Transnova Circuit

[east electronics]

i ve seen this circuit thanks to our friend....here is a linkhttp://www.audio-circuit.dk/Schematics/USA1310.pdf
ok its a transnova i wonder if a design like that ( looks so simple ) worth making in a smaller scale .....

it seems that this schematic is designed to produce loads about power ...but what about quality ????? and if quality is ok then does it worth to built this for 100 w version ????

also thinking that designs like that originate from hafler so it should sound right ....

i also noticed that looks like djk's favourite design

coments are very welcome

thank you

[wg_ski]

Don't let the apparent simplicity fool you. It requires *completely* isolated power supplies for each channel. Which is ok if you were planning for that in the first place. But may not be the least expensive option in onsey twosey quantities.

In my personal opinion, the SQ is limited by the output stage running out of oomph. Make it into a triple (as in the low side of a Crown grounded bridge) and it will be much better. But at only 100 watts, 2 stages of current gain is often enough.

[east electronics]

i thing that seperated power sups are no problem ita could just as well be dual mono ie 2 trafos yet still remains very simple to make ....

on the other hand simple stuff like that most of times play very nice ....

i thing i am going to construct a prototype with like 2outs per rail just to listen to it

[Andy L. Francis]

Sakis, I think these are NOT Transnova circuits!

Anyway check out QSC amp schemas.
Link

and if quality is ok then does it worth to built this for 100 w version ???

Check "Discontinued Models / Series One" for low-power (~100W) modules schema on the QSC site I linked.

[east electronics]

for point this link to me ....actually didnt know that i was looking at a qsc amp any way ....

i thought that this was a copy of qsc since called USA 1310....

looking at this schematic made me even more close to construct this since you can almost use the same pcb for versions from 50 to 500w....

on the other hand i like very much the simplicity and the balance of the circuit symetry was always my thing i like square things ....

but still i get no comments of the expected quality .......

also another question most of this big comercial amps come with this network of transitors arround the drivers or the output transistors in the base area for protection IE monitoring current flow of the output and limiting the drive when amplifier is overdriven or shortcircuited ....

why in such an amplifier is not there ??????? not needed and why ?????

[Andy L. Francis]

but still i get no comments of the expected quality .......

I'd ask DJK.

i thought that this was a copy of qsc since called USA 1310....

USA1310s are made by QSC Corporation.

On the margin I'd change the thread's title 'cause discussion is not running about Transnova circuit here.

And Sakis, I know you're from Greece and the english is not your mother language. There is no problem with your english.
But your sentences are disorganised! They haven't got any front or any end. And that many periods...
Then it's really hard to understand your post.
I'm in the same position 'cause since english is not my native language, but hey I proud the forum members, I making an effort to write undersandable sentences.

[east electronics]

you are probably right since its too many things that i want to ask and too many in my mind.

Girlfriend of mine said that i have a 'popcorn brain " too many things jumping .....

english should be less of the problem though..... amplifiers is the interest .

please advice me how to call this post cause now i am confused and i have to detail look about trans nova.....

finally all my above questions remain unanswered .....

1)what makes this amp so powerfull and yet so simple
2) why the absense of all the ccs, vas, and protection circuits

[Andy L. Francis]

1)what makes this amp so powerfull and yet so simple
2) why the absense of all the ccs, vas, and protection circuits

1., A good design idea and the proper realization.
2., Weird question (too). There are protection circuits - see schematic! The topology don't need any CCS - then why use CCS?
It's not a conventional design. Do not search for conventional VAS/CCS/protection circuits on the schematic.

[wg_ski]

The output stage of the old QSC circuit *is* the VAS. It's common emitter, with the collector output coupled through the power supply. It's an exercise in getting the most output for the least number of stages.

Current limit is buried in the circuit. Short term is limited by limiting the peak output from the 5532 with zener diodes. Long(er) term is limited by how much charge the 100 uF bypass caps that filter the 5532 power supply can hold. The +/-15 is boot strapped by the caps during output excursions above +/-15V. When the caps run dry it limits. The op amp must supply base current to the OPS, and the more you draw the quicker it limits. If the 100 uF caps dry out or fail, the amp's output is limited to +/-15V (ask me how I know this).

[east electronics]

for the reply ....

could you be kind enough tell us more about the sound ....and/or problems ????