Order Code	Recommended Valves	Max Cl. A Power	Primary/Secondary Impedances	Size	Max. Current
TRANS-144	300B / 2A3 / 6B4G	15 w	2K5 - 4/8 Ohms	80x67x68mm	90mA SE

Group B - Single-ended Outputs.

Order Code	Recommended Valves	Max Cl. A Power	Primary/Secondary Impedances	Size	Max. Current
TRANS-150	EL84 / ECL86 / 6V6	20 w	2K6  -  4/8 Ohms	117x98x90 mm	110 mA  PSE
TRANS-152	300B / 2A3 / 6B4G	25 w	2K5  -  4/8 Ohms	117x98x90 mm	90 mA  SE
TRANS-180	211/VT4C	75 w	5K    -   4/8 Ohms	137x115x145 mm	240 mA  PSE
TRANS-189	300B / 2A3 / 6B4G	25 w	2K5 - 4/8/16Ohms	117x98x90 mm	90 mA SE

Group B.  Push-Pull Output

Order Code	Recommended Valves	Max Cl. A Power	Primary/Secondary Impedances	Size	Max. Current
TRANS-200	EL84 / ECL86 / 6V6	15 w	8K  -   4/8 Ohms	80x67x68 mm	PP
TRANS-185	EL34 / 6L6G / 5881	25 w	6K   -    4/8 Ohms	88x73x80 mm	PP
TRANS-175	2A3 / 6B4G / 300B	30 w	5K  -   4/8 Ohms	88x75x80 mm	PP

 

 

 

Tube amplifier transformers
OPTs, mains and interstage transformers

General Properties:

• High quality silicon iron C-cores
   
• very robust open frame structure
   
• Precision winding with insulation between each layer of copper wire for minimum intra-winding capacitance.

Anode chokes, interstage and line output transformers

Tube amplifier transformers
OPTs, mains and interstage transformers

General Properties:

• High quality silicon iron C-cores
   
• very robust open frame structure
   
• Precision winding with insulation between each layer of copper wire for minimum intra-winding capacitance.

Anode chokes, interstage and line output transformers

Type	Comment	Turns ratio	Primary inductance	Recommended DC current	Core Saturating DC current
LL1621/P-P	Noninverting interstage	1+1 : 1+1	300H	-	-
LL1621/6mA	Noninverting interstage / anode choke	1+1 : 1+1	130H	6 mA	10 mA
LL1635/P-P	Interstage	1+1 : 1+1	300H	-	-
LL1635/5mA	Interstage	1+1 : 1+1	130H	5 mA	9 mA
LL1635/20mA	Interstage	1+1 : 1+1	30H	20 mA	35 mA
LL1630/P-P	Line output	7.2+7.2 : 1+1	300 H	-	-
LL1630/5mA	Line output	7.2+7.2 : 1+1	130 H	5 mA	9 mA
LL1660	Interstage and line output	1+1+1+1 : 2.5+2.5	Application dependent	Application dependent	Application dependent
LL1660S	SE - PP and PP - PP Interstage Internal Faraday shields for improved balance	2.5+2.5 : 2 + 2	Application dependent	Application dependent	Application dependent
LL1667 and LL1668	Anode chokes	Dual coil 1+1	Application dependent	Application dependent	Application dependent
LL1671	High current interstage and line output	1+1+1+1 : 2+2	Application dependent	Application dependent	Application dependent
LL1677/80mA	High current interstage transformer (For 300B driving tube)	1+1+1+1 : 4+4	24H	80mA (1.2 Tesla saturation)	115mA
LL1680/5mA	Line output transformer Based on UTC LS-27 specifications	9+9 : 1+1+1+1	210H	5mA	10mA
LL1689	Line output transformer Based on the LL1660 size and structure	9+9 : 1+1+1+1	Application dependent	Application dependent	Application dependent

NOTE1! All types above can be gapped for other DC current than listed

NOTE2! We recommend LL1630/5mA and LL1635/5mA for push-pull preamplifier stages where some DC imbalance occure. The LL1635 data sheet is updated to reflect some limitations in it's use.

NOTE3! For most SE applications, the LL1660 outperforms the LL1630 and LL1635

Output transformers.
The LL1620, LL1623, LL1627 and LL9202 is a range of tube output transformers based on the same core size and winding topology. The range share the same high quality silicon iron C-core and have identical secondary windings. They differ only in the number of turns of the primary windings
Each type can be used for a number of different primary impedance levels by using different secondary terminations.
The transformers are available in push-pull or single end versions with different core air-gap for different DC currents.
The transformers are highly sectioned (in all 10 sections) for excellent frequency response.

The use of C-cores and well defined airgaps results in an almost constant inductance throughout the whole operating voltage range. For SE transformers, the primary inductance variation due to signal level is less than 7%
The tables below displays only a few of many possible uses. Please refer to the full datasheets for more complete information.

Push-Pull. Voltage (RMS) and power @ 30 Hz

Type	Max Prim. Voltage	Inductance	Secondary* connection alt.	Prim. Z @ 8 ohms load	Loss, dB	Power
LL1627	380V	60H	C	1.2k	0.5	125W
LL1623	610V	150H	C	3.0k	0.5	125W
LL1620	860V	300H	C	6.0k	0.5	125W
LL9202	1180V	570H	C	11.0k	0.5	125W
LL1679 (w. UL)	670V	150H	C	4.5k	0.4	105W

Single-End. Voltage (RMS) and power @ 30 Hz

Type	Max Prim. Voltage	DC current	Inductance	Secondary* connection alt.	Prim. Z @ 8 ohms load	Loss, dB	Power
LL1627	170V	140mA	12H	C	1.2k	0.5	25W
LL1623	270V	90mA	30H	C	3.0k	0.5	25W
LL1620	380V	60mA	60H	C	6.0k	0.5	25W
LL1679 (w. UL)	295V	70mA	-	C	4.5k	0.4	20W
LL1620	525V	50mA	100H	C	11.0k	0.5	25W

 

More output transformers!!

The LL1663, LL1664 and LL1682 are small size OPTs with a less flexible structure (and thus much easier to use) than the types above.
 

• The LL1663 is a 5k:8 ohms output transformer available in PP or SE versions
   
• The LL1664 is a 3k:8 ohms output transformer also available in PP or SE versions
   
• The LL1682 is a 5.5k:5 ohms output transformer also available in PP or SE versions

Mains transformers

In our C-core mains transformers, a very small air-gap is used to compensate for any DC unbalance in the mains outlet. Secondary voltages listed are no-load voltages. Voltage drop because of load is to be calculated from transformer copper resistance and load current.
Electrical size is estimated to 250VA, which can be increased with good cooling. For optimal use, about 75% of power should be taken from secondary 1. Primaries should be connected in series for 210 - 250 V, in parallel for 105 - 125V. Table entries are calculated for primary voltage 230 V.

Type	Secondary 1	Secondary 2 and 3	Secondary 4 and 5	Secondary 6
LL1648	350V	5.9V	6.6V	-
LL1649	230V	6.6V	6.6V	-
LL1650	350V	6.6V	6.6V	-
LL1651	500V	6.6V	6.6V	-
LL1683	250V / 0.16mA	6.6V / 3A	5.2V / 3A	48V / 0.1A

Chokes for tube amp power supply

Type	Inductance	Rec. DC current	Saturating current	DC resistance
LL1638 / 4H	4 H	400mA	575 mA	36 ohms
LL1638 / 8H	8 H	200mA	290 mA	36 ohms
LL1638 / 10H	10 H	150 mA	215 mA	36 ohms
LL1673 / 10H	10 H	200 mA	290 mA	60 ohms
LL1673 / 15H	15 H	140 mA	200 mA	60 ohms
LL1673 / 20H	20 H	100 mA	145 mA	60 ohms
LL1685 / 100mA	17 H	100 mA	145 mA	130 ohms
LL1685 / 160mA	10 H	160 mA	230 mA	130 ohms

Note: Data and Product Listing is under permission from Mr. Per Lundahl, Lundahl Transformers AB, SWEDEN
 

Others Transformer

ITEMS	DESCRIPTION	PICTURE
Toroid	OEM part: Pri:0-220V-240V 2.5V-4V-5V-9V-CT 2A, 18W