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Printed Circuit Boards by Emissionlabs.

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EE50 Moving Coil Kit

Can be used with LL1636, LL1678, LL1681, LL1931, LL1933, LL1941, LL1943, LL1961, LL1963, LL1971, L9206, LL9226(XL)

Introduction

The popular EE50 kit, can use all MC transformers, but it is larger size than EE51. Whereas the more compact EE51 can use only the small transformers. Electrical functioning of EE50 and EE51 is identical.

EE50 ready build, with LL1943, face plate not attached

EE50 ready build, with LL9226XL, face plate attached

 

 

We offer three versions:

Order Number: 310-050-09. EE50 Kit with PCB and all parts, but without transformers and housing.
Order Number: 310-150-52. EE50 Kit with PCB and all parts, but without connectors, transformers and housing.
Order Number: 310-250-93. EE50 Kit ready build, but without transformers and housing.

Order the transformer of your choice separately

Features:

• Depending on the transformer, gain can be set to from 3.1 to 32x.
• Each transformer offers two gain two steps.
• The ground lift option can be used with shielded transformers.
• Needle damping is adjustable in five steps, from very soft, to very hard.
• GOLD plated PCB, RCA connectors, Jumpers and Ground connector.
• The jumpers are a special high contact force type.
• The resistors are low noise, metal film.
• We do not supply a housing with it. You can design your own housing, or use Hammond Box 1590BB in which the PCB fits nice.
  

Dimensions:

• Bare PCB without connectors: 104 x 67mm
• Height with transformers mounted: 30mm.
• Drill holes for RCA Connectors: 13mm
• Fits in Hammond Box 1590B3 (not supplied by us)

Gain settings

Line	Input	Gain	Core	Characteristic	Ground Lift	Frequency
01	LL1636	1:10 1:20	Amorphous Cobalt	Lundahl's only MC transformer with internal Faraday shield. Best product for environment with a lot of mains hum.	Closed or open. If open, shield is activated.	10 Hz--25 kHz @1dB
02	LL1678	1:16 1:32	Amorphous Cobalt	High Gain	recommended Closed	10 Hz--35 kHz @1dB
03	LL1931	8x 16x	Amorphous Cobalt	Wound with 6N 'Cardas' wire. Best Sound of Amorphous.	Recommended Closed	10Hz--100kHz @1dB
04	LL1933	8x 16x	Amorphous Nickel	Wound with 6N 'Cardas' wire. Also amorphous sound, but cleaner as cobalt.	Recommended Closed	8Hz--100kHz @1dB
05	LL1681	13x 26x	Mu Metal	Much preferred product by professional users. Has internal shield, for very low hum. Neutral sound.	Closed or open. If open, shield is activated.	7Hz--55kHz @ 1dB
06	LL1941	16x 32X	Amorphous Cobalt	Wound with 6N 'Cardas' wire. Best Sound of Amorphous.	Recommended Closed	10Hz--100kHz @1dB
07	LL1943	16x 32X	Amorphous Nickel	Wound with 6N 'Cardas' wire. Best Sound of Amorphous.	Recommended Closed	8Hz--100kHz @1dB
08	LL1961	3.2x 6.4x	Amorphous Cobalt	Wound with 6N 'Cardas' wire. Best Sound of Amorphous. Has internal shield, for very low hum.	Closed or open. If open, shield is activated.	12Hz--100kHz @1dB
09	LL1963	3.1x 6.2x	Mu Metal	Wound with 6N 'Cardas' wire. Neutral sound	Closed or open. If open, shield is activated.	20Hz--100kHz @1dB
10	LL1971	12x 24x	Amorphous Cobalt	Wound with 6N 'Cardas' wire. Best Sound of Amorphous. Has internal shield, for very low hum.	Recommended Closed	10Hz--100kHz @1dB
11	LL9206	1:10 1:20	Amorphous Cobalt	Just an older type, but very good transformer. You can use it with EE50 when you have a pair around.	recommended Closed	10Hz--90 kHz @ 1.5B
12	LL9226	1:10 1:20	Amorphous Cobalt	One of the best transformers.	recommended Closed	5Hz--100kHz @ 1.5dB
13	LL9226-XL	1:10 1:20	Amorphous Cobalt	Top model version of LL9226, with less loss, and less distortion.	recommended Closed	4Hz--90kHz @1.5dB

 

Explanation page: To choose between MOVING COIL transformers

Ground Lift Option (GND jumpers)

Ground lift is used for failure finding with all transformers, or can be used for the shielded transformers, which can handle extreme hum situations. Such as in studios with very long wiring and a lot of equipment. For home use, Ground Lift it is not needed. This means, the GND Links are normally permanently closed, giving primary and secondary a common ground.

Needle damping Setting

The needle has to be damped correctly. There is no general, best setting for this, it depends on the cartridge, the gain, and the whole tone arm. However, it is not drastic. You can begin with "soft" or "very soft" damping, and there is a good chance this will be right. If not, you may need more damping, or less damping. Here is how to recognise if this is the case:

Not enough damping leads to reduced groove contact during loud sound parts, which is a form of distortion. Because of the V-shape of the groove, the needle at very loud music will be forced a little bit higher up in the groove, which is not where it should be. In severe cases it can even cause the needle to skip a groove with very loud music parts. This is mistakenly judged sometimes as a bad adjustment of the tone arm. Though increasing the needle pressure may also seem help, you would be curing it at the wrong place. It only wears out the needle and the records faster. If this can be solved by adjusting the damping, it is a much better way,

Too much damping gives loss of high frequency, and loss of stereo information. That is because faster needle movements (as needed for high frequency) get damped a lot more than low frequencies. Imagine if a record has tones from 20Hz to 20kHz, it is a factor 1000 difference in needle movement speed. So you will initially recognise too much damping, when the higher frequencies seem attenuated. You should avoid this situation, because the stereo information is coded in the vertical needle movement, which get damped just as well.

This is why we recommend to take as much as possible damping, but not exceed the point where you begin to loose high frequency. The only good way is simply try it out with some hearing sessions. Here is some more information about needle damping.

Table for low impedance cartridges with EE50

Cartridge Load at 1:8

Cartridge Load at 1:12

Cartridge Load at 1:13

Cartridge Load at 1:16

Cartridge Load at 1:24

Cartridge Load at 1:26

Cartridge Load at 1:32

Damping

A

B

C

D

GND

LL1931 LL1933

LL1971

LL1681

LL1931 LL1933 LL1941 LL1943

LL1971

LL1681

LL1941 LL1943

Very soft

X

734 Ohms

326 Ohms

278 Ohms

184 Ohms

82 Ohms

70 Ohms

46 Ohms

Soft

X

X

573 Ohms

270 Ohms

231 Ohms

152 Ohms

68 Ohms

58 Ohms

38 Ohms

Medium

X

X

X

500 Ohms

222 Ohms

189 Ohms

125 Ohms

55 Ohms

47 Ohms

32 Ohms

Hard

X

X

X

X

438 Ohms

194 Ohms

166 Ohms

109 Ohms

49 Ohms

67 Ohms

27 Ohms

Very Hard

X

X

X

X

297 Ohms

132 Ohms

112 Ohms

74 Ohms

33 Ohms

28 Ohms

19 Ohms

 

Table for medium impedance cartridges with EE50
						Cartridge Load at 1:3.1	Cartridge Load at 1:3.2	Cartridge Load at 1:6.2	Cartridge Load at 1:6.4
Damping	A	B	C	D	GND	LL1963	LL1961	LL1963	LL1961
Very soft					X	4900 Ohms	4600 Ohms	1200 Ohms	1100 Ohms
Soft	X				X	4100 Ohms	3800 Ohms	1000 Ohms	953 Ohms
Medium	X	X			X	3300 Ohms	3100 Ohms	832 Ohms	781 Ohms
Hard	X	X		X	X	2900 Ohms	2700 Ohms	728 Ohms	684 Ohms
Very Hard	X	X	X		X	1900 Ohms	1800 Ohms	494 Ohms	464Ohms

Note: The Jumper A switches the damping of the EE50 on or off. When off, this leaves only the damping of the RIAA amplifier, which is always a "Very Soft" damping. For instance, when set for "Hard", with jumpers A-B+D, just by removing Jumper A, you go from "Hard" to "Very soft". Like this you can quickly compare the effect, while playing music. This works for the other settings as well.

PART2. Building instructions:

 

These PCBs fit exactly into Hammond case, type 1590BB. This nice box, you can order it in five colors. Or, take any other box you like. LL1590BB drawing

Never test an MC transformer with an Ohms meter. This will magnetize the core permanently, and sound will become distorted. For this reason, buying second hand MC transformers, is generally not a very good idea.

A nice project by Bratislav S. from Serbia, Belgrade.

This was actually build with EE51, but with EE50 it would look the same, just 1cm larger size. Our customer send us these nice, inspiring pictures of his EE51 build.

Video of this system. Thank you Bratislav!

Templates

Under the connectors are dummy holes in the PCB, which can be used as a template for drilling the connector holes.

Here is a hint you may like: When drilling holes in Aluminum, use normal household cleaning alcohol as a lubricant, and drill at low speed. This gives a much nicer drill hole as when drilling dry. You won't believe this if you have never tried it.

 

The EE50 PCB has this break-off template attached to it. First, break off the template, it is used to line up the connectors perfectly. Use this procedure: Plug in the connectors on the board, without solder, and hand tighten the face plate to the connectors. Then solder this assembly on the board, with only two of the tine wires. One of the left outside, and one of right outside of the board. After soldering like this, you can still re position the assembly. Check carefully if the connectors are nicely aligned to the board itself. If so, solder all thin wires, and you can still align the angle of the assembly. If the angle is good, solder the thick wires. Later, the template can also be used as a face plate if you like.

 

Settings

Above is the default setting, this is for high gain, and very soft damping. Also note the correct placement of the damping resistors (look at the color rings). The jumpers, if not used, you can put them on one pin only.

Large picture here.

 

Grounding:

The PCB is double sided grounded, and the two mounting screws are also the ground connections. In general, screws of PCB's tend to get somewhat loose over the years. To prevent a bad ground connection by this, there is also a soldered ground connection. This should be connected with a wire, to the ground plug of the metal case. If the chassis is colored or surface treated (such as passivated aluminum), remember to clean the metal beneath the screw.

In addition to the four RCA Connectors, the metal case needs also a ground screw at the outside, which connects to the record player, with a simple single wire. Since Dec 2023, this ground screw is also provided, a nice gold plated version.

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Settings for some cartridges

The EE50 board works with most cartridges needing a gain from 3 to 32x.

The table which is linked here, will quickly assist with the choice.

Green Box: This is a recommended setting.
Black Box: The output signal is much too high or too low.
Blue Box: The output signal is above normal, thus improving signal to noise ratio. However it gives higher load to the cartridge, and needle damping becomes higher. This may be compensated by choosing the lowest possible damping. If the cartridge has a green and a blue box, choose the one which sounds best in your system.

Choosing a transformer for a specific cartridge. Some examples.

1. Denon DL103. One of the most popular cartridges ever. LL1678 would be possible to use 1:16, it gives 3.9mV. Using 1:32 setting would give a theoretical 8.8mV, but it doesn't work well, otherwise this box would have been blue. The 8.8mV will not appear, because load on the cartridge is very high. Also it will give high frequency loss. So LL1678 makes only sense for DL103 when you already have a pair, and you want to try if it works perhaps. A better choice is the LL9226-XL transformer and set it for 1:20. This gives a nice 4.4mV, which is very good, and cartridge load is optimized, as with all green boxes.
2. Fidelity Research FR-1 Mk3F. In the table, it has a blue box with LL1678 and 1:16. If your pre amplifier is too noisy, this by itself is the real problem. It may be solved however by choosing this blue box, and get 7.4mV signal. However there is some risk, because when it appears wrong, there is no green box setting. The official, recommended use for this cartridge is 1:10 with the transformer LL9226-XL This gives even 4.8mV which is even a very good value. So here, the recommended choice is LL9226-XL. Or, use LL1678 which has higher needle damping as intended for the cartridge.
3. Benz Wood M2. It has only a blue box, and it is the only option anyway for this curious cartridge. Using a blue box means the damping may be higher as expected. From our side, we can only say it is a little bit risky to have only a blue box. Ask at Benz company if they advise this.
4. Benz Micro Reference S Copper. This is a nice one for noisy pre amplifiers. In that case use the LL1678, and try it for 1:32. Though 32x gain is quite a load for the cartridge, it can take this because impedance is an incredible low 5 Ohms. Even so, minimum load is low, with 40 Ohms. This is why the blue box is highlighted. In case some high frequency is lost, you can still go for the green box and get 4mV, which is a nice value. Some other brand cartridges give only 3.2mV and these are also good.

Complete table.

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Fault finding hints

This MC unit designed to work right away. If there is hum however, the EE50 board has a some modes for fault finding.

Fault finding methods.