[Judge Buff]

Can anyone tell me the maximum height of C2 for the Serpac H-65? Is it 15 or 16mm?

This BOM is getting a little pricey... I may need to do a little sweet-talking to the Mrs.

 

[tangent]

Quote:

Originally Posted by Judge Buff /img/forum/go_quote.gif Can anyone tell me the maximum height of C2 for the Serpac H-65? Is it 15 or 16mm?

More like 10 mm or 12.5 mm, depending on the cap diameter and whether you're willing to bevel the board edges so it sits lower in the case.

I like to bevel the edges regardless so I can run the pot shaft straight out of the exact center of the front panel.

 

[Judge Buff]

Quote:

Originally Posted by tangent /img/forum/go_quote.gif More like 10 mm or 12.5 mm, depending on the cap diameter and whether you're willing to bevel the board edges so it sits lower in the case. I like to bevel the edges regardless so I can run the pot shaft straight out of the exact center of the front panel.

Thanks, tangent. Since I will only be using a 9V NIMH, can I get away with 10V caps at C2 or do I need to go with 16V or higher?

Sorry for the noob questions...

 

[tangent]

Quote:

Originally Posted by Judge Buff /img/forum/go_quote.gif can I get away with 10V caps at C2

"9 V NiMH" is a misnomer.

There are three varieties, with 6, 7 and 8 cells, at 1.2 V each nominal, for 7.2, 8.4 and 9.6 V nominal for the battery. Charging NiMHs requires about 1.5 V per cell, so only the 7.2 V variety will let you get away with 10 V rail caps.

 

[pulsar08]

I have a +/-12v dual regulated supply that is lying around. I checked to see if it's isolated and I think it is. Is it possible to use a dual supply with a pimeta that also has nimh batteries? Do I just keep TLE2426 as designed and connect the V+ and V- and leave ground unconnected or would there be a way to leave TLE2426 out and still charge the batteries (15xAA nimh)

I also have a +/-15v dual regulated but Power Supply Matters says: Quote:

The PIMETA can run on anything from about 5 to 30 V. The extremes pose some problems

What are the issues involved with this much voltage? From the data sheets I think ad86xx are only useable with below 26v so this might be what you're refering to but I'm not sure I'm even reading that right.

 

[pulsar08]

Oh yeah. Sorry. I forgot about the second issue I have.

Which caps would be best for power supply rails. Assuming I can use the +/-12v supply/15xAA nimh. The tallest caps my enclosure can hold are 34mm.

I'm considering these which are available on mouser:

3x 647-UHD1H681MHD 680uf 50v Nichicon HD 12.5x31.5mm total impedance .007ohms

3x 647-UPM1V681MHD 680uf 35v Nichicon PM 12.5x25mm total impedance .012ohms

3x 647-UPM1E681MPD 680uf 25v Nichicon PM 10x31.5mm total impedance .0153ohms

I'm not sure if impedance was the main thing to look at or if being near to the max voltage was more important.

 

[tangent]

Quote:

Originally Posted by pulsar08 /img/forum/go_quote.gif Is it possible to use a dual supply with a pimeta that also has nimh batteries?

I don't see why not.

The ground channel isn't pulling much weight when you use a dual supply. Consider converting your PIMETA to a 2-channel amp if you use this supply.

Quote:

What are the issues involved with this much voltage?

Aside from limiting your chip selection, it pushes you to 35 V rail caps, which means you sacrifice quality or capacity relative to equivalent 25 V ones if you can get away with a 24 V or lower supply. It also means the amp gets warmer.

Quote:

Originally Posted by pulsar08 /img/forum/go_quote.gif Which caps would be best for power supply rails.

There's vast advice on this topic in the archives, and a fair bit in the PIMETA docs, too.

 

[pulsar08]

Quote:

Originally Posted by tangent /img/forum/go_quote.gif it pushes you to 35 V rail caps, which means you sacrifice quality or capacity relative to equivalent 25 V

I don't understand this relationship you claim between voltage and quality. Looking at previous discussions to me has been inconclusive because some claim that the voltage rating doesn't influence quality at all and some claim it does.

This list I posted for instance seems to indicate the complete opposite because the 50v capacitors have a lower impedance.

Quote:

Originally Posted by pulsar08 /img/forum/go_quote.gif I'm considering these which are available on mouser: 3x 647-UHD1H681MHD 680uf 50v Nichicon HD 12.5x31.5mm total impedance .007ohms 3x 647-UPM1V681MHD 680uf 35v Nichicon PM 12.5x25mm total impedance .012ohms 3x 647-UPM1E681MPD 680uf 25v Nichicon PM 10x31.5mm total impedance .0153ohms

Could you please just look at this list to help me understand which is the best choice.

 

[tangent]

You're not comparing apples to apples. You'd have to compare caps varying only in voltage ratings. The ones you're comparing vary in can size, too, at the least.

As to your plea that I give specific part advice, sorry, won't do it. Maybe someone else will. I much prefer to give more general advice that will help you pick your own parts. This is DIY, not letmeDIYthatforyou.

 

[jcaps]

Quote:

If you are using a RK27 pot simply connect a wire from one of the terminals on the switch to one of the "S1" pads on the circuit board.
Then connect another wire from the other switch terminal to the other "S1" pad on the circuit board (It doesn't matter which switch terminal is wired to which pad with a SPST switch (nobody is going to call a wambulance if you install your switch upside down)).
If you are using a RK097 pot you won't need to wire in a switch...

First off, I'm super new to this stuff as well. Just completed two CMoys, so decided to move onto the Pimeta v2.
 
I'm using the RK097 with built in switch. Therefore, I don't need an additional switch at S1 (right?). So can I just jumper S1 - I figure I still need to complete the circuit? I don't see any reason to use a molex here either (as tangent uses) with the RK097.
 
Am I correct here.
 
Cheers.

 

[MisterX]

Quote:

First off, I'm super new to this stuff as well. Just completed two CMoys, so decided to move onto the Pimeta v2.
 
I'm using the RK097 with built in switch. Therefore, I don't need an additional switch at S1 (right?). So can I just jumper S1 - I figure I still need to complete the circuit? I don't see any reason to use a molex here either (as tangent uses) with the RK097.
 
Am I correct here.
 
Cheers.

Depends.
Jumpering the S1 pads would defeat the switch in the RK097 (you would not be able to turn the amp off) so you might want to re-think that one

 

[tangent]

I've updated the new schematic to show that the RK097's built-in switch connects V+ and B+, just as S1 does.

 

[GregVDS]

Hello,
 
Long time no see!
 
I'm interested by the Pimeta V2 with Linkwitz. But I would mainly use it with a Nagra VI. Source would come from the balanced XLR 4.4V, and power from the Hirose 12V of the Nagra.
I'm wondering if someone knows how I can convert balanced to unbalanced input, so I can feed it to the Pimeta?
I was also fearing to have ground loops and hum and buzz from mixing ground from the Hirose and balanced cold?
 
What do you think?
 
And some more in fact:
If I want to replicate balanced input signal towards balanced output XLR, what should I do, simply hardwire it? What will be the sonic effect of having a headphone amp in parallel on the output of the Nagra with other fed equipments?
 
Gedupaaaaa

 

[tangent]

Quote:

I'm wondering if someone knows how I can convert balanced to unbalanced input, so I can feed it to the Pimeta?

http://pinouts.ru/Home/xlr3_pinout.shtml
 
 
Quote:

I was also fearing to have ground loops and hum and buzz from mixing ground from the Hirose and balanced cold?

 
Unlikely.  I can't say I've ever heard of someone getting a new ground loop after adding a headphone amp to a previously quiet system.
 
 
 
Quote:

What will be the sonic effect of having a headphone amp in parallel on the output of the Nagra with other fed equipments?

 
Not a good idea.  That parallels the input sections, which means they'll likely interact audibly.
 
Preamps exist for a reason, and almost all of them are active for the same reason.
 

 

[GregVDS]

mmh,
 
the pinout of an XLR is one of my knowledge. At least I can find docs explaining without too much problem.
 
I was more thinking of something like this:
 
http://www.jensen-transformers.com/an/an003.pdf
 
in which one can find active circuits to pass a balanced signal into an unbalanced one, and vice-versa.
 
So I was thinking of using such schematic in front of the input of the pim, maybe with a selector switch to select a second unbalanced input.
 
Now I would like to keep balanced line through the pimeta, so I should pick up the signal, and have it re-balanced to an output.
 
So, Anyone with suggestions for this is welcome.
 
Thanks,
 
Greg