- Nov 10, 2006
- Norfolk - UK
Ruffrecords' PCB Emporium
Welcome to Ruffrecords' PCB Emporium. Here you can purchase any of the PCBs for my various GroupDIY projects as well as other general purpose PCBs such as the tube HT PCB. Here you will also find links to the documentation for each project and to the original threads on GroupDIY.com.
To order a PCB just drop me an email at [email protected] with a list of what you require, your name and shipping address. I will respond with an email and a PayPal invoice for your order. Just click on the Pay Invoice button to pay the invoice and I will send you the PCBs.
Stock changes rapidly so I am keeping a separate document of the current stock levels and prices (including any special offers). Check out the the Ruffrecords PCB EMporium page at my new web site
Please note that all prices are in GBP and shipping is charged at a flat rate of 2GBP for UK, 3GBP for Europe and 4GBP for the rest of the world.
Poor Man's EQP1A
Many people have built clones of the Pultec EQP1A passive equaliser. However, it is quite expensive to build because it uses several transformers and an inductor. The idea behind the Poor Man's EQP1A is to keep most of the features of the original but at much reduced cost. The core PCB (PMEQP1A) uses a low cost 2 pole 6 way switch that can be built as either the hi or lo boost/cut frequency select. The circuit has been modified so that no inductor is needed which means that two of these PCBS and just four pots make the entire EQ.
As it is a passive EQ it needs a gain make up amplifier and many constructors have used a low cost op amp for this. If you want to go for tube based gain make up you can use the Poor Man's Tube Gain Make Up PCB (PMTGMU) which uses a single tube instead of the two in the original. No interstage transformer is required and an output transformer is optional.
The power supply for the tube stage can be built using normal point to point wiring or you can use my HT Supply PCB which holds the rectifiers, RC smoothing components and and heater elevation supply.
As a result of many requests I was eventually persuaded to develop a mid boost/cut option which is now available as a separate PCB (PMMID), Unfortunately there is an error on these PCBS but there is a workaround which is included in the documentation so this PCB is still quite usable. The workaround is only necessary if you use the specified inductor from Carnhill. If you use the inductors made by Chrion for GroupDIY then no modification to the PCB is necessary.
Documentation for the Poor Man's Pultec can be found here: http://www.ianbell.ukfsn.org/EzTubeMixer/docs/PMEQP1A
The original group DIY discussion about the design of the Poor Man's EQP1A can be found here: http://www.groupdiy.com/index.php?topic=43859.0
The groupDIY support thread for this project is here: http://www.groupdiy.com/index.php?topic=44213.
The groupDIY discussion thread leading to the addition of the mid boost/cut can be found here: http://www.groupdiy.com/index.php?topic=45475.0
The groupDIY discussion about the poor man's tube gain make up stage is here: http://www.groupdiy.com/index.php?topic=43973.0
This project grew out of the need to extend my standard mu follower based mixer designs to include flexible per channel EQ, direct outputs and pre and post AUX sends. Mu follower designs cannot meet all these objectives because of their fixed gain and limited drive capability. So a new variable gain, high drive capability amplifier design was required and the result forms the basis of the EzTubeMixer. The core PCB (EZMIXERV3) is a standard single Eurocard sized PCB that holds two identical amplifiers, The first, which acts as a mic/line preamp has additional input signal conditioning (48V, phase, pad and mic/line switch), a HIZ instrument input option, a microphone input transformer and a 12 position stepped gain switch covering a 26dB to 60dB range. The second amplifier has a pre-set pot for gain setting and is intended primarily for gain make up after EQ and/or a fader.
Together with separate passive EQ PCBs (3 band Pultec and Helios 69), this Eurocard can be used to build a complete all tube channel amplifier. The rear of the PCB has a 32 way 0.2inch pitch connector that provides all the input/output and power connections required along with provision for four mix buses.
This same Eurocard amplifier PCB is also used for gain make up for passive mixing, and by simply changing two tubes and some passive components, converts into an all tube stereo headphones amplifier.
Documentation for the EzTubeMixer can be found here: http://www.ianbell.ukfsn.org/EzTubeMixer/docs/EzTubeMixer
The documentation for the 3 Band Pultec EQ PCB which will do everything that the poor ma's Pultec will do and more can be found here: http://www.ianbell.ukfsn.org/EzTubeMixer/docs/EzTubeMixer/3BandPultec/
The documentation for the new Helios 3 band EQ can be found here:
The groupDIY discussion of the Poor Man's Tube Mic pre (which becaome the EzTubeMixer) is here: http://www.groupdiy.com/index.php?topic=47424.0
The subsequent discussion about the EzTubeMixer is here: http://www.groupdiy.com/index.php?topic=48039.0
Support thread for builders of the EZTubeMixer is here: http://www.groupdiy.com/index.php?topic=51829.msg658803#msg658803
db25 summing PCB
This project arose out of my own need for a simple interface between a Tascam standard 25 way D-type connector and a balanced summing bus. Surprisingly nothing like this is available right now (Holger had a design but not the time to update it) so I did my own. A couple of these, a couple of XLRs and a handful of resistors and you can build yourself a balanced passive summer.
The original thread is here:
If you have any questions, please feel free to email me at [email protected] or post on the appropriate thread at groupDIY.com