Hey man hope all is well
Used that RTA software today to check out mixer, here are the results For each channel i used the line and then out of direct out I sent various signals through from a 20HZ – 20000HZ sweep to a 500HZ square wave Channel 1 & 7 were dead Channel 2, 3, 4, 5, 6, 8, 11, 14, 15 & 16 were intermittent on gain pot Channel 10 & 12 seem like they have capacitor problems Apart from 9 & 13 all have noise(20HZ – 20000HZ) when channel is engaged(switched on) Channel 9 & 13 were silent(Great) Noise floor was -35dB on all channels
Left monitor out silent when no signal is routed to it, but 50HZ hum when channel 13 is routed to it Right monitor out 50hz hum when no signal added to it and when channel 13 is routed to it
Headphone left channel out, slight 50HZ when at full gfain Headphone right channel out, considerable 50HZ hum and noise 20HZ-20000HZ
Left 2trk out, seeks to have a high shelf dip from about 450HZ up to 20000HZ Right 2trk out, fine
What do you think?
Thanks as always
Paul
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Well if it’s one channel per board you can. Otherwise, if there are two channels to a board, the power rails will be connected as soon as you plug the multi-connector ribbon cable I guess. Try and reconnect one board at a time after cleaning etc to see which one makes the most noise. Then try adding two at a time, then three etc. You’ll figure out if there’s any interaction going on that way.
Nothing will harm. It’s just like having a one channel preamp with 4 or 8 different options for the signal to go to. You should be able to power down the aux buss amps as well and see if that affects the masters. Because it’s all plugs and sockets, it’s very easy to do this sort of thing. It’s a lot harder when everything is hard soldered into place!
Btw, how much did this thing cost you?
Hi Paul!
Here’s what I think, not in any real order. Remember, it’s ages since I’ve done this stuff, and I haven’t seen the channels or layout or groupings… Sometimes these will help trace problems if you know this.
Ch 1 + 7 check power rails are actually on to the board and powered up and the ic sockets for security (re-seat ICs if you can). Check power is getting to the IC power pins, you’ll need the pinouts for that. Use your (HiZ) multimeter with teeny probes for that.
Ch 10 + 12 I don’t know how you can tell it’s capacitors’.
Ch 9 +13 if quiet when shorted but only -35dB noise floor in action means they are crap. For a studio mixer that’s appalling. Are you sure it’s being measured correctly with the gear? I was a bit dubious about the stuff in the beginning. I think I said that it depends on the quality of the test equipment inputs/impedance matching as well. I’m not criticising, just thinking aloud. What’s the noise floor figure related to? Is it related to line level?
Ch all the rest, need a damn good squirt with servisol. Failing that, there may be mechanical oddities with the board connections that may disappear with a bit of solder + heat.
Ch 13 has dodgy earth somewhere or a loose joint picking up radio. (Is 13 + 9 connected in some way with a common rail at all?)
Headphone amp earths need looking at. Or they need screening. Are they near the power transformer?
Left 2trk clean the board of all debris. It’s loosing hf via a capacitance leak somewhere. Dirty board, wet fluff, miniscule wisps of solder will do this. Otherwise, the bypass capacitors are breaking down, probably find them across the power rails on the board. Somebody may have added one with too high a value!!! Has any previous bodge work been done anywhere? That goes for the whole mixer..? Are there any coils or ferrite inductance thingies anywhere? Have you tested the mic inputs and do they have coils/transformers?
SUMMARY.
Servisol clean time for all moving electrical components, esp the gain/pads for each channel and the jack insert and outlet points.
Go over all earths with a soldering iron and fresh solder or unscrew, squirt and re-tighten.
Redo all +ve and –ve main joints similarly.
Try and get the power supply outboard from the mixer.
Is the inside of the mixer lined with tinfoil? (for screening)
All this soldering is easy-peasy but time consuming. Remember, it’s a bit like doing it for the first time. The joint must be thoroughly wetted and cooled down without any motion whatsoever. Don’t overdo the heat. Don’t underdo the heat. About ¾ a second is usually enough for small components, 3 secs for big spade terminals. The joint must look like a nice shiny metallic snot without a trace of roughness. Use fresh solder as you apply the heat but not too much to make a mess, just enough to help the metal flow with that little bit of flux…. The solder should look like it’s wetted the component wire and not run off like Teflon. Remember, solder does two things: it mechanically locates the device against movement and makes a low resistance electrical connection.
Then have another go and see if anything has changed!
Cool man thanks for that
What the best way to extract those ICs?(tool wise or finger) I have pics of everything so maybe Ill post them up on photobucket NOw as of power rails and bus wires to all channels these are on multiple wires with pins that connect to each channel, shall i squirt these with servisol and push on and off a few times?
As capacitors, you use a 500HZ square wave to test the channels. see below link http://www.tangible-technology.com/audiobasics/upgrades/upgrade1_opamp_cap.htm
As of -35dB noise floor on good channels 9&13, thats no gain, just the input and output of testing software connected and it monitors the noise floor As of resoldering, i just find all earth connections to components and add 3/4 second of head and some new solder to newify the connection?
1.Headphone amp earths need looking at. 2.Or they need screening. 3.Are they near the power transformer?
1. How do i do this? 2. How do i do this? 3. They are right above it, within an inch to two No previous mods have been made to mixer Redo all +ve and -ve main joints similarly.
?
Try and get the power supply outboard from the mixer.
I think i could maybe do this, do i stick it in a metal case of its own with good venting?
Is the inside of the mixer lined with tinfoil? (for screening) No it is not just enough to help the metal flow with that little bit of flux ?
Wow this is quite fun isnt it?
Thanks once again for all your help
Paul
Thats great man, thanks
The only bit im not quite sure i understand is,
Each channel has 11 pins for power and stuff and 10 for buses and other stuff, thats 21 pins per channel Theres 7 wires that connect the strips to PSU, so i think if i extend those wires i can have an external PSU
If the ICs are socketted, just jiggle them out. They may be stiff from a small amount of oxide. If you have teeny fingers, it helps! If they are soldered in, check the underside of the board to make sure all joints look okay. It’s always one of the number 2 or 3 pins that will not be making good contact if there’s a problem in that area. You need a strong light.
Manually re-assemble each connection just like you say. Any trace of whiteness or stiffness and give a little squirt. Wipe up the excess mess from the circuit board as you go.
I still don’t understand what the -35dB is relative to?
For joints, if the look good and shiny, then they probably are. Anything else, make it so the wire looks good and wetted. Nothing crystalline looking. Teeny op-amp pins only need a touch – same as transistors. But the connection must melt all the way through – any connection. Big connection = more heat and time; little connection = quick heat and time.
1. Headphone earths are just connections – see above etc!
2. Put the whole thing in a metal screen or don’t use it and connect a different little amp in it’s place. It’s only foldback monitoring and stuff. Make it outboard if you want.
3. There’s your answer! Move the transformer as far away from everything! Other side of the room preferably!
+ve & -ve have joints as well! They ALL need checking! ANY dodgy joint has diodic characteristics. Check “Cat’s Whisker Radio” or “Crystal Set” in Google/Wikipedia! If the wire or component moves while the solder cools, it makes little crystals that are quite visible. Hence, don’t move even if your fingers are burning! You’ll only have to do it again! (I developed about 2mm of thick heat-proof skin on my finger ends at one point)
Get the PS out! Yes, try. It’s your best and easiest bet to get rid of hum. You’ll need a connector, maybe like the Seck one although a 4 pin XLR type would do, I think. +48V, +15V,0V,-15V probably.
Put tag strips for each rail IN the mixer case to take all the connections from the channels etc. You’ll get a nice earth star arrangement (this is what I did which is why my cases are filled with black wires , black for 0V). Then take nice fat wires to the back of the socket and use heavy duty cable to take it to a similar affair in a nice metal box containing all the power supply bits.
Or disconnect the power supply and buy one ready made and connect up similarly!
It may be that your mixer is a metal box. What I did was have a strong wooden box, glued bacofoil all around the inside and then the XLR & jack sockets clamped down on the foil to make the earth connection. All internal screened wires were earthed at the external socket end only, not to the boards. This way you get good screening and no earth loops. I followed the general principal of earthing at the signal source end of a wire when internal connections were made. This is all “good practice”.
Another way to screen is to spray the inside of the box with aluminium paint. Obviously, this is before the box gets filled with bits!
Conclusion.
The mixer I made using the ETI designed boards with my own mods was better than your commercial ones for noise & hum. I followed best practice at all times which they clearly haven’t! My mixer lacked really complex tone controls though. I couldn’t afford them! I didn’t use ribbon cable or a metal bussbar for connections. I could have, but I thought that it would introduce too much cross-talk. All signal paths were properly screened as described above. You can’t do this with ribbon cable.
Happy soldering.
Rees
Something like this for a tag strip http://www.maplin.co.uk/module.aspx?moduleno=1956
Join all the tags together with some nice fat copper wire like http://www.maplin.co.uk/Module.aspx?ModuleNo=6187&DOY=8m10 or http://www.maplin.co.uk/Module.aspx?ModuleNo=6200&&source=14&doy=8m10 or http://www.maplin.co.uk/module.aspx?moduleno=44 or http://www.maplin.co.uk/Search.aspx?menuno=13087
If it’s insulated, take all the insulation off. They used to do this which is best and easiest but it’s not there now http://www.maplin.co.uk/free_uk_delivery/Tinned_Copper_Wire_45/Tinned_Copper_Wire_45.htm so try here instead http://www.tracysworkshop.com/p-4391-tinned-copper-wire.aspx?currencysetting=gbp&affiliateid=10051
What you then have is a nice big fat earth point that you can solder all your earths to!
Do the same with the power rails but be careful not to connect the centre to the chassis or the PSU will pop. Either snip off the tag, bend it up or connect to the box with insulated screws and washers.
So that’s what’s inside your box. The nice fat wire(s) makes it easy for electricity to whizz along. Also, if there’s a fault, the equipment dies and not you! It doesn’t affect the signal. The signal goes along other wires although it does affect the ability of the op-amps to respond to transients i.e. if they don’t get enough power, they can’t work so fast. But in the real world of trying to get duff stuff to work, it’s got nowt to do with the signal. An op-amp only needs 10mA (say) to work properly. If the power rail can deliver 1A, that means the rail can power 100 op-amps easily. Now count them up!
You need a nice heavy duty connector capable of taking 1 amp per pin. 7-pin XLRs exist to do this. Basically, you are always after robustness whenever you are looking at equipment like this that may get manhandled a lot. Any slight short on the power rails can mean instant pop for the components and a clean pair of underpants for yourself when you see the spark! (I know that there is inbuilt protection, but I always ignore it from the point of view of safety and good practice. It’s a like a condom; protection can break!)
Belkin do connectors as well. Just hunt around. You can always use two connectors if you can’t find anything suitable.
They usually do stuff arse about tit with wiring! Probably, but if you check the mains cables to the transformer from the socket, they will be big and fat, but the secondaries and coming off your PSU will quite often be thin inter-connecting wire.
In actual fact the current drawn from the mains will be about a tenth of an amp and the current delivered by each rail of your PSU can exceed 1 amp!
It’s the amperage that determines the thickness of the copper you need! The insulation is there to protect you from high voltage (fatter = more protection for more volts) and also the copper from the outside world (knocks, shorts, cuts etc).
So think about it. The transformer takes mains at 220V and puts out 22V-0-22V which is a tenth. So as volts goes down, amps goes up the same to balance (Volts = amps x ohms) or (volts = watts / amps)
Seeing the cabling is a good visual test to see how much thought has gone into a design. This is really basic stuff but it’s amazing how many companies will cut costs here.
My guess for you is that the headphone amps use a separate feed to the rest. If you omit these, then you can probably get away with 5 rails which will probably be:
0v
+48v for phantom
+15V
0V
-15V for ops amps (all the rest of the mixer)
The phones will need probably
+15 to +25V
0V
-15 to -25V
Although there are many variations on this. This is just what I’d expect and it’s inline with the Seck PSU requirements also, from the same era.
You could use car batteries!
Rees
WOW man, awesome
SO do i need just one tag strip for all the connections OR do i need an eyelet for each connection DO i connect the tag strip straight to the chassis?
Do the same with the power rails but be careful not to connect the centre to the chassis or the PSU will pop. Either snip off the tag, bend it up or connect to the box with insulated screws and washers.
?
Slowly, slowly, im a novice, but an expert in learning lol
You are just giving yourself a nice big central area for all the
common connections to meet. If it’s an earth, then use the tag to
connect to the chassis else make sure it doesn’t touch.
When you’ve make your central point, just make a shepherds crook sort
of loop on your wires and solder them over your central wire. That
way, you can tell them apart and easily unsolder if necessary in
future without disturbing the rest. If you’ve 16 channels and 4 mix
down subs and two main outs and each has a 0V connection then you will
have 22 0V (or earth) connections all meeting in the one place – so it
gets a bit crowded. This solution solves that.
Same goes for the main power rails, +ve and -ve. Just make sure that
they’re not gonna touch the chassis – or pop! Check the tag strip in
the photo, you can see what I mean. One of the tags has a “grounding”
or “fixing” tag at the bottom to allow various options for fixing.
The tags are all separate. I’m suggesting to join them together to
facilitate all these 22 wires meeting at one point.
Tag strips are very useful. If you’ve only a few wires, then you can
mix common +ve, -ve and 0V terminations all on one strip. You can
usually loop about half a dozen wires on one tab. After that it gets a
bit crowded so you double up – or join the whole lot together, which
is what I’m suggesting.
Rees
Hey man, drawings would definetely help as i think i understand the all channels to ground BUT the +ve, -ve, v0 for power supply i dont if the ground(chassis) is connected to the upper face plate of mixer, of course im gonna be touching it?
thanks
I assume the faceplate is metal. Then, Yes. that’s quite normal. If you check the circuit diag for your PSU you’ll probably find the transformer centre tap(s) go to earth. It makes sure that 0V really is 0V amongst lots of other benefits like hum and spurious RF getting trapped.
Unless everything is double insulated, it’s normal (in fact law) that all metal parts that can be touched by a user of any mains electrical equipment should be directly connected to earth with a nice fat wire!
Rees
Cool, so when i make the PSU external will the earth of PSU then go to the meatal case that ITS in?
Almost certainly. Unless you make it double insulated, which you
wouldn’t! (double insulated just means like a vacuum cleaner where the
mains motor is in a plastic mount which is in turn mounted in the
plastic body of the cleaner. All switches etc have to be similarly
constructed.)
You’d still have the earth connected to your mixer chassis via the
socket etc. Everything is continuously screened and earthed then.
Rees
Hey man, hope all is good on your end
You’d still have the earth connected to your mixer chassis via the socket etc?
Do you mean for the cabling that goes to the external PSU?
How about these for connectors that will take the cabling form the mixer to external PSU(they have 8 pin versions)?
http://www.maplin.co.uk/Module.aspx?ModuleNo=43120&DOY=8m10
Will it be easier for me to send you the pics of mixer on a cd or shall i just upload them to photobucket?
The auction on that synth ends today, we’ll see how that goes Im looking for something that i can do thos Dark side of the moon sounds thanks for all your help
PAUL
Paul.
You’ve really got to pay attention to the circuit diagram. I’ve just checked the stuff so far that I put on my website here: http://strangelyperfect.tv/1291/studiomaster-16-4-8-restore/
Two things:
Check the circuit here: http://i390.photobucket.com/albums/oo345/paulrichards7/PSUschem16-8-16.jpg
You’ll see that there are three earths in the connector! Follow the heavy black lines and it even says that it’s connected to the chassis! What they are doing is making sure the return power feed has enough capacity by trebling up the wiring. It’s all the same 0V (earth)!
Second, check the photos you put up of the PSU and look carefully at the wiring? What I mean is, it’s quite fat! Now compare to the Maplin 8-pin pins. It says it’s 5A rated. I don’t know what that means, is it the pins individually or the whole connector? I can’t tell. But what I can tell is that the pins are thinner than the wiring coming from the PSU. This is bad!
Try this, which is what I suggested in the first place, and with good reason. http://www.maplin.co.uk/Module.aspx?ModuleNo=44123&DOY=9m10 or use two 3 pin ones (better) or even better, use the Neutrik power connector or power type XLR connector.
If you check the circuit diagram again, you’ll see that you only need five wires if they are fat enough! That’s 0V (earth), 15 & -15 for the op-amps, +48V for the phantom and a separate 15V feed for the headphone amps. Do away with phones and you only need 4 wires. They can be nice and fat and use a good quality connector as well. If you did this you could use a 4 pin Speakon or other speaker type connector. These things are designed to take heavy currents.
If you take the phantom powering out of the equation, that’s a 3-pin connector! The phantom could come in on it’s own 2-pin connector in that case. Lots of the mods people recommend a separate ready made supply for this anyway as the current demand is so low.
Don’t muck around when you’ve got large currents floating around. You need a connection and wiring capable of at least 10 times the current you expect. The electricity in your mixer is like a river with tributaries all feeding in. The tributary streams are small like the current from each op-amp but when they all join at the river mouth (PSU), there’s a lot of water and the river must be wide enough to take it all with room to spare for all the wear and tear expected. Think how big a standard 3-pin house plug is and the big oblong pins? Right! They are only rated at 13A! Your PSU chips can deliver in excess of 1A. So that means the pins must have 1/13th of the cross-sectional area of a UK mains pin to have an equivalent current or power rating.you see what I mean about safety margins? Remember, current is the electrons whizzing along the wire. The electrons don’t know that it’s only 15V pushing them along and not 220V! They’re electrons, after all! But the heating effect in a wire comes from the square of the current; remember,
Power in watts W = I squared R
So if there’s any increased resistive points in the current flow (like a kink in a wire or a bad joint in the connector or rust on the connector), that’s where it very rapidly heats up, so that’s why you ALWAYS over-engineer for power connections. Especially ones with idiots wandering around. It’s so easy to trip over cables etc so the connections MUST be physically robust with connections having a cross-sectional area well capable of carrying lots of electrons.
Put it another way; I never had power supply problems but I’ve seen smoke come from other people’s gear on stage followed very rapidly by silence! Who looks the twit then?
As for your bid, I hope you get it. I hear the Pink’s have a vacancy for a keyboard player now!. From boy-band to studiotoe to psychedelic! Wahay!
Rees
Cool man, thanks for that
i actually want to keep the headphone fo0r use on mix down so ill have to work around that I will go over details a few more times to familiarise myself with them I think i will have a go at bidding on that Transendental, what is the most you think it is worth?
i was gonna bid £100
thanks
paul
Seems a good price. I wouldn’t worry too much about the phones. There are loads of places you can tap into the signal chain for monitoring. Because it’s so hummy it’s not much cop as it is. Does the pfl come out on the phones or are they just on the main busses?
Hey man, missed the bid, it went for £155 but what do youthink of this
http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=250304059094
could i sent normal sound like a hammond through this and use all the filters and stuff?
Ill have to get abck to you oin the PFL stuff Ive attached the schematics and also the manaul for the 16-8-16 which is the same as mine just 4 more busses thanks for all your help im off the next couple of days so im gonna strip her down again and go over your notes paul
I think it’s pants. It’s worth a fiver. ;-)
Just use your PC stuff like that moog emulator etc.
I’ve checked the circuit diags. Like I thought, there’s not much actual electronics as it’s all done in the op-amps. Nearly everything is switches and pots, which are mechanical, collect dirt and wear out!
But of course, this is the whole point of a mixer. It’s easy to make an amp to get a signal up to line level. Two transistors can do that. It’s what happens afterwards that gives the mixer it’s power and flexibility. And the more flexibility you want, means more routing and busses to choose and thus more switches and level controls and thus more mechanical things to go wrong.
You should see your dad for a bit of help or something – he’s mechanical, and that’s what most of your problems stem from (the mechanics, not the dad!).
Like I said, about a gallon of Servisol and loads of jiggling and wiping up! So happy squirting Studiotoe.
The phones amps are a simple tap off the main stereo monitor mix, not independently from each channel from what I can see. They aren’t particularly good, the one I made from the ETI circuit is better (it can drive very low loads whereas the mixer one says 8ohms minimum or pop!) So you could easily ditch them and have that functionality in your next stage (PC or EMU presumably)
The circuit also shows a 1kHz tone generator for setting up, which is good, as well as a studio talkback mic and switch. This is good but no use to you, I think.
They’ve started to use FET switching for some of the busses. This is also good as it stops clicks going through the signal. This is used to mute each channel, so if you get a click there, than it means that something is duff in that area as they should mute smoothly without a thump. They haven’t used it on the EQ cut switch….it’s a cost thing and also, they probably had a load of old boards to use up.
The pan controls are ganged. These don’t always sweep at the same rate. Basically it’s like having two volume controls wired back to back across the stereo outs. My design just used a single. There are pros and cons to any panning design, cost being one of them of course.
Each board seems to include bypass and smoothing capacitors.
Bypass is also included in the negative feedback loop of most op-amps to stop local rf runaway. This is good. You’ll see this as 22pF or 220nF capacitors around the op-amps.
Each stage seems to be properly DC decoupled. They seem to use 33uF throughout. These are probably tantalums.
Hope this helps. It’s pretty well designed but lacks some of the outs that I included on mine that made life pretty useful. I never used busses much. Our system never extended that much and the “buss” would be what we called a mix down bounce – so we had to plan well ahead.
Like I said, the flexibility is the routing, but that means more mechanical bits to break. Reaper does all that so much better, and without the Servisol!
Rees
Cool thanks for that, the thing is the digital world doesnt sound as good as the analog world. i trust my ears and feelings so if you know anyone or come across anything that would work for that clip i sent you, let me know
Thanks for all the breakdowns on the mixer. Apart from me drowning it in servisol, what do you think are its weaknesses and what do i do about them?
On the final mixdown i use all of my outs from EMU, therefore i cant use output 5/6 for headphones. this is why i need to use the headphones on mixer. so i have to get around this im gonna strip her back down in a bit and have another go and a friend of mine is gonna bring over his oscilloscope on monday
thanks again paul
Ha Ha!
It’s actually quite hard to get any more routing and stuff from it because it’s all done on each board after seeing the manual thingy. If you need any extra break points you have to cut the track and insert your own, which is incredibly fiddly. And you also need some box real estate to come out on. You’ve probably got enough options to keep you going.
They quote -85dB roughly for the noise on mic amps. This is good, but nowhere near the capability of your EMU, which is something like 120dB down if I recall. So if you define analogue noise as good, then that’s your prerogative. The figure that you measured -35 I think, is really bad. Does it actually sound like a blizzard? Because if not, then the test setup is a bit cronky. This was my gut feeling when you said you’d done that.
I did a lot of measuring in Physics and it’s a devil to make sure you know which bit your are talking about and what it’s related to!. Everything to do with noise and amplification is related to something else and the standards try to get it so that like is compared with like.
I’d still ditch the phones amp if you can’t stop it humming. It’d save a separate power supply connection and you can always get one cheap to stick across the monitor outs anyway. With an outboard amp, you can monitor each aux feed etc as well with the phones as they are switched in/out. Basically, you can attach the phones to any source you’d want. Think of the phones as an amp/phones combo and you’ll see what I mean. It looks like the mixer phones amp has little connectivity as it is; unless I’ve missed something! ;-)
AS for the clip, there aren’t that many filters and stuff in the box for you to pump your Hammond through! It’s still mutton dressed as lamb. You’ve probably got more than enough filters on the mixer to keep you going! The actual sounds it’s producing are about the same, and about the same controllability as the guitar effects processor I made. The filter you are after is a steep Chebyschev probably, anything higher is hard to implement stably. You can make one for a quid or two. It’s the next one up from a Bessel and has a peak before the slope. This is what you can hear when he sweeps it around. If you were really creative, you could set aside a couple of mixer channels and modify the tone controls/filters on them for the required functionality. You’d still have a dozen to play with normally and it wouldn’t affect anything. Check the circuits round the tone op-amps and compare to here say:
logic: http://en.wikipedia.org/wiki/Chebyshev_filter
Op-amp implementation: http://people.seas.harvard.edu/~jones/es154/lectures/lecture_1/filters/filters.html at the bottom. It wouldn’t take much as most of the circuit is already made on the channel board anyway, you’d only need one or two flying leads and change a component or two. The part of your circuit to look at is the two op-amps at middle left on page 1 of your circuit diagram. The far left one does the swept mid EQ and the right one is a standard Baxendall tone control.
Happy soldering and scoping!
Rees
Cool thanks man
i got in there today on channel 16 & 15 and gave it a serious working over with servisol, it really helped to get them free and stuff coming out now heres something. i wanna try these modules before i put them back in. can i just attach one channel to the channel strip to power supply OR do i have to attach multiple?
im gonna upload pics to photobucket tonight ill let you know when theyre done
thanks paul
Cool, didnt know if it needed to have at least a few boards connected so there wasnt too much power?(still dont quite understand power requirements it cost me £78.86, bargain if you ask me!
heres the new pics
http://s390.photobucket.com/albums/oo345/paulrichards7/?action=view¤t=Buswireconfig.jpg
http://s390.photobucket.com/albums/oo345/paulrichards7/?action=view¤t=DSC02490.jpg
http://s390.photobucket.com/albums/oo345/paulrichards7/?action=view¤t=DSC02534.jpg
http://s390.photobucket.com/albums/oo345/paulrichards7/?action=view¤t=Innersraised.jpg
i took pics of the channels in 2s, i was then gonna merge them but that doesnt work. so im gonna have to take pics again
cool man paul
The power comes from regulator chips which keep a nice constant voltage. Each board can be viewed as a resistor across the power rails so only so many electrons can squeeze through it. The more boards you connect then the more paths for the electrons to travel. So more current flow out of the power supply. So it is said that the PSU is delivering more power at that point in time.
If you disconnect all boards and just have the PSU sitting on the table but plugged in, it is delivering negligible power as the electrons are going through the air to get from one rail to another. Air is a very good insulator, so only one or two make it. (they sound a bit like sperms in this description) Not enough to register on most equipment.
The thing looks clean and tidy from the pix. I’m surprised it’s so noisy. As you’ll see, everything, all the pots and switches are circuit board mounted. If there’s any strain, then it’s nearly always because of wire pulling the boards around a bit against the resistance of the pot pins. This makes the boards move to and fro against the pot pins and they can work a hole around the pins when they are supposed to be nicely soldered. I’ve seen a few like that. Re-solder the pots into their holes solves that. Hopefully, any movement hasn’t moved the copper tracks on the boards. That’s what usually goes through my mind when I’ve seen it. I can see little angle brackets supporting the boards at the bottom and pop riveted to them(which is good). This probably helps earthing as well with the front panel.
It should be a pleasure to work on and pretty simple. Well done!
Cool man, thanks
i will try re-soldering em
a 35watt soldering iron ok?
you said just a touch of solder, any particular guage?
and 3/4 of a second on contact, right?
thats so cool that i can just test each single board before re-installing anything i should make sure i dont touch on channel board?
should i thicken up those grounding wires coming off the grounds on top left of pictures?
thnaks and ill keep you updated
paul
hi
i have a studiomaster 16-4-2 mixer
on the phantom power switch theres 4 wires 2 yellow 2 pink they came off of it …can you tell me how they go back on it…tx…:O)