Low cost SMD stepped attenuators

[s0rce]

I was wondering if anyone has any experience with the small SMD stepped attenuators from china, ex. SMT Resistor 50K Step Attenuator Volume Control Alps | eBay.

For small amps they might be a good upgrade? Anyone know how they compare to the little green ALPS pots (1pc Japan ALPS Volume Potentiometer 10KAX2 RK09 Type | eBay).

Thanks,
Lyle

[454Casull]

I suppose it would depend on the type of resistors and the quality of the switch itself. Definitely inexpensive.

[wintermute]

I bought one of these DACT Type 21 Stepped Attenuator 20K FOR PASS B1 DIY | eBay though I haven't used it yet.

my main criteria was good channel matching and checking with the multimeter it certainly achieves that! Not sure what the longevity will be like or whether the 21 steps will be fine enough, but it seems to be what it claims Note that as far as I can tell it is effectively a bunch of smd resistors connected in series and a wiper tapping in at various points along that series of resistors, so somewhat like a conventional pot made up of smd resistors.

Tony.

[stratus46]

Have you considered a shaft encoder interfaced to a PGA2310? They claim some pretty good specs and would be a snap to add remote capabilities. A PIC or my favorites Freescale HC908 series processors would be pretty simple.

Of course you hollow state guys might not like it.

G²

[hitachi_nut]

I bought a Chinese stepped attenuator with the loudness tap several years ago for a Marantz preamp rebuild and it still works. The tracking is light years better than the old pot (CTC) it replaced. The only question was the longevity, 3 years in service is not long enough.

It looks like this one but with the loudness tap -> 1*ALPS 500K 'A' Log Potentiometer Attenuator Stereo New | eBay

[MellowFellow]

I've been running the "gigawork" attenuator wintermute linked for about a year now. It replaced the standard pot from my Yaqin MC-100b amp that looked basically like a copy of the ALPS blue velvet, but wasn't an ALPS. I assume it was just some good-ish quality Chinese pot.

The attenuator sounds better than that pot. I don't like using all the audiophile adjectives, so I'll just say it sounded clearer.

[Mark2727]

I've just recently discovered these volume pots using the SMD type fly speck size resistors. I'm using a 10K one that a buddy of mine gave me in a passive preamp. I'm sure glad he did. I don't even know the brand of it.

I feel this the most transparent, quick sounding volume pot I've ever tried. Better than wirewounds, ladder or series types using 1/4 watt (?) resistors for sure!

It sounds great with every amp I've thrown at it so far. All the way from my my giant 300 watt per channel Emotiva XPA-2 to my 3/4 watt per channel Darling tube amp.

I have not played with optical volume pots such as the Optivol yet. I'm a bit reluctant to have to supply power to a passive. And they are around $50as I recall, so not exceptionally cheap.

Mark

[djQUAN]

I ordered a few of these to try in an amp I'm building. They appear to be better sealed versions of the ones linked above. I hope they work well.

[Mark2727]

Yep, I plan to order some also. I just have to decide if I want 10K or 20K.

Picking the "K" has always been somewhat of a mystery for me. I used to make passives with 100K Radio Shack pots, but often experienced a little bzzzz noise in them. I switched to 50K Alps blue......similar effect.

Then I thought I'd try a 25K in a Pass B1 Buffered preamp. NO noise. I think experiented with a wirewound 10K. No noise there either. With the large solid state amp I have (Emotiva XPA-2) or with all the tube amps I use. No noise with the 25K or 10K devices.

Mark