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About VanArn

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  • Birthday 25/07/1941

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  1. The speaker is the RS/12/DD, not the Super 12/RS/DD. It is an excellent full range speaker. I know of another that is available but it has the later cone with the smaller H.F. cone. Famo actually has the first cone version of this speaker.
  2. Can you confirm that your version of the Project Essential III is the Recordmaster, which has a USB output as well as the stereo rca sockets with the line or phono level switching option? The Stream Magic, I believe, uses a 3 pin IEC power lead and if this is left in the system, it is possible that your problem could be an earth loop via the USB cable, if these are left connected to form a loop. The ground wire from the turntable should connect to the earth on the preamp and not left disconnected as it screens the pickup arm.
  3. Shifting the turntable is a good start in trying to find the cause of the buzz problem, as some times a phono cartridge can be too close to a mains transformer. The Rotel preamp and amplifier are double insulated models and therefore are not earthed via the mains. The XLR balanced option should be the preferable method of connection between the preamp and amplifier. The Project turntable is supplied in optional types. Some have a mm/ line preamp fitted and this should be in the line mode if plugged into the Rotel preamps phono inputs. Also there needs to be a cable connection from the turntable earth screen to the earth lug on the preamp. The latter applies to the Project TT,s with and without the Project phono preamp.
  4. Since you have supplied details of the Toshiba amplifier model and while I suggested checking fuses previously; your amplifier is fitted with four resettable cut-out switches for protection. Have you checked to see if one of them needs to be reset? If it still needs to be serviced after that check, you could try Audiophile at 150 Northern Road, Heidelberg Heights but you may find he only opens on Saturdays.
  5. Frequency doubling does not receive the same attention in the Hi Fi literature as it once did. In fact looking up the term via the web drew blanks. Here is how Gilbert Briggs described it in his book ''A to Z in Audio'' FREQUENCY DOUBLING. This usually occurs in a loudspeaker at frequencies below the main cone resonance, but it depends also on linearity of suspension, power input and method of mounting. When it occurs, notes one or two octaves above the input frequency are produced and a pure tone may be converted into a rattle. Testing at a low frequency, say 20 Hz, the speaker which makes the most noise is always the worst. Distortion from doubling can of course be avoided by using very low input level, with very little cone movement. A moving coil microphone with input of a few milliwatts may be quite linear in cone movement, but used as a loudspeaker and fed with a full watt from an amplifier it would double frequencies over a wide range and probably double up completely in a short time.' ChaddoNobby has supplied information on the speakers that are giving him a problem and it seems that they may have been overdriven and possibly they suffered either voice coil damage or the suspensions have gone soft with use. Many speaker systems using single small bass drivers ( 5'' or less ) in small sealed enclosures actually rely on frequency doubling to provide a sense of going deeper in the bass range by exploiting the peculiarity of hearing to supply the missing fundamental frequencies as a result of increased harmonic distortion when the speaker system is driven below the resonant frequency and at levels that require high excursions.
  6. I have not heard of this company and a street address is not listed. Perhaps another member can furnish information about Audio classic HiFi. I would suggest that you check all the fuses as a first step. If there is a more serious fault, the cost of repairs could exceed the commercial value of this old Toshiba amplifier. Sometimes it is better to put your money into new equipment. Whatever happened to trade-ins ?
  7. Bypassing RF signals at the input ground points with ceramic capacitors is the correct method. Film capacitors have more inductance and as a result are not as effective in this role. Microphonic issues do not come into this scenario as the caps. are not in series with an audio gain stage, where, certainly quality capacitors should be used.
  8. RF signals can be picked up on the outer shielding of connecting cables as they act as aerials. If you allow the signal earth returns to be contaminated circuits within the amplifier can be effected. The bypass capacitors stop this problem. Any RF pickup on the 'active' inputs are dealt with by a simple resistor/capacitor network and sometimes the addition of ferrite beads.
  9. It is better to look at where the components are attached. Each capacitor ( ideally ceramic ) should connect directly to the individual rca socket shroud and the other end directly to the chassis by the shortest possible route. This bypasses any RF signal that may be present, to ground. The links between all the rca sockets indicate a common ground buss that connects to common ground point elsewhere.
  10. It is a horn without a compression driver, i.e. it is a mess. For true horn loading a throat with a phase equalising plug is required; such as Tannoy's pepperpot or the radial slits such as JBL provide. Basically the throat area needs to be around 50% of the effective diaphragm area and correction is needed for the time differences from the various sections of the diaphragm. It is a difficult proposition with a horn to cover more than three octaves of the spectrum and maintain a high sensitivity together with a fixed distribution pattern. I would think the designer of this speaker in trying to utilise an inefficient tweeter has resorted to a P.A. horn in an effort to match up with the bass midrange driver .
  11. Although the Model No. looks like a Duntech type, I think the speakers are more likely to have been manufactured by Bill Webb. He was the early importer of the Audax speaker range and he supplied some drivers to Duntech.
  12. When testing with pure tones you need to keep the level at a point that will not damage the speakers or your ears. Tests are normally conducted at a one watt level as a standard and this can be very loud with high efficiency speakers. If your speakers use a small bass driver then less power should be used to test them and many small speakers will not play low frequencies without doubling, especially in sealed enclosures.
  13. My old turntable , a Thorens TD 125 with a modified Acos Hi-Light pickup arm has been virtually in storage for about 20 years. That information is just to conform with the request by Jake123. In the past I used the BJ alignment protractor supplied by Burne-Jones & Co. Ltd. This innovative device allows the tracking error to be measured anywhere on a disc ( in inches only ) and this means you can set up an arm accurately when you do not have the manufacturer's pivot to spindle, overhang and offset information to start with and you do not have to decide on of whose formula is the flavour of the month. Keeping inner groove distortion to the barest minimum requires precision in adjusting the arm and cartridge and the fine line styli ( Shibata, microline etc ) are certainly better in this regard ; however inner groove distortion still occurs with linear tracking arms and is an inherent weakness in LP microgroove recordings.
  14. The BJD factory was at one time located in Box Hill . Speaker cabinets and assembly took place there and Linear Design was one of the models manufactured there and sometime later the Jensen brand became the main product.
  15. Garry Cawsey may be able to help you. Depending on the fault being one that does not require original parts such as switches, he should be able to sort out the problems in reasonable time.
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