ASR Mini-Basis MK II User manual

ASR Audio Systems Friedrich Schaefer, D- 35 745 Herborn [phone]
0.0 Table of contents of this manual Page 01
1.0 Setting up the ASR Mini-Basis Page 02
2.1 Important safety precautions
2.0 Connecting the ASR Mini-Basis Page 03
2.1 Connecting to a pre- or an integrated amplifier
2.2 Connecting the tone arm cable
3.0 A justing the ASR Mini-Basis
3.1 Adjusting the input resistance ( 10 pole DI switch ) Page 04
3.2 Adjusting the input capacity ( 10 pole DI switch )
3.3 Adjusting the gain ( 6 pole DI switch )
4.0 Trouble-shooting Page 05
4.1 The unit is not working
4.2 Hum
4.3 Noise
4.4 Channel-volume difference during phono-playback
4.5 Just in case: repair
5.0 Technical ata Page 06
Dear music lover,
all of us at ASR would like to offer thanks and congratulations to you for purchasing the
ASR Mini-Basis hono- re-Amplifier. We sincerely believe that your ASR Mini-Basis
will bring you many years of musical pleasure and enjoyment.
All ASR products are handmade with greatest care to details and with high-grade selected parts.
Enjoy your high quality records even more with this musical hono- re-Amplifier!
While every new owner is anxious to begin listening, we encourage you to
take a few minutes to rea this manual an familiarize yourself with the
full capabilities of the ASR Mini-Basis.
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ASR Audio Systems Friedrich Schaefer, D- 35 745 Herborn [phone]
1.0 Setting up the ASR Mini-Basis
Check to make sure, your ASR Mini-Basis has been manufacture for operation at
your AC line voltage. Attempting to use your ASR Mini-Basis at any voltage other
than the specifie on the backsi e may amage the unit.
Damage cause by improper operation is not covere by ASR warranty.
If the voltage specifie is ifferent from your AC voltage, contact your ASR ealer.
lace the unit close to your turntable and use a cable as short as possible to connect your turntable
to the main unit. Do not place the ASR Mini-Basis main unit close to any power supply.
1.1 Important safety precautions
To get the best performance from your ASR Mini-Basis, and for your own safety, please read
and follow these important safety instructions.
1. Before operating the ASR Mini-Basis hono re-Amplifier, please rea ALL operating
and safety instructions.
2. Never place the ASR Mini-Basis near heat sources such as radiators, fireplaces, stove,
or other appliances that produce heat. Avoid placing the ASR Mini-Basis where it will
be subject to direct sunlight or low temperatures.
3. This product is equipped with a three wire AC power cord which includes an earth
groun connection. To prevent shock hazard, all three connectors must always be used.
If your AC outlets will not accept this type of plug, an adaptor may be purchased.
If an adaptor is necessary, be sure it is an approved type and that it is used properly,
supplying an earth ground. If you are not sure of the integrity of your home’s
electrical system, contact an licensed electrician for assistance.
4. Before cleaning the ASR Mini-Basis always disconnect the AC power supply cord.
5. If you smell smoke, or an abnormal smell, immediately unplug the ASR Mini-Basis
from the AC power and contact your ASR dealer.
6. In case the unit becomes wet unplug it immediately, and dry it completely before using it again.
7. Replace fuse in the small drawer at the power plug only with the exact type originally included.
115 Volt: 1 Amps slow blow 230 Volt: 0,5 Amps slow blow
8. THERE ARE NO SERVICEABLE PARTS INSIDE THE ASR Mini-Basis !
- Do not attempt to repair or modify your ASR Mini-Basis.
- All service should be performed by qualified service personnel.
- Do not open the unit while it is attached to the AC outlet.
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ASR Audio Systems Friedrich Schaefer, D- 35 745 Herborn [phone]
2.0 Connecting the ASR Mini-Basis
2.1 Connecting t o a pre- or an integrate amplifier
ATTENTION: lease disconnect the power cord from the AC outlet before you connect
any cables at the ASR Mini Basis.
The input sockets are located on the back panel of the main unit left and right of the ground
clamp. The input sockets are located left and right of the output sockets. The sockets for the
right channel are marked with a re ring, for the left channel with a black ring.
lease connect the output sockets of the ASR Mini Basis with high quality unbalanced
(RCA) cables to a high level input of your pre- or main amplifier.
2.2 Connecting the tone arm cable
Either Moving Magnet (MM) or Moving Coil (MC) cartridges can be connected to the
ASR Mini-Basis via unbalanced (RCA) cables.
lease connect the ground cable of your turntable to the ground clamp on the back panel of
the ASR Mini-Basis. If any hum occurs, try to route the ground cable in different manners –
your goal should be to eliminate hum completely.
3.0 A justing the ASR Mini-Basis
Before you o any a justments insi e the ASR Mini-Basis please isconnect
the power cor from the AC outlet.
a) to adjust the ASR Mini-Basis, please remove the cover of the main unit.
lease use a 3 mm Allen wrench to loose the four screws
b) inside the main unit you find four DI switches to adjust the ASR Mini-Basis
c) in input resistance can be adjusted at the 10 pole DI switches
d) the gain can be adjusted at the 6 pole DI switches
d) the DI switches have two different settings: „ON“ or „OFF“; be sure, that the switches
are correctly set (when set correctly, you will hear a slight „klick“)
c) please set the DI switches exactly the same for the right and the left channel
3.1 A justing the input resistance
The ASR Mini-Basis can be perfectly adjusted to bring out the best sound out of every cartridge
you may ever use. Adjustment of the input resistance can be made from 47 kOhms for MM
cartridges to 12 Ohms for low output MC cartridges.
We know from experience that if you are using an adjustment with a lower input resistance the
ambiance is improved with limited dynamics, with a higher input resistance the overall performance
is brighter and more dynamic, but definition and precision are limited.
You can easily find out the perfect setting for you: make an adjustment and listen to the system.
The adjustment you like best is the one you should choose!
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ASR Audio Systems Friedrich Schaefer, D- 35 745 Herborn [phone]
(DI switch = „No.“) (47 k when all Dips are OFF )
15K 10K 2K2 1K 470 360 220 100 94 47 22 15 12 Value
1 -- -- -- -- -- -- -- -- -- -- on on on 22
2 -- -- -- -- -- -- -- -- -- on -- on on 47
3 -- -- -- -- -- -- -- on on -- -- -- on 100
4 -- -- -- -- -- -- on -- on -- -- -- on 220
5 -- -- -- -- on on -- -- -- -- -- -- on 475
6 -- -- -- on -- on -- -- -- -- -- -- on 1K
7 -- -- on -- -- -- -- -- -- -- -- -- on 2K2
8 -- on -- -- -- -- -- -- -- -- -- -- on 10K
9 on -- -- -- -- -- -- -- -- -- -- -- on 22K
By using combinations of Dip switches you can get additionally values for the resistance.
Formula for the Calculation : 1/R total = 1/R1+ 1/R2+ 1/R3......
Example: 100 and 221 Ohm combined (47 k is fix): 1/Rt=1/100+1/221+1/47000 =1/0,015 Rt=69
3.2 A justing the input capacity
The input capacity can be adjusted on DI switch No. 10: position „Off“ = 100 pF, „On“ = 320pF.
You can easily determine the value for your cartridge by using the cartridge manufacturer’s
recommended value and subtract the capacity of the phono cable you are going to use –
the result is the value you have to adjust in your ASR Mini Basis.
3. 3 A justing the gain
The gain can easily be adjusted on the 6 fold DI switches „Gain Adjust“. The switches can be
combined to get higher gain. The minimal gain of +30 dB is obtained with all Dip switches in OFF,
the Maximum gain of +72 dB is obtained by putting all DI switches to „ON“.
To know the adjusted gain please add the following values to 30 dB :
switch No. „ON“ none 6 5 4 3 2 1 All 1-6
Gain 0dB +6dB +12dB +18dB +24dB +30dB +36dB +42dB
lease set the DI switches exactly the same for the right and the left channel (only exception from
this rule: your cartridge has different output from the right and left channel).
!! The gain shoul be set as low as necessary to get lowest possible noise !!
3.4 Settings for common cartri ges
Input Resistance Gain cartridge type
(s itch no.) (s itch no.)
1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6
-- -- -- -- -- -- -- -- -- -- -- -- -- -- -- on MM,MC High Output
-- -- -- -- on -- -- -- -- -- -- -- -- on -- -- MC Lo Output
-- on -- -- -- -- -- -- -- -- -- on -- -- -- -- MC Very Lo Out
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ASR Audio Systems Friedrich Schaefer, D- 35 745 Herborn [phone]
4.0 Trouble-shooting
4.1 The unit is not working
lease check if the two Le s inside the main unit are shining.
If not please check if the power cable is connected correctly to the Mini Basis and the power outlet.
Also you may check the fuse in the little rawer at the power cable connector at the Mini Basis.
When the Leds are shining please check the cables and your cartridge.
4.2 Hum
To avoid hum the ASR Mini-Basis should not be placed near power supplies, televisions, video
equipment, AM/FM-receivers, cordless phones, computers etc. Also do not route the input or
output cables parallel to the power cord. Hum can occur because of a groun loops caused by
multiple grounding of the cartridge/tone arm/ amplifiers. lease try to reverse the plug of the
power cord. That may interrupt the ground loop. Also try different ways of grounding.
4.3 Noise
If noise occurs while playing an L , you should lower the gain. The noise at the cartridge’s
internal resistance of a very low output MC cartridge might be already higher, than the noise
of the input stage of the ASR Mini Basis!
4.4 Different channel volumes uring phono playback
lease check if all DI switches are set in the same way for both channels and are positioned
into their places properly.
4.5 Just in case: repair
If all the help we provided in this trouble-shooting-section of the manual did not help to make
the ASR Mini-Basis operate properly, please contact your authorized ASR dealer.
lease pack the units into the original ASR boxes and with the original ASR packing accessories.
Your authorized ASR dealer will take care of your unit and will repair it properly.
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ASR Audio Systems Friedrich Schaefer, D- 35 745 Herborn [phone]
5.0 Technical Data
The Mini Basis is a hono- reamplifier for Moving Magnet and Moving Coil cartridges.
Signal-to-noise-ratio: better 60 dB (depends on settings)
RIAA equalisation: better than 1dB from 20Hz to 20kHz
Distortion s: lower than 0.01% from 0,5V to 3VAC Output (100 Ohm load)
at 1 kHz , from 20Hz to 20 kHz lower than 0.05%
Transformer: 72 VA, total buffering capacity 200.000 µF
fuse 0,5 A slow 230 Volt, 1A slow for 115 V
Dimensions: 268 x 320 x 110 mm ( width x depth x height )
Manufacturer :
ASR Audio Systeme
Friedrich Schäfer
Hohe Straße 700, House 5A,
D 35 745 Herborn / Germany
hone +49 ( 27 72 ) 42 905,
Fax +49 ( 27 72 ) 40 488
E- Mail [email protected]
Internet www.asraudio.com
 January 2008 Frie rich Schaefer, ASR Au io
Subject to change without notice.
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