Sondekker
18-08-2023, 15:36
I purchased this preamp 2nd hand a few weeks ago with the intention of using it to feed my beloved EWA M50A power amp. Unfortunately, there appears to be a rare mismatch insofar as the bass performance, while still producing deep notes just didn't have a great deal of weight. I managed to borrow a different solid state power amp last weekend which when connected to the Pre4 delivered considerably more weight to bass notes and produced a fine performance across the audio band. I don't wish to part with my EWA and so regrettably the Pre4 needs to find a new home.
The original owner purchased the Pre4 professionally built in CF (cathode follower) configuration together with the PSU3 power supply which was also professionally built some 15 months ago. In November of last year the Pre4 was returned to World Designs and modified by them to XL specification which included transformer coupling with balanced outputs, upgraded internal cabling, upgraded valves and upgraded capacitors.
From World Designs:-
''The Pre4 is derived from the highly acclaimed Pre3 pre-amplifier, now providing remote control of volume, input selection and a mute function. In addition the Pre4 now has variable gain (up to +21dB) to match with a wider range of source components and an optional balanced output for driving long interconnect cables.
Pre4 is an innovative valve pre-amplifier featuring low impedance drive to suit any power amplifier. This 5 input line level preamp is essentially an SE triode power amplifier in concept. Pre4 uses an ECC82 double triode arranged as input voltage amplifier and power output amplifier stages, the latter driving large output transformers.
The use of output transformers not only provides a low impedance drive but also avoids any possibility of slew rate limiting in the output stage making the performance independent of the capacitance of interconnect cables. Thus the Pre4 will successfully drive long cables connecting to power amplifiers near the speakers if you wish. Twin pairs of outputs allow easy connection to power amplifier and headphone amplifier, or bi-amping. The output can be configured to provide a balanced line connection between the Pre4 and the power amplifier.''
PSU3 is a high performance choke power supply with separate HT and Heater feeds for the Pre3, Pre3 CF, Pre4, Pre4 CF and Phono3 & Phono3S pre-amplifiers and phono stages. The PSU3 supplies the correct, smoothed, HT voltage for each unit. It can be used with either unit individually or both together. Outputs are via low impedance, multi-way sockets & plugs and umbilical cables supplied for use with our pre-amplifiers and phono stages. Offered in a single version only, the PSU3 features full Star Earthing and is supplied with Ultra Fast, Low Noise, Schottky Heater Diodes
The Pre4 and PSU3 will be provided complete with umbilical cord, remote control and comprehensive paperwork which includes full and detailed build notes and operational user guide. For those with the technical knowledge and appropriate skills there is plenty of space within the Pre4 for further upgrades and modifications. Please note that World Designs do not ship these items in purpose designed boxes but instead use staightforward cardboard boxes with individual items wrapped and separated in copious amounts of bubble wrap. Please see last photo below.
These items bought from World Designs in professionally built form would cost £1565 plus postage.
Asking £925 including RMSD (UK only) or can be collected from Ipswich. Willing to deliver/meet for cost of petrol up to 100 miles.
https://i.ibb.co/b6zgcHk/WD1-1.jpg
https://i.ibb.co/Rj4DD2N/WD2-1.jpg
https://i.ibb.co/PGHh9Z5/WD3-1.jpg
https://i.ibb.co/3pSryvy/WD4-1.jpg
https://i.ibb.co/0VgT5cm/WD5-1.jpg
https://i.ibb.co/ZTxLh8x/WD6-1.jpg
The original owner purchased the Pre4 professionally built in CF (cathode follower) configuration together with the PSU3 power supply which was also professionally built some 15 months ago. In November of last year the Pre4 was returned to World Designs and modified by them to XL specification which included transformer coupling with balanced outputs, upgraded internal cabling, upgraded valves and upgraded capacitors.
From World Designs:-
''The Pre4 is derived from the highly acclaimed Pre3 pre-amplifier, now providing remote control of volume, input selection and a mute function. In addition the Pre4 now has variable gain (up to +21dB) to match with a wider range of source components and an optional balanced output for driving long interconnect cables.
Pre4 is an innovative valve pre-amplifier featuring low impedance drive to suit any power amplifier. This 5 input line level preamp is essentially an SE triode power amplifier in concept. Pre4 uses an ECC82 double triode arranged as input voltage amplifier and power output amplifier stages, the latter driving large output transformers.
The use of output transformers not only provides a low impedance drive but also avoids any possibility of slew rate limiting in the output stage making the performance independent of the capacitance of interconnect cables. Thus the Pre4 will successfully drive long cables connecting to power amplifiers near the speakers if you wish. Twin pairs of outputs allow easy connection to power amplifier and headphone amplifier, or bi-amping. The output can be configured to provide a balanced line connection between the Pre4 and the power amplifier.''
PSU3 is a high performance choke power supply with separate HT and Heater feeds for the Pre3, Pre3 CF, Pre4, Pre4 CF and Phono3 & Phono3S pre-amplifiers and phono stages. The PSU3 supplies the correct, smoothed, HT voltage for each unit. It can be used with either unit individually or both together. Outputs are via low impedance, multi-way sockets & plugs and umbilical cables supplied for use with our pre-amplifiers and phono stages. Offered in a single version only, the PSU3 features full Star Earthing and is supplied with Ultra Fast, Low Noise, Schottky Heater Diodes
The Pre4 and PSU3 will be provided complete with umbilical cord, remote control and comprehensive paperwork which includes full and detailed build notes and operational user guide. For those with the technical knowledge and appropriate skills there is plenty of space within the Pre4 for further upgrades and modifications. Please note that World Designs do not ship these items in purpose designed boxes but instead use staightforward cardboard boxes with individual items wrapped and separated in copious amounts of bubble wrap. Please see last photo below.
These items bought from World Designs in professionally built form would cost £1565 plus postage.
Asking £925 including RMSD (UK only) or can be collected from Ipswich. Willing to deliver/meet for cost of petrol up to 100 miles.
https://i.ibb.co/b6zgcHk/WD1-1.jpg
https://i.ibb.co/Rj4DD2N/WD2-1.jpg
https://i.ibb.co/PGHh9Z5/WD3-1.jpg
https://i.ibb.co/3pSryvy/WD4-1.jpg
https://i.ibb.co/0VgT5cm/WD5-1.jpg
https://i.ibb.co/ZTxLh8x/WD6-1.jpg