesting. I can see why more uF = heavier bass but I'm not sure how less uF = better mid/treble clarity.
Maybe I should bi-amp. Could do a much smaller version for the tweeters - wouldn't need to use an electrolytic for feedback cap
I just searched the thread but couldn't find Chris's report.
Geoff,
You are correct. That was my experience with the regulated PSU the same exact PSU post with pictures in your site. At the time when I reported this I did not understand the significant of details that I've missed to enclose. These details were actually the main reason of what I have experienced.
See picture, the way I connected the bypass caps and the result of how they sound differently when using only 1 set of caps connected to the rail, then 2 sets, and then finally 3 sets.
You are correct.
That was my experience with the regulated PSU the same exact PSU post with pictures in your site. At the time when I reported this I did not understand the significant of details that I've missed to enclose. These details were actually the main reason of what I have experienced. See picture, the way I connected the bypass caps and the result of how they sound differently when using only 1 set of caps connected to the rail, then 2 sets, and then finally 3 sets.
Attachments
Now I am using all three sets per rail before the regulator boards. In this arrangement there is no significant change in dynamic of mid/high sound that I can detect like previously; except that the more sets I used the bass get better without affecting the dynamic.
The Butcher
The Butcher
Attachments
