Studiomaster and soldering Iron questions.

[BEEFY]

I figured I would kill two birds with one stone and just ask both questions in one topic. I have the parts on order to recap a studiomaster 12 into 2b. I'm planning on doing that and seeing where that gets me but after that I want to start swapping op amps. Mine has the 471 and the tl071 all over the place. I heard the 471 s were horrible and swap them out with anything. I was wondering if anybody could recommend something to replace them with? I would like to know some replacements that would just be reasonably price and what would be considered some higher quality replacements because there's a lot of them in there. I thik I may want to replace the tl071s eventually as well and if anybody could recomend a good drop in replacement for these that would be great.
I was also wondering if anybody has any experience with these if all the green wires are grounds and if I could just connect them directly to the ground where the power cord comes in or make a grounding point. One other thing about the studiomasters does anybody have any experience with how they sound after being upgraded. I'm going to work on this project anyway but it would be nice to have some feedback on them.

As for soldering Irons I have a 25 watt weller which is better than the radio shack I started out with but every once in a while I have problems heating up an old solder to get it to melt so I can use my desoldering pump on it. I was talking to a computer guy and he kind of told me that I needed a higher watt hotter Iron any help on this would be extremely useful.

 

[mikefatom]

I don't have experience with the studiomaster stuff, but with regards to the soldering iron, I suggest you get yourself a Weller  or Hako soldering station with adjustable power/temp. I have the Weller WES51 and it's all I ever need, along with a good collection of tips.

good luck!

 

[tchgtr]

Hey Beefy,
  I've restored two SMs over the past two years, both of them a bit newer than yours -- an 8 into 4, and a Mixdown 16-8-16.
I like the sound and features of both of them. Much better than the 1604 I used to have. EQs are nice, and I like the layout. Both are built like tanks, and restored well.
    Sounds like you have the electros covered. I would replace the EQ caps even before I started with op amps, as I think on that board they might be always "in". I'm lucky to have a surplus store nearby with a decent stock of polypros. It seems from other posts I've seen from you, you probably know what to get. Major difference on the EQs--much less distortion.
  Does that mixer also have the RIAA-ready channels? It's pretty easy to find the components on the back of the channel boards if you want to remove that. I did that on the 8 into 4. Those button switches get old, and are the only problem I have with it.
  I only played with ICs on the Mixdown as they are socketed, and liked the results. It had TL072s and 5532s. Tried a lot of things. It's fun to have different ICs on the channels to try, but I kept coming back to the OP275, as they seemed to have more dimension. I'd mix something like drum OHs on them, and then throw it in channels with the old 072s, and the staging and panning was just gone...tried TLE2072 also, but they were only slightly better. I have never replaced 471s, so I'm sorry not to have better advice for you there. If they are all soldered in, I would start with the output channels. Are those 471s also?
  I did put some LT1351s in place of some of the few 071s on the Mixdown, and they seem to work fine. Tried some 1358s in place of the 072s, but they were a bit thin for my taste. The LTs are nice due to lower current draw, but may need some taming.
  As to irons, I got a small Hakko at Frys that works great. Maybe $30. 
  The Mixdown gives me a lot of joy to work on, and seldom gets in the way. Even before I did anything to it, it sounded better than my 1604. Also did some nice live recordings right off the direct outs.
  The 8 into 4 is similar to yours, and works really well for almost anything, though I mainly use it for rehearsals/lessons. Full sounding, and only slightly grainy. My hat's off to the Brits.
 

 

[BEEFY]

      I hope from my other posts I don't sound to tech savvy because I really don't know that much about this stuff. As far as the caps goes I just ordered equivalent or the same values with higher voltage of panasonic fm and one of them pw series for everything except the one little goldfish cap on each channel I figured I would just leave them in for now and order some film caps for them maybe later.
      As far as the op amps goes I don't have anything ordered yet I'm going to wait and see how it sounds recapped and with all the pots thoroughly cleaned. I am also at a loss as to what to order for the op amps. I would like to put sockets in for all the op amps that way if I ever want to try different things out It would be easy, but I wouldn't know where on mouser or digikey to start looking for sockets.
      To tell the truth I don't even know what an RIAA channel is. It would be nice if someone would explain that to so so in the future I don't look dumb or possibly even look smart.
      The mixer is kind of weird it doesn't have any line ins inserts or phantom power but has direct outs on every channel. I'm going to just use the pres though the direct outs on it hopefully buy a couple nice pre amps with phantom power. Then run about 6 or 8 of the channels into a patch bay with the other 2 pre amps I' hopefully will buy and run those into to 2 adat tape machines. From there I will mix everything down add compressors and reverb on my allen and heath mix wiz. For mastering I won't even tell you what I'm going to do because every one would ridicule me anyway.
      For the Irons the only problem I have with the 25 watt weller is it isn't melting all the solders I'm trying to remove. I use flux clean my Iron I every baord It's like there is one solder I could hold this thing on all day and it wouldn't melt besides that its fine I'm just wondering if there is a way I don't have to buy a 100 dollar soldering station.
      I like the way The board sounds it just needs a lot of cleaning up and a lot of removing the destortion and the only way you can beat 70db of gain is with 71db or higher of gain, but the pre amps on my A&H only have 60 So when this thing is done I still think I'm moving uup in the world.

 

[tchgtr]

The RIAA inputs are for turntables. Must not have it on the board since it has no line inputs.
Does the board have the classic SM EQ, with the sweepable lows? Is there an in/out switch for the EQ? If not, look for some green or red "chicklets" caps near the EQ pots. Replace with same values, but with some polypro, metal film, or even polyester caps. Try to avoid mylar. People around here like WIMAs for this kinda thing.
If the EQ can be switched out, it's not so important, but if you want to use the EQ or can't remove it from the circuit, this is a big one.
We're already risking ridicule by talking about op amps, so WTF
If the caps have never been replaced, you'll probably like it after you restore it.

 

[BEEFY]

There's no in out switch on the eq but I think it has sweepable lows mids and highs. For the chiclet looikng caps there's nothing that looks like that but there is some square things Im not sure about they have flat metal sides and plastic inbetween them that says 250 then 22n under that and that just repeats I'm going to look on the schematics and see if I see anything and I do want to use the eqs. No one still has anything on the op amps?

 

[tchgtr]

Those are probably the EQ caps. They are the old style film caps, and you should find them in different values for each band of the EQ. Maybe somewhere between 1n and 1uf...
If you can put up a photo of that area of the board, I could likely ID the caps.
Try just replacing them in two channels with nice WIMAs or something, and see what you think.

 

[BEEFY]

The schematics are hard to read it looks like one is 68n or 6.8n I dont not if that sounds right one looks to be 22n and one looks like it says Ins but maybe it says 1nf I'm wondering if it would just be okay to pop in 1 uf wimas in there?

 

[tchgtr]

You have to replace with the same value, or the EQ center-frequency will change.
Might be easier to read on the cap itself.
Low freqs will have the larger cap values.

 

[iyahdub]

Does any of you happen to have the schematics for a studiomaster mixdown 16-8-16 ?  Please ?!?

 

[tchgtr]

Well, maybe you should look in the technical document section under "Studiomaster".
Please search B4 asking...

 

[iyahdub]

Sorry, youre right !!.
Im still quite new to the forum. But i remember reading about the meta search , now that you mention it ! Only asked as it came to the list of last post replies since my last visit and hadnt noticed it before.
Apologies and thanks !!

 

[tchgtr]

It's the schemo for the Mixdown Gold, so just ignore everything having to do with the MIDI mutes.
Otherwise, it seems identical to the standard Mixdown 16x8x16.
Good luck!

 

[college101]

Get a weller soldering iron mate!

Grounds need to be isolated from the IEC ground..The IEC ground always stays to itself

Everything else, try and connect close items to the same ground if at all possible