Hi guy i just try to make some measures and i have just discovery that my x-ccs bosoz gain is only 2 or so (6db)
I compared its fft with my 6sn7 tube preamp ( i love his timbric),I'd likeit to amplify more (10db) and that had a predominance of second harmonic.
What are the elements that manage the gain ratio?
What can I do to manage the second harmonic distortion like I did with my F5 v2 turbo Power Amp?
To better interpret the values of the FFT 1Khz I also measured the sound card slot in 5,8db and 3,8db.
Later I performed the measurements on the X-ccs Bosoz.
My primary need, however, is trying to get more gain.
Please can you help me?
Thanks in advantage
Antonio
I compared its fft with my 6sn7 tube preamp ( i love his timbric),I'd likeit to amplify more (10db) and that had a predominance of second harmonic.
What are the elements that manage the gain ratio?
What can I do to manage the second harmonic distortion like I did with my F5 v2 turbo Power Amp?
To better interpret the values of the FFT 1Khz I also measured the sound card slot in 5,8db and 3,8db.
Later I performed the measurements on the X-ccs Bosoz.
My primary need, however, is trying to get more gain.
Please can you help me?
Thanks in advantage
Antonio
Attachments
as I said , for increasing gain - decrease value of both source resistors
regarding miniscule gain - triple check values of resistors you put on pcb
regarding invoking nonsymmetry in circ (invoking 2nd) , few tricks :
-different values of source resistors
-different values of drain resistors
-different values for NFB resistors (4K7/47K)
different meaning - not equal values left vs. right side
edit: quick analysis of voltage points and currents in your schematic is showing that 680/68R resistors are correct
what is a way of driving the preamp : bal in/bal out or ..... ?
regarding miniscule gain - triple check values of resistors you put on pcb
regarding invoking nonsymmetry in circ (invoking 2nd) , few tricks :
-different values of source resistors
-different values of drain resistors
-different values for NFB resistors (4K7/47K)
different meaning - not equal values left vs. right side
edit: quick analysis of voltage points and currents in your schematic is showing that 680/68R resistors are correct
what is a way of driving the preamp : bal in/bal out or ..... ?
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if you're keen of connecting output to gnd at all , then ground positive output , not negative
so , try it like this (using SE Input):
1. IN- grounded , none output grounded , use whichever OUT you want as SE hot
2. IN- grounded , OUT+ grounded , use OUT- as SE hot
choose which way you like more , and inform us what is gain in both cases
..... for now , only worse thing you didn't tried , is grounding all inputs and all outputs
so , try it like this (using SE Input):
1. IN- grounded , none output grounded , use whichever OUT you want as SE hot
2. IN- grounded , OUT+ grounded , use OUT- as SE hot
choose which way you like more , and inform us what is gain in both cases
..... for now , only worse thing you didn't tried , is grounding all inputs and all outputs
Hi the picture show :
Righ channel= IN- grounded , OUT+ grounded , used OUT- as SE hot
Left channel= IN- grounded , OUT - grounded , used OUT+ as SE hot
In both cases, if not short-circuit the pole consideration not used to exit (out + or -out) depends on the case mentioned above, the exit used accordingly becomes slightly more low.
I tried with 1,957 Vin and 4,242 Vout so the gain is 2.16.
Tried also by taking the + and - poles simultaneously same result gain.
Righ channel= IN- grounded , OUT+ grounded , used OUT- as SE hot
Left channel= IN- grounded , OUT - grounded , used OUT+ as SE hot
In both cases, if not short-circuit the pole consideration not used to exit (out + or -out) depends on the case mentioned above, the exit used accordingly becomes slightly more low.
I tried with 1,957 Vin and 4,242 Vout so the gain is 2.16.
Tried also by taking the + and - poles simultaneously same result gain.
Attachments
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Yes i'm using 5K volume on output .
Gain are measured without any other load on output , only input impedence of my sound card audio emu 0202
Input Impedance: 2.5Kohms
OK, made some LTSpice sim
everything (voltages,currents on your schm) is by the book - when used balanced in/out , gain is something under 4V/V
when used SE in SE out, gain is aroind 2V/V , as you got
for more , decrease source resistors for Q1 and Q2
with 6R8 there (R5 and R6) , you'll get gain around 4V/V
with 2R2 (hopefully Q1 and Q2 are matched !) , gain should be 4.4V/V
and ....... that would be max with that circuit , without changing it too much and naming in then differently
all other values as per schematic
for 6R8 you can use ordinary 600mW metal film resistors
everything (voltages,currents on your schm) is by the book - when used balanced in/out , gain is something under 4V/V
when used SE in SE out, gain is aroind 2V/V , as you got
for more , decrease source resistors for Q1 and Q2
with 6R8 there (R5 and R6) , you'll get gain around 4V/V
with 2R2 (hopefully Q1 and Q2 are matched !) , gain should be 4.4V/V
and ....... that would be max with that circuit , without changing it too much and naming in then differently
all other values as per schematic
for 6R8 you can use ordinary 600mW metal film resistors
Sorry...I almost forgot!
I ask myself if is possible to simulate a square wave form responce and observe whatsup with some nf cap // 470k feedback resistors.
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