The cartridge used for all the Shure 545 and PE54 microphones
giving them their tonal character and response.
R45 cartridge replacement manual
The Shure 545 UNIDYNE® III and PE54 UNIDYNE® III series were all fitted with the same R45 Dynamic Cartridge, as was the Shure 544 UNIDYNE® III. The internal 51E23 transformer has low impedance and high impedance windings, and is what makes the mic so powerful and versatile. If these transformers were provided with SM57 and SM58, they would be equally treasured by harp players. The only real difference between the 545 and PE54 mics was the 545 was sold setup for low impedance, and the PE54 was sold setup for high impedance. With the exception of the first PE54, and 545L, all these mics can be switched to high or low impedance. The 545L is the only model that cannot be wired to high impedance.
I understand that the discontinued Shure: 545; 545S; 545D; 545SD; 544; PE54; PE54D; and PE54D-CN were all made in USA with the US made R45 cartridge. However my sources have been either contradictory or vague, so if you know of corrections that need to be made please contact me with the correct information.
There are a number of Shure 545 & PE54 models that followed, which came with Shure R45 element made in Mexico, rather than USA. The Mexican R45 are apparently deliberately designed to have a slightly lower output to be more compatible with balanced low impedance equipment. However their frequency response and tonal characteristics are identical. There is no hard evidence there is any appreciable difference.
For playing amplified harmonica through an amplifier these work best configured for high impedance, and used with a shielded signal cable less than 25' long with a 1/4" plug. It is possible to leave the mic setup for balanced low impedance and use an impedance adapter, but players experience has shown that the internal setup wired for high impedance gives better results. The manual itself shows you get more top end cut when its wired hot. Most mixing desks and PAs can handle high impedance mics properly.
The 545 & PE54 wand configured mics weigh 255grams (9oz) which may or may not have a built in on/off switch depending on the model, while the 545 models mounted on a on/off switch housing by a swivel are considerably bulkier and weigh in at 425grams (15oz).
The current Shure 545SD UNIDYNE® III comes with the same Mexican R45 element used in the later discontinued models. It's a very good and highly recommended harmonica microphone. Unlike most good bullet mics its available brand new it music shops that stock Shure products. The Mexican made R45 elements are just as good as the original US model, with no difference in tone or performance.
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R45 Dynamic Cartridge The cartridge used for all the Shure 545 and PE54 microphones giving them their tonal character and response.
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50Hz - 15,000Hz range R45 cartridge replacement manual | |
The discontinued Shure 545 & PE54 series came in one of a number of configurations, the original US made 545 wand with four pin connector that selects the impedance, the 545D & 545SD as well as the PE54D & PE54CN wand with XLR jack selected the impedance with an internal jumper. The 545S, 545SH, original PE54 and PE54SH all come mounted on a switch housing with swivel connection to the mic. The 545S had a 4 pin connector where the impedance is determined by the cable wiring. The original PE54 cannot be wired for low impedance. The 545L cannot be wired for high impedance. All the others have XLR jacks and the impedance is selected by an internal jumper found in the mic's housing.
With the exception of the 545L, all of these get the best results when set up for high impedance and used directly into the amplifier chain. It is not enough to use them setup for low impedance with an impedance convertor.
For your convenience I have typed out the instructions for changing impedance for each model from their respective manual. All of the following instructions are ©Copyright Shure Inc.
Either High- or Low-impedance operation of these microphones is selected by the leads chosen for connection at the equipment end of the microphone cable. [comments in square brackets are in addition to the original manual, 'pin #' refers to four pin plug].
For high impedance, the RED lead [pin 2] is the "hot" conductor [connect to tip of 1/4" plug]; the shield [pin 1] is connected to the amplifier or chassis ground [connect to sheath of 1/4" plug]. For balanced-line low impedance, the BLACK [pin 3] and WHITE [pin 4] leads are the "hot" conductors [wire to XLR pins 2 & 3 respectively]; the shield [pin 1] is connected to the amplifier or chassis ground [wire to XLR pin 1 and ground]. For unbalanced low impedance, the WHITE lead [pin 4] is the "hot" conductor [connect to tip of 1/4" plug] with the BLACK lead [pin 3] and shield [pin 1] connected together to the amplifier or chassis ground [connect to sheath of 1/4" plug]. Any leads not being used for a particular connection should be insulated at the equipment end of the cable.
The low-impedance [balanced] connection is recommended where long cable lengths are required or under conditions of severe hum disturbance. The permissible cable length is practically unlimited, since neither response nor level is appreciably affected. For use with high-impedance amplifiers, the Shure Model A95 Series Line Matching Transformers are available for coupling a low-impedance line to the amplifier input. The Model A95 Series transformers permit coupling a 19-300 ohm microphone to a high-impedance input.
When using the microphone with a balanced input, pins 2 and 3 are the audio signal carriers. When using the microphone with an unbalanced input, use a cable wired with pin 2 as the sig-nal carrier and pin 3 connected to the cable shield (ground), such as the Shure C20HZ high-impedance cable.
The microphone is shipped connected for low impedance operation. To change to high impedance, proceed as follows:
When using the microphone in low impedance, the cable conductors from connectior pins 2 and 3 are the audio signal carriers. Connect the shield to amplifier or chassis ground.
When using the microphone in high impedance, the cable conductor from pin 3 and the shield are the audio signal carriers. Connect the conductor from pin 3 to the "hot" amplifier input; connect the shield to amplifier or chassis ground. An unused lead attached to pin 2 should be insulated before attaching a connector to a two-conductor shielded bare-ended cable.
The Model 545SH is supplied wired for low impedance for operation. The low-impedance connection is recommended where long cable lengths are required or under conditions of severe hum disturbance. The permissible cable length is practically unlimited since neither response nor level is appreciably affected by long cables. Shure Model A95 Series Line Matching transformers are available for use when a low-impedance microphone line is desirable but the associated amplifier has a high-impedance input. These transformers provide a proper impedance match between a 19 to 300 ohm microphone line and a high-impedance input and are available with various input and output connectors.
To change the Model 545SH to high-impedance, proceed as follows.
When using the microphone in low impedance, the BLACK and RED cable leads are the "hot" conductors for balanced-line connections; the shield is connected to the chassis or amplifier ground.
NOTE: After following the above directions, the PE54SH with supplied single-conductor C5-X cable will be suitable for connecting to unbalanced low-impedance inputs. For balanced-line low-impedance operation, replace the C5-X cable with the C51CN cable: 7.6m (25ft) two-conductor shielded, with three-pin professional audio connectors (male and female).
Microphone rating impedence is 150 Ohm (250 Ohm actual) for connection to microphone inputs rated at 75 to 300 Ohms.
The 545L is hard wired with its own cable, and low impedance only. It is more than one inch shorter and lighter than the other 545 and PE54 wand mics.
When using the microphone with a balanced input, pins 2 and 3 are the audio signal carriers. When using the microphone with an unbalanced input, use a cable wired with pin 2 as the sig-nal carrier and pin 3 connected to the cable shield (ground), such as the Shure C20HZ high-impedance cable.
The microphone is shipped connected for low impedance operation. To change to high impedance, proceed as follows:
Your Model PE54 is a high impedance microphone. If cable lengths over 7.6 meters (25 feet) are required or if the microphone is to be connected to a low impedance input, it will be neccessary to transform the microphone line to low impedance. [The PE54 cannot be switched to balanced low impedance requires a seperate impedance adapter]
Your microphone is supplied wired for high impedance for connection to high-impedance microphone inputs. To change the microphone wiring for connection to low-impedance microphone inputs (rated at 19 to 300 ohms), remove the male plug insert by turning the slotted setscrew inward (counterclockwise). Disconnect the two-terminal impedance selection socket (see Figure 2) from the rear of the male insert, and reconnect the socket in the reverse position so that pin 3 of the male insert is inserted in socket terminal "L."
NOTE: 1. After following the above directions, the PE54D
with supplied single-conductor C5-X cable will be suitable for
connecting to unbalanced low-impedance inputs. For balanced-line
low-impedance operation, replace the C5-X cable with the C50CN
cable: 6.1m (20ft) two-conductor shielded, with three-pin
professional audio connectors (male and female).
2. Replacement Case Assembly RK150C is shipped wired for low
impedance; change to high impedance by reversing the above
procedure.
You microphone is supplied wired for low impedance for connection to low-impedance microphone inputs (rated at 19 to 300 ohms). To change the microphone wiring for connection to high-impedance microphone inputs, remove the male plug insert by turning the slotted setscrew inward (counterclockwise). Disconnect the two-terminal impedance selection socket (see Figure 2) from the rear of the male insert, and reconnect the socket in the reverse position so that pin 3 of the male insert is inserted in socket terminal "H."
NOTE: After following the above directions, the PE54D-CN with the supplied two-conductor C51CN cable will be suitable for connecting directly to high-impedance inputs using three-pin professional audio connectors. For direct connection to 1/4 in. phone jack inputs, replace the C51CN cable with the C5-X: 6.1m (20ft) signle conductor shielded with three-pin professional audio connector (female) on microphone end and 1/4in. phone plug on equipment end.
Your microphone is supplied wired for high impedance for connection to high-impedance microphone inputs. To change the microphone wiring for connection to low-impedance microphone inputs (rated at 19 to 300 ohms), remove the two screws holding the switch. Taking care not to break any leads, remove the switch and switch housing from the microphone swivel. With a pair of long-nose pliers, lift upward and disconnect the 2-terminal black plastic impedance selection socket from the back of pin 3 of the audio connector. Replace the socket with pin 3 inserted in socket terminal "L". Press the plastic socket firmly in place. Reassemble the switch housing, switch, and switch-plate, taking care not to pinch any leads. Fasten securely with the two previously removed screws.
NOTE: After following the above directions, the PE54SH with supplied single-conductor C5-X cable will be suitable for connecting to unbalanced low-impedance inputs. For balanced-line low-impedance operation, replace the C5-X cable with the C51CN cable: 7.6m (25ft) two-conductor shielded, with three-pin professional audio connectors (male and female).
The following are a brief comparison of the different
Shure 545 models, Shure PE54
models, and a few modern Shure products for
comparison.
The links are to their respective data sheets on Shure's website
where you can compare their frequency response charts.
PDF format,
Adobe Reader required.
You can visit Shure's discontinued products page.
© Copyright 2005, Harp On! G. All rights reserved.
Do not copy or reproduce without express permission from the author.
All parts quoted from Shure Inc. literature are
© Copyright Shure Inc.