Breadboard of GU32 Amplifier

I have built the amplifier with the values specified in the schematic (http://www.audiohobbyist.com/images/832/832sch.jpg), but I have a power transformer that is rated 230VAC to 200V, and the grid voltage is up to 238Vin my neighborhood. This gives me B+ unloaded of 302V and loaded 283V which is to high it should be 250V. I´ll get back to this problem in a later post. 
For now I´ll describe the circuit as built. First on the far right a custom Edcor transformer XPWR146: Pri: 230V 50Hz  Sec. 200V 250mA  and 6,3V 4,5A, this is rectified by a  KBU8M 1000V, 5A rated solid state rectifier in the upper middle of the picture. Filtering is by a single 800uF 385V electrolytic capacitor.
This B+ power is then fed to the center input of an Edcor CXPP25-MS-8k where Plate 1 and 2 of the GU32 is connected. The B+ is also connected to a turret board containing the plate supplies for the 12AT7, the star ground points, and cathode bias of the GU32. Here is the schematic for the turret board:
The colors of the wire follow no particular system.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s