Revox A77 Abbey Road mods

Electrical and mechanical conversion of ReVox A 77 to studio

  • The Swiss recorder Revox from Studer have formed the world standard in o situ kind. Nevertheless, the current h version A 77 (Mk 1-3) some bristerk resulting by the inevitable compromises.
  • Due to the machine's mechanical and electrical design is so logical and forward-looking designed can, however, build on the tape player to oltka degrees of sophistication. Revoxen is extremely ' trim bar, and many have over the years developed-cessful taken enhancements in the parts that seemed eager to change.
  • They are already in the original sound data as A 77 possesses can be improved quite a lot, and both electrically and mechanically, a Revox converted sä längtgäende, that it will meet completely all individuals wishing-targeted requirements for data, performance and ma-növrering as well as availability and generally all-performance
  • RT has in many ar peddling Re-vox-trimming, and we start now a detailed line description over the rebuilding of A 77 after at length practical experiments, recording aingsverksamhet and data analyses. Idégi-ERS and the design team is the young Gothenburg sound techniques Anders Hede ach Göran Finnberg who in consultation with RT's Uf B Strange started from the wish-eel and preferences that practical approach-course of trade imposes as well as over uvud ' 1 tvaspårsmaskin.
  • small Studio's "assets on the first episode deals with the MU-k zniska construction. See also front.

When the Revox A 77 came on the market around 1968, it drew great attention to it is a transistor of successors to them classic J6 machines (e RT 1968 No. 10).
Bandmates saw a band player here had good data but not at the price of a studio machine. The professional finders found Revox A77 is good enough to have it as an extra machine. Its low price and weight also made it diligently used "Live" -upptagningar.

Several discs have been recorded with a Revox A77. We can mention, for example, Hákan Sjögren for Proprius done so.

The tuner has electrical and even de- Significantly modified a number of times: just now there is one on the Swedish market model called Mark IV. Abroad, and especially in England, you can get Revox A77 in synchronous version with variable speed from 10 cm / s to 100 cm / s.



Tests have shown deficiencies at A77

However, the band player has some shortcomings, which Over the years has been noted in a number of test- is performed by Radio & Television, Musikreyy, Studio Sound, with fera. Among other things, have one complained that it is difficult to eat the main kit for cleaning and editing. We dare it does not work well enough, currently used in professional Context. You have also thought equipment To The design and plasticity are concessions for The gate has been clarified but is perceived as The intentions are too bad. Etc. - flaws of many.

Metal fronts are available for language labs

We have used Revox A77 for a number of years ins pelningar to discs m m. We soon found that
the noise from the playback amplifier was rela- tightly loud and that it entered the network. We pre-
Wore different solutions and could after a while eliminate most of the shortcomings and even make one
new design on the tape player.

Because we mostly have the bandplayers too mobile recordings, they often get out of hand
hard droughts. The machines have been hit in doors, fallen into the floor, etc. Over the head has band games
Because we mostly have band games for mobile pelts, they often get out with hairy thighs. The machines have been hit in doors, fallen into the floor, etc. Over the head has band games clean treated unmixed.

AB was told that there were metal fronts Revox A77 was considering whether these customers could
be useful to the machines. We would have to a flat deck that would be easy to edit- rave on Studying factory outlines metal fronts- after to their sprayers. Because these just to play off, there is only on the front
Tape Headset Outlet, Spool Plates and pushbuttons "Reel Motors off and "Speakers". We mean that a mobile bandspelare for use in both occupations and in HiFi equipment should be controllable input and output levels. Furthermore, equipment The indicators indicate the level of the boat before or before efter band.

We tested a copy and tested it is practically out on the field. The result was over...

Fig. 1. Front view of the converted Revox A 77.

Fig 2. Mounting of EMI joint block.

Fig. 3. Mounting of the joint on the original fitting.

Fig. 4. For a check-in check, a plate is manufactured drawing 4. The triangular plate is visible in the image my.

Fig. 5. Switching on the power switch in the dummy- g. "Power off" is used as a power switch.

Fig. 6. Shoulder plate and drawing 2, placed between the engine and circuit boards.

Fig. 8. Connection diagram for master card and om- coupler. Some wires are cut. The potentiometers replaced. MeMurdo Flat Plug Connectors are connected at K. (Elfa 44-1030-4).



Especially good because the output amplifier i Hi fi equipment should normally be loaded with 50 kohm or 100 kohm and thus will cut by strong passages

We have found that Revox’s original potential meters mechanically are not particularly advantageous at the entrances. Therefore, they are axchanged for otentio meters such as Piher 5k log with 6mm shaft- diameter
All potentiometers and switch axes cut off the drawing 8. The new potential the meters are placed in a hole. which was moored with the figure as ahown in Figure 7. Figure 8 shows the coupling sche- and the change of the “input ampl” connector food for to connect the meter before and after tires.
It is advisable to study coupling carefully because a miss can cause a lot of trouble later on!

In the throat that was previously occupied by the screws to the switches S3 and 54, place 4 dis- tines with a length of 13 mm. One should ensure that metal covers on the input potentiometers and the distances do not come into contact with ground on the master card. If this were to come in hit. can a brass loop be formed. Where to go Revox A77's chassis and electronics are grounded in
a dot. This is shown in Fit 8, Item A.

It is likely that you will loose new cables headphone tap, AB12. ABI1. AB8. AB7, AB14. AB4, AB6. ABI3, AB I0 and AB9. The appropriate length of the cables is about 8 cm. VU meters
As equipment we will continue rant to use Revox own instruments. because we already have demons and they fit

Ian the metal front and the plate and the drawing 7. Frán "Input ampl" connector 1.077.700 pulled cables
from pins 3 and 4 plus 7 and 8. The first goes to the left channel instrument (CHI) and the second right channel instrument (CH2) via a 4-pin connector, mounted on the plot and the drawing 7.
When you've done everything 8 years old, the card can mounted on the plate as shown in Figure 7. First, mar. However, on the plate mount two 10-pole McMurdo flat pin connectors as shown in Figures 8 and 9.
Instead, it is advisable that the entire package is mon teras in its original place in the band clean.
Now all cables were soldered to the two flat pins

Fig 12. Lights for illumination tension of the VU meters To indicate recording. The LA 301 lamp is on
continuously after turn-on of the device.

Fig. 11. Electrical connection of flat pin contact States.

Fig. 13. Assembly of screen plate 2, and figure 3.