mnats rev-H 1176 schem/files

[Redhouse]

Anyone here save the details on the mnats rev-H boards from a few years back?

Reason is, I made a couple self-etch boards from his rev-H PDF's and finally now getting time to do these builds but the details of this rev are unclear (and my memory is less clear) specifically the C* parts and R* parts and stuff specific to that board and don't seem to be around anymore. Back in the day they were listed in the meta, and there were files on mnats website but now he's moved on to rev-J and other builds.

I have PM'd mnats but get no response so I'm asking the rest of the group, I've tried reconciling the (mnats) rev-H board to the UREI schems floating around but some stuff is still unclear to me, so I'm hoping someone here saved the support files that were going around back when this was a new build.

 

[ruairioflaherty]

http://mnats.net/1176_H_info.html

 

[Redhouse]

Thanks, found that myself.

Still, theres no schem there (which is what I'm after) if you read my post above I'm looking for the schem that matches that rev-h board, there are parts that are optional, or something.
(C*, C*1, C*3, R*, R*1 etc, etc.)

 

[kepeb]

hey,
I was looking for info on those a while back.
They should be the same parts as in the rev J as are all based on the original/alternate Gyraf board.

C* - 100uf 35v
C*1 - 100uf 35v
C*2 - 0.1uf
C*3 - 0.1uf
R* and R*1 - I believe are used only if you have an input transformer.

 

[Redhouse]

hey,
I was looking for info on those a while back.
They should be the same parts as in the rev J as are all based on the original/alternate Gyraf board.

C* - 100uf 35v
C*1 - 100uf 35v
C*2 - 0.1uf
C*3 - 0.1uf
R* and R*1 - I believe are used only if you have an input transformer.

Thanks, do you recall what the significance of the caps with the * is?
(why are they an alternative style part number, what the story is)

Anyone know if mnats is still hangs around here?


Also, whatever happened to kev's website? I been gone from here a couple years did I miss something?

 

[kepeb]

it was kindly pointed out to me by another member that these caps are additional power filtering caps and it's recommended you add them.
check the rev j thread, i'm sure you'll find all your answers there

 

[gemini86]

Those are the caps you leave out when using the off board psu PCB, I do believe.

 

[kepeb]

well, I've probably done mine all wrong if thats the case.

http://www.axtsystems.com/index.php?option=com_content&view=article&id=50:1176lnmodule&catid=34:1176ln&Itemid=62

the picture there highlights the components mounted if you are using an external PS, this includes the ones mentioned above.

 

[gemini86]

well, I've probably done mine all wrong if thats the case.

http://www.axtsystems.com/index.php?option=com_content&view=article&id=50:1176lnmodule&catid=34:1176ln&Itemid=62

the picture there highlights the components mounted if you are using an external PS, this includes the ones mentioned above.

nope, I was wrong... they are the components that are NOT in the original 1176 schem, therfore not NEEDED to build a working unit, but are added for performance sake. The R* resistors are for the input trafo option (termination) and for the lundahl option are supposed to be 10K, according to lundahl.

 

[EvLoutonian]

C* - 100uf 35v
C*1 - 100uf 35v
C*2 - 0.1uf
C*3 - 0.1uf

On the PDF detailing Jakob's boards it looks like C* is 1000uf, not 100uF.
Can anyone confirm which is right?    100uF or 1000uF?

Here:
http://www.gyraf.dk/gy_pd/1176/1176.pdf

 

[gswan]

Unless you have a really rubbish power supply, 100uF should be more than ample.

 

[EvLoutonian]

Unless you have a really rubbish power supply, 100uF should be more than ample.

Thanks gswan.  I so far have almost all the components soldered in place on my boards, but I hadn't noticed those optional c* parts when I was making by bulk order. 

In your opinion, is it a worthy addition to include those extra four cap's?

Also, my friend (who I'm building with) suggested that, in his opinion, the BC107 transistors have a relatively poor noise spec compared to say the BC547, and he even suggested to maybe consider using the extra low noise BC550.

From his explanation, it does seem odd (or perhaps just a bit overly simplistic) to substitute all three of the original transistor types, 2N3391, 2N2925 & 2N3707, from the Urei 1176 schematic with the BC107 type. 

I'd love to hear any other opinions on this from people who've built the circuit and/or used any substitutes in place of these parts.  To be honest, I'm a total beginner with transistor electronics myself and I was just gonna follow the build instructions as directly as I possible, including using the BC107's across all those designated spots on the board.  But since my friend was making data comparisons between these transistors & the Urei originals, it did get me wondering.. 

I'm trying to learn more through working on this project, and really just trying to get my Rev J boards completed with the best results that I can at this stage.  Any insights or explanations in regard to these questions would be hugely appreciated!

Thanks, people!
Evan.

 

[gswan]

Unless you have a really rubbish power supply, 100uF should be more than ample.

Thanks gswan.  I so far have almost all the components soldered in place on my boards, but I hadn't noticed those optional c* parts when I was making by bulk order. 

In your opinion, is it a worthy addition to include those extra four cap's?

It won't hurt to include them, it adds some additional bypass for the power supply.

Also, my friend (who I'm building with) suggested that, in his opinion, the BC107 transistors have a relatively poor noise spec compared to say the BC547, and he even suggested to maybe consider using the extra low noise BC550.

From his explanation, it does seem odd (or perhaps just a bit overly simplistic) to substitute all three of the original transistor types, 2N3391, 2N2925 & 2N3707, from the Urei 1176 schematic with the BC107 type. 

I'd love to hear any other opinions on this from people who've built the circuit and/or used any substitutes in place of these parts.  To be honest, I'm a total beginner with transistor electronics myself and I was just gonna follow the build instructions as directly as I possible, including using the BC107's across all those designated spots on the board.  But since my friend was making data comparisons between these transistors & the Urei originals, it did get me wondering.. 

I'm trying to learn more through working on this project, and really just trying to get my Rev J boards completed with the best results that I can at this stage.  Any insights or explanations in regard to these questions would be hugely appreciated!

I'd use BC547 instead of the old tin can BC107, just like I'd use metal film resistors rather than the old carbon composition types. Modern processes have improved the noise and performance of most components.

One thing worth mentioning is the little side note of selecting the transistors in the GR amp based on their hfe. If you have a meter capable of performing an hfe measurement then it's a relatively simple task to do so. Ideally they should be >250.

 

[EvLoutonian]

I'd use BC547 instead of the old tin can BC107, just like I'd use metal film resistors rather than the old carbon composition types. Modern processes have improved the noise and performance of most components.

One thing worth mentioning is the little side note of selecting the transistors in the GR amp based on their hfe. If you have a meter capable of performing an hfe measurement then it's a relatively simple task to do so. Ideally they should be >250.

Thanks again, gswan, that's all really helpful.  I believe I can measure the HFE on my multimeter and check for ones in the 250 and under range.  I may even add transistor sockets on my first PCB so I can test BC107 vs BC547 etc (seeing as I already ordered 50 pieces of the BC107!)

Another thing I was wondering is, does it matter that I didn't get the large size fancy cap's for C1, C10, or C17?
I noticed that most people have used great big chunky blocks there.
I did get nice cap's when I ordered from Mouser, but it turns out they are just the regular smaller size format (as you can see in the following pic of my board as it is right now)..

If it makes much of a difference I would look into upgrading these. 
What is the advantage of up-sizing those cap's?

Also, because I accidentally ordered the 2200uF cap's for positions C24, C25 & C26 (looking at the Rev F schematic by mistake) I am thinking I will just use those in place of the 1000uF filter cap's indicated on the Rev J board.  Is there any reason not to use the 2200uF cap's here?

THANKS AGAIN!

 

[gswan]

Thanks again, gswan, that's all really helpful.  I believe I can measure the HFE on my multimeter and check for ones in the 250 and under range.  I may even add transistor sockets on my first PCB so I can test BC107 vs BC547 etc (seeing as I already ordered 50 pieces of the BC107!)

Once you have settled on the transistors you want to use, get rid of the sockets. They can eventually corrode over time and cause weird problems, or if the unit is moved around a lot the transistors can fall out with excessive vibration.

Another thing I was wondering is, does it matter that I didn't get the large size fancy cap's for C1, C10, or C17?
I noticed that most people have used great big chunky blocks there.
I did get nice cap's when I ordered from Mouser, but it turns out they are just the regular smaller size format (as you can see in the following pic of my board as it is right now)..

There's no problem with the 1u 63V poly caps you have. Larger ones will make absolutely no difference.

If it makes much of a difference I would look into upgrading these. 
What is the advantage of up-sizing those cap's?

None in this circuit. The large ones will have a higher working voltage (110V, 250V, 415V etc).

Also, because I accidentally ordered the 2200uF cap's for positions C24, C25 & C26 (looking at the Rev F schematic by mistake) I am thinking I will just use those in place of the 1000uF filter cap's indicated on the Rev J board.  Is there any reason not to use the 2200uF cap's here?

I think these are the power supply filter caps. I've always used an external, higher quality PSU than the one on the PCB, however it usually does not hurt to use a higher value in this case. The only thing you need to check is the voltage rating and the physical size (diameter and pin spacing).

 

[EvLoutonian]

Excellent.  Thanks a lot for the tips! 
It's great to get a bit of reassurance on those topics.
  Cheers

 

[EvLoutonian]

.. One thing worth mentioning is the little side note of selecting the transistors in the GR amp based on their hfe. If you have a meter capable of performing an hfe measurement then it's a relatively simple task to do so. Ideally they should be >250.

Hey again, Gswan..

- Sorry, one more question:
When referring to the HFE of transistors, as in your advice above, does >250 mean "up to" (but not over) a value of 250, or "greater than" 250?

Thanks again!
Evan

 

[gswan]

For the GR amp it is best to use transistors with a gain of greater than 250 if you can select them.