TO-3 SYMASYM

[Rudi_Ratlos]

Gentlemen,

the PCBs are due to arrive the week of Feb. 8th.

I will ship them out immediately after their arrival.
The letters are already prepared.

Sorry for the delay. It has been due to "New Year's Holiday" in China.

I will send to you all the "TO-264 Builder's Manual" in a minute.

Best regards - Rudi_Ratlos

[meanman1964]

Rudi,
Great news!!

[Rudi_Ratlos]

Patrick,

there is nothing "great" about this news.

It simply says: "Gentlemen, don't get impatient please! You will receive the PCBs of a very, very good sounding amplifier in a week or two".

I am sorry for the delay.

Best regards - Rudi

[Rudi_Ratlos]

Gentlemen,

I am happy to tell you that the PCBs have been etched today and are already on their way to me.

Here is the URL of the tracking ID:

DHL | Tracking | English

if you like to follow their way.

Best regards - Rudi

[Rudi_Ratlos]

Gentlemen,

I received the PCBs today:



http://www.abload.de/img/joe019mluo6.jpg

(they are flawless as usual)

and will dispatch them tomorrow.

You all will have them in your hands in the course of next week.

I wish you a nice build and a nice sound!

Best regards - Rudi_Ratlos

[Vigier]

I received my PCB's! Thank you for the great service and good packaging.
Kind regards, Vigier

[butch_vlad]

So did I, very good quality!!!

Should we make a new thread for these boards? I will start building a Symasym and I have some questions I would like to ask, have lots of compatible parts and I would like to hear other opinions regarding them. Also I was wondering if it's possible to use higher voltage rails and what components need to be upgraded...?

[Rudi_Ratlos]

Butch,

I do not think that it is necessary to open an extra builder's thread.
Since the group-buy is closed, you can use this thread to post your thoughts / questions in here.

Yes: you can of course raise the rail-voltages! You are even welcome to do this!
EVETTE did this as well and is absolutely content with the results.

Be aware of the value of the rail-capacitors C16 and C17 then!
And do not forget and activate the cap-multiplier with the ZENER.

Best regards - Rudi

[butch_vlad]

Thanks Rudi, I'll examine the schematics and see what can be easily upgraded.
Can you tell me what was the max voltage for Symasym, that worked stable?
I am fimiliar with Rod's capacitance multiplier but I have no idea what you mean by "activate the cap multiplier with the zenner". I feel a bit rusty now, need to do some reading to remember few things.
My main question is about the LEDs present on the PCB, not sure what are they for.

Cheers,
Vlad

[Rudi_Ratlos]

Vlad,

the LEDs simply reflect the status of the power rails.
If they burn, it means: power rail voltage is present. So the LEDs should burn all the time.

I have added a jumper (two jumpers) on the PCB to bypass or not the cap-multipliers for the positive and negative rail.

If the jumper is set (activated), the cap-multiplier will be bypassed and the frontend will be powered by the backend PSU (voltage).
But take care then: if you drive the AMP from a 30 VAC PSU (f.e.), this may blow the sensitive input transistors!

If the jumper is not set, the cap-multiplier is activated.
It includes a ZENER diode to limit the voltage for the frontend to a value that is convenient (f.e. 39V) and will prevent any harm
to the input transistors, even if you drive the backend with a higher voltage.


Best regards - Rudi