Top Hat Electronics

01/06/2026

This weekend I had the absolute pleasure of playing a lot of records on the Turbosound Floodlight rig I refurbished recently at Retallack Woodlands, such a lovely venue.

I don't think I've yet shared photos of the speakers on here but they are sounding excellent, a testament to their original build quality.
The compression drivers' diaphragms were replaced and some minor work here and there, but in general due to careful ownership the rig is sounding as good as new after the extensive work to the amps themselves.

I also repaired and serviced the pair of DP200 crossovers, installed as an upgrade from the original analogue processing. XTA have now discontinued support for these older units, and others, however I'm more than happy to consider their older products for refurb on a case-by-case basis.

26/05/2026

Repaired a Pioneer XDJ-RX3 for DJ Brady

22/05/2026

Refurbished a pair of TL Audio PA-5001 and a TL Audio Ebony A1 for Ryan Jones

These are high quality multi-function mic preamps with adjustable valve warmth / colouration. The PA-5001 uses low-noise OP-AMPs for input and output buffering whereas the Ebony uses discrete class A transistor preamps, and has additional instrument DI inputs. This allows for a useful choice of clean or coloured signal paths depending on requirements as is well thought-out.

The refurbishment work was required mainly due to overheating over time, causing degrading components, mainly capacitors and the valves themselves. The units get very warm and prolonged studio use significantly degraded performance over time.

By request of their owner I Investigated forum claims of flawed design, which tended to be unfounded, and possible upgrade paths within reason. The valve stage feeds a TL07x OP-AMP buffer and this is correctly implemented. The OP-AMP in this location does not need to be upgraded from this series due to it not being a high gain stage.

I investigated the general design of whole signal chain with respect to OP-AMPs and their suitability etc. The implementation of SSM2017 as the main gain stage is correct this an important area and very high grade OP-AMP used in this location. The output buffers are NE5532 with external CMRR compensation, this is also high grade and correctly implemented, I found there was no clear benefit to upgrading OP-AMPs due their existing careful selection according to position in signal chain.

I replaced and upgraded all electrolytic capacitors in each unit, paying attention to type, temperature ratings and quality. General servicing was carried out such as re-working of solder as necessary on PCBs, cleaning headers, switches, pots, sockets,
checking internal mains wiring, earth connections, transformer, power supply, heatsink fixings, insulation and suchlike for reliability.

During testing I discovered two faulty ECC83 valves in one unit and proceeded with testing other valves before replacement. A third was measuring poorly with respect to linearity and therefore decision made to replace all four valves in one unit. I retested the unit with new valves and compared the performance with other unit with Edicron valves, which were previously replaced.

I carried out a lot more subjective sound quality tests than I would usually do with equipment, because the valve stages are designed to colour the sound. Usually I would primarily rely on measurements of performance rather than my ears, but listening tests were necessary in this case.

In the TLA 5001 there is a SSM2017 doing most of the heavy lifting and the tube warmth is proportionally added according to gain control position, the tube isn't the front end. However in the A1, one triode is acting as the high impedance front end for the instrument DI, therefore that unit needed to be treated differently with respect to what valves were eventually used.

There were faults with the instrument DI on channel 2, this had short-circuit surge protection causing 10dB difference in signal, so I replaced these components. I improved the internal grounding by adding straps to star ground from jack sockets to reduce noise, and replaced the sockets themselves, among other work as needed.

Many thanks to Russ Fletcher for his advice about which types of valves to use and their relative merits and matching requirements.

18/05/2026

Here is some of the work that I feel is now necessary for reliability reasons when faced with the early revision of Technics SL-1200MK2 and SL-1210MK2 turntables.

The early PCBs are easily identified by the ageing appearance, and component selection and placement such as large ceramic bypass capacitors glued to the underside of the PCB, among other things.

This often causes a problem where access is needed to re-work solder in areas prone to overheating, and during full servicing I now remove these caps and carefully clean up the board in their locations. Most of the solder is re-worked on these older PCBs.

All the electrolytic capacitors are replaced with high quality Panasonic, Nichicon or Vishay to ensure longevity. The caps on the underside of the board are upgraded to modern types in each location, that are physically smaller and don't require gluing. It is important to spec the correct types when upgrading these.

Another common issue is overheating of the motor drive controller, so the thermal grease is renewed and temperature monitored during soak testing, otherwise the motor controller IC is at risk of failure. Any other areas of the PCB that are overheating are checked and reworked.

Most of this work is only currently necessary on the earliest PCBs - due to Panasonic's initial design and spec of high quality components in general, the later PCBs generally don't (yet) require re-capping, but they are checked for dry solder and other obvious issues

Before > after.

15/05/2026

Repaired and partially re-designed the power supply in a Musical Fidelity A3 CD player and repaired faults with the CD mechanism.
The main fault was a blown mains transformer which was a custom-wound toroid providing three windings of quite non-standard voltages: 0-3, 0-9, and 13-0-13 centre-tapped.
This in turn provided several DC rails suitable for different sections of the unit. I reversed engineered the PSU circuits to see exactly what was going on.

13-0-13 is full-wave rectified and regulated to provide standard +/-15V for the analogue AF sections (OP-AMPs, etc.)
One leg of this AC winding also feeds a voltage-doubler that is regulated to provide -30VDC, combined with the zener-referenced 0-3 winding, these combine to provide the odd voltages needed for the fluorescent front panel display.

The decision was made to use an off-the-shelf Carnhill toroid to provide the standard 13-0-13 or so for the analogue circuits as a starting point. This was modified by adding an extra winding to provide the 3V AC required by the flouro display.

Two more DC rails for the digital logic and motor controller were dealt with by adding a small 12V SMPS, to in turn feed linear 7.5 and 5V regulators. Small modifications were made to the the existing PSU circuit to ensure regulators were in safe limits, and capacitors were upgraded/replaced. Most of the existing PSU was kept as-is, rather instead fed from suitable sources, to keep the analogue and digital regulation separate as per original design.

The CD mechanism was diagnosed to have a worn-out spindle motor so this was replaced with one from a donor unit. The Sony KSS-240A is a very good pickup and this was tested by watching the RF eye pattern to ensure the pickup was reliable with test CDs.

21/04/2026

PSA: I've had to label myself as temporarily closed again on Google. This isn't accurate - it's to avoid trending for electronics repairs in general across the South West, due to there not being many engineers. Unfortunately while I would very much like to help everyone and love the attention, I'd rather spend my days getting the work done that I specialise in, instead of fielding phone calls for all sorts of other things. I'll probably figure out a better way around this at some point. Many thanks to everyone for the recent recommendations...

17/04/2026

Repaired & refurbished a pair of Numark TTX1 turntables for Olly Waddington.
These both had faults with the motor controller drive ICs and associated circuits, requiring quite a lot of work, re-capping the PSU, reconditioning the pitch controls, replacing all the switches and so-forth.

They are quite a bit different to work on than Technics turntables. They have more features in some areas such as up to +/-50% pitch range at three speeds 33,45,78, and much more torque and variable start/stop. Therefore more creativity can potentially be unleashed (that I don't possess)

The downsides compared to Technics are the general build quality and tonearm mechanics, however it must be said that they are one of the preferred alternatives and this pair were worth refurbishing.

The Formula Sound PM100 mixer has also just been fully serviced, this is an excellent mixer.

Full service & refurb including repairs to motor controller drivers in both units, power supply areas, pitch controls, switches and various other issues.

03/04/2026

For sale: Kef Concerto pair (kit form) with Coles super tweeters, external hybrid active/passive crossovers in 1U rack case, designed and built by me a long time ago. The active crossovers are 3-way and the passives are also 3-way, and you can choose what goes where, it's currently configured for active bass and passive everything else. The mains PSU is separate and safe. The speaker boxes were built very well (not by me) and I think there are passive tweeter protection networks inside the cabs.

This all worked fine and sounded great last time it was all tested, which was fairly recently, but needs some wiring and tidying up, mostly speaker to crossover etc., nothing that complex. There are diagrams and schematics of how it works. Only buy if you're willing to take on a bit of a project, unfortunately I don't have time to work on it but happy to answer questions. Bargain £300 collection only.

02/04/2026

Some recent Technics turntable refurbishments.
Thanks to DJSpares for pitch controls, legends and cable grips and for the very decent slipmats.
Work done for Eco Park Porthtowan, Joshua Bamford, Caroline Dann, Kemeny Turner and others.

26/03/2026

Free to collect, quantity of PCBs mostly older mixer and amp but some random things too. Quite a lot of useful components.