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lexvortex
Joined: May 14, 2008
Posts: 155
Location: Toronto
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 Posted: Fri Feb 06, 2009 4:37 pm Post subject:
Subject description: Polyester capacitor help |
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Hi JH,
I've started building the FS1A and have gotten through most of it  (I was worried about the SMD stuff but it was surprisingly easy  ) I'm down to the capacitors, I picked up some generic polyester caps (eg, 2A104J, I believe +-5% tolerance) for the list under Wima MKS, Siemens MKT because I don't have easy access to the higher quality ones. Will this have a negative effect on the sound quality? Also I was able to find only BC550B instead of BC550C will that make any difference? Also can I replace the two 10 ohm resistors near MOTM style MTA power connector on the Dome filter board with ferrite beads?
Thanks,
Dave |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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Posted: Fri Feb 06, 2009 6:01 pm Post subject:
Subject description: Polyester capacitor help |
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| lexvortex wrote: | Hi JH,
I've started building the FS1A and have gotten through most of it (I was worried about the SMD stuff but it was surprisingly easy ) I'm down to the capacitors, I picked up some generic polyester caps (eg, 2A104J, I believe +-5% tolerance) for the list under Wima MKS, Siemens MKT because I don't have easy access to the higher quality ones. Will this have a negative effect on the sound quality? |
I don't think so. Just make sure the caps in the dome filter, multiplied with the resistor values, have a tight tolerance.
| Quote: | | Also I was able to find only BC550B instead of BC550C will that make any difference? |
Shouldn't.
| Quote: | | Also can I replace the two 10 ohm resistors near MOTM style MTA power connector on the Dome filter board with ferrite beads? |
Why would you want to do this? It probably won't hurt, but what advantage would you hope to get?
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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lexvortex
Joined: May 14, 2008
Posts: 155
Location: Toronto
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| Posted: Sat Feb 07, 2009 10:06 am Post subject:
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Hi JH,
The reason I ask about the ferrite beads has to do with a discussion in a different thread that talks about using ferrite beads instead of low ohm resistors as discussed in this thread
http://electro-music.com/forum/viewtopic.php?highlight=ferrite+beads&t=25712
| Quote: | Good discussion! I've always been unhappy about how people automatically put in the series resistors. What these resistors do is turn your nice hard regulated supply into a soft supply -- IOW the voltage supplied to the circuit depends on how much current it draws. You turn a regulated suppply into an unregulated one.
The combination of the resistor and capacitor does provide lowpass filtering, but if you look at the numbers this filtering usually only goes down to the audio range. Slowly varying signals -- LFOs EGs, etc. -- go through unchanged. So the voltage supplied to the circuit also varies with frequency!
There certainly are situations where the RC decoupling is helpful, but there are also many situations where it is harmful. It is best IMO to use the ferrite beads and a fair amount of capacitance to kill HF garbage and to make sure your power distribution wiring is done carefully to avoid ground loops.
Very Happy
Ian |
I thought (maybe wrong  ) that the 10 ohm resistors could be replaced by ferrite beads to avoid the situation that Ian was talking about above. I will keep the 10ohm resistors now  Sorry for all the newbie questions 
Thanks again,
Dave |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Sun Feb 08, 2009 9:31 am Post subject:
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I remember that thread! And explained my general philosophy about it there, too.
| Quote: |
I thought (maybe wrong ) that the 10 ohm resistors could be replaced by ferrite beads to avoid the situation that Ian was talking about above. I will keep the 10ohm resistors now |
I only decouple *audio* circuits with RC. CV and precision parts have no series resistor in the supplies, of course.
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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lexvortex
Joined: May 14, 2008
Posts: 155
Location: Toronto
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Posted: Sun Feb 08, 2009 10:20 am Post subject:
Subject description: Another component question |
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Hi JH,
Thanks for the ferrite bead info .
Sorry to bother you again with another question about components . I've got a lot invested in this project and what to make sure I get it right  . I went to my local electronic store and bought a bunch of BC560s, unfortunately when I got home and tested them they were all nonfunctional  . A quick trip back confirmed that his entire supply of BC560s are nonfunctional , he looked up the data sheet and got me some BC557Bs that were ~ equivalent. If I remember correctly the BC560 are a low noise version of the BC557. Should I try and track down some BC560s or will it make little difference if I use the BC557Bs?
Thanks again,
Dave |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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Posted: Sun Feb 08, 2009 12:13 pm Post subject:
Subject description: Another component question |
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| lexvortex wrote: | Hi JH,
Thanks for the ferrite bead info .
Sorry to bother you again with another question about components . I've got a lot invested in this project and what to make sure I get it right . I went to my local electronic store and bought a bunch of BC560s, unfortunately when I got home and tested them they were all nonfunctional . A quick trip back confirmed that his entire supply of BC560s are nonfunctional , he looked up the data sheet and got me some BC557Bs that were ~ equivalent. If I remember correctly the BC560 are a low noise version of the BC557. Should I try and track down some BC560s or will it make little difference if I use the BC557Bs?
Thanks again,
Dave |
No need for low noise transistors here. I guess any small signal pnp with the right pinout will do.
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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lexvortex
Joined: May 14, 2008
Posts: 155
Location: Toronto
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| Posted: Sun Feb 08, 2009 7:24 pm Post subject:
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Thanks again
Dave |
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davebr
Joined: Jun 09, 2007
Posts: 198
Location: portland, or
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Posted: Tue Feb 24, 2009 9:27 pm Post subject:
Frequency Shifter
Subject description: Updated build progress |
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I've received my FrontPanelExpress panel and made an aluminum bracket to mount the PCBs. I'm just waiting now for my batch of BI Technologies potentiometers to arrive to wire up the front panel. I put updated photos on my site. - Dave
http://modularsynthesis.com/jhaible/shifter/jhshifter.htm |
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lexvortex
Joined: May 14, 2008
Posts: 155
Location: Toronto
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| Posted: Wed Feb 25, 2009 5:38 am Post subject:
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Hey Dave,
Very nice panel I remember reading about those pots in the Yahoo Oakley group. I'm interested in trying them out, where did you end up getting them from and for how much?
Cheers,
Dave |
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davebr
Joined: Jun 09, 2007
Posts: 198
Location: portland, or
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Posted: Wed Feb 25, 2009 6:31 pm Post subject:
Frequency Shifter
Subject description: BI Technologies potentiometers |
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I couldn't find anyone in the US that distributes BI Technologies P260P series potentiometers. Freight from Rapid in the UK is astronomical. I ended up going direct to the BI Technologies through Arrow. Their minimum order quantity is 240, so I got 5 samples to confirm the physical dimensions and ordered 240. Their leadtime is 7 weeks so I expect them in the last half of March. I don't need 240 but they were reasonably priced and I will not pay the skyrocket prices for Vishay/Spectrol. I think these are similar quality.
This would be a great opportunity for someone to resell to the DIY community. I approached a couple of folks but got no interest. I am not interested in selling them in small quantities but if someone wanted to buy half I certainly have a lifetime supply.
Dave |
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davebr
Joined: Jun 09, 2007
Posts: 198
Location: portland, or
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Posted: Sat Mar 21, 2009 3:10 pm Post subject:
Frequency Shifter
Subject description: I'm Done !!! |
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I got my shipment of BI Technologies potentiometers and finished up my frequency shifter. This is one nice module! Updated photos at
http://modularsynthesis.com/jhaible/shifter/jhshifter.htm
Dave |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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Posted: Sat Mar 21, 2009 3:45 pm Post subject:
Re: Frequency Shifter
Subject description: I'm Done !!! |
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Very nice documentation page!
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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funkyfarm
Joined: Jan 21, 2007
Posts: 583
Location: France
Audio files: 3
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| Posted: Sat Mar 21, 2009 4:02 pm Post subject:
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Amazing !
so professionnal.
I have a PCBset i've bought for my old days |
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mosc
Site Admin
Joined: Jan 31, 2003
Posts: 18249
Location: Durham, NC
Audio files: 226
G2 patch files: 60
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Posted: Sat Mar 21, 2009 5:36 pm Post subject:
Re: Frequency Shifter
Subject description: I'm Done !!! |
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Beautiful work.
_________________
--Howard
my music and other stuff |
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sduck
Joined: Dec 16, 2007
Posts: 459
Location: Nashville
Audio files: 5
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| Posted: Sun Mar 22, 2009 5:36 pm Post subject:
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| Dave, that is really awesome. So much so, that it's kick-started my plan to build one - I hope you don't mind if I copy your front panel design! |
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davebr
Joined: Jun 09, 2007
Posts: 198
Location: portland, or
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Posted: Sun Mar 22, 2009 8:08 pm Post subject:
Frequency Shifter
Subject description: Front Panel |
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| Go ahead, that's why I post them. I could have done the Manual control legends in a -5 to +5 instead of 0 to 10. I thought about it but wasn't sure if that control was really centered (which it is). I figured it didn't make much difference. - Dave |
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funkyfarm
Joined: Jan 21, 2007
Posts: 583
Location: France
Audio files: 3
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| Posted: Mon Mar 23, 2009 3:26 pm Post subject:
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| You've put IC sockets only for 13700 ic ? |
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davebr
Joined: Jun 09, 2007
Posts: 198
Location: portland, or
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Posted: Mon Mar 23, 2009 5:18 pm Post subject:
Frequency Shifter
Subject description: Sockets |
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| funkyfarm wrote: | | You've put IC sockets only for 13700 ic ? |
I rarely use sockets. I find over time that they cause more problems then they solve. I haven't had to replace many ICs but I sure have had to reseat lots of them over the years.
In this case I used sockets for the two 13700 ICs and the two MC1496 ICs. Generally I also don't use connectors for all the offboard wires but I did in this case since it was a dual board setup with lots of wires.
Dave |
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funkyfarm
Joined: Jan 21, 2007
Posts: 583
Location: France
Audio files: 3
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| Posted: Tue Mar 24, 2009 1:19 pm Post subject:
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Thank you.
connectors are not luxury here. (hmm or all this is luxury)
I've checked Jurgen's site for a pcb for this impressive project till 2002, or maybe it was 2001
Thanks for the preview. |
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zthee
Joined: Feb 20, 2008
Posts: 414
Location: Stockholm
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mono-poly
Joined: Jul 07, 2004
Posts: 937
Location: Rotterdam, Netherlands
Audio files: 2
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| Posted: Sat Mar 28, 2009 4:24 am Post subject:
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| Amazing man! |
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lexvortex
Joined: May 14, 2008
Posts: 155
Location: Toronto
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Tue Mar 31, 2009 10:39 am Post subject:
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Beautiful!
You can also post pictures like this in the "gallery thread":
http://electro-music.com/forum/topic-24079.html
(Pictures are *welcome* here in *this* thread, too, of course.)
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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sduck
Joined: Dec 16, 2007
Posts: 459
Location: Nashville
Audio files: 5
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| Posted: Sat Apr 04, 2009 6:21 pm Post subject:
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I seem to have hit a problem in the construction of my FS1a.
The caps for the dome filter. I bought the 2% tolerance ones Dave Brown has in his BOM. I've just discovered that my fluke 115 only reads capacitance to the single digits in the nanofarad range - not the one or two decimal points that the spreadsheet uses.
Do I need to worry about this? Should I get a better dmm for this purpose? Any other ideas? |
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jhaible
Joined: May 25, 2007
Posts: 2014
Location: Germany
Audio files: 24
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| Posted: Sun Apr 05, 2009 6:38 am Post subject:
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| sduck wrote: | I seem to have hit a problem in the construction of my FS1a.
The caps for the dome filter. I bought the 2% tolerance ones Dave Brown has in his BOM. I've just discovered that my fluke 115 only reads capacitance to the single digits in the nanofarad range - not the one or two decimal points that the spreadsheet uses.
Do I need to worry about this? Should I get a better dmm for this purpose? Any other ideas? |
Having caps with higher tolerance doesn't meant the FS will stop working - it just may have a bit less sideband rejection. Which probably won't hurt too much. You could simply try the caps you have, see (hear) if you like the results, and you can still upgrade to tighter spec'ed caps later.
If you like it the way you have it, don't search for faults.
(Pragmatical approach.)
JH.
_________________
"I tell you the truth, if anyone says to this mountain, 'Go, throw yourself into the sea,' and does not doubt in his heart but believes that what he says will happen, it will be done for him. Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours." (Mk 11,23f) |
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