You can scroll through the images above using the Image scroll controls or you can use the Left and Right arrow keys on your keyboard.

HOFFMAN TRANSFORMER WIRE DIAGRAMS AND SPECIFICATIONS

Note : All of these transformers were discontinued a long time ago.
This page is here for informational purposes only

Output transformer and Power transformers

HOFFMAN OUTPUT TRANSFORMERS
Part Numbers	DESCRIPTION
H30W0	30 Watt Output Transformer
H50W0	50 Watt Output Transformer
H100W0	100 Watt Output Transformer

HOFFMAN OUTPUT TRANSFORMER SPECS
OUTPUT SPEC'S	H30WO	H50WO	H100WO	H50MC choke
MOUNTING CENTERS	2" X 2 1/4"	2 1/2" X 3"	2 1/2" X 3"	2 3/8"
WIDTH	2 1/2"	3 1/8"	3 1/8"	1 5/8"
DEPTH	3 1/8"	4 1/8"	4 1/8"	2"
HEIGHT	3 1/8"	3 7/8"	3 7/8"	1 5/8"
WEIGHT	3 LBS	6 1/2 LBS	6 1/2 LBS	10 oz.
MAX RATING ANY TAP	50 WATTS	75 WATTS	150 WATTS	50 MA
PRIMARY IMPEDANCE	4000 OHMS	4400 OHMS	2200 OHMS	8 Henry

CONNECTING OUTPUT TRANSFORMERS.
Connect the black and white leads to the plates (Usually Pin 3).
If the amp squeals from POSITIVE feedback, reverse the black and white leads so that the amp receives NEGATIVE feedback.
On most amps the black lead usually goes to the power tube closest to the rectifier tube or power transformer.

Power transformers
Note: All my power transformers used a bridge rectifier.

HOFFMAN POWER TRANSFORMER SPECS
POWER SPEC'S	H3APA	H30WP	H50WP	H100WP
MOUNTING CENTERS	3 1/8"	2 1/2" X 2 7/8"	3" X 3 5/8"	2 1/2" X 3"
WIDTH	2 1/2"	3 1/8"	3 3/4"	3 3/4"
DEPTH	2 3/4"	4 1/8"	4 5/8"	4 5/8"
HEIGHT	2 1/4"	3 7/8"	4 5/8"	4 5/8"
WEIGHT	2 LBS	6 1/2 LBS	10 1/2 LBS	10 1/2 LBS
B+ WINDING AC	225 VAC	282.8 VAC	343.5 VAC	343.5 VAC
B+ RECTIFIED DC	290 VDC	360 VDC	460 VDC	460 VDC
B+ WINDING CURRENT	100 MA	.5 AMP MAX	.5 AMP MAX	.7 AMP MAX
BIAS WINDING AC	NONE	100 VAC	100 VAC	100 VAC
HEATER WINDING	6.3 VAC	6.3 VAC	6.3 VAC	6.3 VAC
HEATER CURRENT	3 AMPS MAX	6 AMPS MAX	6 AMPS MAX	8 AMPS MAX

NOTE: ALL B+ WINDINGS USE A BRIDGE RECTIFIER .
THE FORMULA IS AC VOLTS X 1.4 = DC VOLTS UNLOADED.
EXAMPLE 282.8 VAC X 1.4 = 395.92 VDC.
ONCE THE AMP IS UP AND RUNNING THE B+ WILL COME DOWN.
EXPECT AROUND 350 TO 360 VDC UNDER LOAD.
NOTE: This is just a rough estimate, this formula is not exact.
There is no way to get an exact figure.
The final B+ voltage depends on many other factors in the amp.

HOFFMAN POWER TRANSFORMER HOOK UP CHART
	LINE	CONNECT	CONNECT	DO NOT USE
100 VAC	1 & 4 - 2 & 5	1 & 4	2 & 5	3 & 6 * Note
120 VAC	1 & 4 - 3 & 6	1 & 4	3 & 6	2 & 5 *Note
220 VAC	1 & 5	3 & 4		2 & 6 * Note
240 VAC	1 & 6	3 & 4		2 & 5 * Note
* Note: do not twist these leads together, keep them separate. Heat shrink each end so they do not touch anything.
EXAMPLE : For 120 VAC use * Twist together leads 1 and 4. * Twist together leads 3 and 6. * Use leads 1 & 4 and 3 & 6 for connection to the power cord. * Do not use leads 2 and 5. Do not twist leads 2 and 5 together. Heat shrink them separately and tuck them out of the way.

Home - Ordering Information - PayPal info - Returning parts - Search the Hoffman Amps parts catalog - Links
Shipping Info/policy - E-mail Me - Amplifier Service Technicians - About Hoffman Amps
Sound Clips - LED Bike light build info - Guitar Rig and Behringer FCB1010 info

The Tube amp Library of information - Charts - Diagrams - How To's - Projects
Click the link above for Tube amp info, Schematics, Board building information, Projects, Mods, Transformer diagrams, Photo's, Sound clips.
There are hundreds of pages of Tube amp information on my library page.
Check out our huge library of Tube Amp Schematics here

Please visit my Tube Amplifier Forum
Here's the place you can go to ask tube amplifier questions.
You will find a large community of friendly amp builders at the link above.

@	MEMBER OF PROJECT HONEY POT Spam Harvester Protection Network provided by Unspam