DIY Audio Projects Forum

Hi Everyone, (this is a copy of a posting I made on another forum but I figure some folks here might be interested as well) "I got a pair of these (there are several sources) and I was rather surprised at the quality of sound they produced. They are digital "preamps" and use the TI/BB PGA2311 chip. This thing not only does the volume level setting (-95 to +31 DB) but is as you can see from the +31 it amplifies. Dang thing is really clean and easy to use. That is a good thing as there are no instructions. Fortunately all you need is a 6-0-6 AC source at about 100ma. It can be used as is but I removed the jacks so I could turn it around in the case. Output is supposed to be 600 ohms and up to about 3VRMS. If you want a preamp with three inputs (unfortunately labeled DC, PC, DAC ) with gain this is for you. The remote is rather cheap and If it was my main system (and not in the shop for back ground ) I would replace the remote."

http://www.ebay.com/itm/New-version-Ass ... SwpDdVUye-

I know that we are pretty much diy...but modules that do a lot of things well (and are cheap) are scarce IMO. These do. I am now using one in my shop to do the switching and volume chores on the system there. It is driving at the moment the power amp section of a Marantz 1060. Really nice. I will try to send photos of the build next time I pull it out of the case.

Good listening
Bruce

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Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

Hi, An update and cheap DIY way to use headphones. Since the IC is rated for a 600 ohm load and according to the spec able to deliver up to about 8ma....It seemed as if it would work to drive headphones with a suitable matching trannie. Searching through my hoard of stuff I found a pair of Edcor 1/2 watt matchers. They are the 2570/600 ones. Designed for either 25 or 70 volt line to 600 ct load. Doing some quick checking with a low voltage AC supply I found that the ratios were 40 to 1, 20 to 1 15 to one and 7.5 to one. Since my phones are 62 ohms there are a couple of possibilities that might work. I settled on the 15 to 1. It works well as the phones are pretty sensitive and the loudness is quite enough. Using a phono preamp and TT for a source the gain setting for normal use was right on the "0" db of the Assembly. The max gain is +31 db....lots more than needed. Very clean sound and nearly no cost as the matchers are really inexpensive. BTW the same process can be used on any source / preamp that can deliver a few ma. It works on the Forewatt with a 15K to 150 ct matcher as well, just use the CT and one side. Also excellent sound.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

Hi, Some photos...See how nice the preamp goes with the mini-blocks.

Good listening
Bruce

_________________
Some of my DIY Tube Amplifier Projects:

• PoddWatt: 5751 / EL84 Push-Pull DIY Tube Amplifier Project
• OddBlocks: KT88 Push-Pull DIY Tube Amplifiers (Mono Blocks)
• ForeWatt: ECC802S (12AU7 / ECC82) DIY Tube Preamplifier Project
• GrooveWatt: Tube (Valve) RIAA Phono Preamplifier Project

I have a version of the module that uses a CS3310 chip. I used an aluminum case, also from e-bay, that is fully machined to accept the module and its display, and an inexpensive 12vac transformer from Jameco.
This module is excellent. I use it ahead of my Forewatt preamp and tube amp. I keep the Forewatt volume control at maximum and use the digital module to control volume and switch sources.
It works great - no degradation in sound quality, no hiss, no hum. I'm very pleased with the product. I have also obtained a similiar module that uses the PGA2310 and uses a 15-0-15 volt transformer, making it capable of handling a larger swing.. I'm anxious to compare the two.

The PGA3211 is a great chip. I have used the PGA2310 which is the same chip except the 2310 allows for a much higher analog +/- voltages. The price has gone threw the ceiling though. I payed less than 1/3 the price at the time. Anyone considering using one however will not be disappointed.