All things G1176 - the new "repost" thread.

[gswan]

Don't know about the suppliers in the UK, but the Flashstar VU meters are usually OK (may need a schottky diode bridge on the back of the meter) and seem to be available fro a reasonable price.

 

[emreyazgin]

Don't know about the suppliers in the UK, but the Flashstar VU meters are usually OK (may need a schottky diode bridge on the back of the meter) and seem to be available fro a reasonable price.

Is there any way of knowing whether or not a VU meter will work for the purpose without actually trying it? By specs ?? I found these in farnell :

http://uk.farnell.com/jsp/search/browse.jsp;jsessionid=L3UX4AFTKKF3YCQLCIQZMMQ?N=0&Ntk=gensearch_001&Ntt=vu+meter&Ntx=&suggestions=false&ref=globalsearch&_requestid=265226

 

[gswan]

Any VU meter will work and it largely becomes a matter of mechanicals and aesthetics. Some have illumination, others don't and there are many different sizes and shapes. It will depend on the panel space and look you are after.

Some VU meters do not have internal rectifiers (ie are DC meters) and you will need to wire up a little bridge on the back of the meter for it to give a reading.

 

[emreyazgin]

Any VU meter will work and it largely becomes a matter of mechanicals and aesthetics. Some have illumination, others don't and there are many different sizes and shapes. It will depend on the panel space and look you are after.

Some VU meters do not have internal rectifiers (ie are DC meters) and you will need to wire up a little bridge on the back of the meter for it to give a reading.

Thank you so much. I will look into that.

 

[emreyazgin]

OK, I am ready to stuff the board and I don't want to make any mistakes at this stage as I am not good at all in troubleshooting (never done it before!)

For a background information:

- I am using the MNATS Rev J. design
- I am NOT using the input transformer
- I am using the lundahl output transformer (AND I AM NOT SURE WHETHER I SHOULD DO THE REVERSE TRAFO OPTION OR NOT, Inputs please?)

So please tell me if I am missing anything. Due to my choices above I should:

- Start off with the power supply section and test the 30V and -10 volt as explained in other posts
- Then  test all resistors and stuff them first and then the rest
- Ignore the R* and R*1
- DO stuff ALL components within the white outline shown on the bottom right (because I'm not using the input trafo)
- Use the "BAL INPUT" as my audio input rather than "Optional IN"
- What about C* and C*3  ?? (and what are their values??)


Anything I am missing out or anything I should ignore while stuffing but I forgot to mention??

Cheers,
Emre

 

[gswan]

Due to my choices above I should:

- Start off with the power supply section and test the 30V and -10 volt as explained in other posts
- Then  test all resistors and stuff them first and then the rest
- Ignore the R* and R*1
- DO stuff ALL components within the white outline shown on the bottom right (because I'm not using the input trafo)
- Use the "BAL INPUT" as my audio input rather than "Optional IN"
- What about C* and C*3  ?? (and what are their values??)


Anything I am missing out or anything I should ignore while stuffing but I forgot to mention??

Cheers,
Emre

1. Perform Vgs vs Id tests for your FETs and select a pair that are suitable matched.
2. Measure the hfe of the transistors Q12, Q13, Q14, Q15 and use those with hfe > 250.
3. Match the resistors R1-A, B, C as close as possible (to within 0.1% is best).
4. C* and C*1 are 100uF electro.
5. C*2 and C*3 are 0.1uF ceramic.

 

[emreyazgin]

1. Perform Vgs vs Id tests fro your FETs and select a pair that are suitable matched.
2. Measure the hfe of the transistors Q12, Q13, Q14, Q15 and use those with hfe > 250.
3. Match the resistors R1-A, B, C as close as possible (to within 0.1% is best).
4. C* and C*1 are 100uF electro.
5. C*2 and C*3 are 0.1uF ceramic.

OK perfect, thanks a lot once again. You have been a great help, I am really grateful Geoff!

E.

 

[Chrome Heart]

1. Perform Vgs vs Id tests fro your FETs and select a pair that are suitable matched.
2. Measure the hfe of the transistors Q12, Q13, Q14, Q15 and use those with hfe > 250.
3. Match the resistors R1-A, B, C as close as possible (to within 0.1% is best).
4. C* and C*1 are 100uF electro.
5. C*2 and C*3 are 0.1uF ceramic.

OK perfect, thanks a lot once again. You have been a great help, I am really grateful Geoff!

E.

Ive done the Lundahl output tranny both ways. My preference is the 1:2 configuration. I didnt feel I was getting the output I needed in the other position.
Youve probably seen this but mnats has this well explained here http://mnats.net/1176_revision_j.html
Of course, you could just try it both ways and see what works best for you.

 

[emreyazgin]

1. Perform Vgs vs Id tests fro your FETs and select a pair that are suitable matched.
2. Measure the hfe of the transistors Q12, Q13, Q14, Q15 and use those with hfe > 250.
3. Match the resistors R1-A, B, C as close as possible (to within 0.1% is best).
4. C* and C*1 are 100uF electro.
5. C*2 and C*3 are 0.1uF ceramic.

OK perfect, thanks a lot once again. You have been a great help, I am really grateful Geoff!

E.

Ive done the Lundahl output tranny both ways. My preference is the 1:2 configuration. I didnt feel I was getting the output I needed in the other position.
Youve probably seen this but mnats has this well explained here http://mnats.net/1176_revision_j.html
Of course, you could just try it both ways and see what works best for you.

Thanks a lot.

By the way, I still couldn't find a 1.1k 1watt carbon resistor, can I use two 2.2K .4 or .6watt resistors in parallel??

Also, "carbon composition" and "carbon film" mean "CARBON" on the BOM right? Same thing?

 

[casrec]

I don't know what the voltage or current is there, but running two of the same resistors in parallel doesn't mean you will get half the resistance. Also you can use any 1 watt resistor here, Metal film or Carbon. 1/2 watt carbon composition will work here too. They can withstand the heat better then film resistors and this is what was in the original.


Brandon

 

[emreyazgin]

I don't know what the voltage or current is there, but running two of the same resistors in parallel doesn't mean you will get half the resistance. Also you can use any 1 watt resistor here, Metal film or Carbon. 1/2 watt carbon composition will work here too. They can withstand the heat better then film resistors and this is what was in the original.


Brandon

I always assumed 1/R1+1/R2=1/R(Eq)  ?? Is this wrong?? And if its in parallel wattage increases and if its series wattage stays the same but you add the resistance values, isn't this true? OR is it dependent on other factors?

I found a carbon composition 1/2 watt 1.1k thanks for the recommendation

 

[sahib]

I don't know what the voltage or current is there, but running two of the same resistors in parallel doesn't mean you will get half the resistance. Also you can use any 1 watt resistor here, Metal film or Carbon. 1/2 watt carbon composition will work here too. They can withstand the heat better then film resistors and this is what was in the original.

Brandon

You just have to brush up your fundamentals of electrics.


Emre, you are on the right track.

 

[casrec]

I'm sorry, I rechecked my math. I have never knowingly used two of the same resistors in parallel just to get half the resistance. I would use the one. But that's just me. And not that I need to brush up, I just need to learn more.

 

[Chrome Heart]

I'm sorry, I rechecked my math. I have never knowingly used two of the same resistors in parallel just to get half the resistance. I would use the one. But that's just me. And not that I need to brush up, I just need to learn more.

Besides, it'll look better with just one. And thats all I care about.

 

[gswan]

1K 1W carbon resistors are cheap and plentiful. You should be able to find one of these.

 

[a2d]

If you not useing an input transformer  do you need to install C* and c*1?

Due to my choices above I should:

- Start off with the power supply section and test the 30V and -10 volt as explained in other posts
- Then  test all resistors and stuff them first and then the rest
- Ignore the R* and R*1
- DO stuff ALL components within the white outline shown on the bottom right (because I'm not using the input trafo)
- Use the "BAL INPUT" as my audio input rather than "Optional IN"
- What about C* and C*3  ?? (and what are their values??)


Anything I am missing out or anything I should ignore while stuffing but I forgot to mention??

Cheers,
Emre

1. Perform Vgs vs Id tests for your FETs and select a pair that are suitable matched.
2. Measure the hfe of the transistors Q12, Q13, Q14, Q15 and use those with hfe > 250.
3. Match the resistors R1-A, B, C as close as possible (to within 0.1% is best).
4. C* and C*1 are 100uF electro.
5. C*2 and C*3 are 0.1uF ceramic.

 

[a2d]

ok So I got the new pots from U/A today,,,, hey guess what the meter doesn't move with the pot, but........ I'm finding some other things are wrong. loud humming,sounds like square wave on the output......and with the release pot full CW the signal seems brighter,,, ,ummmmm
I think I've pretty much had enough of this thing, I'm guessing DIY is not my thing if it doesn't work ,,,,,lol
I started to build another board, so we'll see whats what, maybe someone here might be intrested in building or fixing mine???

Hey Bryan,,,, Haven't seen you around,,,,,,,I wanted to get thoes Caps from you and another output transformer.    whats going on???,  I bet the house is looking mighty good

Mike

 

[gswan]

They have nothing to do with the transformer. They are additional PSU bypass caps, local to a particular section of circuitry. It's a good idea to install them.

 

[a2d]

I never installed them, I don't think its the problem, I will add them,

 

[emreyazgin]

1K 1W carbon resistors are cheap and plentiful. You should be able to find one of these.

But what I need is 1.1K, can I use 1k instead of that?