[Jcoffey1]

I cant afford the Alps Blue, but I was looking at this Vishay SQ 100k pot. Is this what I need?

http://www.mouser.com/index.cfm?hand...e_pcodeid=5941

Its going to be panel mounted, and I've got everything else I think I need.

The 4556 opamp, Vishay 1/4W resistors, Solen 5uF Caps, And Xicon .12uF100v poly film radial caps. Should I try to get a better .12uF cap?
Any thoughts and suggestions would be greatly appreciated.

 

[morsel]

That is a linear taper single gang pot, useless for audio. You need a dual gang logarithmic (audio) taper pot. You can get the Alps Blue for $15 from Tangent or the Panasonic EVJC for $3 from Digikey.

 

[was ist los?]

Or the authentic RA-1 Alps pot from Radioshack for $3.

 

[uniuniunium]

what was said

 

[Jcoffey1]

Even better.

Radio Crack it is then........
I'm not worried too much with super high end with this one, as it's more of a test amp right now. Hoping everything works ok, and I get good sq, I'm planning on building a second clone with higher end parts that will be integrated into a Gainclone integrated amp that I'm in the process of starting, using top of the line components, Nutrik connectors, Alps Blue pot, Cardas wires and RCA's, etc.

 

[Beagle]

Quote:

Originally posted by was ist los? Or the authentic RA-1 Alps pot from Radioshack for $3.

Could somebody please post the RS part #. I'd like to find out if it's available in Canada.

 

[dokebi]

271-1732 or 271-1732C. I had serious tracking issues with a few of these. Not recommended at all.

 

[Tomo]

Hello,

I beg to differ on the matter of Linear Potentiometers. They are actually "Better." You will naturally get better tracking and matching than logarithmic pots.

Expensive Log Pot such as ALPS BLUE would have very good tracking and matching also. However, you can get as good tracking and matching with something far cheaper with a Linear Potentiometer.

As far as making a Linear Pot behave like a Log Pot, you simply need ONE SINGLE RESISTOR. This has been covered at ELLIOT SOUND:

http://sound.westhost.com/project01.htm

You will notice irregularity at Lowest and Highest Volume Possible. However, you get very nice logarithmic characteristics in between.

In fact, I use a linear stepped attenuator bypassed the ELLIOT way. I found it superb. (Also, getting 46 matched resistors is very easy and cheap.)

Tomo

 

[stereth]

Tomo, personally, I've had a bad experience with tracking on a linear pot, the one time I screwed up an order. The log EVJs I've gotten have generally been good, channels usually within about 5% of each other.

Jcoffey, the caps you're wondering about should be fine. Any upgrade there would be a last 1% deal.

 

[Tomo]

stereth -

Your problems may rise from the choice of bypass resistance. You must absolutely read ELLIOT's article for the proper choice of resistance. Otherwise, you will not get good 1dB or 2dB per step curve. You can also try online sources.

Extra couple minutes of math can decrease my cost by half without performance degradation sounds good at least to experiment. It certainly does not deserve to be SHUNNED without even a moment of consideration. I, for one, am extremely happy with it. (And, please note that I am no-causal HeadFier. I have been around you know?)

(If your pot is seriously screwed up, you should return it. Linear Pots have industry standards and broken one should have stopped at their testing facilities)

T

 

[stereth]

Actually, Tomo, I hooked up the pot straight - no resistor. I know how that's supposed to sound. On the lower half of rotation, the sound was shifted heavily to one side. I replaced it with a log pot and it's fine. The linear one was an EVJ, hardly worth the effort to return. Anyway, I can't make any generalizations, but I meant to say two things: one, that linear pots do not necessarily track well; and two, that log pots often have good tracking.

 

[Tomo]

No,

If what you say is correct, your pot was BROKEN. You must have ordered more than one pot. Have you tried others? I am sure you got unlucky on that one. It happens that we do have NON-ZERO failure rate and you are bound to pick up something broken however unlikely it may be.

So you must test every components you get and you must buy extra especially if the component is cheap. That's one of the reason why we mass produce. If it ain't work, try another.

Some expensive components are expensive because of stringent testing involved such as RN and CMF series resistors. However, vast majorities are mass produced components with better parts. Thus, the failure rate is about the same. In other words, your log pot works because you did not get unlucky.

Being unlucky for a pot like these is a bit more likely than winning a lottery ticket. Most manufacturers list their failure rate of the components. I recommend going through them because some parts have particularly high values.

T

 

[Voodoochile]

5% would be a huge error, IMO. Ouch. I know you don't get too much for your $3, bu it ought to be tighter than that, we all hope.