Is there a better bargain than the $56 Nobsound Passive Preamp?

charmerci · « **Reply #220 on:** 19 Mar 2019, 12:02 am »

The fourth ebay photo has an OzarkTom quote from reply #179 on p.9.

KR500 · « **Reply #221 on:** 19 Mar 2019, 02:34 pm »

lacro;

Thanks for posting your pictures and links re: your input switch and DACT attenuator .

I wondered if you preferred your DACT over the ALPS 27 pot ?

Several people have posted positive experiences online with the DACT: and a couple of others have posted about returning to the ALPS after a period of use.

I can't help but noticing that I don't see any mention of the use of the DACT in the build guides at diy audios Pass Lab. Just the ALPS .

wushuliu · « **Reply #222 on:** 19 Mar 2019, 02:51 pm »

Quote from: KR500 on 19 Mar 2019, 02:34 pm

lacro;

Thanks for posting your pictures and links re: your input switch and DACT attenuator .

I wondered if you preferred your DACT over the ALPS 27 pot ?

Several people have posted positive experiences online with the DACT: and a couple of others have posted about returning to the ALPS after a period of use.

I can't help but noticing that I don't see any mention of the use of the DACT in the build guides at diy audios Pass Lab. Just the ALPS .

Nelson isn't fussy about non critical parts and recommends what's easily accessible to most people. The Chinese dacts are based on real DACT pots so I doubt he would recommend them for IP reasons and the real ones are very expensive. These Chinese dacts have been around for years now and used widely in diy. Diyaudio was where they were first discussed IIRC.

lacro · « **Reply #223 on:** 19 Mar 2019, 04:54 pm »

Quote from: KR500 on 19 Mar 2019, 02:34 pm

lacro;

Thanks for posting your pictures and links re: your input switch and DACT attenuator .

I wondered if you preferred your DACT over the ALPS 27 pot ?

Several people have posted positive experiences online with the DACT: and a couple of others have posted about returning to the ALPS after a period of use.

I can't help but noticing that I don't see any mention of the use of the DACT in the build guides at diy audios Pass Lab. Just the ALPS .

KR500,
I keep swapping the two in and out, and to be honest, I like them both. They do have a different sound, but I can't really say one is better, just different. Sorry, I am not very good at describing the sound difference.

The Alps 27 in this implementation is not really a good comparison as it's being used in a shunt passive preamp. I don't fully understand the concept of the shunt. It's something I learned about from Hifix, and have been playing with it for a couple years, trying different resistors which do offer different sound. The design as I understand it is based on the Harry Haller circuit where the signal never passes through the attenuator. It only passes through one resistor. I don't know how the Alps 27 pot sounds when wired the conventional way.

They are cheap enough that it's not going to break the bank to try them both.

KR500 · « **Reply #224 on:** 19 Mar 2019, 11:29 pm »

Thanks for your comments macro and wushuliu.

I have a Chinese DACT on my Folsom amp and also my Pass B 1 buffer , and then the ALPS 27 on my WHAMMY headphone amp
Both types work well .
I just wanted your thoughts on the two pots I guess .
My next project is a Charlize 2 PCB I bought from someone on Diy audio and I'm deciding which pot , (or pots ) to order for the amp.

charmerci · « **Reply #225 on:** 25 Mar 2019, 11:24 pm »

The SMD Dact passive is.... well, it's OK. On my system, the high end/frequencies are more forward with more clarity but ever so slightly harsher (at louder levels) than my Odyssey Tempest. But soundstage isn't as good. They make my system sound more like the music is coming from two speakers without as much depth or layers. I think (though I could be wrong?) it doesn't go as low. The overall bass is much less full across the lower frequencies though tighter (quicker/more "snap") with less wooliness than the Tempest. I think that the Odyssey also sounds smoother overall. I prefer the Odyssey with it's trade-off than with this passive.

I guess this is one of those system dependent pieces.

I also wanted to recommend it with the $30+ Signstek DAC that Wishilu recommended here - except they don't seem to be making that DAC anymore. Regardless, paired with the SMD Passive and the JBL305P MkII - it just doesn't get very loud at all - otherwise I would have recommended this in the Sub $1K systems unless you use it as a desktop computer system - to listen at your desk only!

Poultrygeist · « **Reply #226 on:** 26 Mar 2019, 12:23 am »

My SMD DACT sounds like nothing and that's the highest compliment any passive can receive.

JohnR · « **Reply #227 on:** 26 Mar 2019, 12:25 am »

I believe Charmerci is not referring to a DACT but the "DACT clone" from China. Basically, it seems a stepped attenuator made with SMD resistors is now called a "DACT"....

charmerci · « **Reply #228 on:** 26 Mar 2019, 12:50 am »

Yeah, this one.

https://www.ebay.com/itm/SMD-Dact-type-Stepped-attenuator-Passive-Preamplifier/192132688811?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

Poultrygeist · « **Reply #229 on:** 26 Mar 2019, 08:26 am »

And the Hong Kong DACT clone is what I have. This is the C&C forum.

charmerci · « **Reply #230 on:** 26 Mar 2019, 11:30 pm »

This one seems like a better built one for slightly more.

https://www.ebay.com/itm/Rockappella-Passive-Pre-Amp-Stepped-Attenuator-Preamplifier-Gold-Knob-23-Point-/163009641745

OzarkTom · « **Reply #231 on:** 26 Mar 2019, 11:48 pm »

Here is a Danish Dact for $350. I think still in the C&C range.

https://www.ebay.com/itm/Passive-preamplifier-with-DACT-CT2-attenuator-and-CMC-golden-plated-RCA/202167840390?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

fredgarvin · « **Reply #232 on:** 27 Mar 2019, 03:37 pm »

What the Chinese model offers that the others don't is two outputs, great for bi-amping, plus a third 'record' out that could be used to feed a subwoofer.

cujobob · « **Reply #233 on:** 27 Mar 2019, 03:49 pm »

Quote from: OzarkTom on 26 Mar 2019, 11:48 pm

Here is a Danish Dact for $350. I think still in the C&C range.

https://www.ebay.com/itm/Passive-preamplifier-with-DACT-CT2-attenuator-and-CMC-golden-plated-RCA/202167840390?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649

I thoroughly enjoyed this part of the description:

"Box is made from exotic well sounding wood with wooden legs."

You might not be wrong that this could be a quality unit for the cost, but I would probably recommend something like a Schiit Saga which has a remote for the same price. It's possible the stepped attenuators could be higher quality, but we don't really know.

srb · « **Reply #234 on:** 27 Mar 2019, 03:58 pm »

Quote from: fredgarvin on 27 Mar 2019, 03:37 pm

What the Chinese model offers that the others don't is two outputs, great for bi-amping, plus a third 'record' out that could be used to feed a subwoofer.

Generally, "Record Out" are fixed level outputs that bypass the volume control, and would not be suitable to feed a subwoofer which would require variable line out.

OzarkTom · « **Reply #235 on:** 27 Mar 2019, 05:24 pm »

Quote from: cujobob on 27 Mar 2019, 03:49 pm

I thoroughly enjoyed this part of the description:

"Box is made from exotic well sounding wood with wooden legs."

You might not be wrong that this could be a quality unit for the cost, but I would probably recommend something like a Schiit Saga which has a remote for the same price. It's possible the stepped attenuators could be higher quality, but we don't really know.

For SQ, this will beat the Saga. But with no remote, the Saga will be more popular.

davidldl · « **Reply #236 on:** 27 Mar 2019, 05:38 pm »

The seller of the Hong Kong dact actually has several version, click on 'See other items':

regular rca jacks: $99

higher quality cmc rca jacks: $120
https://www.ebay.com/itm/SMD-Dact-type-Stepped-attenuator-Passive-Preamplifier-with-CMC-RCA-socket/271394425956?hash=item3f305e4c64:g:3W8AAOxyDgRQ9g0e

higher quality stepped attenuator: $150
https://www.ebay.com/itm/Passive-Preamplifier-Stepped-attenuator-passive-preamp/271424718624?hash=item3f322c8720:g:6YcAAMXQ9rVQ6nB9

alps volume pot with xlr: $165
https://www.ebay.com/itm/passive-preamp-XLR-Balance-version-Alps-Volume-pot/272602310760?hash=item3f785d2868:g:emcAAOSwDKtY1FqP

dale resistor attenuator: $199
https://www.ebay.com/itm/Passive-Preamplifier-Dale-Resistor-Stepped-attenuator/271214681553?hash=item3f25a79dd1:g:FI8AAOxySE9Q50ON

David

OzarkTom · « **Reply #237 on:** 27 Mar 2019, 06:23 pm »

The Dale Resistor unit sounds tempting. Here is one you can build.

http://www.hi-fi-insight.com/custom-passive-pre-amp.html

fredgarvin · « **Reply #238 on:** 27 Mar 2019, 07:50 pm »

Quote from: srb on 27 Mar 2019, 03:58 pm

Generally, "Record Out" are fixed level outputs that bypass the volume control, and would not be suitable to feed a subwoofer which would require variable line out.

Wouldn't a sub's own volume control and crossover work with the bypassed volume control from the dac?

srb · « **Reply #239 on:** 27 Mar 2019, 07:57 pm »

Quote from: fredgarvin on 27 Mar 2019, 07:50 pm

Wouldn't a sub's own volume control and crossover work with the bypassed volume control from the dac?

Yes, but each and every time you adjusted the preamp's volume control, the subwoofer's volume would remain constant and you would also have to adjust the volume control on the sub.