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

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ClefChef

What is the beef now Folsom? Rex now owns a much better sounding amp than yours. Is anyone trashing your amp thread? I am going to buy a Dact passive, and I have sent Rex the info to read. I am sure he will also buy one. He likes to do DIY, he will probably build one. He just sold some audio gear, so he will get his before I do.

Rex, is that you?

OzarkTom

And Folsom, it is not personal. In fact I even said your chip amps were probably the best if you go back far enough in your long thread. I had chip amps in the past, but I figured you had the best.

Folsom

 

I and maybe others got very tired of all the BS of Ncore fanboys several years ago. They said all other amps was trash or junk. Just because you know what is best, let others here slowly learn what is better. It is called trading up. Many are very skeptic that passives can beat their multi thousand dollar tube preamps. The Nobsound and other cheap pasives can be a learning curve for others here. In my sysytem and others here, the Nobsound is not harsh or trashy sounding. Maybe your amp makes then nobsound sound harsh? Or maybe we have all gone deaf?

Because of the Nobsound, I sold my tube preamp for $1275, I can probably now sell my power cord for $50. That makes the Nobsound as extra good value, like this thread is called. Do any Dact sellers  give a 30 day money back guarantee? If so, who? There is an original Danish Dact on Ebay for around $700. Not everyone in the world does DIY.

As one person asked, how much would you charge to make these? People are still spending $3-5K+ for preamps that is inferior to the passives.

I can't compete with China. I would never be able to sell anything for $50 that anyone would buy. If people want a high end volume there is a lot of stuff available for passive. The only way for me to offer a preamp is to make it powered, so I'm not dealing with the choice between it and Chinese things on eBay.

There are things out there that allow people to "downgrade" and save $. I know a guy who had Devialet $10k amp, and decided mine was good enough that he didn't need it anymore. You can imagine the savings since he's good at DIY.

What I would suggest is to not see passive in competition per se with active. My suggestion would be if you have a nice preamp that's active, swap the pot in it for an eBay DACT, Goldpoint, Kuzman, or DACT (danish). Dynaco had offered the upgrade for the Chinese DACT for awhile because it's the only substantial upgrade they've had in, I dunno? Decades? But they recently just redid themselves so now the amps are just as-is, no retro stuff.

Sometimes we got hooked on actives just because they sounded different, and we don't recall attributes that may have been better without. Sometimes some stereos flat out need gain.

sumoking

  • Jr. Member
  • Posts: 229
I can't compete with China. I would never be able to sell anything for $50 that anyone would buy. If people want a high end volume there is a lot of stuff available for passive. The only way for me to offer a preamp is to make it powered, so I'm not dealing with the choice between it and Chinese things on eBay.

There are things out there that allow people to "downgrade" and save $. I know a guy who had Devialet $10k amp, and decided mine was good enough that he didn't need it anymore. You can imagine the savings since he's good at DIY.

What I would suggest is to not see passive in competition per se with active. My suggestion would be if you have a nice preamp that's active, swap the pot in it for an eBay DACT, Goldpoint, Kuzman, or DACT (danish). Dynaco had offered the upgrade for the Chinese DACT for awhile because it's the only substantial upgrade they've had in, I dunno? Decades? But they recently just redid themselves so now the amps are just as-is, no retro stuff.

Sometimes we got hooked on actives just because they sounded different, and we don't recall attributes that may have been better without. Sometimes some stereos flat out need gain.

When I had my Reference Line preeminence  passive preamp- everything in it was point to point wiring w/o circuit boards.  I'm quite sure this gave it more transparency.  I see a lot written about the pot which is critical for sure, but also think the point to point wiring (with good wire) is also a big contributor to the sound.

What I think I need is:
- Two XLR outputs
- one single ended input
- one xlr input
- high quality pot
-point to point wiring

wondering if this can be had for $250 or less...  what do you think?

OzarkTom

So you cannot match the $200 Dact passive that you showed us on Ebay? $700 for an Original Dact passive? You could offer special orders or sell them one at a time on Ebay. I sell more used audio gear on Ebay than anywhere else.

The TBI chip amp with improved PSU will beat a Devialet IMO. It is more musical.

Folsom

Sumoking, Maybe? It would take a minimum order. And point to point raises the price over a PCB and PCB mounted stuff. Making it work with balanced is an extra step for sure, because you need a double eBay DACT.

You realize you if you have single ended input then you would have single ended output, right? I'm not sure I follow your reasoning behind input/output. To me it seems like the nob got that right.

To me the $200 unit is a great buy. It uses a PCB.

The DACT (danish) unit alone is $410 before an enclosure etc, if you want balanced.

You guys might be confusing whether or not something can be made, and whether or not I have any desire to make $20 a sale while taking on emails and shipping... To someone in China that's a sweet pay, here it's kind of a burden. I don't mind taking on some burden for people that want to DIY, but for finished products I feel very differently.

OzarkTom

Just asking. The guy in england the sells Tisbury for $200+ including shipping has sold 768 of them. He sold two yesterday.

OzarkTom

One more question on the China dact like. Do I need 1 or two volume controls? How is the balance at very low levels?

Folsom

1 for SE

I found balanced to be pretty good, but I've never used the lower level of it because my speakers are not sensitive enough for that. Matching the impedance helps with that.

That's cool for the Tisbury guy. That's pretty good. His is a little more advanced with selection options to tune it. Maybe I'll look into making one, more so.

JohnR

Just when I was going to go on the Dact bandwagon. So how was the sound in comparison to others?

Other passive preamps? I don't know, I didn't build any others.

BTW with regard to the gain thing, someone DIYing can always put a series resistor and wire the attenuator in shunt.

maty

Tisbury preamp, below:

[Big IMG] https://www.tisburyaudio.co.uk/images/products/mini-passive-preamp-4.jpg

Years ago I exchanged emails, shortly after the first version came out, without the attenuators and when the headphone amp (out).

In my house, with "tons" of RF/EMI in electrical grid and in the atmosphere too I need case with steel walls or thick aluminum walls.

Well, or the audio furniture, wood shelf with 1mm galvanized steel sheet glued below (and hidden) with silicone or equivalent. It is what I did in my first audio system, the most expensive but kidnapped for other purposes and the family -> I have a cheap second audio system, with PC, only to me (connected to the first via WiFi, up to 24/192).

maty

The problem with the below attenuators will be if you often alternate recordings with high DR and low DR (modern/commercial music).

sumoking

  • Jr. Member
  • Posts: 229
Sumoking, Maybe? It would take a minimum order. And point to point raises the price over a PCB and PCB mounted stuff. Making it work with balanced is an extra step for sure, because you need a double eBay DACT.

You realize you if you have single ended input then you would have single ended output, right? I'm not sure I follow your reasoning behind input/output. To me it seems like the nob got that right.

To me the $200 unit is a great buy. It uses a PCB.

The DACT (danish) unit alone is $410 before an enclosure etc, if you want balanced.

You guys might be confusing whether or not something can be made, and whether or not I have any desire to make $20 a sale while taking on emails and shipping... To someone in China that's a sweet pay, here it's kind of a burden. I don't mind taking on some burden for people that want to DIY, but for finished products I feel very differently.

Folsom-
I saw a unit that was around $150, not $200.  Did I miss it?

The Nob works fantastic for the buck, but I need two XLR outputs, one for amp and one for sub. Now my signal is going through the sub and back to my amp. This isn't the cleanest path, plus I know point to point will also clean things up again. With a better pot, now I have three improvements that will add up to a significant upgrade IMO.

OzarkTom

Folsom-
I saw a unit that was around $150, not $200.  Did I miss it?

The Nob works fantastic for the buck, but I need two XLR outputs, one for amp and one for sub. Now my signal is going through the sub and back to my amp. This isn't the cleanest path, plus I know point to point will also clean things up again. With a better pot, now I have three improvements that will add up to a significant upgrade IMO.

Nobsound also makes this XLR splitter.

https://www.amazon.com/dp/B07D7P7366/ref=twister_B07G525RS7?_encoding=UTF8&th=1

OzarkTom


BTW with regard to the gain thing, someone DIYing can always put a series resistor and wire the attenuator in shunt.

That is good to know. I always thought speakers like Magnepan or Acoustat needed the extra gain of a preamp.

ClefChef

I would offer some technical details regarding "passive" preamps.

The major function of a preamp is to even out output impedance and to drive interconnect cables between preamp and your amplifier. Believe it or not, those interconnects act as a sort of capacitor which, coupled with output and input impedance, forms a variable RC filter that may affect frequency response in extreme cases of impedance mismatch.

A volume pot with no driving buffer followed by a shielded interconnect of significant length may impact sound quality, especially if source output impedance is high enough and amp input impedance is low enough, such as in most solid state gear.

Tortuga offers "constant impedance" volume control of around 8-10k that requires output impedance of around 600ohm-1kOhm to drive a typical 26k input stage. 50k pot requires 47k input impedance at minimum, 100k pot is only suitable for tube amplifiers.

wushuliu

Tortuga offers "constant impedance" volume control of around 8-10k that requires output impedance of around 600ohm-1kOhm to drive a typical 26k input stage. 50k pot requires 47k input impedance at minimum, 100k pot is only suitable for tube amplifiers.

This sounds a little confusing since you mention output impedance numbers then jump to input impedance, I assume for an amp. So to clarify, an 8-10K pot (or equivalent with Tortuga) is good for, but not limited to, 600-1k output impedance for low input impedance amps like say a 26k Class D. A 50k pot or equivalent is good for an amp that has ~47k input impedance, and a 100k pot for amps with even higher input impedances, typically tube amps.

Is this what you're saying?

OzarkTom

I would offer some technical details regarding "passive" preamps.

The major function of a preamp is to even out output impedance and to drive interconnect cables between preamp and your amplifier. Believe it or not, those interconnects act as a sort of capacitor which, coupled with output and input impedance, forms a variable RC filter that may affect frequency response in extreme cases of impedance mismatch.

A volume pot with no driving buffer followed by a shielded interconnect of significant length may impact sound quality, especially if source output impedance is high enough and amp input impedance is low enough, such as in most solid state gear.

Tortuga offers "constant impedance" volume control of around 8-10k that requires output impedance of around 600ohm-1kOhm to drive a typical 26k input stage. 50k pot requires 47k input impedance at minimum, 100k pot is only suitable for tube amplifiers.

Rex will sell you his Totuga if you need one.

ClefChef

Rex will sell you his Totuga if you need one.

Who da *** is Rex?

JohnR

My buddy Norm says that's a good question.