aldwin HiFi.Co.Uk
www.ReelAudio.Co.UK
The Home for Vintage Analogue Tape Recorder and Specialist Repairs Information
Click this to Return to the Home Page
Passive

P
r
e
A
m
p
l
i
f
i
e
r

S
e
t
u
p
s

Baldwin HiFi Pre-Amplifier Setups and Discussion.

There are 7 different PreAmplifiers available in the Baldwin HiFi range.

Click this link for PreAmplifier Pricing Stucture

P3S
P3S
3 input Passive Attenuator
EQ2205
EQ2205
Active 1 input EQ PreAmplifier
A2205
A2205
4 input Active Only
PRM1
PRM1
5 input Passive Attenuator
PA2205
PA2205
5 input Passive/Active
PARM1
PARM1
5 input Passive/Active
BZPARM
BZPARM
5 input Passive/Active Wide Version

Each PreAmplifier is constructed with dual Phono (RCA) high quality sockets for Left (top) and Right (bottom) input channels.

Each of these inputs (apart from the EQ2205) has an internal trimmer potentiometer which allows adjustment to the sensitivity of the input.
With the trimmer turned on Full - then the input is 'open' giving an input impedance presented to the source of 100k Ohms.

P3S
Components
3 sets of Input Adjusters
A2205, PRM1, PA2205 & PARM1
Components
4 or 5 sets of Input Adjusters

The trimmers allow you to attenuate the input for the following reasons:
Let's assume you have a CD Player and an old HiFi Tuner as musical sources.
The Tuner will have a Stereo Output of typically 150mV per channel.
The CD Player will have Outputs typically in the 1V to 2V region per channel.
Consequently, the CD Player will appear to be 'shouting' in comparison to the Tuner.

Mr Tuner giving 150mV
150mV
Mr CD giving 1.5V
1.5V
If you have the CD Player plugged into Channel 1 and the Tuner into Channel 2,
with the front Volume Control on the PreAmplifier say at 12 O'Clock - when you switch between the CD and the Tuner then the volume levels will be totally different. The CD will be much louder than the Tuner.

The EQ2205 is designed to suppliment an existing Passive PreAmplifier - giving an input 'GAIN' control to adjust sensitivities.

You can remove the lid of any Baldwin HiFi PreAmplifier (there are no dangerous Voltages inside).

If you have a PA2205 or PARM1 then undertake this operation in PASSIVE mode. With all other PreAmps - don't worry - the setup will still work.

With a small slotted screwdriver you can rotate the input adjustment trimmers associated with the CD to 'turn them down' a little.
Switch between the Tuner and CD Player then the trimmers allow you to adjust the sensitivity of the CD Left and Right hand inputs to the same level as the Tuner.

The trimmers do not affect the quality of the sound throughput, colouration or equalisation at all - they just allow you to trim the levels of your signal sources to even up in volume when you switch between them.

Input Sensitivities:
Each Baldwin HiFi PreAmp has 1, 3, 4 or 5 LINE Inputs via the sets of Phono (RCA) Sockets on the rear.

A LINE Input allows source devices to be plugged in which have outputs varying from 100mVolt through to up to 2Volts @ 100kOhms Impedance.
So - in effect - you can plug in CD Players, Tuners, Tape Recorders, Computers, DAC units et al - All except Magnetic Cartridges in TurnTables which would produce a very weak low level sound. In this instance you need an additional Equalisation PreAmplifier known as an RIAA equaliser (see below).

If you have a Turntable with a Crystal Cartridge - then this will plug into a LINE input fine - albeit with a bit of additional distortion noise (a trait of Crystal Cartridges).

RIAA: If you have a Turntable with a MM or MC Cartridge - you will need an additional amplifier to make the very small signal out (less than 2mV up to 20mV) 'louder'.
The RIAA circuit also has additional inbuilt equalisation to electronically change the tones generated by the Cartrdge to make the Vinyl you are playing sound right.

The PA2205 and PARM1 PreAmplifiers are supplied with an inbuilt RIAA circuit. They are switched in/on differently, described below

PA2205:
Each of the 4 main input sets marked 1 to 4 have the ability to amplify Magnetic Cartridges with the inbuilt RIAA circuit. The circuit is controlled by the front panel push button marked "RIAA" or "R" which gives a standard LINE Level to the rest of the PreAmp when OUT - and engages the RIAA additional circuit when IN.

By this switching - you could have up to 4 different Turntables with Magnetic Cartridges installed switched by push button inputs 1 through 4. A Turntable comparitor!!

PARM1 & BZPARM
The PARM1 & BZPARM PreAmps also have an RIAA circuit inbuilt for Turntables with Magnetic Cartridges.
It is dedicated to input channel set 4. There is an internal toggle switch clearly marked which can be switched between LINE and RIAA.
In the Picture shown on the right the toggle switch is in the LINE input position.

All production units are sent out with the RIAA engaged on Input Set 4 - if you want to use switch setting 4 for a NON Turntable (LINE Input) then you can unscrew / lift the lid and switch the internal toggle away from the RIAA position (no dangerous Voltages inside).
RIAA Switch
RIAA Switch
Tape Input:
The Baldwin HiFi PreAmp PRM1, PA2205 and PARM1 all have Tape inputs on Channel Input set 5.
Each of these inputs can be used as a standard LINE input for a Tape Recorder, CD Player etc.

Each PreAmp in this range also have a Button or switch position which is Marked "T", "Tape" or "TM" which enables you to switch between the source (eg: a CD player on Channel 1) and the Tape Machine itself. If the Tape is in Record (with a 3 Head machine) you will be able to listen to the source and what the machine has just Recorded. The Tape monitor switch allows this feature on the PreAmp.


Outputs - Tape, Variable and BI-Amp Options

All of the Baldwin HiFi PreAmps have what is known as a Variable Output.
It is variable by use of the Volume Control on the Front Panel whether the Volume Control is being fed by a Passive or Active internal circuitry.
This Variable Output feeds the Power Amplifier via the 2 x Phono (RCA) Connectors on the rear.
P3S
Variable Output
1 set of Variable Output
A2205
Variable Output
2 sets of Variable Outputs (Bi Amp)
PRM1, PA2205 & PARM1
Variable Output
1 set of direct Variable Output

P3S & EQ2205:
1 set of outputs to connect to a Power Amplifier (Top Row = Left - Bottom Row = Right).

A2205:
2 sets of outputs allowing Bi Amp operation should you have 2 x stereo Power Amps. Either set can be used if you only have 1 Power Amp.

The PRM1, PA2205 and PARM1 PreAmps are slightly different:
The left hand Output Sockets (looking at the rear) marked Var are dedicated Variable Ouputs - (Top Row = Left - Bottom Row = Right).
The next right OUT Socket Pair (marked Tape) are controlled by the Bi and Tape toggle switch.
With the switch DOWN the Tape Output feeds a constant 250mV out to drive a Tape Recorder Auxiliary Input (for Recording).

Do NOT plug a Power Amplifier into the Tape Output Sockets with the switch DOWN as there will be NO CONTROL of the Volume - you could damage the Power Amp and/or Speakers!!! It would be stupidly LOUD!!!!!

If you want to use the secondary Socket set marked Tape to drive another Power Amp then you must ensure the switch is fully UP.
This will then feed another Variable (controlled by the Volume Control position) output to the secondary Power Amp. Bi-Amping.

Be VERY CAREFUL using this facility - ensure you have the switch in the correct position (Fully DOWN for Tape - Fully UP for Bi Amp) before powering your system up.

As an aside - I always recommend turning your audio system on with the PreAmp Volume Control fully anti-Clockwise (ie: fully DOWN) - wait a few seconds for things to settle before gradually bring the Volume UP.

What is the difference between Passive and Active PreAmplifiers?

In the early days of HiFi Analogue Separates nearly all PreAmplifiers were 'Active' as all signal sources were on average 150milliVolts [apart from turntables with magnetic cartidges (see RIAA above)] and required small amplification and adjustment prior to going to the Power Amplifier to drive the loudspeakers.

Active Pre-Amplifier
Active PreAmp Note the signal increase at each stage

Having a Valve or Transistorised Active PreAmplifier also allowed the designers to include Bass & Treble Equaliser controls - 'Loudness' controls and all sorts of wizardry to make the HiFi experience 'adjustable'.

Passive Pre-Amplifier
Passive PreAmp Note the signal decrease at the PreAmplifier Output stage

With the advent of higher powered Power Amps and Digital Equipment (the CD player being one of the first to be available) the signal levels changed. The old Analogue industry standards where a 0dB reference level was measured @ 0.775VAC changed to new digital standards where the 0dB reference level became LOUDER - 1.228VAC to be precise.
In order to achieve this increase - signal source devices such as the CD player and laterly the computer/DAC units have increased their outputs to between 1V and a whopping 2.5V as the NEW industry standard.

A Power Amplifier would be quite happy with a signal source of 1VAC to 2 VAC to drive it - so in a way, the PreAmplifier as an Active stage in amplification has become redundant - you, now, just need a volume control.

The HiFi industry took this increase in signal source and decided to invent Passive PreAmplifiers with just a volume control - no tone controls or anything to make the experience especial.
In real terms the Passive PreAmplifier is just an ATTENUATOR - it allows the volume to be changed but the original signal will always be slightly smaller at the back end of the attenuator no matter the volume level - even on FULL.
This allowed the industry to introduce extremely expensive stepped potentiometers (attenuators) saying that "you will hear a clarity difference". I make no further comment on this theory/practice!

Active Circuitry within the Baldwin HiFi PreAmplifiers EQ2205, A2205, PA2205, PARM1 and BZPARM

Each ACTIVE PreAmplifier within the range uses a modified Mullard 1953 Old School circuit implementing modern solid state transistors, capacitors and resistors.

The sound quality in ACTIVE mode is superb - some customers (who know) have said "WOW - sounds like a valve preamp".

As well as giving a 6 to 8 dB increase in volume level from the PASSIVE mode, the circuit includes Balance, Bass and Treble controls.
The sweeps on the Baldwin HiFi Bass and Treble equalisation controls are huge. Instead of increasing the boxiness/boom Bass that a lot of PreAmps give with their Loudness and Bass controls, the superb circuitry gives a DEPTH Bass increase and a superb light/tinkley adjustment to the Treble high frequencies.

You have to hear the equalisation sweeps to appreciate the quality of sound achievable - should you need to use the controls.


Features of the Baldwin HiFi PreAmplifier Series

Features

Notes:
Passive: This means that the PreAmp will work without an external Power Supply (PSU) - acting as a plain Attenuator.
If the unit has VU Meters and Headphone drive the PSU will have to powered on to make these facilities work.
Active: The PreAmp includes the modified Mullard 1953 Analogue transistor driven circuitry giving that superb Valvey sound and a 6 to 8dB increase in gain.


Warranty:

The ReelAudio Custom Built Baldwin HiFi Pre-Amplifiers 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
Paul will be unavailable from 27th June 2017 (for 10 days) while installing wiring and equipment into a new HiFi Venue in Ibiza
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.

Back   Previous Screen Contact the WebMaster Contact Us
Hits since 12th November 2012