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Stingray aftermarket 2 band pre

#581
Spencer! said:
I wouldn't use tantalums in the audio path (or anywhere, really).
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Why? They sound fine. I've been using them for years in audio projects.

Tantalum capacitors have lower ESR and leakage than other electrolytic caps. Aluminum cans are very lossy. Tantalums have tighter tolerances as well. They are generally much better caps than aluminum cans.

The original version also used tantalums.

Tantalum Capacitors About - Engineers Edge
 
#583
SGD Lutherie said:
Why? They sound fine. I've been using them for years in audio projects.

Tantalum capacitors have lower ESR and leakage than other electrolytic caps. Aluminum cans are very lossy. Tantalums have tighter tolerances as well. They are generally much better caps than aluminum cans.

The original version also used tantalums.

Tantalum Capacitors About - Engineers Edge
Click to expand...

Reliability reasons. I hardly use electolytics anymore either - just ceramics and the occasional film or electrolytic when I need something in a large value in the audio path.
 
#585
UncleFluffy said:
How are you doing assembly? Modified toaster oven?

(I ask because I'm putting together a homebrew reflow setup of my own for some other projects and I'd be interested in people's experiences).
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I hand-solder prototypes using a Weller digital iron and hot tweezers, and I have a local place do assembly on production runs. All you really need is a good eye and a steady hand.
 
#587
UncleFluffy said:
Yeah, probably true for this sort of thing.

The other project uses BGA parts though. How pricy are you finding contract assembly?
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Ah, a BGA would have to be done with temperature-controlled reflow - a toaster oven's not gonna cut it there.

Assembly prices depend on what the project is and how many you want assembled. Getting one of anything assembled is pricey, although there are shops that specialize in that. At 100, the prices look pretty good. Certainly a lot less than my time is worth!
 
#588
Spencer! said:
Reliability reasons. I hardly use electolytics anymore either - just ceramics and the occasional film or electrolytic when I need something in a large value in the audio path.
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I certainly haven't had any reliability problems. I have pedals I built 30+ years ago that work fine. Tantalums don't have a lifespan, unlike aluminum cans which will dry out after a while. Tantalums last forever.

Also some circuits require polarized caps. There's no way around that. That's been wring fine for people for a very long time.
 
#589
SGD Lutherie said:
Also some circuits require polarized caps. There's no way around that. That's been wring fine for people for a very long time.
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What circuit needs a polarized cap?

Tantalums work fine when they're correctly biased with DC but I wouldn't use them in the signal path when there are good alternatives available.
 
#590
Spencer! said:
What circuit needs a polarized cap?
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OK I should say that you use polarized caps when you need a large value. Non polarized caps are generally physically too large to use in many applications at high values.

Tantalums work fine when they're correctly biased with DC but I wouldn't use them in the signal path when there are good alternatives available.
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If you say so. And those alternatives are? Aluminum caps? They are inferior to tantalums as far as electrolytic caps are concerned. There's no reason to bias a cap with DC. In the usual configuration, the DC voltage on the positive side of the cap is always higher than the DC voltage on the negative side. We are using these for passing AC current, and mainly use them as DC blocking caps. If there wasn't some DC bias in the circuit, we wouldn't need coupling caps at all. But that's never the case in audio circuits.

Of course you can use a transformer instead of a coupling cap, but that's impractical and colors the sound.

Ideally we would use all non polarized caps, but they are big and expensive.
 
#592
Spencer! said:
Ceramic!
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Alrighty then. Ceramics are fine for some applications. I use some nice multilayer ceramics in my version of the preamp.
Until recently you'd be hard pressed to find a 10µF ceramic cap, but there are some surface mount versions in that range. Taiyo Yuden introduced some axial lead 10µF multilayer ceramics back in '06. Ceramics are also prone to ringing and parasitic inductance.

I didn't just haphazardly chose parts here. I also didn't go with the parts a lot of people were using. I went through several iterations of prototypes until I got the combination I liked. This included aluminum cans and ceramic caps for some of the smaller values. I tested these all out by playing through them at gigs. I stopped when I liked what I heard.

I use polyester film box caps, multilayer ceramics and the tantalums for the 1µF and 10µF values. That along with metal film resistors, and this is a very quiet version of the preamp. I've had a couple of customers A/B this to a vintage Stingray and the tone is dead on but my version is quieter.
 
#593
SGD Lutherie said:
Alrighty then. Ceramics are fine for some applications. I use some nice multilayer ceramics in my version of the preamp.
Click to expand...

SMD technology has come really far just in the last couple of years - I'm using 47uF ceramics in my power supplies, and they're a smaller footprint than the equivalent electrolytic. You can even get NP0 ceramics up to 100n now.
 
#594
Spencer! said:
SMD technology has come really far just in the last couple of years - I'm using 47uF ceramics in my power supplies, and they're a smaller footprint than the equivalent electrolytic. You can even get NP0 ceramics up to 100n now.
Click to expand...

I agree. SMD is the way to go, as all the new fangled parts are being introduced in SMD packages.
 
#595
Spencer! said:
I wouldn't use tantalums in the audio path (or anywhere, really). The absolute best 10uf caps are the Nichicon MUSE series, which only come in through-hole.
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I use those MUSE series in all my preamps and they sound great! I also found out through experimenting the type of cap used for 47n makes a difference in tone. The Nichicon polyester films sound warmer and less harsh to my ears
 
#599
SGD Lutherie said:
Unusually noisy or distorted. Generally when an op amp fails it just stops working.
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well ive got a lot of noise. i wired up my other working pre that john made and connected my stingray 5 pickup to it. i get a similar noise when i touch the top edge of the chip. except on this board i wired up, im getting this noise at a much louder degree and its constant. i didnt wire in the 1k resistor, but i cant see where i would have had a short anywhere.
 
#600
narud said:
well ive got a lot of noise. i wired up my other working pre that john made and connected my stingray 5 pickup to it. i get a similar noise when i touch the top edge of the chip. except on this board i wired up, im getting this noise at a much louder degree and its constant. i didnt wire in the 1k resistor, but i cant see where i would have had a short anywhere.
Click to expand...

when I get a lot of noise in a project either I soldered something incorrectly or a solder joint is bad. I would check each solder point for continuity with the next. that usually solves the problem for me. Are you getting DC through the output jack? It should be a very low millivolt reading. If you're getting 9 volts through the jack it might be a ground problem
 

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