[TestSubject]

Well, i am building a CMoy amp, I curently live in france and the only supplier that doesnt charge 30$ (20Euros) for shipping is RS components.
 
On the list of parts needed, 0.1 µF metallized polyester cap whish is no where to be found.
 
Thanks for helping me out.
 
http://tangentsoft.net/audio/cmoy-tutorial/parts.html#req
 
Any good components website for international maybe?

 

[Avro_Arrow]

You don't have to use that exact value.
As a matter of fact it is a bit on the low side.
Any value from there on up to 1uF would
be fine.

 

[Avro_Arrow]

Like this one

 

[TestSubject]

Thanks for the help!
 
I was wondering the voltage on the Caps doesnt really matter as long as its not to big. it will take a bit more time to charge up right?
 
Will a common wall multi-voltage transformer be okay?
 
Do you think its better to buy the supplies and etch your own pcb or just use a breadboard?
 
Thanks

 

[Avro_Arrow]

Higher voltage than you need in a cap just means more cost/ bigger size for
no real return. 63 volts is a pretty common value for film caps.
 
As for etching a board, the start up cost is the problem. If you are only
going to do this one project, I would say do it on perfboard. If you are
planning on doing lots more projects, then I would say have a look at
learn to etch your own boards. Everything I do, I etch my own boards.
The "Iron On" method has the lowest start up cost but is the hardest
to get good results without lots of practice. Photo etching is pretty
easy to get good results but is more expensive to start up and the
presensitized board are more expensive. There are several threads and
tutorials on Head-Fi and on the web for both methods. I use photo etching.
 
Look for a transformer of at least 12 volts and maybe as high as 16 volts.
If you have more voltage it makes it easier to add a regulator to improve
the quality of the power supply. Regulators need a few extra volts to
do their job. Plan on your transformer/wall wort to be about 3 volts higher
than you think you will need. Remeber too, that the power supply voltage
you pick will have some effect of the power supply caps in you CMoy.
You will want caps rated about two times the voltage of your power supply.

 

[TestSubject]

Thanks A lot for the info.
 
Now i get to choose the OP Amp, here are the different option.
 
 
[size=8pt]

[size=8pt] OP07CP ​ [/size]	[size=8pt]   Ampli opérationnel ​ [/size]	[size=8pt] DIL08​ [/size]	[size=8pt] 42300​ [/size]	[size=8pt]   1.20 €​ [/size]
[size=8pt]   OP07EP ​ [/size]	[size=8pt]   Ampli op très faible bruit ​ [/size]	[size=8pt] DIL08​ [/size]	[size=8pt] 21240​ [/size]	[size=8pt]   6.80 €​ [/size]
[size=8pt]   OP27GP ​ [/size]	[size=8pt]   Ampli op très faible bruit ​ [/size]	[size=8pt] DIL08​ [/size]	[size=8pt] 21241​ [/size]	[size=8pt]   3.25 €​ [/size]
[size=8pt]   OP37GP ​ [/size]	[size=8pt]   Ampli opérationnel très faible bruit ​ [/size]	[size=8pt] DIL08​ [/size]	[size=8pt] 42467​ [/size]	[size=8pt]   3.60 €​ [/size]
[size=8pt]   OP177FP ​ [/size]	[size=8pt]   Ampli op ultra précis ​ [/size]	[size=8pt] DIL08​ [/size]	[size=8pt] 42651​ [/size]	[size=8pt]   5.90 €​ [/size]
[size=8pt]   OPA134PA ​ [/size]	[size=8pt]   Ampli op audio 8 MHz ​ [/size]	[size=8pt] DIL08​ [/size]	[size=8pt] 42469​ [/size]	[size=8pt]   2.70 €​ [/size]
[size=8pt]   OPA604AP ​ [/size]	[size=8pt]   Ampli op 20 MHz 25 V/µs ​ [/size]	[size=8pt] DIL08​ [/size]	[size=8pt] 42470​ [/size]	[size=8pt]   4.20 €​ [/size]
[size=8pt]   OPA2134PA ​ [/size]	[size=8pt]   Double ampli op audio 8 MHz ​ [/size]	[size=8pt] DIL08​ [/size]	[size=8pt] 42471​ [/size]	[size=8pt]   3.20 €​ [/size]
[size=8pt]   OPA2604AP ​ [/size]	[size=8pt]   Double ampli op 20 MHz 25 V/µs ​ [/size]	[size=8pt] DIL08​ [/size]	[size=8pt] 42472​ [/size]	[size=8pt]   6.80 €​ [/size]

[/size]  
The OPA2134PA VS OPA2604AP mainly. Does the price justify the quality?
 
http://tangentsoft.net/audio/opamps.html#134 Doesnt go into details of those 2 amps.

 

[Avro_Arrow]

For a first time project, I would probably stick with the tried and true OPA2134.
You can always roll different op amps into it later. Higher performance op amp
are often tricker to get working properly.

 

[Sergelisses]

Bonjour
 
Linear Technoloy is very dynamic with the samples .
One week ,Maximum two weeks and you receive your samples .

 
Is not the same song with NS

 
Well the LT1364 is a very good AOP better for me thant the 2134 !!!!!
I have one LT1364 ( DIP )  i can send it to you ( I live also in FRANCE  !!!! ) ...
I have also two  OPA 2134 but in SOIC package
 
Bonnes écoutes
Serge
 

 

[Avro_Arrow]

LT1364 ia also one of my favourates, but you failed to warn him that
it is a Bi-Polar Op Amp, not JFET like OPA2134, and as such needs
a different design than he is doing to avoid DC offset.
 
Quote:

Bonjour
 
Linear Technoloy is very dynamic with the samples .
One week ,Maximum two weeks and you receive your samples .

 
Is not the same song with NS

 
Well the LT1364 is a very good AOP better for me thant the 2134 !!!!!
I have one LT1364 ( DIP )  i can send it to you ( I live also in FRANCE  !!!! ) ...
I have also two  OPA 2134 but in SOIC package
 
Bonnes écoutes
Serge
 

 

 

[Sergelisses]

Quote:

LT1364 ia also one of my favourates, but you failed to warn him that
it is a Bi-Polar Op Amp, not JFET like OPA2134, and as such needs
a different design than he is doing to avoid DC offset.
 


 

I don't really understand what do you mean by to avoid DC offset.
I 'am using a SALAS Shunt regulation +10,-10v  without Input Capacitor ( 0.1µf ) and it seems to be good ...
Today the  best results are two LT1363 and the SALAS Shunt Reg ...
 
Serge


 
 

 

[Avro_Arrow]

How much DC offset do you get?
 
For LT1364 with an input cap with 100k resistor, you get about 200mV offset.
For LT1364 with a 10k audio pot (no input cap) you can expect 20mV
with the volume at max, less as the volume is lower.
 
The OP's design uses an input cap with 100k resistor. Not a good
choice for LT1364.

 
Quote:

I don't really understand what do you mean by to avoid DC offset.
I 'am using a SALAS Shunt regulation +10,-10v  without Input Capacitor ( 0.1µf ) and it seems to be good ...
Today the  best results are two LT1363 and the SALAS Shunt Reg ...
 
Serge


 
 

 

 

[Sergelisses]

 
Quote:

How much DC offset do you get?
 
For LT1364 with an input cap with 100k resistor, you get about 200mV offset.
For LT1364 with a 10k audio pot (no input cap) you can expect 20mV
with the volume at max, less as the volume is lower.
 
The OP's design uses an input cap with 100k resistor. Not a good
choice for LT1364.

 


 

How much DC offset do you get?
 
With  no Input cap and no 100k resistor
Pot =Min Offset = around -7mv
Pot =Max Offset = around +7mv
 
 
What are your others favourite AOP ?
 
Thanks for your advices
 
 
 
Serge
 
 

 

[TestSubject]

Okay im almost through with my question (I hope).
 
Would "Normal"Carbon resistor be good enough or does it have to be metal film?
 
Thanks for the assist.

 

[Fred_fred2004]

It will work with carbon but use 1% metal film they will be quieter
 
cheers

 

[TestSubject]

is 1/2 W metal film resistor okay? That's all they sell.
 
Can't thank you enough.