TESORO GOLDEN SABRE

[simonbaker]

I suppose the coupling capacitors are on the solder side of the board, but what location are those ? Perhaps they are the reason for the calm operation of the deviced + the bigger GND ring around the board outline.
Yup there are no labels on the board, would be good to have them labeled, the board is very nice, small size could fit to many small md boxes, hmm perhaps I should try it

I guess he is saying "decoupling capacitors", or bypass capacitors, maybe across rails or certain supply pins of ICs to suppress high-freq noise, like voltage spikes, etc. I found some useful places to put them on my proto-board TGSL, but wondered if needed on actual PCB.

It sure is nice looking board, thanks to Ivconic many experiments and designs.

Cheers,

-SB

[ivconic]

Yes those are.
I will prepare .lay with values. I used to observe schematic and printed pcb mutualy during soldering components (very good method - twice the accuracy - double checking) , that's why i didnt write values. But if that will help you more; i will prepare and repost it again.

[Unregistered]

Hi Ivconic:
... can you explain "coupling capacitors" (.1uF) more? Did you put them on PCB or schematic? What is function?
-SB

"Coupling capacitor" is a misnomer. More correct would be "decoupling capacitor". Or, "supply bypass capacitor". They are absolutely essential in circuits that use many digital IC (at high speeds) and become less important at lower frequencies. Think of them as preventive medicine.

They are usually placed near to IC supply pins (especially on digital IC), to provide for instantaneous current demands - keeping the supply voltages smooooth. A good plan is to use the usual big power supply cap and spread some small decoupling caps around. Small caps -should- have a lower impedance at the high (switching) frequencies than large electrolytics will.

(Coupling capacitors are used between different stages of an audio amplifier (or an RF amplifier, for example) to couple the signal but at the same time maintain isolation of DC voltages in the various stages.)

[ivconic]

"Coupling capacitor" is a misnomer. More correct would be "decoupling capacitor". Or, "supply bypass capacitor". They are absolutely essential in circuits that use many digital IC (at high speeds) and become less important at lower frequencies. Think of them as preventive medicine.

They are usually placed near to IC supply pins (especially on digital IC), to provide for instantaneous current demands - keeping the supply voltages smooooth. A good plan is to use the usual big power supply cap and spread some small decoupling caps around. Small caps -should- have a lower impedance at the high (switching) frequencies than large electrolytics will.

(Coupling capacitors are used between different stages of an audio amplifier (or an RF amplifier, for example) to couple the signal but at the same time maintain isolation of DC voltages in the various stages.)

Correct. I made mistake. Must remind you that English language is not my native language. So many times i made simillar mistakes; wanted to point on something else but wrote something quite inproper instead!? Ha,ha,ha!!!
Sorry and please understand my situation.
Regards!

[simonbaker]

Correct. I made mistake. Must remind you that English language is not my native language. So many times i made simillar mistakes; wanted to point on something else but wrote something quite inproper instead!? Ha,ha,ha!!!
Sorry and please understand my situation.
Regards!

You communicate in more than one language, better than me!

Can you show the decoupling caps on the schematic too for helping us understand your improvements?

Best regards,

-SB

[ivconic]

Look on posted photo of pcb, blue circles (elipses)...
Also i am preparing better pic with components values...

[ivconic]

Values...

[Unregistered]

Correct. I made mistake. Must remind you that English language is not my native language. So many times i made simillar mistakes; wanted to point on something else but wrote something quite inproper instead!? Ha,ha,ha!!!
Sorry and please understand my situation.
Regards!

Hey, I wasn't trying to put you down. You're the teacher here. I just have better command of the English language. (My former English teachers might take issue with that.) Now, if you had to read me as I tried to explain anything in a language other than English, then you might not know whether to laugh or cry. It would be very difficult.

I don't know everything, but I thought I knew the answer to SB's question. I responded, but maybe I should have stayed home?

Anyway, good work on your TGSL! I especially like your speaker driver, it looks very efficient.

[simonbaker]

R5

Hi Ivconic:

Just noticed last schematic has two "R5" resistors at speaker, needs relabel.

Also, is the 330 ohm "R5" at the collector of TR3 important? What happens if not there?

Comparing to original TGSL schematic, interesting to see no JFet feedback path on TX oscillator -- must not be important after all. Also we have new supply filter capacitor C3 at +8v output of LM7808, like on Molzar PCB.

One more idea for experimenters -- remember original TGS (Molzar PCB) did not have diode D11.

Cheers,

-SB

[Unregistered]

Simon,

If relabeling also three "R6" around Tx, and two "D5".

Audio looks interesting can't wait to try out.

Many thanks Ivconic!

Molzar

[ivconic]

Yes...i am usually using ExpressPCB (schematic part) for drawing fast schematics. Initially this schematic was made long time ago as first TGSL. Version by version i just deleted some components and add another ones. Pretty oftenly i forgot to relabel some new components. ExpressPCB schematic editor is descent editor yet not that "smart" to automatically redesignate new part. Also i am i to lazy to pay attention on that. Those schematics and most of pcb draws are mostly for my personal use, so i dont mind pretty much on designators and labels. I am not used to be that neat when comes to final documentation. Usually i never finish completelly those documents.... story of my life, always in hurry somewhere...
But so as i see; you are fully awared what is right and what need to be corrected, so not a big deal after all.
Point is that device is checked and accurate, so you can start making it with no second thoughts at all.
Regards!

[simonbaker]

Yes...i am usually using ExpressPCB (schematic part) for drawing fast schematics. Initially this schematic was made long time ago as first TGSL. Version by version i just deleted some components and add another ones. Pretty oftenly i forgot to relabel some new components. ExpressPCB schematic editor is descent editor yet not that "smart" to automatically redesignate new part. Also i am i to lazy to pay attention on that. Those schematics and most of pcb draws are mostly for my personal use, so i dont mind pretty much on designators and labels. I am not used to be that neat when comes to final documentation. Usually i never finish completelly those documents.... story of my life, always in hurry somewhere...
But so as i see; you are fully awared what is right and what need to be corrected, so not a big deal after all.
Point is that device is checked and accurate, so you can start making it with no second thoughts at all.
Regards!

Yes, we appreciate the real work you do and the results.

We newcomers can help by working on documentation, hopefully useful for everyone.

Regards,

-SB

[ivconic]

You are welcome to do that! Thanks in advance!

[simonbaker]

You are welcome to do that! Thanks in advance!

Ivconic: what software do you use to draw schematics?

-SB

[ivconic]

ExpressSch (part of ExpressPCB) for fast schematics and Sprint Layout 4.0 for pcb's...