BMF
contributing
Posts: 99 
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Post by BMF on Feb 1, 2017 13:10:39 GMT
One more question: do you have any plans for filters for OPPO PM-1, OPPO PM-3, and Grado PS1000?
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solderdude
Administrator
measureutternutter
Posts: 4,886
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Post by solderdude on Feb 2, 2017 7:00:23 GMT
Grado doesn't react positive to EQ.
At least not the Grado's I tried.
I need to find representative measurements of the PM1 and PM3.
There are some measurements around so may look into those
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BMF
contributing
Posts: 99
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Post by BMF on Feb 13, 2017 10:17:10 GMT
I built the K7xx filter. I did not have 1.5 uF for c5 so used 0805 50v 1 uF I had on hand. I'll orderthe correct part swap them out. What effect will this have on sound?
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solderdude
Administrator
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Post by solderdude on Feb 13, 2017 19:34:45 GMT
There will be a bit more bass compared to when you would be using 1.5uF.
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BMF
contributing
Posts: 99
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Post by BMF on Feb 13, 2017 22:08:10 GMT
There will be a bit more bass compared to when you would be using 1.5uF. Thanks. I think I may just leave it as is since I like the sound.   |
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juke
very active
Posts: 396
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Post by juke on Feb 24, 2017 14:05:35 GMT
r5r seems to have an incorrect product code for Farnell, is this one OK? 2008395
Thanks
Syd
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solderdude
Administrator
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Post by solderdude on Feb 24, 2017 14:51:08 GMT
yes, is O.K.
Will have a look at the BOM list and repair.
Going to add the PH and T50RPmk3 also.
Will post it when it is done.
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juke
very active
Posts: 396
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Post by juke on Feb 24, 2017 18:55:01 GMT
Great, thanks Frans. I'll hold off ordering until then.
I see all the parts are now available in small lots, my first lot were part reels of 50 or 100 plus.
Hobbyists must be making the changeover.
Syd
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Post by tupisac on Mar 22, 2017 20:11:42 GMT
Hey,
I'm thinking how to incorporate some form of easy switching for like 2 or 3 filters. Selector with relays would be great, but expensive and complicated.
Then I though about ethernet patch cord. Ports on the front, operated like old telephone centrals or old-school synthesizers.
But can I do that? Can I route the filter connection through like 20-30 cm of cat5 cable with at least two connectors on the way, without degrading the sound quality?
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solderdude
Administrator
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Posts: 4,886
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Post by solderdude on Mar 22, 2017 22:27:29 GMT
The wires to the - input of the opamps MUST be very short.
Lengthening them with wires and switches may make the opamp oscillate.
I must admit that is only theoretical though and haven't really tried it.
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Post by tupisac on Mar 23, 2017 10:25:05 GMT
Bummer. MUST in caps I will always obey.
What about in-line kameleon then? Does it have output op-amps as well?
I really enjoyed the ability of Sonarworks to switch between filtered, unfiltered and harman curve on the fly. It basically covered all the genres I listen to.
Speaking of harman curve - is it possible to add further bass extension to hd-600 filter, basically combining hd-600 with harman bass boost?
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solderdude
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Post by solderdude on Mar 23, 2017 10:59:18 GMT
The inline kameleon is the same circuit, basically, but using regular opamps at the output instead of a power opamps. It does have a 'bypass' mode in which the filter circuit is literally bypassed, the signal is thus routed around the amp circuit. I haven't tried using long wires to a switch and to 2 or 3 filter modules, but when using fast opamps the '- input' must be low capacitance to avoid instability. Maybe in practice it might work though, perhaps depending on the used opamp and/or miller cap values. When the headphone measures 'flat' on my rig the bass already has an (almost) Harman bass curve to it. There is a hidden slight sub-bass boost there already incorporated in the filter modules. So the filter is somewhat closer to Sonarworks with Harman curve than just Sonarworks 'flat' In between those 2 settings. Flat on my rig = audibly flat = otherwise flat but with a small subbass boost. I have more info on this HEREThere are 2 Harman curves by the way. The one for speakers which has too much bass boost and one for headphones which is quite close to my own 'correction' When the bass is set even higher it starts to sound boomy and fat. |
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Post by tupisac on Mar 24, 2017 22:19:56 GMT
Well, I did quick search on the Miller effect and oscillations of op-amps. As you say, such routing would be a bad idea. And I don't want to ruin good design. The bypass switch seems like the good solution.
Thanks for the link, very interesting. BTW, lots of good articles on your site, really nicely written.
Funny thing - at the end I was mostly using Sonarworks with custom curve, +2 db bass, no tilt. Now I'm just dying to hear them filters working...
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Post by tunkejazz on Apr 27, 2017 17:48:03 GMT
Frans, have you ever considered creating a modified version of the desktop/portable version to accomodate the functionality of the inline filter + desktop/portable amp? That way it would be possible to use it also with tube amps and as a standalone amp...
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solderdude
Administrator
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Post by solderdude on Apr 27, 2017 21:23:16 GMT
So add a line-out to the portable/desktop version ?
The problem would be that the line-out would go through the volume control of the amp.
Would be a question of adding 2 resistors and 2 line-out RCA's in that case.
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