Connecting bass to Pleiades V5 and then to the radio

The Yamaha electron bass was to start with connected to the JVC radio at AUX in.


It sounded nice but when the E string was played it sounded as the radio woofer was operating unessaerily and unnaturally hard as expected.


One would abandon all other effort but when the aux connector was unplugged the radio started automatically go play again and it happened to be tunes at Kiss FM which happened to be playing Getaway with it all - James


It sounded fantastic.


So immediately afterwards it seemed fit to try between the two the Pleiades V5 electron tube battery preamplifier normally designed for moving coil microphones.


The provision for a 1/4in input for instruments is connected directly to the secondary of the Pleiades input transformer. This inductance creates a Pleiades filter low cutting the bass and happens to be what is needed for an electric bass to sound correct to brain (due to Fletcher Munson curves). This is described on other euroelectron posts by listening to the reference HD580 headphones.


It indeed sounded amazing directly connected to the radio too. The sound was there. The bass sound sounded produced. The bass guitar was easy to play the sound smooth and very natural as expected from the very minimal electron tube signal path. The volume and tone control  on the Yamaha bass
used was bypassed. So connection is direct to the coil pickup.


Setup, signal path:


Modified Yamaha Bass - Pleiades V5 - JVC Nivico radio 9425W at aux in


The Pleiades V5 is a 2 stage preamp using 2 EF183 triode connected tubes. Power supply is by just 2 3.7V li-ion batteries powering both heaters and anode resistors. This is made possibly by an a few Megohm resistor from each anode to each grid to free electrons. This gives extreme portability, amazing sound, and unheard of low noise. Originally the V5 wa designed to connect microphones such as Electro-Voice RE16 or Sennheiser MD441. It sounds amazing with them too and the primary of the input transformer was made with a few turns to compensate for the proximity effect. Primary inductance is 47 millHenries and secondary inductance 5 Henries. So the stepup ratio is 10. The bass being connected to the secondary sees 5Henries and it is this inductance that low cuts so that the bass sound correct at low frequencies while having amazing mid an treble detail.