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TO-3 SYMASYM

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#762
One more SymAsym is running

Hi Rudi,

Thank you 🙂 for these wonderful SymAsym boards I have got from you !

The first channel did run at once, following your procedure 😉 of course, without any problem, and I have measured the DC value at the output as <-1mV ... 😀. I did not expect to get a negative number, but it is so small 🙂 that I am happy with it.

I will now populate the second board and when all will be running OK, I will post some photography of the baby. But before I will hear some music with both channels running. I think that my friend will be more than happy with such a good amplifier !

The explanations you have provided to all of us were outstanding and really a very good and friendly help as every problem that might occur is solved inside.

Thank you Rudi 😀 !

Best regards

rephil
 
#763
Hi Rudi,

Sorry, I was so euphoric yesterday due to the good results with my build that I have written the following : "DC value at the output was <-1mV", it should obviously be understood that "the absolute value was and remained <1mV" ...

I should sometimes follow your suggestions with more care 🙄, using a smaller 😱 bottle of very good italian 😀 wine in order to perform what you did write in your "Benutzerhandbuch" (Instructions for use) : "Yetzt einen kräftiger Schluck Whisky (oder Weissbier) - und Power On" (Now a huge draught of Whisky (or white beer) - and Power On) ... I had neither whisky nor white beer at hand, so as always in diy I used what I had home - italian wine -, willing more than enough help 😉 ...

Thank you again Rudi 😀😀 : I am more than happy 🙂 with this SymAsym.

Best regards

rephil
 
#764
Rephil, thank you for your kind words!

I know myself that the SYMASYM is a real gem: easy and uncomplicate to build, it does not need any fancy
components, and it sounds amazingly well, especially, if you you have gone for the TO3 - version.

I have ordered a small couple of my current SYMASYM-TO3 - PCBs a minute ago (see attached image).
I have 3 PCBs left.

If anybody wants to have these 3 PCBs: send me a PM.
I will offer to this one an additional PCB as well. SURPRISE!

Best regards - Rudi_Ratlos
 

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#765
Rudi_Ratlos said:
Rephil, thank you for your kind words!

I know myself that the SYMASYM is a real gem: easy and uncomplicate to build, it does not need any fancy
components, and it sounds amazingly well, especially, if you you have gone for the TO3 - version.

I have ordered a small couple of my current SYMASYM-TO3 - PCBs a minute ago (see attached image).
I have 3 PCBs left.

If anybody wants to have these 3 PCBs: send me a PM.
I will offer to this one an additional PCB as well. SURPRISE!

Best regards - Rudi_Ratlos
Click to expand...

Hi Rudi,

You got mail.

rephil
 
#768
Hi Rudi,

I could not resist to it ... I wanted to hear what kind of quality of the music could be produced by the first channel I have built of the SymAsym 😱.

It is fantastic with good bass frequencies, sweet high, it is also very powerful 😀 😀. All that gives really great satisfactions ... 😀. Thank you Rudi for this SymAsym TO3 😀, I enjoy the music, and my friend that will get the amp has no idea of how good this power amp is 😉😀.

BTW, it is time - you should do it please - to organise another group buy for this outstanding amp :Olympic:. I understand now why some of us did buy so many boards from you : it is the best amp that I have here ! I didn't know 🙁...

The only drawback is the THD 😱 ... well the spectrum has mostly only the 2nd and 4th harmonics, but for my taste, I should like to get also "wonderful numbers" for the THD ... But the sonics resulting is really top notch! I don't want to hear anything else ...

Thank you again Rudi 😀.

Best regards

rephil
 
#774
Gentlemen, SYMASYM-friends, I have received several feedbacks concerning my currently offered TO3/SYMASYM - PCBs (Rephil, Jorge, ... for example), telling me that my SYMASYM sounds best
(compared to nearly every competitor - DIY-Amplifier ) and that an audible improvement will not be possible 😉 .

Will it not be?

According to my experience: an amplifier sounds at is best, if the PSU (the reservoir CAPs !) is mounted as close as possible to the consumers (the output transistors),
and therefore did a "final" layout of the (my) SYMASYM.



http://abload.de/img/njw-symasym_v3-topviedasww.png

I have mounted the big reservoir CAPs on top of the PCB, the output-transistors (NJW-transistors, the MJE-drivers and the TEMPCO - BD139) being mounted below the PCB and hope: this is it!
The Signal-GND (on the bottom of the PCB) will not be affected by the "noise" inserted by charging / dis-charging the Solid-GND (on top of the PCB).

I am sorry that my Gerber-File-Viewer (GERBV) is not able to present the layout of this PCB correctly. There are a lot of horizontal black, small tracks to disturb the overall view!

The PCB incorporates CAP-Multipliers to provide smoothed frontend-voltages (consuming less than 15mA per rail) - as you can see (for example) on the bottom right of the PCB.

I will go and order 10 of these PCBs on the the coming weekend. Six of them are already reserved.
If somebody of you will this PCB a try (since they are prototypes) and wants to have it (price is 12€ per PCB - shipping is 3.45€ worldwide): 4 of these PCBs are not yet reserved.

Best regards - Rudi_Ratlos

P.S.: The size of the PCB is 150x100mm.
 

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#776
Andrew, I am referring to the SYMASYM-version as show in post #764.
It uses 2 pairs of TO3 - MJ21195G/MJ21196G as output transistors.

The SYMASYM sounds very well with those TO3-transistors.

My current effort is to include part of the PSU (reservoir-capacitors) on the amplifier's PCB.
Since I couldn't come up with a reasonable layout using TO3s, I changed to NJW0281G/NJW0302G (TO-3P case) and will mount them beneath the PCB.

This way the "hot area" - charging and de-charging the reservoir caps - is on top of the PCB and does not (this is what I think) affect the "small signal" area,
which is on the bottom of the PCB and which is fed by 2 cap-multipliers.

Best regards - Rudi_Ratlos

P.S.: All of the "new" PCBs are already reserved.
 
#778
Loek: the 22R resistors around the input are only used, if you operate the SYMASYM from an "active PreAmplifier (Gain >0)" .
In case you use a passive PreAmplifier (Source Selection + potentiometer), the 22R resistors are replaced by wires (will be bridged).

Best regards - Rudi_Ratlos

P.S.: In the meanwhile I have the enhanced (?) the on-top reservoir-capacitor layout by a new one, since I have had some luck and "inherited" a couple of "ELNA for AUDIO caps" for a very nice offering.
I wonder, how the NJW0 transistors will sound as compared to the TO3.

Best regards - Rudi_Ratlos
 

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#780
Patrick: I have given my word to somebody and will show him that the sound of the SYMASYM will be improved (will be "quicker"), if you mount the PSU-reservoir-CAPs
very close to the consumers (the output transistors).

Best regards - Rudi_Ratlos

P.S.: I will not offer this layout as a "Group-Buy - layout". I only did it to approve my assumption.
 
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