Official LYNX Power Amp builder’s thread

[bigpanda]

Tks Jan, Holiday Greetings.

Now I have to start looking for the supplier.

Prosperous 2009!!!

 

[Ragnwald]

ELFA have all types of Vishay resistors, and you can buy them in small quantitys, and as a privat person.
https://www1.elfa.se/elfa/index.jsp

 

[bigpanda]

Tks Ragnwald ,

I will try looking there.

Holiday Greetings

 

[Idefixes]

Hi Jan,

I want to replace R128 to R135 by equivalent (in global value and power rating) 0,6W 1% metal film resistor in parallel. So i need to know if the 5w power rating is real necessary. I will apply about +/-35VDc rail power. I choose 0R33 as value for these resistors.

Marc

 

[Jan Dupont]

I want to replace R128 to R135 by equivalent (in global value and power rating) 0,6W 1% metal film resistor in parallel. So i need to know if the 5w power rating is real necessary. I will apply about +/-35VDc rail power. I choose 0R33 as value for these resistors.

It all depends on no. of output devices and speaker load.
Then it's straight forward using Ohms law........

 

[Idefixes]

It all depends on no. of output devices and speaker load.
Then it's straight forward using Ohms law........

I will take your configuration with 4 MJL3281/1302 pair. I will be able to drive easy 3 or 4 ohms speaker.

Marc

 

[Jan Dupont]

Taking worst case senario;

Vout: 32VDC
RL: 4Ohm
Re: 0.33Ohm

Vout/(RL+Re)= Iout
Iout x Re= Vre
Vre x Iout= WRe
As you use 4 output devices then result for each Re is WRe/4

 

[Idefixes]

Thanks Jan!; Your Ohm law picture is pretty cool with it's multiple entry. I save it on my HD for more consulting.

Marc

 

[Jan Dupont]

Thanks Marc, however I can't take credit for the Ohms Law schematic presentation.................

 

[masteramp]

Hi, this is my fifth prototype of modified Lynx.
I sent some pictures and schematic of a third prototype to ACD. ACD called it "Baby of LYNX". This name Likes me . Baby of Lynx have a power supply with symetrical 40V (only one pair of power transistors).
I measured BoL with AP2722:
Output power:
105W / 4 Ohm
75W / 8 Ohm
THD < 0,004%
SNR (A- weighted) > 120dB
Spectrum of output signal:
http://img125.imageshack.us/img125/6199/spektrumal7.gif

This foto shows only prototype. The final amplifier will be done in February.

 

[masteramp]

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An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

An externally hosted image should be here but it was not working when we last tested it.

 

[Jan Dupont]

Your baby looks nice

 

[bigpanda]

Sorry to disturb again about the emitter resistors

When I look at the spec. of the AC05, they measures 7.5mmD x 17mmL. I had a sample (which is probably not an AC05 and it isn't 0R47 ) which measures 9mmD x 19mmL. Does anybody knows anything about it?

The 1st one from the top seems to be a KNP series (24Lx8D)
The 2nd one from the top is the one I am talking about.
The 3rd one from the top would be a 3w KNP

Correct me if I am wrong, tks

 

[bigpanda]

forget the photo

 

[bomellberg]

Rail voltages

Sorry to interrupt your question, bigpanda.

I'm ready to install and make the first tests on the LYNX. I bought Jan's big toroid which has 42Vac secondaries. When I measure the rail voltages they are 4x61.4Vdc. In the specs and in the assembly guide, Jan has written +/-60V as the maximum.

Am I too far off here to be able to use this trafo? Or are my 61.4V ok for the LYNX?

Thanks for any help.

/Bo

 

[peranders]

Sorry to disturb again about the emitter resistors

When I look at the spec. of the AC05, they measures 7.5mmD x 17mmL. I had a sample (which is probably not an AC05 and it isn't 0R47 ) which measures 9mmD x 19mmL. Does anybody knows anything about it?

The 1st one from the top seems to be a KNP series (24Lx8D)
The 2nd one from the top is the one I am talking about.
The 3rd one from the top would be a 3w KNP

Correct me if I am wrong, tks

You should avoid the wire wound resistor = inductance

Metal oxide is fine.

 

[Jan Dupont]

Bo

You have no need to worry.
You can use the toroid without any problems.
I wouldn't have sold it to you if you couldn't use it

I have examples of LYNXs running on +/-90VDC........

You should use high power resistors for the zeners resistors.

 

[bomellberg]

Thanks Jan! That's reassuring for me.

I believe I used the 2W resistors that you specify in the QAG. Hopefully they will suffice.

Best regards,

/Bo

 

[Ragnwald]

We can also go highend and let the input IC have its own regulated supply, with a very little transformer.

 

[Jan Dupont]

Bo;

You might want to use two resistors in either parallel or in series to manage the heat....

Ragnwald;
Right