Pass Labs Aleph 1.7 開工

Cat sir,

This passlab is solid state amp right?

how much u pay for this kit?

If i'm greedy, want 胆味道 and 原子粒機動態, 細節&大場面, do u think can obtain by using tube preamp and solid state power amp?

Frankly i really salute those who like to play LP.
For me it is cumbersome, need tuning, need cleanning..... wow need to do a lot work only can get good sound...... i surrender....

Cat Sir,

U had done a lot in 1.5years......

I'm spending a lot of time on testing cap, build and dismantle.... all are direct connection except the recently build  mrz M7 is using pcb.

So far only made 3 pcs 5687 tube buffer/preamp for friends, 1 m7 for myself.....



Dear all,

do u think iron casing will have more hum compare a aluminium casing??

I ad try my best to reduce the hum of my preamp to zero but unsuccess..

i had try floating the signal ground with 10ohm resistor, totally separate signal ground with power supply ground.... using more stage of RCR filter, use higher capacitance... but i still able to hear the hum at ~15cm from my speaker...even though this hum will not increase when volume level increase....

so any otehr suggestion? the worse is that this hum sound level will vary when use with different type of power amp, with audilab is lower hum, with quad 606 is higher hum.... fainted

We were always informed that cu casing better than Al casing, al casing better than iron...But what's the the output difference? quieter? better dynamic, lower background noise or??

Dear Accphoto,

I follow your advice and redo the grounding for my friend's 5687 tube preamp... now very quiet .....very very minimum hum..

the only unperfection is that this tube preamp very microphonics, the casing need to be isolated very well to keep the microponic effect low... even by just softly touch on the casing, the microphonic can be heard....


any idea on reducing the microphonics effect?

Yes shifu, it come from the tube, when touch the casing, the vibration transfer to the tube.... the tube is act like microphone....

so far this issue only occurs for 5687 tube..... other tube don't have this problem....

i was told by some otehr DIYER that 5687 tube is quite microphonic...

Bad luck....my transformer in my tube preamp burned...

i had use the same brand, same spec of the power transformer, it work fine for ~3-6month then the secondary coil of the transformer will burn...any idea or suggestion? So far had burn 3 pieces... all burn after working for several months...

Dear ALC,

The transformer i use is 350V-0-350V,100mA at secondary... preamp normally run below 50mA right? anyway the wire in 2ndary seem really thin... i think u r right, i shall use a bigger 1.....

I try to use the foil inductor again, but this round i use opposite direction then sound seems not as fast as last time....
Modify speaker seems much more difficult than amp & cdp, just little bit of changes can make a lot diffrences and result can be worse most of the time....

CAT,

Your PASSL really beautiful especially at night.....