Wednesday, 25 June 2008


After some more reading, and some more research, passive EQ seems for me the ideal option. With this decided, the choices then boil down to either a one stage RIAA equalisation or a split EQ. Having read some information regarding the Tango EQ-600 LCR RIAA equalisation 'unit', I become interested. This was short lived as I discovered they are no longer produced. However, upon further seraching, I have discovered two current manufacturer/supplier of a LCR RIAA EQ unit. One from Silk (which can be found from DIY Hifi Supply (bottom of page)) and the other from Acoustic Dimension. Both are reasonably costly (in the US$470, and Euro 420, respectively). More to follow.


After some debate, and conversations with a few different hifi store vendors, the conclusion was reached, a Rega P3 with an Ortofon 2m Black cartridge. My original turntable choice, was a Project RPM5, but given the cost of that, with an Ortofon 2M Red was already AU$1100, the P3 with Black at AU$1500 was not too much of a stretch. The unit should be fully set up and arriving with a week or so. This is quite exciting.

Meanwhile, I have begun shopping at local Salvation Army, etc stores looking for old LP. Gound a great range of classical music in very good condition. Found one or two 'modern' LP, the rest of the usual Irish Greatish Hits, Scores from Scotland, Nana Mouskouri, Barry Croker, etc. Prices were typically $1 per LP, but I found one store that was selling them at $0.50 per LP, with a much larger selection then most.

Time to start purchasing the cleaning kits, replacement inner sleeves, etc. Fun times ahead!

Sunday, 15 June 2008

Markaudio 2" Speaker Projects

Currently for my surround setup, I am using the older Mark Audio J6T. These are still available from the Australian distributor, Decibel Hifi. They also sell some very compact 1 litre enclosures for these speakers, of which I purchased and have installed the drivers into. They are superb! The sound is crystal clear, articulate and refined. Quite different to my Fostex 127, but not necessarily better or worse. In fact, they do go down quite low. From design, the f-3dB is around 150 Hz, but in some music records it does reach quite low in the normal musical octaves. Not great for LFE in movies, but when talking about music, voice, etc (rather then effects), it is very pleasurable. I enjoy them so much that I am considering upgrading to the new Alpair 5 speakers, which is an improvement/refinement of the 6T. In doing so, I also want to move up to using Tasmanian Oak (or commonly called KDHW). The following are two designs for a 1l and 2l cabinet using standard stock KDHW readily available in Australia. The f-3dB should be around 150 Hz and 130 Hz respectively. (All dimensions in mm, and uses 135mm wide and 110mm wide boards.) 1 Litre. Internal: 97(w) x 110(d) x 97(h) = 1.035 l Externa: 135(w) x 135(h) x 148(d) BoQ (all 19mm thick, with butt joints (no rebates,etc)): 2x 135x135mm, 2x 110x135mm and 2x 110x97mm. 2 Litre. Internal: 97(w) x 110(d) x 232(h) = 2.475 l Externa: 135(w) x 1270(h) x 148(d) BoQ (all 19mm thick, with butt joints (no rebates,etc)): 2x 135x270mm, 2x 110x135mm and 2x 110x232mm.

Wednesday, 11 June 2008

Tube Information

Great site (most will probably already know it) that contains some basic information on various popular, and not so popular, tubes.

PCB Prototyping

Found a few more PCB proto-typing manufacturers who do low volume PCB. This is going to come in handy for some future and current projects. 4PCB PCB Express Express PCB

Thursday, 5 June 2008

Phono Preamps

Excellent link and description of a tube phono preamplifier. This design is quite well documented and has been through some 20 iterations by the designer/author since 2000. This appears to be someone who is not just designing by paper, but also iteratively refining the designer after auditions and contemplation. The design uses a lot of irons and uses D3a and 5687 tubes. Another interesting design is coming by Andrea Ciuffoli. He seems to be updating his site with regards to vinyl stuff quite recently. His' Phono 2 design makes use of all D3a tubes, and appears to be a relatively straight-forward design with a passive EQ. It appears from many of the sites that I have read, is that the power supply quality is very important. Above and beyond these designs, I have ordered a simple Bugle PCB from Hagtech. This is a battery powered OPAMP phono stage that is simple and cheap to implement. Should provide a good 'sanity check' reference to the more exotic (and expensive) options. Continuing to explore.

Monday, 2 June 2008

Turntable Decisions

From not wanting to use vinyl, to wanting to switch to vinyl has been a quick and steep learning curve. Having read up on the Internet as much as I could fine relating to vinyl, it appears that there is a wide range of choices and opinions regarding turntables. The Project RMP5 and Rega P3 seems to be a consistent theme when discussion relates to starter turntables of a decent quality. Over the weekend, I visited a local audio shop and had a look at the RPM5. It looks to be a decent unit, and well made. However, the salespeople were unwilling to hook with the demo unit and play some music through it. Apparently they said that "it would sound different". Obviously. Not great service. The intention is to purchase a decent unit, with a decent resale or trade-in value so that if this vinyl experiement works out, it can be upgraded to a higher quality unit. Regarding the type of cartridge, it seems universally accepted that MC cartridges will offer a better quality sound, at the cost of a lower output signal (less than 1 mV). However, it also appears that they cost more and the stylus cannot be easily (if at all) replaced. Which then leads to the phono preamp. A transformer step up from MC to MM seems to be best way to ensure that both MC and MM cartridges can be accommodated. Therefore, the two distinct questions in the phono preamp is then: 1) Active or Passive RIAA equilisation; and 2) Tube, Solid-state or hybrid amplification stages. More comments to follow, but for me, it appears that a hybrid amplication using passive equalisation may be the direction I want to head in...

Sunday, 1 June 2008

Since the last post....

A few things have happened since the last posting, all of which has kept me from updating this blog as much as I'd like to.
  1. Completed timber chassis for the Uniamp. With one amp fully wire and connected, had problems with the fuse being blown every time. I suspect this may be due to the powre transformer not being rated for 240V, even though I specifically requested a 240V primary. Had not had the chance to fully ascertian the reasons yet. Will wire up the other one and see if the same problem occurs.
  2. Almost purchased all componets for the DRD45. Some circuit design changes. But filled out with ASC X386S in the PSU, Caddock MK132 in the signal, Mundorf TubeCap for the Ultrapath, Electra-print irons.
  3. Starting out with Vinyl. Contemplating Project RPM5 turntable. Beginning to investigate DIY phono preamps.
Hopefully more updates to follow, along with some photos.