4u7 Capacitor Education
Hi Zen Mod (or other clever ones),
Could you educate me a bit:
In your "Convert your lousy Aleph to a Babelfish" guide, you talk about the 4u7 (C2) capacitor acting to block DC.
There is a similar capacitor in your final Balanced Version.
I cannot understand how this capacitor protects against DC.
However, I CAN understand how it works in this EARLIER Balanced version, because it is in series with the Negative Input.
(All of these files are from this thread.)
Please, could you explain this to me, so I might be able to understand something of what I am doing when I build this circuit?
Regards and thanks,
George.
Hi Zen Mod (or other clever ones),
Could you educate me a bit:
In your "Convert your lousy Aleph to a Babelfish" guide, you talk about the 4u7 (C2) capacitor acting to block DC.
There is a similar capacitor in your final Balanced Version.
I cannot understand how this capacitor protects against DC.
However, I CAN understand how it works in this EARLIER Balanced version, because it is in series with the Negative Input.
(All of these files are from this thread.)
Please, could you explain this to me, so I might be able to understand something of what I am doing when I build this circuit?
Regards and thanks,
George.
Re: 4u7 Capacitor Education
point is in your exact level of paranoia.........
SE input - you use that cap in feedback chain if you aren't confident in your just finished amp,regarding oscillations and temp drift ; so -if you are confident,just toss it out ;
balanced input : keeping that cap anywhere in chain is same issue as in previous paragraph ,or just laziness to toss it out ; that "previous balanced version " was just quickie for someone asking for universal convert.......so that Babelfish is probably half a day catholic,half a day protestant..... and all night long just poor bstrd ,with one leg longer.......
point is- with balanced outputs (where your Babelfish will look in first llook...........in fact in half look ......other half of look is on spkr side......Babelfish have 4 eyes,as me ) ....ahem: any decent box with balanced outputs is certainly dc-offset free,so you can couple it DC with Babelfish,without fear...
'nuff?
or I'm just dumb,as usuall.........?
edit:
after quick look on that converting paper again (after looong time) ...I can say :
I'm just dumb,as usuall.........
GeorgeBoles said:
point is in your exact level of paranoia.........
SE input - you use that cap in feedback chain if you aren't confident in your just finished amp,regarding oscillations and temp drift ; so -if you are confident,just toss it out ;
balanced input : keeping that cap anywhere in chain is same issue as in previous paragraph ,or just laziness to toss it out ; that "previous balanced version " was just quickie for someone asking for universal convert.......so that Babelfish is probably half a day catholic,half a day protestant..... and all night long just poor bstrd ,with one leg longer.......
point is- with balanced outputs (where your Babelfish will look in first llook...........in fact in half look ......other half of look is on spkr side......Babelfish have 4 eyes,as me
) ....ahem: any decent box with balanced outputs is certainly dc-offset free,so you can couple it DC with Babelfish,without fear...'nuff?
or I'm just dumb,as usuall.........?
edit:
after quick look on that converting paper again (after looong time) ...I can say :
I'm just dumb,as usuall.........
Yunick said:I'm still here..
Soon after my last post, My son arrived and we went fishing, that I earlier promised him....
There will be a longer listening session tomorrow night....
.....
seems that someone is little older than I conclude from pics
why you need that junk ?
everyone knows that preamp without toobz can't be good
Yunick said:
Nice, I have 4 of those stashed away
Keep at it while you are on a roll, its best to keep rollin
If one takes a pause, its too hard to get rollin again George, are you planning on a Babel-X? I am working on it, boards are soldered and the Babelamp has returned home (sentimental reunion
) so I am ready to proceed. I just want to finish the new preamp first. The preamp will sport relay controlled volume and input/output selection and handles both SE and Bal signal as well. Ultimately there will be a display and remote control. Quite a Twisted thing that will be the base for future preamp adventures Pumpkin anyone I thought it best to have the case ready, before the Pumpkin is incomming Steen
Yesterday it wen't up to 47C. It was hooked up for 1.5hours....
I measured between the "clampingbar" of the mosfet and the heatsink..
Hehe.. The pic's are of my brother.. he is 21.. I'm 11 years older
no worries..Long time ago I have stached up on black gate's and the boards are assembled so I'll try them out atleast..
It will do until you release you pumkin boards
Yunick said:
Yesterday it wen't up to 47C. It was hooked up for 1.5hours....
I measured between the "clampingbar" of the mosfet and the heatsink..
Hehe.. The pic's are of my brother.. he is 21.. I'm 11 years older
Long time ago I have stached up on black gate's and the boards are assembled so I'll try them out atleast..
It will do until you release you pumkin boards
more impressions about sound............and thermal-offset behaviour?
Steenoe reply
Hi Steenoe,
Yes, I am planning to make a Babel-J-X and probably a Babel-J-normal. I have about 200 IRFP140N's arriving soon (hopefully). I am going, right now to try to design some circuit boards for the J-X.
But a look at your boards might save me a lot of time, if you wouldn't mind.
I think I will have the power mosfets on "daughter-boards" so that I can maximize my layout options. I try to make everything I do re-usable ... no nasty holes in the middle of heat-sinks to make them look ugly and difficult to use for another project.
Regards,
George.
Hi Steenoe,
Yes, I am planning to make a Babel-J-X and probably a Babel-J-normal. I have about 200 IRFP140N's arriving soon (hopefully). I am going, right now to try to design some circuit boards for the J-X.
But a look at your boards might save me a lot of time, if you wouldn't mind.
I think I will have the power mosfets on "daughter-boards" so that I can maximize my layout options. I try to make everything I do re-usable ... no nasty holes in the middle of heat-sinks to make them look ugly and difficult to use for another project.
Regards,
George.
Yunick reply
Thanks, Yunick.
That temperature is very acceptable. I presume the heat-sink will be hotter, but I imagine still a lot lower than "danger zone"!
Could you show how you did the mosfet mounting bar please?
I have done something similar with my 8 channels of LM3886 chip-amps, but I used some old insect-screen track 25 cm long and it had a bit of a bow in it ... so the pressure on the chips was not even. I needed an extra screw in the middle of the bar/heat-sink to even it out.
Looking at another picture of your other idea would be useful.
Regards,
George.
Thanks, Yunick.
That temperature is very acceptable. I presume the heat-sink will be hotter, but I imagine still a lot lower than "danger zone"!
Could you show how you did the mosfet mounting bar please?
I have done something similar with my 8 channels of LM3886 chip-amps, but I used some old insect-screen track 25 cm long and it had a bit of a bow in it ... so the pressure on the chips was not even. I needed an extra screw in the middle of the bar/heat-sink to even it out.
Looking at another picture of your other idea would be useful.
Regards,
George.
Re: Steenoe reply
I am not sure it will help you a lot, but I posted some pic's here and a little longer downstream:
http://www.diyaudio.com/forums/showthread.php?postid=1218943#post1218943
Its Kari's AX boards that are P2P modified to Choky's Babel-X.
GeorgeBoles said:
I am not sure it will help you a lot, but I posted some pic's here and a little longer downstream:
http://www.diyaudio.com/forums/showthread.php?postid=1218943#post1218943
Its Kari's AX boards that are P2P modified to Choky's Babel-X.
TO CONTINUE OR NOT
OK
I have 2SJ109BLs for just two more Babelfish combos (two pcbs and pair of jfets) ;
I'll not bug Papa to sell me more ( as he promissed in moment of weakness and insane sympathy ) , if nobody ask .
this trade was solely because boyz from here (DiyA) were interested
summary :
53 Euro paypal-ed will bring postman (fresh from plain) to your door - doesn't matter where you live . He'll surprise you wearing 2SJ109s as earings and two slice of pizza on nice blue quad mini dishes .
just don't let him rrrring twice .
costly or not ,I can't make it for less .........and - after so much (repetitive) wuss to find ,steal,buy and rape for those little jfet critters ...I'm not in loss ,but pretty close .
so - If I receive several mails from you that you are interested in B combos at THAT price , just then I'll bug Papa for more jfets ; in that case - price can be adjusted according to his price for little critters.
roger and over
OK
I have 2SJ109BLs for just two more Babelfish combos (two pcbs and pair of jfets) ;
I'll not bug Papa to sell me more ( as he promissed in moment of weakness and insane sympathy ) , if nobody ask .
this trade was solely because boyz from here (DiyA) were interested
summary :
53 Euro paypal-ed will bring postman (fresh from plain) to your door - doesn't matter where you live . He'll surprise you wearing 2SJ109s as earings and two slice of pizza on nice blue quad mini dishes .
just don't let him rrrring twice .
costly or not ,I can't make it for less .........and - after so much (repetitive) wuss to find ,steal,buy and rape for those little jfet critters ...I'm not in loss ,but pretty close .
so - If I receive several mails from you that you are interested in B combos at THAT price , just then I'll bug Papa for more jfets ; in that case - price can be adjusted according to his price for little critters.
roger and over
Better late than never ...
I finally got my JFish boards stuffed:
I'm going to try them on these 11x6 heatsinks - hopefully the output devices won't be too close to the edges - I'll add very thick endplates to boost cooling at the edges if I have to ... now just have to wire it up for testing
big pictures are here
http://www.flickr.com/photos/stephentom/sets/72157600431514564/
I finally got my JFish boards stuffed:
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I'm going to try them on these 11x6 heatsinks - hopefully the output devices won't be too close to the edges - I'll add very thick endplates to boost cooling at the edges if I have to ... now just have to wire it up for testing
big pictures are here
http://www.flickr.com/photos/stephentom/sets/72157600431514564/
If the others are all ugly mine is attractive.
Had to have a listen to see what the fuss was about.
Got a 4.7K in place of a 47K in r13 so had no current D'oH, once I realised this (it was all cold and clipped / distorted easy) I cut r13 out and the magic began to happen. due to the size of the heatsinks and components I had on hand I have 0.47r in place of the 0.33r, running full throttle (no r13) I ended up with 1.5 amp bias. after 45 mins the heatsink was 62deg C 49 over ambient so need to bring this down for extended pleasure. I only wanted a listen before I go any further.
Dc was around 105mv per side
The transformer is one of the antek 115 - 115 -- 20 - 20 but running 240 over the primary with the pair of fish as loads gives me +-28.6v. talk about getting close to the edge.
Who will be kind enough to send me the board files for a dual output fet version?
Currently using BL grade, I assume using V grade 109's I will be able to drag a wee bit more than 5-6ma through them? this should help feed a few more fets.
So how's the sound I hear you scream, I only had it running with the digital volume from the cd player (not a great way to do things) but the top end is magic the bottom end appeared similar to the average aleph. In time (with bigger heatsinks) I will hook it up to my proper system to get a better comparison.
Now where are the boards for the X'd version?
Had to give you guys a picture as it brings a new meaning to "breadboard" build.
Had to have a listen to see what the fuss was about.
Got a 4.7K in place of a 47K in r13 so had no current D'oH, once I realised this (it was all cold and clipped / distorted easy) I cut r13 out and the magic began to happen. due to the size of the heatsinks and components I had on hand I have 0.47r in place of the 0.33r, running full throttle (no r13) I ended up with 1.5 amp bias. after 45 mins the heatsink was 62deg C 49 over ambient so need to bring this down for extended pleasure. I only wanted a listen before I go any further.
Dc was around 105mv per side
The transformer is one of the antek 115 - 115 -- 20 - 20 but running 240 over the primary with the pair of fish as loads gives me +-28.6v. talk about getting close to the edge.
Who will be kind enough to send me the board files for a dual output fet version?
Currently using BL grade, I assume using V grade 109's I will be able to drag a wee bit more than 5-6ma through them? this should help feed a few more fets.
So how's the sound I hear you scream, I only had it running with the digital volume from the cd player (not a great way to do things) but the top end is magic the bottom end appeared similar to the average aleph. In time (with bigger heatsinks) I will hook it up to my proper system to get a better comparison.
Now where are the boards for the X'd version?
Had to give you guys a picture as it brings a new meaning to "breadboard" build.
Attachments
Re: If the others are all ugly mine is attractive.
If you want this layout: http://www.diyaudio.com/forums/showthread.php?s=&threadid=100258
you can send me an email. I also have a single layered version which twitchie showed a few posts ago.
Stones said:
If you want this layout: http://www.diyaudio.com/forums/showthread.php?s=&threadid=100258
you can send me an email. I also have a single layered version which twitchie showed a few posts ago.
Re: If the others are all ugly mine is attractive.
without full bias you cant have full potential in bass ; even with full bias,I can't expect that Babelfish can be better than plain A3 in bass region. you can expect some differences in every other area,but not in bass.
frankly- I never hear "plain " A3 before Babelfish .
using more current through little critters means that you must make some changes to achieve less dissipation for each half.
that means cascoding or other sorts of level shifting , to decrease voltage across jfets.
even then, you can't go much above ...say....7-8 mA per leg . in my book (no matter how tiny is) that's good for .......lalalala......thinkin'..... 3 gates.
what you can do with 3 gates and what you can gain?
all depends on your goals.
Stones said:
without full bias you cant have full potential in bass ; even with full bias,I can't expect that Babelfish can be better than plain A3 in bass region. you can expect some differences in every other area,but not in bass.
frankly- I never hear "plain " A3 before Babelfish .
using more current through little critters means that you must make some changes to achieve less dissipation for each half.
that means cascoding or other sorts of level shifting , to decrease voltage across jfets.
even then, you can't go much above ...say....7-8 mA per leg . in my book (no matter how tiny is) that's good for .......lalalala......thinkin'..... 3 gates.
what you can do with 3 gates and what you can gain?
all depends on your goals.
Request for editorial assistance
Hello Folks,
Do you think you could have a look at this PCB plan. I have checked for terrible wiring errors, however an extra pair of eyes is always helpful. I am also for advice if I really should re-route anything of any major importance. It is designed to fit on my 150mm wide * 350mm long heatsinks.It has lots of options incorporated: different capacitor sizes, and the R0 and input protection zeners from the Aleph-X. It is sort of an "experimental or developmental" board so I can play with components and the circuits.
1. I plan to use a Ground Plane or a "starry" tree of Ground connections on top copper side.
2. Numbering is based on the numbered version of Zenmod's circuit diagram ... see next post.
3. It will be made with toner transfer process (home grown version) so there are a couple of vias which are just to join top and bottom planes. I haven't double checked that I have put in all the ones I need, yet. Don't worry about that ... I can do it.
4. Some of the resistors (the "important ones") have the leads under the component in case I ever want to put in (Texas Components') Vishay bulk foil resistors. They sell individual components to people like you and me.
5. Also could I have some advice on this: R25 and R33 have little trimpots. It seems that these resistors are the ones to adjust (on the Zen diagrams, anyway) so as to adjust the AC/Aleph gain. Is this a somewhat independent of the adjustment of the overall gain using R28/VR28 and R36/VR36. I can see that what the resistors do is totally independent if, for instance the Aleph feedback loop is removed, or if the R28 and R36 resistors are removed. Essentially, should I just get rid of the VR25 and VR33 trimpots and save space and components???
6. I apologize that pad names do not show up. I have tried for years to get this to show up when printing, but no luck
Anyway, if you could give me some feedback, I would be happy.
Regards and thanks,
George.
P.S. I have done lots of variations of "normal" aleph type boards, and they very nearly all turn out to look the same ... they are never as pretty as other people's look. I have even started with other people's vastly different designs, and by the time I have put in my own requirements (LTP components together; on board or off board power mosfets; short signal paths, especially at the input ... they all end up looking like all the others I have done. Sigh.
Hello Folks,
Do you think you could have a look at this PCB plan. I have checked for terrible wiring errors, however an extra pair of eyes is always helpful. I am also for advice if I really should re-route anything of any major importance. It is designed to fit on my 150mm wide * 350mm long heatsinks.It has lots of options incorporated: different capacitor sizes, and the R0 and input protection zeners from the Aleph-X. It is sort of an "experimental or developmental" board so I can play with components and the circuits.
1. I plan to use a Ground Plane or a "starry" tree of Ground connections on top copper side.
2. Numbering is based on the numbered version of Zenmod's circuit diagram ... see next post.
3. It will be made with toner transfer process (home grown version) so there are a couple of vias which are just to join top and bottom planes. I haven't double checked that I have put in all the ones I need, yet. Don't worry about that ... I can do it.
4. Some of the resistors (the "important ones") have the leads under the component in case I ever want to put in (Texas Components') Vishay bulk foil resistors. They sell individual components to people like you and me.
5. Also could I have some advice on this: R25 and R33 have little trimpots. It seems that these resistors are the ones to adjust (on the Zen diagrams, anyway) so as to adjust the AC/Aleph gain. Is this a somewhat independent of the adjustment of the overall gain using R28/VR28 and R36/VR36. I can see that what the resistors do is totally independent if, for instance the Aleph feedback loop is removed, or if the R28 and R36 resistors are removed. Essentially, should I just get rid of the VR25 and VR33 trimpots and save space and components???
6. I apologize that pad names do not show up. I have tried for years to get this to show up when printing, but no luck
Anyway, if you could give me some feedback, I would be happy.
Regards and thanks,
George.
P.S. I have done lots of variations of "normal" aleph type boards, and they very nearly all turn out to look the same ... they are never as pretty as other people's look. I have even started with other people's vastly different designs, and by the time I have put in my own requirements (LTP components together; on board or off board power mosfets; short signal paths, especially at the input ... they all end up looking like all the others I have done. Sigh.
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