Volume Control
Volume Control!
Recently a DIY Audio Guide follower was asking for advice on simple AND inexpensive solution for his DIY setup.
Inexpensive? That’s pretty tough for a tube head like me. Therefore, I went to eBay to search for some ideas. 3 kits grabbed my attention. They’re using the famous chips like the PGA2311 & the CS3310.
It will not be as warm sounding as a dedicated DIY tube preamplifier that that will do since the price he’s asking is way too low to DIY anything meaningful. The 3 kits cost from U$15.37 – U$49.99. That’s darn inexpensive! A decent vacuum tube already cost more, like my beloved 801A direct heated triode. (I’m still waiting for the LL9202 transformers to arrive, how sad to wait for so long! See below blog post.)
Lundahl Transformers
Note: eBay listings might expire and the links below might not work in near future. It's OK, just do a new search with the same keywords, for example, PGA2311, CS3310, digital volume control and etc.
I’ve sent this 3 kits information to him:
Kit 1: U$15.37 + $20 standard shipping from Hong Kong
Kit 1
Kit 2: U$28.50 + $14 standard shipping from Hong Kong
Kit 2
Kit 3: U$49.99 + $6 standard shipping from Hong Kong
Kit 3
The 6 channel is something usable for people with 3-way open baffle speaker. 2 channels are for the highs, 2 for the mids and 2 for the lows. It is super convenient!
How do they sound? I’ve no idea seriously but should not be bad since the PGA2311 and CS3310 are used in super expensive audio gears. For those with upgradigitis, there are ways to make it even better!
- Change to audiophile capacitors
- Change the relays
- Change the Opamp (kit 3)
- Change the RCA jacks
Some background on the PGA2311:
- Digitally controlled analog volume control
- Wide gain and attenuation range: +31.5dB to -95.5dB with 0.5dB steps
- Low noise and distortion: 120dB dynamic range, 0.0002-0.0004% THD+N
The PGA2311 is a high−performance, stereo audio volume control designed for professional and high-end consumer audio systems. Using high performance operational amplifier stages internal to the PGA2311 yields low noise and distortion, while providing the capability to drive 600 Ohm loads directly without buffering.
There are 2 grades to this chip too – the U-grade and the A-grade. A-grade is specially parts and yields better specifications & sound.
Check the following link for the PGA2311 datasheet:PGA2311 datasheet.
Some background the CS3310:
- Digitally controlled analog volume control
- Wide gain and attenuation range: +31.5dB to -95.5dB with 0.5dB steps
- Low noise and distortion: 117dB dynamic range, 0.001% THD+N
The CS3310 is a complete stereo digital volume control designed specifically for audio systems. It features a 16-bit serial interface that controls two independent, low distortion audio channels. The CS3310 includes an array of well-matched resistors and a low noise active output stage that is capable of driving a 600 Ohm load. A total adjustable range of 127 dB, in 0.5 dB steps, is achieved through 95.5 dB of attenuation and 31.5 dB of gain.
Check the following link for the CS3310 datasheet: CS3310 datasheet.
By the way, I’ve no affiliation with the eBay sellers. Try at your own risk! With such a price, it’s worth doing some experiment with! Haha!
If you’re DIY to the core, you can fabricate your own PCB and build it yourself. There are sample circuits in the datasheet listed above.
If you’ve experience using these kits, or using the chips to DIY your own preamplifier, do share your experience with us!
Ken 6/27/2011
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