TSSA - The Simplest Symmetrical Amplifier

[Lazy Cat]

I would love too be there but i cannot find space in the calendar next week. I have two orders that needs to be shipped next week. And we are running as fast as we can. Where in sweden are you located?

Probably top range models shipment, I assume only these can stop you from visiting Munich.

Where did you get that, connecting me with Sweden I've never even visited it, although I would love to. No Sweden, Slovenia is the country of my origin, still.

 

[sonnya]

No, it is electronic parts for home-care equipment. It is booming.

I don't know where i got this idea from that you are from Sweden!??? Now when i look at you flag i can see it!!

Then we will able to meet next year!?

 

[Idefixes]

LC, you have a private massage inbox

Marc

Edit : I take a look at my parts stock : i have 12x IRF610 and 17x IRF9610

Hopefully, i can try to mesure stock par this week-end to see if i need to order more or not mosfet driver...I have no 12V accu but a single 0-12V power supply 7812 base regulated.

Marc

 

[sonnya]

Am i missing a schematic of a TSSA with CCS???? Or am i dreaming???

 

[Lazy Cat]

TSSA Basic 1.1

Sure, i just build it as is to study it. What do you think to replace the 1kOhm resistors with CCS´s ? Gives more open loop gain but stability has to be watched.

Gerhard and all interested, I finally found spare moment to make an upgrade to basic version, now with CCS integrated.

I'm sure this would measure even better than the first basic version built by Sonnya, sound quality should follow as well.

Regards, Andrej

 

[Lazy Cat]

Or am i dreaming???

Not anymore.

 

[Lazy Cat]

Gerhard and all interested, I finally found spare moment to make an upgrade to basic version, now with CCS integrated.

I'm sure this would measure even better than the first basic version built by Sonnya, sound quality should follow as well.

Regards, Andrej

Few more words about TSSA Basic 1.1
- CCS pair transistor's flats should be glued together
- input pair transistor's flats should be glued together
- BF245B source-gate resistor value for Id=2 mA
- 500 ohm MT (multi turn) trimmers set output bias current (0,25-2A) and output DC offset (zero volts)

Amplifier power output 50 Wrms/4 ohm.

 

[tinitus]

Amplifier power output 50 Wrms/4 ohm.

I thought that would be into 8ohm, with +/-32V

 

[sonnya]

Gerhard and all interested, I finally found spare moment to make an upgrade to basic version, now with CCS integrated.

I'm sure this would measure even better than the first basic version built by Sonnya, sound quality should follow as well.

Regards, Andrej

The OLG will not change much. The open loopgain is more or less set by the RC divided by the feedback resistors which are => 2K2/(36R||1K) => 2K2 / 34 => 65gg

It is multiplied by: (RLOAD/(1/gfs)).

For the exicon (10N20 and 10P20) it is: gfs = 2.5S @ ID=2.5A.

=>

65gg x (8/(1/2.5)) => 1300gg or 62dB.

 

[Lazy Cat]

I thought that would be into 8ohm, with +/-32V

56 Vpp is max output voltage swing just before clipping, so if power supply can deliver current, max output power will be 49 Wrms/8 ohm or 98 Wrms/4 ohm.

I stated output power at -3 dB, so more relaxed, unclipped, not heavily distorted one.

 

[Lazy Cat]

The OLG will not change much. The open loopgain is more or less set by the RC divided by the feedback resistors which are => 2K2/(36R||1K) => 2K2 / 34 => 65gg

It is multiplied by: (RLOAD/(1/gfs)).

For the exicon (10N20 and 10P20) it is: gfs = 2.5S @ ID=2.5A.

=>

65gg x (8/(1/2.5)) => 1300gg or 62dB.

OLG 62 dB is OK. Distortion spectral profile will be much more clear than before. What do you think, will you test it?

 

[Joachim Gerhard]

I build the circuit from post 1 and also added constant current sources, but floating depletion mosfets. The sound got much better. Less distortion and bigger soundstage.

 

[tinitus]

I stated output power at -3 dB, so more relaxed, unclipped, not heavily distorted one.

 

[franzm]

I build the circuit from post 1 and also added constant current sources, but floating depletion mosfets. The sound got much better. Less distortion and bigger soundstage.

What type? Siemens/Infineon BSP series?

 

[Joachim Gerhard]

Supertex, the ones that SY uses in "His Masters Noise".

 

[sonnya]

OLG 62 dB is OK. Distortion spectral profile will be much more clear than before. What do you think, will you test it?

I am not a fan of pure CLASS A (It is not ECO friendly ) but i will maybe test the attached version.

This way the current through the input BJT will be the same and symmetrical regardless of bias current and offset adjustment. => Every amp will sound the same way.

 

[Tekko]

I'm saddened to see how ppl nowdays put eco friendlyness before sound quality

 

[sonnya]

Class AB is fine with me. But Pure class A dissipating +150Watt per channel, i think is a bit over the top when we struggle to keep CO2 emission down.

My own CFP EXICON's runs with 35Watt per channel.

 

[Tekko]

My current class A amp dissipates around 60-75 watts per channel with a bias of 2.5A, the previous one ran six Amps per channel. My lafet amp(2SK135 and 2SJ50) i have no clue on dissipation as its stone cold despite 150mA bias per channel.

All my other amp project run between 30-70mA bias per channel.

 

[sonnya]

My current class A amp dissipates around 60-75 watts per channel with a bias of 2.5A, the previous one ran six Amps per channel. My lafet amp(2SK135 and 2SJ50) i have no clue on dissipation as its stone cold despite 150mA bias per channel.

All my other amp project run between 30-70mA bias per channel.

Sorry i did not want to Pick on you...