Hi-Fi Chip Amplifier (chipamp) with TDA2050

Thomas from Germany has put together a build log of his recent DIY TDA2050 Hi-Fi Chip Amplifier (chipamp) build. The chipamp project is built around a single chip - the TDA2050V integrated circuit (IC) which is produced by STMicroelectronics. The TDA2050 chip is capable of producing about 25W of output into 8 ohms with 24V power supply rails. Like most chipamp projects, the circuit is very simple and can easily be constructed on perfboards.


The power supply is also constructed on a perfboard. For the power supply Thomas uses a 120VA torroidal transformer with dual 18V secondaries and generally followed the "snubberized" Gainclone power supply design by CarlosFM with 10,000 uF per rail.

For the enclosure Thomas used a Hammond satin black steel 12" x 8" x 3" chassis (Model 1441-24). The amplifier controls including a headphone output are on the front.

Thomas reports that the chipamp produces very good sound and that the small amp can hold it own against various high quality amplifiers that he has used. For complete project details, see the DIY TDA2050 Hi-Fi Chip Amplifier (chipamp) page.

These chipamps are simple to build, low-cost and when properly implemented can deliver very good fidelity. If you are looking for a project to try out, give one a try.

Additional Chipamp / Gainclone Projects:

• Mark's Nano LM3875 DIY ChipAmp (gainclone)
• Bruce's LM3875 DIY Chip Amplifier (Gainclone) Kit
• Mark's LM3875 Gainclone Chip Amplifier in a Roasting Pan
• Gio's LM3886 DIY Chipamp Project Kit
  
• Mark's Point to Point LM3875 Gainclone / ChipAmp instructions
  

What's Playing: Natalie Mechant - San Adreas Fault

Prototype Boards for DIP Chips (op-amps)

There are several printed circuit board (PCB) manufactures who cater to hobbyists by offering small quantity orders of PCBs. Some of the larger manufacturers offer free PCB design software that makes it very simple to come up with your own PCB designs. This is all great until you see the price estimate for that pair of simple boards can be in the order of $50 to $100US. Well, when I am spending that much money on parts it is generally for vacuum tubes, an enclosure or perhaps a transformer - a simple PCB, no thanks! Fortunately for simple circuits a prototype board (protoboard) will often suffice and they are generally inexpensive and commonly available. This post examines some of the low cost protoboards that are available for use with an integrated circuit (IC) that comes in a dual in-line package (DIP) - such as an operational amplifier (op-amp).

The noted costs are from 15 June 2009
Dual General-Purpose IC PC Board - Radio Shack 276-159 - ($2.49US)
This general purpose board is perforated and can be split into two pieces. Each piece will accept up to a DIP20 package or a couple of smaller DIPs can be fit on a board. The overall dimensions are 1-3/4" x 3-3/8" and when split apart each board measures 1-3/4" x 1-3/4".

The board is constructed from phenolic which is generally flimsy, but given the small size of the boards that is not an issue. Be careful when mounting using the screw holes as it is easy to break a corner off the board. The board is easy to work with but the small size will limit it to small projects. One problem with the board is that the solder pads are fairly thin and as a result with rarely survive desoldering and re-soldering if you need to make changes to the circuit.

What is nice about the boards is that they are often locally available and their low cost. The boards are available from Radio Shack in the US for $2.49US:

• Dual General-Purpose IC PC Board - Radio Shack Catalog # 276-159
  

Here are a couple of DIY Audio Projects that use the boards:

• Mark's CMoy / Grado RA1 Headphone Amplifier
• Mark's DIY Op-Amp Hi-Fi Preamplifier
  

Multi-Purpose PC Board - Radio Shack 276-150 - ($1.99US / $4.99CDN / $2.96AU)
The Radio Shack 276-150 is a popular multi-purpose protoboard. The overall dimensions of the protoboard are 1-7/8" x 2-7/8" (48 x 73 mm). There are 417 holes on the board and up to a DIP50 package or a few smaller ones can be fit on the board. Two traces run down the center of the board which can be used for grounding or power rails.

Like the previous Radio Shack protoboard it is also constructed from phenolic. On the 276-150 board the mounting screws are very close to the edge and it is very easy to break a corner off. Also, the solder pads are thin and will lift off the board if too much heat is applied. The boards are a good size and very easy to work with. There is plenty of space to get three DIP8 op-amps on a board.

These boards are very common and available in the US ($1.99US) , Canada ($4.99CDN) and Australia ($2.69AU):

• US - Multipurpose PC Board with 417 Holes - Radio Shack Catalog # 276-150
• Canada - Multi-purpose PC board - The Source Catalog Number 2760150
• Australia - PCB Prototype Board 21-113 - Dick Smith Cat No. H5608
  

DIY Audio Projects that use these boards:

• CMoy Mint Tin Headphone Amplifier
  

D-4 Prototype Board - audioXpress PCBD-4 - ($4US)
Darren of DH Labs was kind enough to send us a sample of his prototype board design. The board measures about 2-1/4" x 3-1/4" and can hold a DIP50 package with space left over. A ground trace runs down the center of the board and there are also two power supply traces on either side. The board is constructed from fiberglass and the pads are tinned.

With the ground and power traces the D-4 Prototype Board is ideal for use with op-amps. There is plenty of room to fit up to four DIP8 packages on the board. The fiberglass construction and distance of the mounting screws from the edge make it unlikely that the corners will break off when mounting. The soldering pads are fairly durable and will survive desoldering and re-soldering if you need to make circuit changes. Considering the cost of the 276-150 boards in Canada, the switch to the D-4 boards is an easy one for me.

The D-4 Prototype Board is available online through audioXpress ($4US):

• D-4 Prototype Board - audioXpress Item# PCBD-4
  

The photo below is a DIY Phono Preamplifier that Darren put together using the board.


Please let us know if you have a favorite protoboard that you use with op-amps.


What's Playing: Rebecca Pidgeon - Grandmother

OddWatt Audio - Tube Amplifier Kits

Our friends Bruce and Rodney sent a message informing us that their website - OddWattAudio.com is now active and that it should be fully functional in the next few days or so. Some of you will will recognize the term "OddWatt" which is the name Bruce gave to his scalable push-pull amplifier projects. The DIY versions of the OddWatt tube amplifiers are documented on the DIY Audio Projects website and are listed below.

• ECC802S SRPP / EL84 Push-Pull Tube Amp
• 6SL7 SRPP / KT77 Push-Pull Tube Amplifier
• 12SL7 SRPP / KT88 Push-Pull DIY Tube Amp

The OddWatt tube amplifier project pages provide full details of the amplifiers as well as instructions on how to build the amplifier.

The OddWatt circuit is failry simple and consists of a SRPP driver stage which feeds a self-inverting push-pull (SIPP) output stage. The output stage operates only in Class-A mode and the bias is set using a LM317HV regulator that is configured as a constant current source (CCS).

Currently OddWattAudio.com is offering KT77 and KT88 OddWatt amplifier kits as mono-blocks. However, their website indicates that stereo EL84 OddWatt kits should be ready around July. The OddWatt site also indicates that a stereo preamplifier and a headphone amplifier kit may be available in the future. Photographs of the KT77 and KT88 tube amp kits are shown below.

Photograph 1: OddWatt - OddBlock KT77 Push-Pull DIY Tube Amplifier Kit Parts

Photograph 2: OddWatt - OddBlock KT88 Push-Pull DIY Tube Amplifier Kit Parts

The photos below show a the finished OddWatt KT77 and KT88 tube amplifier kits.

Photograph 3: OddWatt Audio - OddBlock KT77 Push-Pull DIY Tube Amplifier Kit

Photograph 4: OddWatt Audio - OddBlock KT88 Push-Pull DIY Tube Amplifier Kit

Photograph 5: OddWatt Audio - OddBlock KT88 Push-Pull DIY Tube Amplifier Kit

The finished mono-block kits look great. Based on the information on the site, the kit comes complete with all the parts required to build the amplifier. I've been meaning to build an OddWatt amplifier for some time now so the timing was good and I placed an order for a pair of KT88 mono-blocks last week. My kits should arrive in the next few days. When they do arrive I'll post an update complete with photographs.

Cheers,
Gio

What's Playing: Tracy Chapman - Give Me One Reason

DIY Hi-Fi Cable Projects

We have added a couple new DIY Hi-Fi Audio Cable Projects to the website.

DIY Belden 89259 RCA Cables
A couple of weeks back we added detailed instructions that were put together by our friends at auDIYo.com to construct the popular Belden 89259 line-level RCA interconnect cable design by Jon Risch. The cables are a simple unbalanced RCA interconnect cable design that uses the high-quality and low capacitance Belden 89259 coaxial cable. Through the use of TechFlex Expandable Sleeving, shrink wrap and good male RCA plugs, a novice can put together a very nice looking set of Hi-Fi interconnect cables that will deliver the performance and not set you back a few hundred dollars. For full details, see the Belden 89259 DIY RCA Interconnect Cable project page. The photo below are DIY Belden 89259 RCA Cables put together by Paul from Kent, UK. Click the image to enlarge.


DIY Low-Inductance Speaker Cables
We have also added instructions to construct simple DIY low-inductance speaker cables. Adam has put together these fine looking speaker cables for his DIY 3-Way Hi-Vi Tower Loudspeakers. The cables are very simple to construct and consist of plain 16 gauge wire that is twisted together in alternating directions. The alternating cable geometry results in a speaker cable that has a very low-inductance and the equivalent wire gauge 10 and thus the cable resistance is also low. For that Hi-Fi finish, Adam uses a set of high-quality gold plated banana plugs, TechFlex Expandable Sleeving and a custom laser etched decorative oak sleeve. The results are a sharp looking speaker cable that rivals the performance of commercial speaker cables at a fraction of the cost. For full instructions, see the Low-Inductance DIY Speaker Cable page.

What's Playing: Roy Orbison - In Dreams (live)