|  | | 
02-03-2013, 11:27 AM
| | Registered User | | Join Date: Jul 2007 Location: Yorkshire, England, UK | | Quote:
Originally Posted by FunkMetalBass  | You need to add "DC Simulation" that gets rid of the "DC action required" error.
Your schematic around the second opamp is not right so it still does not simulate.
You also need a DC path where the bias goes to both opamps.
__________________
G&L L-2500 -> Art Pro Channel II -> 35Hz HPF -> Peavey IPR1600 -> fEARful 15/6 and/or 12/6
|
02-03-2013, 01:32 PM
| | Registered User
Endorsing Artist: J.C. Basses | | Join Date: Aug 2005 Location: Phoenix, Arizona 85029 | | Quote:
Originally Posted by delta7fred | Wow, thanks. That worked great!
So, I read online that the Stingray 3-band frequencies were approximately 40Hz, 500Hz, and 12kHz. According to QUCS, it looks like they are actually closer to 80Hz, 350Hz, and 12kHz.
I haven't figured out the magic cap values to shift the mids up (I like ~600Hz) and the bass down (I'd prefer 60Hz). Any suggestions? It looks like increasing the cap on the bass pot isn't doing a darn thing to shift the peak frequency.
__________________ Quote:
Originally Posted by McThumpenstein I don't think the wife would buy the "I need to take off this knob and put a whole new bass under it" story. | |
02-03-2013, 01:49 PM
| | Registered User | | Join Date: Jul 2007 Location: Yorkshire, England, UK | | Quote:
Originally Posted by FunkMetalBass Wow, thanks. That worked great!
So, I read online that the Stingray 3-band frequencies were approximately 40Hz, 500Hz, and 12kHz. According to QUCS, it looks like they are actually closer to 80Hz, 350Hz, and 12kHz.
I haven't figured out the magic cap values to shift the mids up (I like ~600Hz) and the bass down (I'd prefer 60Hz). Any suggestions? It looks like increasing the cap on the bass pot isn't doing a darn thing to shift the peak frequency. | Just play about with the caps and see what pops out. It is the caps round the pots that set the operating frequency. Have you got the scales on the graph set to log, if they are linear you won't really see the differences at low frequencies.
The input circuitry is a HPF, if you put a monitor point after the first opamp you will see it rolls off at 12db/oct IIRC (it is a few years since I played with this circuit) so there is not much point making the bass pot operate too low.
__________________
G&L L-2500 -> Art Pro Channel II -> 35Hz HPF -> Peavey IPR1600 -> fEARful 15/6 and/or 12/6
|
02-03-2013, 02:03 PM
|  | Registered User | | Join Date: Dec 2003 Location: Columbia River Gorge, WA. | | Quote:
Originally Posted by FunkMetalBass Anybody here experienced with SPICE? I was hoping to get this circuit built up in it so that I could play around with a few component values before I buy parts, but I'm not experienced at all with the program and I'm really confused as to how to implement the opamps.
I can post my current .sch file if needed. | Any chance of posting a screen shot of your schematic for those of us who don't use QUCS? I posted some LTspice sim curves of the MM two bander in the long thread and I'd like to take a stab at the three bander as well. |
02-03-2013, 04:53 PM
| | Registered User | | Join Date: Jul 2007 Location: Yorkshire, England, UK | | Charlie
It is based on this hand drawn original (from post #1) http://i267.photobucket.com/albums/i...62_2322510.gif
__________________
G&L L-2500 -> Art Pro Channel II -> 35Hz HPF -> Peavey IPR1600 -> fEARful 15/6 and/or 12/6
|
02-03-2013, 05:21 PM
| | Registered User
Endorsing Artist: J.C. Basses | | Join Date: Aug 2005 Location: Phoenix, Arizona 85029 | | Quote:
Originally Posted by delta7fred Just play about with the caps and see what pops out. It is the caps round the pots that set the operating frequency. Have you got the scales on the graph set to log, if they are linear you won't really see the differences at low frequencies.
The input circuitry is a HPF, if you put a monitor point after the first opamp you will see it rolls off at 12db/oct IIRC (it is a few years since I played with this circuit) so there is not much point making the bass pot operate too low. | They are log scales, and that was the cap I was messing with, but even going to extremes (10uF) wasn't making a noticeable difference.
I can deal with an 80Hz bass, but 350 is far too low for me in the mids.
As soon as I get home, I'll post some screen shots.
__________________ Quote:
Originally Posted by McThumpenstein I don't think the wife would buy the "I need to take off this knob and put a whole new bass under it" story. | |
02-03-2013, 05:49 PM
| | Registered User | | Join Date: Jul 2007 Location: Yorkshire, England, UK | | Quote:
Originally Posted by FunkMetalBass They are log scales, and that was the cap I was messing with, but even going to extremes (10uF) wasn't making a noticeable difference. | Ah, now you mention it I do remember having trouble simulating the High/Mid/low The input HPF and the High were the only ones that worked. I must have an error on my schematic.
I will have another look when I get chance.
__________________
G&L L-2500 -> Art Pro Channel II -> 35Hz HPF -> Peavey IPR1600 -> fEARful 15/6 and/or 12/6
|
02-03-2013, 09:25 PM
| | Registered User
Endorsing Artist: J.C. Basses | | Join Date: Aug 2005 Location: Phoenix, Arizona 85029 | | Quote:
Originally Posted by delta7fred Ah, now you mention it I do remember having trouble simulating the High/Mid/low The input HPF and the High were the only ones that worked. I must have an error on my schematic.
I will have another look when I get chance. | Glad I'm not alone in the matter. Those are the only places I've had any luck changing too.
It looks good to me - I don't see anything in that portion of the schem that's any different from the hand drawing. I'm wondering if it's an issue with QUCS not acknowledging the difference between a junction dot and a crossing without a dot. The treble is the only potion of the EQ section that doesn't contain any crossings.
EDIT: I did find that the opamp on the right was flipped (+ should be on top), but that didn't change anything.
__________________ Quote:
Originally Posted by McThumpenstein I don't think the wife would buy the "I need to take off this knob and put a whole new bass under it" story. |
Last edited by FunkMetalBass : 02-03-2013 at 10:09 PM.
|
02-04-2013, 02:47 AM
| | Registered User | | Join Date: Jul 2007 Location: Yorkshire, England, UK | | Quote:
Originally Posted by FunkMetalBass Glad I'm not alone in the matter. Those are the only places I've had any luck changing too.
It looks good to me - I don't see anything in that portion of the schem that's any different from the hand drawing. I'm wondering if it's an issue with QUCS not acknowledging the difference between a junction dot and a crossing without a dot. The treble is the only potion of the EQ section that doesn't contain any crossings.
EDIT: I did find that the opamp on the right was flipped (+ should be on top), but that didn't change anything. | Yes I saw the flipped opamp after I posted.
You could be right about the trace crossing thing, I will look at some other schematics I have put in, I am sure that is not the only one with traces crossing.
__________________
G&L L-2500 -> Art Pro Channel II -> 35Hz HPF -> Peavey IPR1600 -> fEARful 15/6 and/or 12/6
|
02-04-2013, 05:44 AM
| | Registered User | | Join Date: Jul 2007 Location: Yorkshire, England, UK | | | Ok I re entered it into QUCS, it's a bit quick and dirty but it works this time.
P.S. Not checked for errors so check component values before use.
Again rename from .txt to .sch
__________________
G&L L-2500 -> Art Pro Channel II -> 35Hz HPF -> Peavey IPR1600 -> fEARful 15/6 and/or 12/6
Last edited by delta7fred : 02-04-2013 at 05:54 AM.
|
02-04-2013, 07:46 AM
| | | | Hi everybody!
I think this thread is the exact one that I was looking for. Since the preamp of my Fame Musicman model bass broke (and I can't find a replacement) I want to try to make the preamp myself. So domdec314, I am very curious about your results! |
02-04-2013, 08:29 AM
| | Registered User | | Join Date: Jul 2007 Location: Yorkshire, England, UK | | Quote:
Originally Posted by twerff Hi everybody!
I think this thread is the exact one that I was looking for. Since the preamp of my Fame Musicman model bass broke (and I can't find a replacement) I want to try to make the preamp myself. So domdec314, I am very curious about your results! | You might want to check out this thread Stingray aftermarket 2 band pre for the 2 band MM preamp.
Start at post #139 because the thread starts off with some preamp from Ebay (?) that looks like a chimp soldered it.
__________________
G&L L-2500 -> Art Pro Channel II -> 35Hz HPF -> Peavey IPR1600 -> fEARful 15/6 and/or 12/6
|
02-04-2013, 08:36 AM
| | | Quote:
Originally Posted by delta7fred You might want to check out this thread Stingray aftermarket 2 band pre for the 2 band MM preamp.
Start at post #139 because the thread starts off with some preamp from Ebay (?) that looks like a chimp soldered it. | Thanks, I have to say that I only read the first page of this thread while posting the reply. The stingray model that I have needs a 3band EQ, so I think I'll try to build the proposed preamp 
But I am still not shure which opamp I am going to use, but I'll probably stick with the TL062. |
02-04-2013, 08:43 AM
|  | DiCosimo Audio | | Join Date: Mar 2008 Location: Vero Beach, Florida | | | In case you having seen it yet, my results are on page 2 of this thread.
__________________ DiCosimo 360+ Preamp Pedals
G&L Club #351 - Markbass Club #360 - Florida Bassist Club #152 - Country Bassist Club #38
|
02-04-2013, 09:19 AM
| | Registered User
Endorsing Artist: J.C. Basses | | Join Date: Aug 2005 Location: Phoenix, Arizona 85029 | | Quote:
Originally Posted by delta7fred Ok I re entered it into QUCS, it's a bit quick and dirty but it works this time.
P.S. Not checked for errors so check component values before use.
Again rename from .txt to .sch | Oooh thanks. I'll have to check this out when I get home to my Ubuntu box.
__________________ Quote:
Originally Posted by McThumpenstein I don't think the wife would buy the "I need to take off this knob and put a whole new bass under it" story. | |
02-04-2013, 03:00 PM
| | Registered User
Endorsing Artist: J.C. Basses | | Join Date: Aug 2005 Location: Phoenix, Arizona 85029 | | Quote:
Originally Posted by delta7fred Ok I re entered it into QUCS, it's a bit quick and dirty but it works this time.
P.S. Not checked for errors so check component values before use.
Again rename from .txt to .sch | Still seems to be a problem with it beyond component values. I plotted output_dB vs. acfrequency (where output_dB = dB(output.v)), and it looks like the bass is now the sole variable control. 
Hmm...
__________________ Quote:
Originally Posted by McThumpenstein I don't think the wife would buy the "I need to take off this knob and put a whole new bass under it" story. | |
02-04-2013, 04:35 PM
| | Registered User | | Join Date: Dec 2003 Location: Columbia River Gorge, WA. | | Quote:
Originally Posted by delta7fred | Thanks Fred, I have a working LTspice model of this circuit from your link up now: 
Where did the one in Post #130 come from though? I downloaded QUCS just to double check if we were on the same page...doesn't seem so! I already have yours worked up too though.
Last edited by Passinwind : 02-04-2013 at 06:25 PM.
|
02-04-2013, 04:38 PM
| | Registered User | | Join Date: Jul 2007 Location: Yorkshire, England, UK | | Quote:
Originally Posted by FunkMetalBass Still seems to be a problem with it beyond component values. I plotted output_dB vs. acfrequency (where output_dB = dB(output.v)), and it looks like the bass is now the sole variable control.
Hmm... | Mine works fine.
Did you change the pot rotation setting to "pos" (from 120) in the pot "Edit Properties" for Mid a Treb?
I only swept them one at a time (as there is quite a bit of interaction) so "pos" would only be selected for the last one I tried.
How do you get the graph in dbs, I can only see volts on mine (Version 0.0.15)?
__________________
G&L L-2500 -> Art Pro Channel II -> 35Hz HPF -> Peavey IPR1600 -> fEARful 15/6 and/or 12/6
|
02-04-2013, 06:05 PM
| | Registered User
Endorsing Artist: J.C. Basses | | Join Date: Aug 2005 Location: Phoenix, Arizona 85029 | | Quote:
Originally Posted by delta7fred Mine works fine.
Did you change the pot rotation setting to "pos" (from 120) in the pot "Edit Properties" for Mid a Treb?
I only swept them one at a time (as there is quite a bit of interaction) so "pos" would only be selected for the last one I tried.
How do you get the graph in dbs, I can only see volts on mine (Version 0.0.15)? | Insert an equation. When in the editor, the box on the top right should be output_dB (or whatever you want to call your new variable), and the box below it is dB(output.v). Once you do that and simulate, you will have the option to graph your new dB vs. acfreq.
No, I didn't edit any of the pots on it. I shall try that shortly.
__________________ Quote:
Originally Posted by McThumpenstein I don't think the wife would buy the "I need to take off this knob and put a whole new bass under it" story. | |
02-05-2013, 03:12 AM
| | Registered User | | Join Date: Jul 2007 Location: Yorkshire, England, UK | | Quote:
Originally Posted by FunkMetalBass Insert an equation. When in the editor, the box on the top right should be output_dB (or whatever you want to call your new variable), and the box below it is dB(output.v). Once you do that and simulate, you will have the option to graph your new dB vs. acfreq. | Thanks very much, it was bugging me.
__________________
G&L L-2500 -> Art Pro Channel II -> 35Hz HPF -> Peavey IPR1600 -> fEARful 15/6 and/or 12/6
| | Thread Tools | Search this Thread | | | | 
Posting Rules
| You may not post new threads You may not post replies You may not post attachments You may not edit your posts
HTML code is Off | | | |
