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Post by mrholmes on Jul 24, 2020 4:59:22 GMT -6
What is wrong with the orginal OP AMPS? Why do people want to change them?
Most of the time there is nothing wrong with the opamps. People read through threads like this and it gives them the notion that they can easily get higher quality for less money by just changing a few parts, but they tend to overlook the rest of the story. Honestly, the biggest upgrade you can do is usually local decoupling. A few 100nF caps on the +/- V legs of each opamp will help the opamps work as the opamp manufacturer designed them to. A lot of lower end designs never included these local decoupling caps due to cost. The performance suffers, but in cheap gear that's not a thing they care about. Even the cheapest audio opamp like the 4558 is perfectly capable of reproducing audio into the 100KHz range with gain and into the MHz range at unity. There's no lack of bandwidth available to have the cleanest audio signal.
As always very good information. Any special caps to use for the decoupling brand or type?
The board I bought needs some cleaning too any inspiration for this. Using deoxit and or balistol?
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Post by svart on Jul 24, 2020 7:20:42 GMT -6
Most of the time there is nothing wrong with the opamps. People read through threads like this and it gives them the notion that they can easily get higher quality for less money by just changing a few parts, but they tend to overlook the rest of the story. Honestly, the biggest upgrade you can do is usually local decoupling. A few 100nF caps on the +/- V legs of each opamp will help the opamps work as the opamp manufacturer designed them to. A lot of lower end designs never included these local decoupling caps due to cost. The performance suffers, but in cheap gear that's not a thing they care about. Even the cheapest audio opamp like the 4558 is perfectly capable of reproducing audio into the 100KHz range with gain and into the MHz range at unity. There's no lack of bandwidth available to have the cleanest audio signal.
As always very good information. Any special caps to use for the decoupling brand or type?
The board I bought needs some cleaning too any inspiration for this. Using deoxit and or balistol?
For the 100nf caps, just use whatever ceramic 50v caps you can find for relatively cheap. At this capacitance value and the relative low speed of audio signals, there's no real advantage to using one type/brand/style over another. The only thing I suggest is to buy a brand name from a reputable distributor. Don't buy them from china via ebay or you might get fakes. something like either of these will work perfectly: www.mouser.com/ProductDetail/Vishay-BC-Components/K104K15X7RF53H5?qs=sYfpZ29HcUSlgH5bSUHkYw%3D%3Dwww.mouser.com/ProductDetail/Vishay-BC-Components/A104K15X7RF5UAA?qs=Vv77WW%252BpwicWZOqJxz%2FTNQ%3D%3DThe axial leaded part sometimes makes it a lot easier to run from the pin to a ground that isn't close by so you'll have to figure out which might work better, or buy a handful of both. For cleaning, I use alcohol or acetone on the PCB and "deoxit fader" for pots/switches because that's what I could get at the local electronics place before they closed down.
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Post by mrholmes on Jul 29, 2020 12:06:12 GMT -6
That's the one I bought I keep you guys here up with pictures when it arrives.
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Post by mrholmes on Jul 31, 2020 5:57:05 GMT -6
I would not bother you but my tech guy in town died last year and it's harder than you think to find a new one, sending the DELTA to the USA is no option.
I have some spare time and I read the schematics. Even if it's a long time ago I did read those for amateur radio DIY there is lot that has not been forgotten.
1.
I see on the line input and mix input stages are a lot of diodes too.
Do those diodes get old?
Should I change them?
2.
The OP amp decoupling goes for all OP amps even those found on the direct out section / pan buffer section / mute block all ->> TL072.
THX Andreas
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Post by svart on Jul 31, 2020 6:43:00 GMT -6
I would not bother you but my tech guy in town died last year and it's harder than you think to find a new one, sending the DELTA to the USA is no option.
I have some spare time and I read the schematics. Even if it's a long time ago I did read those for amateur radio DIY there is lot that has not been forgotten.
1.
I see on the line input and mix input stages are a lot of diodes too.
Do those diodes get old?
Should I change them?
2.
The OP amp decoupling goes for all OP amps even those found on the direct out section / pan buffer section / mute block all ->> TL072.
THX Andreas
1. Diodes do not wear out unless damaged. 2. Decoupling goes for all opamps.
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ericn
Temp
Balance Engineer
Posts: 14,921
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Post by ericn on Jul 31, 2020 8:08:04 GMT -6
I would not bother you but my tech guy in town died last year and it's harder than you think to find a new one, sending the DELTA to the USA is no option.
I have some spare time and I read the schematics. Even if it's a long time ago I did read those for amateur radio DIY there is lot that has not been forgotten.
1.
I see on the line input and mix input stages are a lot of diodes too.
Do those diodes get old?
Should I change them?
2.
The OP amp decoupling goes for all OP amps even those found on the direct out section / pan buffer section / mute block all ->> TL072.
THX Andreas
1. Diodes do not wear out unless damaged. 2. Decoupling goes for all opamps. This is an area for our former sewer robot tech.
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Post by kcatthedog on Jul 31, 2020 8:40:37 GMT -6
Remember the modules can be removed perhaps you want to send one for a professional mod which you could then copy?
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Post by mrholmes on Jul 31, 2020 13:42:28 GMT -6
Remember the modules can be removed perhaps you want to send one for a professional mod which you could then copy?
Is that not intellectual robbery?
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Post by kcatthedog on Jul 31, 2020 13:53:37 GMT -6
Well I discussed that with Skip and he said he was fine with it as long as I bought the parts from him and didn’t share it.
I don’t know that there is any ip or copyright of mods done to a preexisting circuit ?
The pro modders definitely provide a good value service as they remove all the parts, install everything and stand behind their work: good value I think !
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Post by mrholmes on Jul 31, 2020 16:46:20 GMT -6
Well I discussed that with Skip and he said he was fine with it as long as I bought the parts from him and didn’t share it. I don’t know that there is any ip or copyright of mods done to a preexisting circuit ? The pro modders definitely provide a good value service as they remove all the parts, install everything and stand behind their work: good value I think !
Who is Skip I know two Skips one by the 80s sitcom ALF and one Skip is form Gearslutz his second name was Burrows.
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Post by kcatthedog on Jul 31, 2020 17:53:15 GMT -6
Skip runs Creation labs, one of the two delta mod shops I have used.
He is an ex Harmon Kardon employee who set up his own shop. He is outside Nashville.
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Post by kcatthedog on Jul 31, 2020 17:54:38 GMT -6
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Post by talkieparade on Oct 12, 2020 16:26:37 GMT -6
Hi All, In the Delta/Venue, I was wondering about what to do about C23? As far as I can tell this is a coupling cap for the Insert section, right? In Tonycamphd photos of his mod C23 is removed and a zero ohm resistor / jumper is inserted... Isn't this capacitor important or is it OK and safe to remove? In Delta's stock condition, C23 is a 47uF 25v part. But different modders treat this spot differently. Sometimes it is removed, sometimes a higher value part is put in, and sometimes the value is kept the same. My concern is that if this cap is removed then depending on what gear you plug into the insert it could potentially be unsafe... yes, no, maybe so? Could someone please take a look at these details of the photos on page 1 . I also took a screen grabof the schematic pointing out C23. Ok Thanks!
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Post by kcatthedog on Oct 12, 2020 17:05:22 GMT -6
Are you working on a TC modded pcp ?
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Post by talkieparade on Oct 12, 2020 18:52:49 GMT -6
I have mods done by JW and CAL. I think TC just recapped his JW mod with Elna caps? Anyway the latest mods by JW and CAL keep a cap in C23. Just wondering if its safe to remove this cap if I don't use the insert. Maybe it sounds better with one less cap?
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Post by kcatthedog on Oct 13, 2020 3:11:53 GMT -6
Why not send a sine wav through it now and record, then remove part repeat and compare, then decide, if you will never use inserts?
I had brought all SC I/o to my bays, so didn’t use the inserts
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Post by talkieparade on Oct 13, 2020 8:14:54 GMT -6
Kcatthedog,
Yeah so you're saying if you want to compress with outboard you patch in a compressor: after your DAC converter, and then before you go into Soundcraft Line input, is that what you do to avoid inserts?
I could try the sine wave test. You got your modules done by JW and CAL right? I wonder if they put in the C23 cap...
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Post by kcatthedog on Oct 13, 2020 8:21:39 GMT -6
I had interface outs go to SC line ins, to use we etc., line outs bs k to patch bay 1-16, all my ob on patchbays and ins back to interface converters.
Then use logic’s utility plug to set gain, as SC drops -6 dB and utility io plug to send/recieve to delta/ob comps and back to interface ?
Also had my 2 bus doing same to Audioscape ssl comp and wa273eq on inserts for its 3 band we and output transformers back to daw to print: so hybrid .
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Post by talkieparade on Oct 13, 2020 8:41:41 GMT -6
Cool Sounds like a smart setup My one issue with not using SC inserts was losing the ability to EQ with board EQ after inserts, like if I wanted to boost high shelf after an inserted compressor. One tjought was I could patch in a compressor after converters before SC Line Inputs then use the board EQ. The way you use it you must EQ before you compress with outboard right? Also do / did you ever print mixes off the Soundcraft Master 2 bus? Seems like you use the SC for only input channels? Thanks for your insights
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Post by kcatthedog on Oct 13, 2020 8:48:52 GMT -6
Thx, I copied wiz’s set up but then lost the inserts. If you brought your interface outs to your patchbays, and half normalled to direct ins, you could patch to your ob and you could have that half normalled to the direct ins? So, you could have either order?
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Post by kcatthedog on Oct 13, 2020 8:52:34 GMT -6
Oh and yes I did print delta outs which was warmer etc, and you can put ob on the delta master out too. As I was sending stereo bus to ob anyway and back to daw , I just defaulted to that workflow. Of course, with a board, you can kind of do whatever you want !
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Post by talkieparade on Oct 13, 2020 10:04:38 GMT -6
Thanks kcat! Honestly, I don't have the best patchbay setup going. I have one 48 point TRS Samson S-Patch that I dont really use. It can do thru, normal, and half normal. I will have to research the half-normalled technique you mentioned to understand it fully. I stubbornly just wanted to avoid patchbays, my strange aversion to them, and have a streamlined approach to mixing, like having 1176's patched directly to SC line ins 1 and 2 for example. A Very minimal approach and also extreme lack of flexibility No but yeah, nice to hear about your 2 bus SSL and EQ set-up. I need to diy some builds for 2 bus. Maybe dual Pultecs? I am not completely sure if I like using a 2 bus compressor, in theory trying to keep the mixes dynamic. But maybe I will build a 2 bus compressor as well...
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Post by kcatthedog on Oct 13, 2020 10:36:57 GMT -6
I has 3 S’s. Nothing wrong with dedicated, other than being dedicated! If you leave things connected then you won’t have excessive wear on your I/o. My buss stuff wasn’t dedicated, depending on song,could turn on and off with the utility plug in !
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