F5 Headamp ?

[EUVL]

Here another example of using a standard 2107 case without any special machined parts :
http://www.diyaudio.com/forums/head...portable-headphone-amplifier.html#post4758783


Patrick

 

[RollE2k]

Is there anybody here that will match transistors for the output stage that possibly would sell also?

 

[EUVL]

You can buy 2K2013 / 2J313 from NicMac.


Patrick

 

[RollE2k]

But his are not matched at these low currents?

 

[EUVL]

That you would have to ask Nic.
Cloud85 have matched Fairchilds, if you ask him nicely.


Patrick

 

[EUVL]

Together with a few Beta testers, we have tried a different way of using the passive cross feed filter.
For the F5-HA, I still suggest keeping the JFET buffer, but now between volume pot wiper and F5-HA input.
This will ensure maximum bandwidth and also get rid of the 100p input capacitor.


Patrick
.

 

[NicMac]

But his are not matched at these low currents?

All the 2SK2013/2SJ313 I acquired and traced had very similar transfer functions and track reasonably well from 50 mA to 1A when sorted for both Vgs and Yfs at a single, not to extreme, current (0.5A in my case).

Of course, matching will never be as good as that achieved when the tracing is conducted under true operating conditions, in which Patrick is the true master!

I would love to sort another batch of devices, if I could find them in numbers at a reasonable cost
Remember that the success of any serious matching effort will be proportional to the number of devices you start out with as well the intrinsic diversity among them.

Cheers,

Nic

 

[Hikari1]

Finally got the regs working (stixx's cap mult) after miswiring the lm329s. Curiously I've got 14.9v on the positive side and -15.4v on the neg side. Same voltage drop across both strings of lm329/led.

Should I be concerned?

 

[EUVL]

Yes. 0.6V is one diode drop. Did you test under load, say 100mA ?
So there might be a mis-wiring somewhere after the LM329 reference.


Patrick

 

[Hikari1]

I will investigate, thanks. I may have damaged some semis after installing lm329s wrong.

In the meantime I might just use a 317/337 reg I have. I know it works.

 

[alazira]

Finally got the regs working (stixx's cap mult) after miswiring the lm329s. Curiously I've got 14.9v on the positive side and -15.4v on the neg side. Same voltage drop across both strings of lm329/led.

Should I be concerned?

I was exploring Stixx's PS in LTSpice and noticed that increasing C10 cap caused oscillation. Even at 330uF there is a little. Decreasing to 220uF seems to improve it.

I also tried adding a cap between Q1 & Q2 which improved the regulation slightly. I know LTSpice isn't necessarily the same as real life. Is there any problem adding a cap here?

 

[EUVL]

Not oscillation.
It is a few mV of ripple voltage due to your dynamic current load at 500Hz (I1).


Patrick

 

[Ryssen]

Will sommeone be matching the optocouplers?For the volumecontrol?

 

[Ryssen]

I´m trying to make an order basket at mouser for the components,they don´t seem to have the Talema trafo.
But I wonder is the Nichicon KA smd or regular elyts?

Edit: I see the trafos are on ebay...

 

[EUVL]

> is the Nichicon KA smd or regular elyts?
Just google.


Patrick

 

[massimo]

But I wonder is the Nichicon KA smd or regular elyts?

Let me google it for you
NICHICON CORPORATION | Product & Technology
Scroll down to "for audio cap"
Yes, (U)KA are T.H.

 

[Ryssen]

Ok,thanks.

 

[cloud85]

For talema. Try digikey

70063K Talema Group LLC | Transformers | DigiKey

 

[Ryssen]

Is it possible to modifie the CCS so that I can use a ligtspeed volume?

 

[Ryssen]

I guess I´d have to have 2 CCS then..