Hello, I have realized a PCB oz Bride of Zen preamp. Before to connect it to my LM3886 chip amp, I ask if someone can chekup the values that I have measured. R104 is a 5W ceramic resistor but is temperature is too hot (that is normal?).
At the input, with no load, +0 V at the output I find some tension in slowly decrease (it's OK?).
I would like to connect ZEN to 100K log pot into my Gainclone amp: it's possible to do? I must put some resistor from C103 to ground (5k pot substitution).
Sorry, I speak a very bad English....
thanks
At the input, with no load, +0 V at the output I find some tension in slowly decrease (it's OK?).
I would like to connect ZEN to 100K log pot into my Gainclone amp: it's possible to do? I must put some resistor from C103 to ground (5k pot substitution).
Sorry, I speak a very bad English....thanks
Attachments
hello.
i think this preamp should work.but you can do some adaptations.
voltage drop at the source res (100 ohm) is 4v,so you have 40ma current trough the transistor.lower it a little bit ,down to around 3,5volt......3volt (gives 35ma.........30ma).this lowers the heat a little bit.
with a 100k pot at the output you should use short (= low capacitance) cable.or you will loose treble with a long cable.
voltage running up and down at the output: you measured it without a load(res).........or you have some (big) humming ,means wrong ground connection or something else.
the irf610 needs a heatsink.
greetings
i think this preamp should work.but you can do some adaptations.
voltage drop at the source res (100 ohm) is 4v,so you have 40ma current trough the transistor.lower it a little bit ,down to around 3,5volt......3volt (gives 35ma.........30ma).this lowers the heat a little bit.
with a 100k pot at the output you should use short (= low capacitance) cable.or you will loose treble with a long cable.
voltage running up and down at the output: you measured it without a load(res).........or you have some (big) humming ,means wrong ground connection or something else.
the irf610 needs a heatsink.
greetings
Last edited:
QUOTE=beetel
in BOZ 10 zeners are used in power supply and 20V zener in preamp circuit.
What is wattage of these zener diodes ? can we use 1/2 zener without any problem?
yes,you can use 1/2 watt zener diodes............
Another things is 5K log volume control which is hard to obtain. Can we use 10K here?
yes,i used a 10k pot (and i kept my audio cable short)...........and later on i paralelled a 10k res from pot output to ground.so it looks like a 5k pot a litte bit........
greetings
in BOZ 10 zeners are used in power supply and 20V zener in preamp circuit.
What is wattage of these zener diodes ? can we use 1/2 zener without any problem?
yes,you can use 1/2 watt zener diodes............
Another things is 5K log volume control which is hard to obtain. Can we use 10K here?
yes,i used a 10k pot (and i kept my audio cable short)...........and later on i paralelled a 10k res from pot output to ground.so it looks like a 5k pot a litte bit........
greetings
Last edited:
Add Phono stage to Bride of Zen
I want to add a phono stage for my DUALC S503-1. I find that circuit, but after build a prototype, the sound is very bad: distorted... a kind of "saturation with electric guitar". Where is the mistake: at the circuit or at the component chosen?
Resistor are film metal 1% (only 750 K are 2 parallel resistor 1M5 carbon), 6,8 n 1,5 n ceramic disc, 1 µF MKT (not polarized) and 10µF (ITT FKT).
I'm tried to throw it all away!
Suggestion?
SIGH!
I want to add a phono stage for my DUALC S503-1. I find that circuit, but after build a prototype, the sound is very bad: distorted... a kind of "saturation with electric guitar". Where is the mistake: at the circuit or at the component chosen?
Resistor are film metal 1% (only 750 K are 2 parallel resistor 1M5 carbon), 6,8 n 1,5 n ceramic disc, 1 µF MKT (not polarized) and 10µF (ITT FKT).
I'm tried to throw it all away!
Suggestion?
SIGH!
Attachments
hello.
.......not throw away..........
had only a quick view on the schematic. i think
the psu voltage (12v) can be increased .........up to 20v......max. 30v
and
the gain of this circuit is rather big,you can lower it.........example:double the 10k res in the first stage (the one connected to the 2,2uf cap)
and double the 1k res in the second stage (connected with the 22uf cap).....
step by step...........
greets
.......not throw away..........
had only a quick view on the schematic. i think
the psu voltage (12v) can be increased .........up to 20v......max. 30v
and
the gain of this circuit is rather big,you can lower it.........example:double the 10k res in the first stage (the one connected to the 2,2uf cap)
and double the 1k res in the second stage (connected with the 22uf cap).....
step by step...........
greets
thank you mjf for your suggestion.
I add one resistor in series (the same value) at 1K and 10K. All work! The sound il better, more better... The "overdrive" effects disappeared.
What kind of capacitor do you suggest me for input (1µF) and output (10µF) stage? aluminum electrolytic, elec. non polarized, polyester, metalized polyester film...
Many thanks for your reply and solution!!!!!
I add one resistor in series (the same value) at 1K and 10K. All work! The sound il better, more better... The "overdrive" effects disappeared.
What kind of capacitor do you suggest me for input (1µF) and output (10µF) stage? aluminum electrolytic, elec. non polarized, polyester, metalized polyester film...
Many thanks for your reply and solution!!!!!
hello.
film/foil caps are preferred over the elco's (1uf,10uf)............;
i would substitute the ceramic caps (1,5n;6,8n) in the riaa network with plastic caps (mkt,mkp,fkp...........or so) because ceramic can colour the sound a little bit..........but this is only a suggestion.
.....and there is often a small cap (220pf......470pf) parallel to the input.the suitable value is often recommended by the manufacturer of your mm system (in a datasheet).if you have no datasheet try out 220pf..................
greets
film/foil caps are preferred over the elco's (1uf,10uf)............;
i would substitute the ceramic caps (1,5n;6,8n) in the riaa network with plastic caps (mkt,mkp,fkp...........or so) because ceramic can colour the sound a little bit..........but this is only a suggestion.
.....and there is often a small cap (220pf......470pf) parallel to the input.the suitable value is often recommended by the manufacturer of your mm system (in a datasheet).if you have no datasheet try out 220pf..................
greets
Last edited:
RIAA mod.
Hello
I've replaced the ceramic Capacitor with WIMA RED Poly like your suggestion...
For the small cap at the input, I've found the old DUAL Turntable instruction:
only capacitance reference is:
TOTALA CAPACITANCE: torearm leads and audio-cables ca. 160 pF.
Is it the value in your suggestion?
Parallel to the input like this schematic?
Many Thanks, greets.
Hello
I've replaced the ceramic Capacitor with WIMA RED Poly like your suggestion...
For the small cap at the input, I've found the old DUAL Turntable instruction:
only capacitance reference is:
TOTALA CAPACITANCE: torearm leads and audio-cables ca. 160 pF.
Is it the value in your suggestion?
Parallel to the input like this schematic?
Many Thanks, greets.
Attachments
QUOTE=Dinosauro
For the small cap at the input, I've found the old DUAL Turntable instruction:
only capacitance reference is:
TOTALA CAPACITANCE: torearm leads and audio-cables ca. 160 pF.
Is it the value in your suggestion?
........no,i think this means only the capacitance of the cables built into your turntable by the manufacturer............the (mm) system (dual,ortophon,shure,.....) needs a specific cap...........perhaps you can find datasheets on the net for your system ................but do not worry too much about this,it is mostly a value between 220pf and 470pf...............
Parallel to the input like this schematic?
........yes.
greetings
For the small cap at the input, I've found the old DUAL Turntable instruction:
only capacitance reference is:
TOTALA CAPACITANCE: torearm leads and audio-cables ca. 160 pF.
Is it the value in your suggestion?
........no,i think this means only the capacitance of the cables built into your turntable by the manufacturer............the (mm) system (dual,ortophon,shure,.....) needs a specific cap...........perhaps you can find datasheets on the net for your system ................but do not worry too much about this,it is mostly a value between 220pf and 470pf...............
Parallel to the input like this schematic?
........yes.
greetings
Last edited:
All works!
Thanks for your help. The work is done and I'm very satisfied!
PCB of BOZ is home made, as the entire job (disign, MDF chassis, front backlight etc). I post some image of preamp with RIAA phono stage and the input selector with Encoder (PIC controlled).
Many thanks
Thanks for your help. The work is done and I'm very satisfied!
PCB of BOZ is home made, as the entire job (disign, MDF chassis, front backlight etc). I post some image of preamp with RIAA phono stage and the input selector with Encoder (PIC controlled).
Many thanks
Attachments
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.