Re: Balanced input on Babbelfish
Michael.....there it is
you can omit 470K and switch ,posted in picture attached in post No.294.
in that case you don't need to switch places of 22K and 4U7,and you need shorting plug for XLR (between minus and Gnd) if you use unbal input
Michael Mik said:
Michael.....there it is
you can omit 470K and switch ,posted in picture attached in post No.294.
in that case you don't need to switch places of 22K and 4U7,and you need shorting plug for XLR (between minus and Gnd) if you use unbal input
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Balanced input on Babbelfish
Thanks Zen Mod, for this neat solution. Right now I´am fighting to tell 4 or 5 relays to switch the volume in a logarithmic curve for an Aleph P (rotary switch 16/24 position, desmo to binary decoded with diodes to 4/5 relays, in order to save space, money and an uP i don´t like to use...)
Cheers
Michael
Thanks Zen Mod, for this neat solution. Right now I´am fighting to tell 4 or 5 relays to switch the volume in a logarithmic curve for an Aleph P (rotary switch 16/24 position, desmo to binary decoded with diodes to 4/5 relays, in order to save space, money and an uP i don´t like to use...)
Cheers
Michael
Re: Balanced input on Babbelfish
whemn you figure out that diode net etc.............just post it here,for our benefit.................... 😉
Michael Mik said:
whemn you figure out that diode net etc.............just post it here,for our benefit.................... 😉
Poor mans volume control
Just an idea:
a rotary switch 16/24 positions + diode matrix, controlling 4/5 relays. On their n.o. contacts, resistors are switched in a designated parallel mode.
So only 1 switch-deck, max 20 relays even for balanced stereo
mode, 20 resistors. Should be enough money left to build a babbelfish.... if its works....🙂)))))
Cheers
Michael
Just an idea:
a rotary switch 16/24 positions + diode matrix, controlling 4/5 relays. On their n.o. contacts, resistors are switched in a designated parallel mode.
So only 1 switch-deck, max 20 relays even for balanced stereo
mode, 20 resistors. Should be enough money left to build a babbelfish.... if its works....🙂)))))
Cheers
Michael
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Hi Choky,
after following the Babbelfish-thread for a while and reading Steen´s and Bill´s listening impressions, I finally could not resist building a pair of Babbelfish monos. They have balanced inputs and run on 25V-rails.
First of all - they sound really really good - very musical and 3-dimensional. Good bass, sweet highs and very detailed. Thanks a lot for sharing the schematic and pcb-layout.
Using the 0,33R source resistors and R13 with 47k I could not reach 2A bias for the output transistors (IRFP 150N) - I could only reach about 1,2A. I removed R13 and now reach 2A for Q6 and Q7. With the higher bias (besides dissipating much more heat) the amps sound more detailed and realistic - but now I ssink sssey are a bit sssibilant. Do I have to change the values of any other components as a result of removing R13?
Thanks in advance for your advise.
Schuhbu
after following the Babbelfish-thread for a while and reading Steen´s and Bill´s listening impressions, I finally could not resist building a pair of Babbelfish monos. They have balanced inputs and run on 25V-rails.
First of all - they sound really really good - very musical and 3-dimensional. Good bass, sweet highs and very detailed. Thanks a lot for sharing the schematic and pcb-layout.
Using the 0,33R source resistors and R13 with 47k I could not reach 2A bias for the output transistors (IRFP 150N) - I could only reach about 1,2A. I removed R13 and now reach 2A for Q6 and Q7. With the higher bias (besides dissipating much more heat) the amps sound more detailed and realistic - but now I ssink sssey are a bit sssibilant. Do I have to change the values of any other components as a result of removing R13?
Thanks in advance for your advise.
Schuhbu
schuhbu said:
I'm glad that you are satisfied wit results of my little sand adventure (in fact that was just a steal......to be frankly 😉 )
anyway-regarding r13- you know that little tweaks are necessary if you count on somewhat different characteristics of various semiconductors here and there...so - using some other little bjts can give you slightly different working point ;
I changed big Rs from 0R22 to 0R33 without actual trying,but I didn't worried about other slight changes ,as overall value of R13 and VR2 is....every half xperienced builder can figure that 😉
ssssssibilance......... check AC gain of output CCS ( vary R14)
if not that.....try tweaking input CCS up or down (probably up) and vary (slightly) R7...........
but-first question must be -did you looked at output with CRO?
sometimes sssssibilance can be sign of something else ,than need for just little ear tuning......
did you use 2SJ109 (BL or V) on input or you substitute them with smthng else?
keep us informed
schuhbu said:
The "sibilant" or too bright sounding could be checked with an oscilloscope. Check the square waves at 1k, 10k, and 100k. If there is a peak on the leading edge as most alephs are with no compensation capacitor, this could be the extra harshess or brightness you are hearing.
Try a 3 pF across the feedback resister like Nelson has suggested previously.
Also, for those who have not built the jfet front end, I have noticed the Aleph mini has the least bass. The Aleph 3 with an additional mosfet seems to have a nicer midrange. I have not tried the Aleph 30 yet with 3 mosfets, but expect it to have better bass than all three.
So far, I like the Aleph 3 over all better than the mini, because it seems to have a better balance throughout the frequency range.
Zen Mod hit all of the points to adjust on the Aleph. If you need any further clarification, I would be glad to offer advice since I prototyped the Aleph and learned what does what.
Bill
Hi Choky, Bill,
thanks a lot for your quick reply.
First of all I have to admit that I am not an experienced Aleph-builder - to be honest, it is my first Aleph power amp. The only Aleph I have built before the babbelfish was an Aleph P. Before I have had a Hiraga Classe A poweramp, a ZAPpulse Class D broadcasting station and a Kaneda pre. I always tought the Kaneda was a good preamp, but the Aleph P made such an improvement to my system that I decided to try a Pass power amp, instead of the two mentioned. So here I am.
Furthermore I have to admit that my next investment should be an oscilloscope - actually I dont have one.
In the input I used 2SJ109 BL.
According to your suggestion I checked AC current gain: it is exactly 50% in both channels.
What made a real difference in sound was turning up the input CCS to 11mA total and putting a mica cap across the feedback resistor - now the top end really shines but is not too bright any more. The DC offset in one channel is about 7-9mV now and in the other channel 30-35mV.
I think I will also try to vary the value of R7 by soldering a pot in place and try out its effect on sound.
I want to thank you (and of course NP) one more time for sharing the schematics and for your support, because the babbelfish in combination with the Aleph P is really the best sounding amp I have had until now. After following your tips I am totally happy with this amp.
Cheers
schuhbu
thanks a lot for your quick reply.
First of all I have to admit that I am not an experienced Aleph-builder - to be honest, it is my first Aleph power amp. The only Aleph I have built before the babbelfish was an Aleph P. Before I have had a Hiraga Classe A poweramp, a ZAPpulse Class D broadcasting station and a Kaneda pre. I always tought the Kaneda was a good preamp, but the Aleph P made such an improvement to my system that I decided to try a Pass power amp, instead of the two mentioned. So here I am.
Furthermore I have to admit that my next investment should be an oscilloscope - actually I dont have one.
In the input I used 2SJ109 BL.
According to your suggestion I checked AC current gain: it is exactly 50% in both channels.
What made a real difference in sound was turning up the input CCS to 11mA total and putting a mica cap across the feedback resistor - now the top end really shines but is not too bright any more. The DC offset in one channel is about 7-9mV now and in the other channel 30-35mV.
I think I will also try to vary the value of R7 by soldering a pot in place and try out its effect on sound.
I want to thank you (and of course NP) one more time for sharing the schematics and for your support, because the babbelfish in combination with the Aleph P is really the best sounding amp I have had until now. After following your tips I am totally happy with this amp.
Cheers
schuhbu
schuhbu said:
I'm glad that these little problems are solved;
anyway-leave R7 as is.........ya don't wanna cook this little 2SJ109 critter,just because you are already in pretty red zone..........mebbe 10% of dissipation more,but not much more than that
scream voltage is 30V and ouch dissipation is 0,2W per side........and overall even below 0,4W (ie not twice 0,2W).......
mebbe is time now for more ear cleaning,less gadget tweaking 😉
(and you can send that lousy Hiraga amp to me,in tweaking purposes
)btw-it was my first Aleph,too 😉
Hi Schuhbu, welcome to the club of proud Babbelfish owners😀
Mine is at 50% current gain and it sounds just fine. BTW 50% means that the CCS delivers 50% of what the gain mosfet does🙂
In other words 1/3 of the total output.
Mine is adjusted to just under 2 amps, and I am considering to change R13 in order to get the last juice😉 As far as I remember I changed the value allready. When adding balanced inputs, I will🙂
Hmmm, I wouldnt be too comfortable, fiddling with R7. Imagine if the 109 is fried
They are pretty hard to come by.
Steen😎
Mine is at 50% current gain and it sounds just fine. BTW 50% means that the CCS delivers 50% of what the gain mosfet does🙂
In other words 1/3 of the total output.
30 volts is more than I would like to run one output-mosfet at! +/-25 Volts is my max.
Mine is adjusted to just under 2 amps, and I am considering to change R13 in order to get the last juice😉 As far as I remember I changed the value allready. When adding balanced inputs, I will🙂
Hmmm, I wouldnt be too comfortable, fiddling with R7. Imagine if the 109 is fried
They are pretty hard to come by.Steen😎
Hmmm, I think I´ve been courageous enough to turn up the input CCS, and I won´t push my luck too hard...
I think I will stay with Chokie´s advice and clean my ears. Particularly because my girl and a friend of mine told me "What you hear are no distortions, it´s the details you never heard before with your crappy system...".
Steen, the club of babbelfish owners is still a rather exclusive club, and you have a part in me joining this club. When I read your listening impressions, I simply had to try this amp. I think this club will soon become bigger, when the great sound of this amp gets around.
Adding balanced inputs made really an improvement - imaging is much more stable now.
The only thing I still want to change is to add some extra heatsinking- just to quiet my mind. My heatsinks are rated 0.35K/W, but I think they become uncomfortable hot. So a little more aluminum can´t be that bad.
schuhbu
I think I will stay with Chokie´s advice and clean my ears. Particularly because my girl and a friend of mine told me "What you hear are no distortions, it´s the details you never heard before with your crappy system...".
Steen, the club of babbelfish owners is still a rather exclusive club, and you have a part in me joining this club. When I read your listening impressions, I simply had to try this amp. I think this club will soon become bigger, when the great sound of this amp gets around.
Adding balanced inputs made really an improvement - imaging is much more stable now.
The only thing I still want to change is to add some extra heatsinking- just to quiet my mind. My heatsinks are rated 0.35K/W, but I think they become uncomfortable hot. So a little more aluminum can´t be that bad.
schuhbu
steenoe said:
mosfets will be hot ( as they aren't already hehe) so no worry for them (with 'nuff 'sinking) but 2SJ109 will be fried instantly..........or just little later 😉
I think the X'ed Babbelfish will have just about 45 watts.
Steen🙂
BTW I think the X'ed Babbelfish would be the ultimate DIY amp project for us Passovians🙂 Why dont we stick our heads together and do a GB on some PCB's?😉 Imagine the bottom-end of an A-X combined with the top-end of the Aleph-J
Man, do I need to say more??
Steen🙂
BTW I think the X'ed Babbelfish would be the ultimate DIY amp project for us Passovians🙂 Why dont we stick our heads together and do a GB on some PCB's?😉 Imagine the bottom-end of an A-X combined with the top-end of the Aleph-J
Man, do I need to say more??
steenoe said:
dunno for power.......try finding xls file floating around for calculating that........I imagined +-15V and each half with 2A....so overall diss will be in ballpark of 120W........is that enough ?
regarding pcbs......in next month or two I'll convince Oly to make pcbs for BabelX......if you are patient enough you'll have a pair for free and all other mmbrs will have pdf
I sure am🙂 Thanks for the kind offer, indeed. No need to hurry or stress your friend Oly. It seems that I have finally got control over my A-X's adjustment. With a little work and some luck they will be hooked up tomorrow🙂 One monoblock working right now.
Here is a pic of the 100 watt monoblocks to spice up this thread a little😀
Steen😎
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