Now available June 2025 a Crimson 510 preamplifier complete with charger Totally Reworked.
This preamplifier was originally battery powered. Batteries are excellent for preamp power sources because of their low noise and zero hum. However, the PP9s are now rare and expensive, and only run for typically 9 months if switched off when not in use. So have I built a 4 cell lithium iron phosphate battery which includes a battery manangement PCB. This PCB prevents over charge and over discharge. Unlike some power tool batteries, this management PCB also keeps the cells in balance for maximum longevity. Expect 10 years until the cells need replacing. The cells are the common 14500 (AA size) LiFePO4 type. I have put these in the invidual mount spring cell holders and replacment is simply by clicking them in and out, with care on polarity!
The battery output is thermally fused for complete safety from any fire risk.
The photos show the Crimson CCP1 charger. This has been modified to work with lithium cells optimally. The charge rate is 50 mA. The cells are 700mAH so full charge would take 14 hours. Hoevever the charger is only connected when the preamp is switched off and 4 hours use will only need 1 hour of charge time once the power switch is off. If the preamp is kept on there will be 50 hours of run time. Once the cell voltages get low the preamp power LED shows red well before the battery manager disconnects. The charger LED is green when idling but goes amber when charging.
In heavy use, perhaps for an 8 hour listening session, full charge will be achieved in 2 hours (as long as the top power switch is switched to “off”).
The preamp has a muting circuit so on/off transients through the speakers, although not zero are quite minimal. The mute circuit has gradual fade in.
Other update items are:-
- Reworked main PCB with precsion disc RIAA EQ values
- High speed low distortion op-amps replacements on the PCB
- Line stage with the low noise highly linear jfets instead of bioplars.
- All new electrolytic capacitors with low ESR audio types in the signal path.
- Replacement switches (gold plated contacts)
- Replacement potentiometers, the volume pot being the audiophile Alps Blue.
- New gold plated phono sockets
The control knobs are new ones with bright aluminium outer shells.
The lower switch shows three inputs Tuner Disc Tape. This may be a little limiting. To add an extra input I re-purposed the (never used these days) tape mon on the top switch as an auxiliary line input. There is a 3.5mm stereo jack on the lower middle of the rear panel for this input. So there are actually three line inputs. As the volume control is first in the line stage there can never be any overload even with very high signal levels. Maximum signal level at the output is greater then 2V RMS and will suit almost any power amp. Input impedance is 50k on line. The disc input is for moving magnet with 47K input at 3.5 mV sensitivity.
There was a test done on this preamp and the distortion was so little it was difficult to measure.https://brianpowellaudio.co.uk/crimson-elektrik-500-series-amplifiers/crimson-510-520-review-c1980
Enjoy 2025 very high end sound quality, totally analog ,but with the retro chassis format from around 1980 which is very much in demand. Cosmetic finish is excellent with the covers having been resprayed. Please use the contact form if you would like to know more about this unit.
Price is £495 delivered.
