[nikalis]

So I am putting together my first hifi setup

Black/Blue tpa 3116 cause it seems to be the easiest to change parts on, read through the thread and have a game plan, all parts on the way
Astron 7amp
GR research x-ls encores based off of recommendations from everyone here

Now i'm already over the budget I wanted to spend and I still need more parts but it seems like it'll be worth it

Now I need a usb DAC but it seems like there are a million chip options and that the technology is advancing so quickly that nothing seems current.  Is it possible to get something cheap and replace parts like in my amp choice to make something good and cheap?  I have my music on a freenas server and would be playing on my laptop through something like jriver


Also do I need a preamp? or would it be possible to control volume elsewhere

thanks in advance

[nikalis]

and also just general links to anything I should learn would be great, any and everything audio

[mlundy57]

Are you wanting to build a DAC or buy one?

If you are wanting to buy one there are some pretty decent options available for not much money. A few I can think of are the Audioquest Dragonfly ($150), GeekOut ($170-$500 depending on model), iFi Nano iDSD ($200) and the iFi Micro iDSD ($500).

I either have or have had all of these except the Nano iDSD. There are some big differences in their capabilities so by keeping in mind the types of files in your music library, both now and what you might want to get in the future, you can get a DAC that will suit your needs without breaking the bank.

When it comes to preamps what you need will depend a lot on the output of your source(s) and the input sensitivity of your power amp. If the output of your source(s) is double the input sensitivity of your power amp you wouldn't need an active preamp, just some way to control the volume and switch inputs if you had more than one source. My setup meets this criteria so I use a passive tube buffer instead of a preamp.

Both of the iDSD DAC's have a volume control but neither has remote control so if you could set your system up so the DAC is within arms reach and it is your only source you wouldn't need any type pf pre, active or passive, just the DAC.

Mike

Also, check out the trading post

[nikalis]

If the output of your source(s) is double the input sensitivity of your power amp you wouldn't need an active preamp

is there a formula to calculate this?

[mlundy57]

If the output of your source(s) is double the input sensitivity of your power amp you wouldn't need an active preamp

is there a formula to calculate this?

You compare the specs of the pieces in question. For example the specifications of the DAC section of the micro iDSD show the output voltage to be >2V. The manual for my power amp shows the input sensitivity to be 600mV (rms input for rated output power which is 35wpc for this particular amp).

This means the DAC is capable of putting out more than three times what the amp needs to reach full power. The reason you want the source (DAC, CD player, phono amp, etc) to put out more than the amp needs is to allow for loss. The longer the interconnects, the more loss there will be.

The other thing to look out for is that there will not be an impedance mismatch between the source and the amp. Again, this information can be found in the specifications section of the pieces in question. You want the input impedance of the power amp to be at least 10 times the output impedance of the source. In the example above, the output impedance of the micro iDSD is <240 Ohms. The input impedance of the power amp is 100 kOhms. Since that's way more than 2.4 kOhms (240*10) There would not be an impedance mismatch.

So since the output voltage of the DAC is more than twice the input sensitivity of the power amp (>2V vs 600mV) and the input impedance of the power amp is more than 10 times the output impedance of the DAC (100 kOhm vs <240 Ohm) I can connect the micro iDSD DAC directly to my power amp and control the volume from the DAC.

In my office this works fine because the micro iDSD DAC is the only source and it is sitting right on the desk within arms reach. However, in my main system, even though the DAC and power amp are just as compatible, I have two other sources, an AVR and a phono preamp, and they are all on the other side of the room from my chair. So I need to be able to switch between three sources, and, because I'm lazy, I wnat remote volume control.

The reason for needing an active preamp (adds gain) would be if one or more of your sources did not put out enough voltage to drive the power amp. Since all of my sources do put out enough voltage to drive the power amp in this system I do not need an active preamp. I only need to be able to switch between inputs and control the volume. That's why I use a passive buffer (0 gain).

Just because I don't need an active preamp doesn't mean I can't use one. It wouldn't damage the system or anything, I just prefer the way the passive sounds and since I can use it, I do.

Mike

[JLM]

The micro iFi DAC is an excellent low cost option if you run only one digital source and can live with remote control.  I had an Emotiva DC-1 which has been on sale for $400 that is compact and well built has remote, multiple digital inputs, an analog input, and both RCA & XLR outputs.

If you run off your computer and can live with your software volume control, all you need is something like a DragonFly plug in USB DAC.

Passive preamps are sensitive not only to relative voltages but system capacitance (including interconnects).  Another cheaper/less convenient option is stepped attenuators that connect between interconnect and power amp.  In either case system dynamics can suffer.

Conventional powered preamps allow for more flexibility and voicing options (especially with tubes).

Two other considerations for saving money:
1.) Subscribe to a music streaming service (millions of songs available);
2.) Consider active monitors (check out AudioStream.com for some home audio friendly options).

With DragonFly and JBL 305's with your software volume control you could have a nice very compact system for $400 that is rated down to 40Hz.

[maty]

First you must answer the QUESTIONS:

* Room size and listening distance?

* What kinds of music do you listen and formats?

* How much do you want to spend?

[Danco]

My set up consist of a Wyred 4 Sound M/Pre an Old Bryston 3B paid $450 and is mint sent to Bryston an works as it should  a Pair of Audio Physic Tempo speakers a Sony Laptop a Wyred 4 Sound Recovery and Audio Sensibility speaker cables and usb cable , an with my old ears it sound good.

[nikalis]

well change of plans, I got a set of paradigm 20v1's in bad shape on the outside but sound really good I'm thinking sand and go piano black with them.  and I'm actually getting somewhere on the aliexpress/ebay/Chinese DAC search.  It looks like a couple of them have potential when you swap the OP amp

I do have a question though.

What is the purpose of an OP amp vs a Preamp?