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The Millett Hybrid Maxed
Bill of Materials
Please note latest BOM changes for production boards in the list below ...
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Millett MAX Bill of Materials (right-click to download the files):
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Important Changes for BOM (last updated 4/16/2008):
- Parts sources have been updated for Beezar.com where applicable.
- The Mouser part number for the CA4L/R and CA5L/R capacitors have been changed to reflect the new 1800uf, 35V capacitor that has been recently added to the Nichicon UPW line. This capacitor - like the Panasonic FM of the same rating - is only 25mm high and will fit in the Hammond case with the MAX board at the 3rd slot from bottom.
- LSDiodes no longer sells LEDs. Alternate vendors are numerous, but none as good as LSDiodes, so Team Millett MAX is not recommending a specific vendor at this time. Purchase the brightest, highest-value MCD LED that is affordable and uses a 20ma current rating. If a new source worthy of a direct recommendation becomes available in the future, the BOM will be updated at that time.
- The Mouser part number for the Panel LED was changed. The part number shown simply varied its letter from "B" to "G" to "R", etc., for various colors. This is a fine, low-power, diffuse LED that works perfectly for the front panel and is inexpensive.
- A note was added explaining the increased options for 3pos terminal blocks on the production MAX board. Up to 4 3-pos terminal blocks may be used on the board.
- BD137/BD138 output transistors were added as a default option. These transistors are equivalent to the MJEs' quality (much better than the often-specified BD139/BD140) and are very cheap at Mouser. Beezar.com was listed as a source for the "boutique" transistors. BDent and MCMinone will have lower prices, but have minimum purchase thresholds.
- References to the MOSFET version of the MAX were removed. An updated BOM specifically for the MOSFET version will be posted on the new MOSFET-MAX website shortly.
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Important Changes for BOM (last updated 11/7/2007):
- DigiKey part numbers for the resistors have been changed to the CMF55 series. This is the Vishay-Dale commercial equivalent of the mil-spec RN55 series at Mouser. Note, however, that the larger CMF60 (RN60) is not carried in the size needed for RR2. That part number remains as before.
As always, Team Millett MAX selects normally stocked items at the listed vendors, but out-of-stock items will occur from time to time.
- The LED resistors have been changed to 2K. This gets them easily in the 1/2 Watt power rating and knocks the current down slightly. The resistor has greater availability in this size, also. Several of the LED's burned out on the prototype using 1K, which was close to the previous BOM recommendation. The part still remains as an inexpensive carbon-film type.
- The brands for the e12 delay circuit electrolytic caps, CM1 and CM3, were changed to inexpensive Xicons at Mouser and Nichicon UVZ's at DigiKey. The cheapest sort of electrolytic will work in these positions as long as the rating and 105deg temp rating is met.
- Some miscellaneous part links were corrected.
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Important Changes for BOM (last updated 11/6/2007):
- Be very careful when selecting CA9. This is the film bypass cap on the tube cathode part of the circuit. Typical blooming-mids-type boutique film caps (Auricaps, Sonicaps) will destroy the MAX's frequency response in this position. Use the Wima MKP10, a Vitamin Q or similar such as the Russian K42 (available on e-bay and elsewhere soon), or nothing at all - let the CA2 electrolytic stand on its own.
- The Russian K42 has been tested by many MAX builders as a great cap to use on the output - very flat and smooth. It's also cheap and small enough to be tombstoned at very little more than 1" height.
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Important Changes for BOM (last updated 10/15/2007):
- CA4L/R and CA5L/R should be 1000uF minimum. This size is recommended to ensure the best bass and to better isolate the DB's from the tube CCS. Part numbers are for the largest sizes available in Nichicon UPW and Panasonic FM that are 1" in height.
- Additional high-performance BJT output transistors have been listed. The 2SC2238/2SA968 pair are available (when in stock) at MCMinone.
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Important Changes for Production Boards (last updated 7/3/2007):
- CA2L/R should be 1000uF. This size is critical to ensure the best bass.
- Heat sinks and caps must be limited to 1" high to fit in the 3rd slot from bottom in the Hammond 1455T1601 case
(30mm caps will actually fit, 35mm caps will not).
- 1-1/2" heat sinks and taller caps must use the lowest slot in the Hammond case. The volume knob will be below the center-line in this scenario.
- Production boards use only 3-pos terminal blocks, the 3rd position on the power input allows an optional path through a fuse.
- Compensation caps (220pF C0G/NP0 ceramic) have been added to the gate-source of the N-channel MOSFETs.
- Board-mtd fuse (5x20mm) and fuse clips have been added.
- An option has been added for 10K and 1K CCS resistors to allow greater availability, CCS current = 0.65ma.
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