DIY-Central.com - Go Create something! - PCB Design, Electronics

IT'S BACK!!! My FIVEFISH STUDIOS CRAZY DEAL SALE again... !!!

DIY-Central.com Administrator — Mon, 01 Feb 2010 20:11:17 GMT

IT'S BACK!!! My FIVEFISH STUDIOS CRAZY DEAL SALE again... !!!

LIMITED QUANTITY OFFER! I have designated a certain number of units for this SALE. LIMITED QUANTITIES AVAILABLE. If my stock runs out in 5 days, or 2 days, that's it. The SALE will be discontinued.

SAVE MONEY!!! $300 for a pre-assembled X-12mk500 preamp.... $300 ready-made (not a kit). Hurry and don't miss out again on this offer!

Please allow 3-4 weeks for delivery. We're still waiting for the trafo shipment from the factory. LIMITED QUANTITIES AVAILABLE for this sale. Sale may be discontinued at any time once stock runs out.

Link and BUY button on this page... http://www.fivefishstudios.com

Low Wattage Guitar Amplifier Kits

DIY-Central.com Administrator — Mon, 04 Jan 2010 17:02:59 GMT

Featured above are working builds of the 8 Watt Ardmore and 1/2 Watt Gilmore Jr Kits designed by Gerhart Amplification tone wizard, Gary Gerhart. Everything is included except solder (use 60/40 rosin core solder, no flux). The chassis are finished for the Customer with all holes being drilled and punched. Note the stainless steel PEM nuts press fitted into the chassis for a solid, quality build. Kits feature a Mil-Std black anodize chassis, Mercury Magnetics power transformers, Gerhart Amplification's proprietary output transformers manufactured by Mercury Magnetics and all stainless steel chassis hardware. The assembly manual guides the builder through each step. The Gilmore Jr or Ardmore Kit are an excellent choice for those who are building for the first time, yet challenging enough for those who have built kits before. Guytronix stands poised and ready to assist the builder throughout the assembly process.

Click here for more details. http://www.guytronix.com/

Miniature Vacuum Tube Preamplifier

DIY-Central.com Administrator — Sun, 03 Jan 2010 22:35:23 GMT

Look at this... A low cost tube preamplifier using two low power consumption Raytheon JAN6418 sub-miniature pentodes. Kit is supplied with PCB and on-board components. Made by Oatley Electronics.com

Push-Pull Vacuum Tube Amplifier

DIY-Central.com Administrator — Sat, 02 Jan 2010 22:31:27 GMT

This 6V6 amp was built following the push-pull (PP) EL84 / 6V6 Dynaco A-410 output transformer schematic. There are a few minor deviations from the original schematics. Instead of Dynaco transformers, Hammond 1608A audio output transformers and a Hammond 272HX power transformer were used. The EL84 / 6V6 PP Dynaco A-410 output transformer schematic showed a 1000 ohm feedback resistor which resulted in bad amplifier oscillation. Feedback resistor Values between about 6 and 10 k-ohm worked well and I settled on 10k. A 5Y3 rectifier would have been to small for a stereo amp so a JJ GZ34 rectifier was used. It became necessary to put a 100 ohm resistor before the first power supply capacitor to bring down the B+ to about 325 volts as I was getting in excess of 345 volts (there is less voltage drop through a GZ34 versus a 5Y3).

Click here for project details. http://diyaudioprojects.com/Schematics/DIY-Push-Pull-PP-6V6-Tube-Amplifier/

TS-2 Rev.B Preamp Redesign

DIY-Central.com Administrator — Mon, 28 Dec 2009 23:04:46 GMT

A flash of inspiration... I found a smaller footprint output transformer I can use... so I created an Eagle part library for that. (Tip: use a digital caliper when creating part libraries)

After some creative rearranging of parts, and I made this.

This is just the motherboard. Measuring about 6" x 6".

Ch-check it out!

2 Input Transformers - NEW FEATURE
2 Output Transformers - NEW FEATURE
Gain and Trim knob for each channel
2 VU Meters
4 Full size XLRs
Relay Controlled switching - NEW FEATURE
Bigger DC Converters - NEW FEATURE
... and better PCB layout by re-arranging parts.

Also, reduced the number of molex connectors from the original (7) to a single 10-pin Molex! That will be a big time-saver.... plus the use of PCB mounted XLR Neutrik Jacks.

Sound Card Interface / AC RMS voltmeter Kit

DIY-Central.com Administrator — Thu, 24 Dec 2009 03:19:43 GMT

This looks like a very interesting project. If you're into audio measurements, this project might also interest you.

From the Pmillett website...

Most of us DIY audio types have been using PC sound cards to make measurements. There are excellent, inexpensive programs available to do test and measurement of audio equipment available. Personally I use Audiotester. If you've been around my web site you've seen FFT plots generated that way.

What has always been lacking is a decent interface between the sound card and the device under test (DUT for you geeks). There has been much discussion in forums like DIYaudio about this, and many proposals and circuits shown, but so far I've not seen anything implemented.

The problem with sound cards is that they are designed for fixed line-level inputs and outputs. Depending on the card this may be between 1V and 5V RMS maximum. They are also not tolerant of overloads - accidentally deliver 20V into your sound card input and you will most likely be looking for a new sounds card.

http://www.pmillett.com/ATEST.htm

Vacuum Tube Amp Kit

DIY-Central.com Administrator — Tue, 22 Dec 2009 17:37:06 GMT

DIY'ers today have it good! There's lots of projects available on the net to build. Here's a Tube Amp Kit by OddWatt Audi.

The manufacturers specifications for the kit are as follows:

Rated Power Output: 25 watts (RMS)
Input Sensitivity: 1.5V (at rated power)
Input Impedance 100 k-ohm
Input Terminal: Line Level RCA
Speaker Output Taps: 4 and 8 ohms
Distortion: less than 0.5% through half power, 1% at full power
Frequency Response: 8Hz to 20 kHz +0/-1db at any rated power
Signal to Noise Ratio: less than 80dB
Tubes: Gold Lion KT88, NOS JAN Philips 5751
Supply Voltage: 120VAC 50/60Hz
Power Consumption: 130 watts (each monoblock)
Weight: 6.3 kg (each monoblock amp)
Dimensions: 205 mm (W) X 225 mm (H) X 300 mm (D

http://diyaudioprojects.com/Tubes/5751-KT88-Tube-Amp-Kit/

TS-2 Mic Preamp Redesign

DIY-Central.com Administrator — Mon, 21 Dec 2009 23:40:15 GMT

I opened up a big box labeled "TS-2" that I've put away for sometime.
Surprise surprise!

I have lots of finished front panels, hundreds of blank VU meter boards, parts for the 48V DC-DC converter, inductors, chips, LEDs, etc... even found some brand new router bits.

I think I'm going to stick with the current front panel design. So we'll have power on/off switch, VU meter on/off switch, 48V on/off, polarity reverse switch, gain, and trim knobs and 5-LED VU meters. This design is as basic as I can make it (while still keeping the features working.)

I think I've got the solution now to reduce labor building a TS-2 preamp. The new board design will:

Reduced molex connectors from (7) to (2).
Eliminated 12 wire to XLR soldering tasks.
Eliminated 12 wire stripping, and 12 heatshrinking tasks.
Made easier soldering the VU meter PCBs to the main motherboard.
Eliminate 14 wire stripping, 14 molex connectors crimping tasks.

I think I can have a prototype PCB for the new board design by late January. So I need to finish the PCB design before the 31st.

Wifi Radio

DIY-Central.com Administrator — Mon, 21 Dec 2009 17:32:49 GMT

Mightyohm documents in his blog the making of a low cost, open source wireless streaming internet radio receiver. All construction details, including schematics, source code, and even the design process itself will be documented on this blog. http://mightyohm.com/blog/2008/10/building-a-wifi-radio-part-1-introduction/

Doing Some CNC Milling Work After A Couple O

DIY-Central.com Administrator — Sun, 20 Dec 2009 03:43:41 GMT

Doing some CNC milling work...

After a couple of hours, I have these babies...

For my TS-2 preamps

TS-2 Preamp by FiveFish Studios

DC-DC Converter How-To

DIY-Central.com Administrator — Sat, 19 Dec 2009 20:10:27 GMT

Maxim offers a great explanation of DC-DC converters.

DC-DC Converter Tutorial

Abstract: Switching power supplies offer higher efficiency than traditional linear power supplies. They can step-up, step-down, and invert. Some designs can isolate output voltage from the input. This article outlines the different types of switching regulators used in DC-DC conversion. It also reviews and compares the various control techniques for these converters.

http://www.maxim-ic.com/app-notes/index.mvp/id/2031

Bliptronic 5000 LED Synthesizer

DIY-Central.com Administrator — Sat, 19 Dec 2009 14:37:48 GMT

This is not DIY per se.... you can buy this musical device ready-made.

But for under $50, you don't need to DIY this. Just buy it. It's loads of fun too.

What's under the hood?

http://www.thinkgeek.com/electronics/portable-audio-video/c4e1/