HK A300 my 1st tube amp - suggested mods?

[Keith TDI]

Finally, I have a cheap tube amp connected to my speakers.

It sure has more impact than the SS stuff I've had connected. Instruments actually sound like they're being "played" compared to instrument sounds just emanating from the speakers without attack.

It would be nice to lower the noise floor. Any suggestions on how to do that? There's no 60 cycle hum, just a background white noise.

Any recommendations on capacitor upgrades? Since a replacement should be done anyway.

Thanks in advance,
Keith.

[jimmy]

Coupling caps:
Very High grade & somewhat expensive- AuriCap
High grade & inexpensive- Sprague 716P (not 715P) Orange Drop

Tubes:
Mullard is usually better than most in any preamp tube position (careful about Mullard tubes with labeled IEC Master on the tube box). I do not know 6V6 or 7308 well enough to recommend a manufacture.

Power Supply caps:
Replace the electrolytic caps as older caps (30 year old stuff) is subject to failure. Even the small 5-50uf @ 25-50 volt caps used on small tube cathodes for imposed bias.

Clean up tube sockets, switches and external connectors such as input RCA type jacks & speaker out connections.

You bought a nice tube amp & if powerful enough, you have a keeper.
:) :) :)

[GordonW]

Actually, AFAIK, the A300 is 6V6GT (octal) outputs... though I need to double check it. Definitely not an EL84, wrong base...

I'm also working on one of these... and have to replace the volume pot on mine. Once I get one of those in there, in go some new tubes and it's time for listening for other possible mods.

Regards,
Gordon.

[jimmy]

.