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Baldwin HiFi External Linear Power Supply Units Discussion.

There are many different types of External Linear Regulated PSUs available in the Baldwin HiFi range.

Click this link for PSU Pricing Stucture

PSU15VA
PSU15VA
15VA Regulated DC 5V to 32V (Variable)
PSUAC15VA
PSUAC15VA
15VA Filtered AC 9V, 12V, 15V, 18V, 24V or 30V (fixed)
PSU25VA
PSU25VA
25VA Regulated DC 5V to 32V (Variable) with AC Filtering
PSUAC25VA
PSUAC25VA
25VA Filtered AC 9V, 12V, 15V, 18V, 24V or 30V (fixed)
PSU50VA
PSU50VA
50VA Regulated DC 5V to 32V (Variable)
PSU50VA
PSUAC15VA
50VA Regulated PSU with AC Filtering
Custom Regulated BIG PSUs
Custom PSU
8 AMP, 12 AMP PSU
Custom Regulated BIG PSUs
Custom PSU
8 AMP, 12 AMP PSU

Lets Discuss how we get electrical power into the home.
There are many sources available - mostly we rely on the Generating Authority to supply us with a clean AC (Alernated Current) Voltage.
We will only deal with the UK and the USA which have different Voltages and different AC frequencies developed and supplied.
The graphic below depicts such supplies.
AC Generation


What can we use Mains Power AC Voltage for?
AC Uses
We will discuss the EU 220VAC & UK 240VAC 50Hz system from here on.
Note - the digital clock depicted above is an interesting example as it uses the UK AC50Hz 'buzz' frequency to maintain its' time.
The generating Board in the UK cannot guarrantee the 50Hz pulses are truely accurate at any one time in the day or night due to (for us, unforseen) generating problems.
However, they do suggest that over a 24 hour period the digital pulse counting clock will become accurate again as the Generating Board change the 50Hz frequency slightly to compensate for any known minor problems encountered during the day.

How does the 50Hz AC frequency affect HiFi equipment?
Well to be honest - in most cases HiFi hates the 'buzz' of Alternating Current and Power Supplies within the Equipment try to get rid of the 50Hz altogether while converting the AC Voltage to DC (Direct Current) - something it can use more readily to amplify / play music etc.
Depicted below are some 50Hz AC fluctuations:
1. Normal
2. Mutiple Harmonic Frequencies caused by bad connections, overloading the supply, modern Switch Mode PSU's (see below) etc.
3. Spikes in the supply caused by the generators switching from station to station, faulty equipment being locally switched on & blowing fuses etc. or a local heavy use customer (on the same phase as you) switching on/off a huge lump of industrial equipment.
Fluctuations in Frequency

How does HiFi equipment convert the 240 AC mains Voltage to a workable Voltage?
Firstly, the Power Supply needs to get the 240VAC into a usable lower AC Voltage.
This is achieved by a Step Down Transformer which converts the 240V down to say 12 Volts.
The 1st graphics below show the transformer symbol and coils on the Primary side (240V in) with a lower voltage on the output(s)
Multiple coils on both the primary (input) and secondary (output) windings allow flexibility.
Toroidal Transformers
The 1st photo shows an older style 'Laminated' Transformer which is still used today, but suffers from some inefficiencies and also mechanical 'buzzing' (in symapathy with the 50Hz) of the mechanical lamination core.
The 2nd photo shows a modern Toroidal Transformer which is more efficient (can deliver more Current in a similar size to that of a laminated transformer) and is relatively mechanically less noisy.
The 3rd photo shows the internal construction of a Toroidal Transformer.

Equipment that needs the 50Hz AC pulses
In the example of a clock radio which needs a Transformer to change the 240VAC source to say 12 Volts DC for its' circuits - it still uses the AC pulse taken from the low voltage side of the transformer to make the clock work.

The spikes that can occur on the mains source do not affect the clock radio to any great degree so need not be Filtered.

Some HiFi Turntables, however, also need the AC pulses to drive their stroboscopic circuits to help keep the motor speed accurate - but do not like the possible spikes - so an AC filtering system is employed to try and keep the pulses smooth.

Example: The Rega TT range of turntables require an external step down transformer to AC24V and an AC Filtered system as its' Power Supply.
Mains Filter


Transformer Technology
We will discuss Toroidal Transformers as most HiFis now employ these.
They come in all sizes - usually the larger - the greater the VA (Volt Amps).
What is VA I hear you ask - well its a measurement of its' Current (Amps) capability related to the output Voltage from the winding(s).

The chart below shows the Current in Amps from a single output winding or output windings wired in series (VAS) and Parallel (VAD).
VA capability

Mains Transformers come with usually 3 possible Input Voltage configurations:
1. 240VAC Single Winding
2. 110VAC Single Winding
3. 110VAC + 110VAC Dual Winding

The Output Windings can also come in many forms:
a. Single Winding
b. Dual Winding
c. Multiple Output Windings with different Voltage and Current capabilities
Input(s)
Input(s)

Transformer Wiring
Have a look at this link to see how to wire the multiple taps on both primary and secondary windings:
http://www.hammondmfg.com/5CHook.htm

Safe to say, the VA Current to Voltage capability shown in the chart above is for a Single Secondary Winding - Parallel (in phase) 2 Secondary Windings will double the Amps available.


Turning AC Volts into DC Volts
Most HiFI units need a DC (Direct Current) Voltage (or Plus & Minus DC Voltages) to operate.

Direct Current circuitry tries to get rid of the AC 50Hz 'buzz' from the Mains Voltage after the Transformer and delivers an almost stable Line Voltage that HiFi circuits can use to make spurious noise free music.
AC to DC

Back to School
Rectification is the conversion of AC to DC.
Rectification is performed. by a diode that allows current to flow in one direction but not in the opposite direction.

Half Wave Rectification uses a single Diode which produces the effect shown on the right to the 50 Hz AC pulses.

As you can see, there are still signs of the top AC sine pulse even when a Capacitor is used to smooth the Rectification.
Half Wave Rectification
Full Bridge Rectification
A Bridge Rectifier is an arrangement of four or more diodes in a bridge circuit configuration which provides the same output polarity for either input polarity.

This is the most common type of Solid State Rectifier used in Power Supplies for HI FI as it allows many variations of wiring to generate DC Rail(s).
Full Wave Rectification
Plus & Minus DC Rectification
The Final Part
Once we have a roughly smooth DC Rail Voltage - there is another problem to overcome.
The Voltage you have is whatever the Transformer Secondary Windings and the Bridge produce.
You need to be able to control the Output DC Volts to the exact Voltage you need.

A Voltage Regulator circuit can be as simple as shown here of far more complex with additional smoothing circuits built in.

The original AC 50Hz pulses can be almost eliminated by clever Regulator designs - and the Voltages 'tuned' to suit the application.
Uncontrolled DC

Controlled DC
Simple Regulation

Switch Mode Power Supplies
Most of the Free Standing DC Power Supply Units (PSUs) that you can inexpensively purchase deliver the fixed Voltage and Current as specified. The problem is that modern PSUs use what is known as Switch Mode (SM) technology.

They contain inverter circuits which generate (usually inaudible) high frequency pulses at high Voltage which is then converted back down to the low (say) 12 Volts DC specified on the box.

Switch Mode PSU's are fine for Computers - but for HiFi are extremely noisy in the higher frequencies, generating harmonic frequencies to the internal inverter circuit frequency which the sensitive HIFI circuits can 'hear' - and amplify.

This technology allows small PSU boxes to deliver high Current and automatically switch between 110VAC sources through to 240VAC sources without the user needing to do anything.
Harmonic Noise

HiFi PSU Solutions using Analogue Technology.
If you need an External Filtered AC or super smooth DC External Power Supply - then Baldwin HiFi should have the noise free solution for you!

1. AC to Filtered AC output: AC 9V, 12V, 15V, 18V, 24V or 30V (fixed)

2. AC to Smoothed Regulated DC output: DC 5V to 32V (Variable)

3. Filtered AC to Smoothed Regulated DC output: DC 5V to 32V (Variable)

4. Multi-Rail Regulated Larger Power Supplies

Please contact Paul (see below) to discuss your requirements.

VA Volts/Amps (Current Capability) components will be carefully chosen for your custom built external Power Supply Unit to directly suit your application.

AC to Filtered AC



AC to DC


Warranty:

The ReelAudio Custom Built Baldwin HiFi Power Supplies are guaranteed for a period of 12 months from the date of purchase.
Normal Usage is implied by the word 'Guarantee' and 'Warranty'.

Click Here to view the Products & Pricing Page.

All Warranty repairs are undertaken on a return to base principle.
Any carriage costs are the responsibility of the Client

REELAUDIO MAKES NO WARRANTY, EITHER EXPRESS OR IMPLIED WITH RESPECT TO ANY PRODUCT, AND SPECIFICALLY DISCLAIMS ALL OTHER WARRANTIES, INCLUDING, WITHOUT LIMITATION, WARRANTIES FOR MERCHANTABILITY, NON-INFRINGEMENT AND FITNESS FOR ANY PARTICULAR PURPOSE. REELAUDIOS' SOLE OBLIGATION AND LIABILITY FOR PRODUCT DEFECTS SHALL BE, AT REELAUDIOS' OPTION, TO REPLACE SUCH DEFECTIVE PRODUCT OR REFUND TO BUYER THE AMOUNT PAID BY BUYER THEREFOR. IN NO EVENT SHALL REELAUDIOS' LIABILITY EXCEED THE BUYER'S PURCHASE PRICE. THE FOREGOING REMEDY SHALL BE SUBJECT TO BUYER'S WRITTEN NOTIFICATION OF DEFECT AND RETURN OF THE DEFECTIVE PRODUCT WITHIN NINETY (90) DAYS OF PURCHASE. THE FOREGOING REMEDY DOES NOT APPLY TO PRODUCTS THAT HAVE BEEN SUBJECTED TO MISUSE (INCLUDING WITHOUT LIMITATION STATIC DISCHARGE), NEGLECT, ACCIDENT OR MODIFICATION, OR TO PRODUCTS THAT HAVE BEEN SOLDERED OR ALTERED DURING ASSEMBLY, OR ARE OTHERWISE NOT CAPABLE OF BEING TESTED, OR IF DAMAGE OCCURS AS A RESULT OF THE FAILURE OF BUYER TO FOLLOW SPECIFIC INSTRUCTIONS.

IN NO EVENT SHALL REELAUDIO BE LIABLE TO THE BUYER OR TO ANY THIRD PARTY FOR ANY INDIRECT, INCIDENTAL, SPECIAL, CONSEQUENTIAL, PUNITIVE OR EXEMPLARY DAMAGES (INCLUDING WITHOUT LIMITATION LOST PROFITS, LOST SAVINGS, OR LOSS OF BUSINESS OPPORTUNITY) ARISING OUT OF OR RELATING TO ANY PRODUCT OR SERVICE PROVIDED OR TO BE PROVIDED BY REELAUDIO OR THE USE OR INABILITY TO USE THE SAME, EVEN IF REELAUDIO HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

Units are Designed and Hand Built by:
Paul Baldwin
www.ReelAudio.Co.UK
BaldwinHiFi.Co.UK
12 Tack Lee Road
Yapton
Arundel
West Sussex
BN18 0HB - UK - Great Britain
Direct EMAIL: neverfinished0@hotmail.com
Tel: 01243 553231 - Mobile: 07858 089421
Please note: Paul may be contacted by telephone during his preferred admin period of between 5pm and 8pm. Thankyou.

Payment for Goods: PAYPAL Account: neverfinished0@hotmail.com
Please specify what you are buying within the PAYPAL Message Area when Making a Payment.

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