Hi,
I'm trying to understand how the whole stuff works.
Sorry about that, but to do that I'm using a simulator (less danger and less smoke).
Let's have a look on the original Pass design for "Aleph 5": http://www.kk-pcb.com/a5serv.pdf that I have reproduced this way:
My question is threefold and always related to the C5 capacitor.
I'm trying to understand how the whole stuff works.
Sorry about that, but to do that I'm using a simulator (less danger and less smoke).
Let's have a look on the original Pass design for "Aleph 5": http://www.kk-pcb.com/a5serv.pdf that I have reproduced this way:
An externally hosted image should be here but it was not working when we last tested it.
My question is threefold and always related to the C5 capacitor.
- My simulations says that the input impedance on the XLR+ and XLR- is very different: 14.7kOhm and 5.3kOhm, respectively. Is this a "fake" result or it's real? and, if it's real, does it have any consequence on the SQ?
- If I replace C5 by an appropriate resistance I can get the two impedance's identical. For sure I have to recheck the OFFFSET and, to get the original gain, I need to raise the NFB resistance R7.
- The "Aleph" architecture is said to be "capacitor free": is anybody worried by the presence of C5 on the XLR- line?
Sorry about that, but, as I mentioned, this is the ORIGINAL schematics: https://scontent-mxp1-1.xx.fbcdn.net/v/t1.0-9/49533919_10156100077712709_2025601096138883072_o.jpg?_nc_cat=109&_nc_ht=scontent-mxp1-1.xx&oh=58942bbe9e8fdd1e6085eebee7f4b5f7&oe=5CC5D6BA.try using original schematic
Perhaps there is something better, among the many schematics I could find on the web. But, who knows?
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My mistake, thanks.R8 is 1K
Now the two impedance's are 10.9kOhm and 9.1kOhm.
Let me guess that I should be satisfied.
But ... a huge capacitor on the XLR- line doesn't worry you?
Thanks
I believe I already pointed you to my Babelfish J thread , where you can see what worries me
anyway , Aleph series was , in general , very successful series of amps , primarily due to sound quality , exquisite craftsmanship and longevity ........ which means that many satisfied customers didn't had nothing to worry about
suddenly , there we are , Greedy Boyz and Grand Tweakers , having doubts about Papa's constructions
if you're worried with that capacitor - just short it ; but only after you make entire amp and prove with DBT that you're able to hear when it is in circuit
anyway , Aleph series was , in general , very successful series of amps , primarily due to sound quality , exquisite craftsmanship and longevity ........ which means that many satisfied customers didn't had nothing to worry about
suddenly , there we are , Greedy Boyz and Grand Tweakers , having doubts about Papa's constructions
if you're worried with that capacitor - just short it ; but only after you make entire amp and prove with DBT that you're able to hear when it is in circuit
This is what I suspected.The original Alephs didn't have symmetrical input impedance.
Me, I would only to be helped to understand.suddenly , there we are , Greedy Boyz and Grand Tweakers , having doubts about Papa's constructions
I have no faiths or misconceptions.
No phase rotations on T2 (see my schematics)? tell me that and I shall trust you.
......
No phase rotations on T2 (see my schematics)? ......
clarify "phase rotation"
Phase shifts between T1 and T2 (the gates of Q1 and Q2), sorry.clarify "phase rotation"
Sorry, but I don't understand your naming convention: long tailed pair - Google Searchit's Long Tailed Pair ...... it's invented with purpose to work with opposite signal phases, or to produce opposite phase to existing one
An externally hosted image should be here but it was not working when we last tested it.
@10kHz
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Just invest some time at my last picture.just invest some time in watching that youtube vid I posted link to
No phase shift? an artifact of the simulator? please tell me!
Even if I worked on that only with tubes I guess I know what a LTP is.
I'm not following you there ..... each time I looked at LTP , it did what is expected to do ......
if you can't see it , it's something wrong with your understanding ...... or sim approach or whatever
I can't force you to understand , especially I can't explain better than it's explained in linked youtube video
if you can't see it , it's something wrong with your understanding ...... or sim approach or whatever
I can't force you to understand , especially I can't explain better than it's explained in linked youtube video
Sorry, but I don't understand your naming convention: long tailed pair - Google Search
An externally hosted image should be here but it was not working when we last tested it.
@10kHz
Short the coupling capacitor and re-run the sim
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- Any problems with the "Aleph" (5, to be specific) architecture ?