BorderPatrol Valve Amplifers S20 P20 P21 S10 SE300B Control Unit Upgrades

Upgrade options for amplifiers, Pre-Amplifiers and PSU's. There is an on-going development program at BP in which new circuitry, materials, components, valves and treatments are evaluated. The aim is to find ways to make the amplifiers sound more natural, revealing, dynamic and more musically satisfying.
Dynamics is an overused term in audio and to most it simply means the ability to play loud and hit hard but equally if not more important is the other end of the dynamic spectrum. At the micro-dynamic end of the spectrum the systems ability to resolve and portray the smallest pieces of information provides the vital clues about instrument timbre, vocal inflections, interplay between musicians and room acoustics that can turn a recording into a living musical event. Improvements in the micro-dynamic capabilities are made by lowering the noise floor and should not be made by engineering a treble lift to give superficial air and space. It is fundamentally important that the overall substance of the music is not lost in the quest for increased information. Many systems dissect recordings in the quest for increased information retrieval and destroy the music in the process and whilst hi-fi may satisfy the mind, its music that stirs the soul.

I will be visiting the UK two to three times a year to upgrade amplifiers. For more details and prices, please e-mail BorderPatrol

Control Unit pre-amplifier upgrades.

I am happy to announce some exciting new pre-amp developments.

Upgrade	Work required	Sonic	Models
6DE7/6DR7/13EM7 conversion NEW	This conversion involves changing the 5687 audio circuit to a new circuit using the 6DE7/6DR7/13EM7's family of triodes. A new circuit board and extra filament transformer is required.	These tubes sound great! They are rich, full, clean, colourful and relaxed, but their real beauty is that they can be AC heated which means the circuit is much simpler. Compared to the 5687 circuit, diodes, capacitors and a choke are no longer needed and this all adds up to a much purer, simpler sound. Long hours were spent optimising the heater circuit of the 5687: Diodes and capacitors were rigorously evaluated and selected, but even the best components leave a sonic fingerprint and removing them completely is a revelation. In this case, less really is more.	All 5687 Control Units
EXT1 conversion NEW	Addition of an external PSU. The PSU uses the low distortion power transformer configuration used in the EXD but with much larger transformers. A much larger choke (the same size as in the power amp PSU's) is also used.	BorderPatrol users will be familiar with the affects of oversized power supply units and this one really is oversized. It improves all aspects of dynamic performance but not in a crash-bang-wallop way (unless the music asks for it). Composure, headroom, bass, solidity, resolution and tonality are all improved. Serious! It easily digs captivating tunes out of almost any recording. In this case, more is definitely more.	All Control Units
EXT 2 conversion NEW	Addition of dual external PSU's and re-configuration to dual mono.	This takes the Control Unit to the ultimate. It build upon the EXT1 modification and gives the superior stereo and composure that only dual mono design can bring.	All Control Units

EXD	A 2nd power transformer is added to the PSU to create the low distortion PSU topology. Custom made polypropylene PSU capacitors are fitted together with a superior selector switch and volume control. Numerous other detail teaks and refinements are installed which brings the Control Units up to latest spec.	Removes background noise and grain which improves resolution and lowers the noise floor. It widens and deepens the sound stage and makes the pre-amp sound much more fluid and free. The overall result is a pre-amp that sounds much more natural.	All Control Units
Service Pack 1	Brings old Control Units up to the latest specification. Involves fitting different resistors and capacitors, superior volume pot, superior selector switch and numerous small tweaks and refinements.	The very first Control Unit's could sound etched and less than relaxed in some systems. Whilst this made for a revealing listen it could be fatiguing. The latest specification is considerably more relaxed and refined whilst being equally dynamic and revealing.	All Control Units prior to 2006
Re-wire	Re-wiring of audio circuit. Boutique input/output sockets - ask for details.	If you have preferred interconnect or cable that is used throughout the rest of the system, re-wiring the audio circuitry with this interconnect will have a profound and beneficial effect.	All Control Units

Amplifier upgrades.

Upgrade

Work required

Sonic

Models

EXD PACK	Complete strip down and re-build of the amplifier into copper chassis parts. Changing the inter-stage and output transformers to cryogenically treated ones. Re-building audio the circuit with our preferred carbon film resistors. Any tweaks and detail changes required to bring up to the latest spec.	The amps become clearer and easier listen to with much finer dexterity and flow coupled to a much more relaxed and natural tonality. The noise floor is much lower improving resolution and clarity The copper chassis parts impart a richer, more lustrous tonality with a cleaner background and less hash and grain. The carbon film resistors are more natural and uniform sounding than the metal film/wire-wounds used previously making for a more relaxed, less edgy sound and the cryogenically treated transformers have superior resolution and micro-dynamic capability coupled to a lower noise floor. The overall effect is a much more natural and relaxed sound with much better clarity, resolution and fluidity.	SE300B, S10, P20, P21, S20
High sensitivity configuration to low sensitivity configuration.	Changing the CV4068/E182CC input/driver circuit to the current specification low sensitivity 6C45pi configuration. * -see below.	The 6C45pi input stage sounds cleaner and 'simpler' than the CV4068/E182CC and the lower input sensitivity allows active pre-amplifiers to be used without noise and gain issues which results in a much more alive and dynamic sound.	SE300B, S10, P20, P21, S20
Convert to Dual Mono	The addition of a 2nd PSU and 2nd set of power supply capacitors and re-configuring the circuit to dual mono.	Adding the 2nd PSU greatly improves the dynamic capabilities of the amplifier in the same way as moving from a stereo amp to mono-blocks. When both amps feed from a common power supply dynamic events on one channel will affect the other channel even if the PSU is very stiff. This compromises stereo separation and image placement and can result in a perceived lack of headroom and security. With a separate PSU for each channel each channel can do its work unaffected by the other one and the result is a more relaxed and secure sound with greater headroom and control.	SE300B, P21
Re-wire audio circuit with Kondo Silver cable or other cable.	Re-wire audio circuit with Kondo Silver cable or cable of you choice.	If you have preferred interconnect or cable that is used throughout the rest of the system, re-wiring the audio circuitry with this interconnect will have a profound and beneficial effect.	SE300B, S10, P20, P21, S20

* BorderPatrol amplifiers have been made in three formats: Low sensitivity, high sensitivity and high sensitivity with volume control added.

The low sensitivity 6C45pi format is designed for use with active pre-amplifiers. It needs plenty of drive and the low sensitivity enables it to be used with a wide variety of active pre-amps without gain and noise issues. Using the low sensitivity configuration with an active pre-amplifier such as the BorderPatrol Control Unit is by far the best option.
Some users have used this format directly connected to a high output CD player with inbuilt variable volume control and while this worked as a 'get off the ground' solution they all subsequently added the BorderPatrol Control Unit.

The high sensitivity amp format can be used with active pre-amps but there are often gain and noise issues, particularly when coupling with very efficient loudspeakers. Using this format with a passive pre-amp solves the gain and noise issues but is usually the worst solution and invariably results in a slow, uninvolving and lifeless sound with poor frequency extension and dynamics.

The high sensitivity format fitted with a volume control has capabilities that lie between those of the active pre-amp and the passive pre-amp. It is significantly more dynamic and alive than the external passive pot solution but not as good as when using an active pre-amp.

Power Supply upgrades