TEL: 01424216245
Below are images and a brief description of interesting items that have come through Servicesound's door.
Click on the image to enlarge it.
A fully rebuilt Rogers Cadet integrated amplifier. Generaly, these little amplifiers need all the electrolytic capacitors replacing and all the resistors checked and replaced where necessary. The ECL86 output valves are getting hard to come by but if the original Mullard ones are fitted they should still be okay.
A Ferrograph Series Seven being put through its paces. Part of a complete overhaul is the spooling motor modifications to replace the variable spool height with solid bearings. This results in a quieter and smoother operation during fast winds.
A rather rare Sony TC-640A in for service.
A Sony TC-377 machine stripped ready for reassembly. As can be seen, the whole deck is dissasembled and cleaned. Both hubs are removed, cleaned and lubricated and the change-speed idler wheel is dismounted and the rubber surface reground.
This is a totally new pre-amp built in an old Quad 22 case. This was quite a tall order as the client wanted to include a headphone amplifier in the pre amp. The four horizonatally mounted valves are the phone stages whilst the remaining three are; two for the headphone amp and one as the cathode follower output to drive the monoblocks.
The new pre amp has been repainted gloss black. The headphone socket has been fitted to the modified knob next to the volume control on the left whilst the push buttons are still used to select the inputs.
Redesigned to bring it up to modern specifications.
Included is a line and phono stage plus a remote control. The remote control system can be seen mounted on the far side.
LEAK Point One pre-amp and its outboard power supply.
A specially built 600 watt amplifier. 12 X 6550 output valves are used.
This shows the wiring etc. The little circuit on the left is the HT protection system.
This shows the sockets and the bias set-up meter and adjustments.
An Art Audio tube amplifier in for rebuilding. We think some sub standard output valves have been fitted and the unit left on overnight resulting in severe damage.
The printed circuit boards have been replaced with aluminuim panels.
Tha ART amplifier is running EL34 output valves in push pull triode Class A operation and delivers 18 Watts per channel.
This came in having not been used for some 30 years. It was decided to replace "all the usuall suspects"
The new components can clearly be seen.
This American amplifier uses 6C33 output valves. Using the same output valves as the Graaf but in a conventional transformer push pull circuit. Nevertheless these are still sensitive to biasing requirements which need to be checked now and again.
The main difference between Ferrograph S7 MKI and MKII is the heads.
This is the MKII the another difference is that the counter is belt driven.
Ferrograph 632 stereo machine.
Ferrograph heads being redied for re-facing and polishing.
This is a special production version of the Logic for broadcast purposes.
This Ferrograph has been sent from Israel for a complete overhaul. It arrived in its own specially made flight case.
This model of Ferrograph was made to bridge the gap between the Series 7 and the Logic. Basically it's a S7 made with a slightly larger chassis with more powerful spooling motors.
These OTL amps are difficult to deal with due to the inherently unstable bias system and the very variable quality of the Russian made 6C33 valves. A new bias system has been designed and added as shown by the two new panels top and bottom. Admittedly the 6C33 valves were never designed for audio use, they were designed for use in transmitter power supplies.
This Leak TL25 has exploded probably because one of the output valves broke down. It is very important to have older amplifiers inspected and overhauled to ensure there are no components that are failing.
This printed circuit board was very badly damaged when something was spilt on the amplifier. One of the reasons why we do not used PCB's.
This shows the aluminuim panel that has replaced the burnt one and the simplicity of the layout.
The output valves in this rebuilt World Audio stereo amplifier are 2A3 directly heated triode valves.
The brief was; how small can you make a stereo valve amplifier that will deliver 12 Watts with low distortion. The footprint of this amp is equal to a A4 sheet of paper and 12 Watts with .1%THD at 10 Watts.
This shows a very worn 1/4 track head before and after refacing and polishing.
This image shows a heads that have been allowed to get clogged up with oxide. If you do not keep the heads regularly cleaned the performance will drop off a cliff resulting in muffled playback and poor or no recording.
This Tandberg is badly gummed up with oxide, note the capstan shaft on the right is also heavily contanimated leading to muffled playback and poor or no recording.
This little French made LECTRON amplifier came in with one channel distorted. This was is a hybrid solid state amplifier using transistors to drive valve output stages. The manufacturer had taken off all the lettering on the transistors plus there is no circuit or design details available anywhere. This hybrid design is not unknown but it is rarely successful. In this instance it was decided to completely redesign the whole amplifier and make it totally valve driven. The finished amplifier greatly exceeds the original in both specifications and sound. It uses British made Partridge transformers.
Superbly designed and really well built, this professional portable machine came in with poor speed control..
This is the 'plug and play" system used to design the electronics.
A Vero board has been used to build the new circuit.
The new circuit board is mounted on top of the original control board.
This little Sony TC-510-2 portable reel to reel machine came in with speed problems. Unfortunately the integrated circuit used to control the capstan motor is not available. It was decided that a new circuit be designed using a readily available motor control chip.
Here we have a very rare Ferrograph Stereo 1/2 track three speed Y632/U/CC ordered for the armed forces. This one was a special build. Ferrograph often built small batches of modified machines for data acquisition and special audio use.
This is a very rare Reflectograph model B made by Pamphonic in the early 1960's. There are probably only a few machines around now but this one responded to a complete overhaul.