Bush DAC90a

[kalee20]

Originally Posted by Helder Crespo

Also, could you help me with your recommended power/voltage ratings for each of the new components? Thanks!
Helder

Capacitors should be at least 250V rating, but 400V would be better. (The 6800pF capacitor could take a hammering if the volume was turned up full so I used 630V here). Resistors... OK at 0.5W except the 4.7k which has already been discussed (use at least a 3W component).

Good luck - let us know what you reckon!

[Helder Crespo]

Originally Posted by kalee20

Capacitors should be at least 250V rating, but 400V would be better. (The 6800pF capacitor could take a hammering if the volume was turned up full so I used 630V here). Resistors... OK at 0.5W except the 4.7k which has already been discussed (use at least a 3W component).

Good luck - let us know what you reckon!

Thanks! I'll have to order the components first, as I only have those for the output transformer mod, but I'll definitely let you know how it came out in the end.

[kalee20]

If you do this, also do the 0.003μF-to-something-smaller on the UBC41 anode mod, or you won't get the full benefit!

[Helder Crespo]

Originally Posted by kalee20

If you do this, also do the 0.003μF-to-something-smaller on the UBC41 anode mod, or you won't get the full benefit!

Thanks! I did that already. In any case, it shouldn't affect the sound quality when using the Bluetooth output, which connects to the volume control top.

[Herald1360]

Yes it will!


The volume control feeds the grid of the UBC41 so any rolloff in its anode circuit will affect the tone since it's further along the signal path.

[Helder Crespo]

Originally Posted by Herald1360

Yes it will!


The volume control feeds the grid of the UBC41 so any rolloff in its anode circuit will affect the tone since it's further along the signal path.

You're totally right. Thanks!

[Helder Crespo]

Originally Posted by kalee20

Capacitors should be at least 250V rating, but 400V would be better. (The 6800pF capacitor could take a hammering if the volume was turned up full so I used 630V here). Resistors... OK at 0.5W except the 4.7k which has already been discussed (use at least a 3W component).

Good luck - let us know what you reckon!

Just a quick update (more to follow) on the result of your mod on a DAC90A with Colin Boggis' great bluetooth add-on: absolutely brilliant!!! I could not believe what I was getting from the single DAC90A original speaker. Thanks to you both! Will probably repeat the treatment on my second DAC90A.