Setup Calibration Kit for Studer 1/4" A807 Tape Machines
CALIBRATION KIT for A807
Nagravox Calibration Kits different to what you might expect. A lot more than just a calibration tape!
Developed over the last 3 years specifically for discerning audio enthusiasts and professionals. The rationale is to provide an appropriate set of tools, instructions and media to test, calibrate and setup a specific model Revox or Studer machine properly. Three resources based on the three fundamental chains of signal processing.
* INPUT OUTPUT CHAIN * PLAYBACK CHAIN *RECORD CHAIN
A cheap short generic reel of tape recorded by an enthusiast to try and make some money from his tape machine on eBay is not realistically going to help you setup and calibrate your machine properly. Calibration is the final step and is not just a process of throwing on a playback tape, tweaking some trimmers and hoping it will all come together. All 3 chains must be considered singly and then together. You also need to understand what gear and instruments are needed and how to use them. Awareness of modern tape formulations, relevant steps, differences, peculiarities and nuances of a particular model, later factory updates not in factory manuals and hints and tips based on experience make calibration and setup a science and not a hit and miss affair.
The Nagravox calibration kit is designed to setup and calibrate your machine fully and properly. Each kit is tailored for a specific machine and your tape type preferences. Feel confident that your machine is setup and performs the way it was designed and manufactured.
PLEASE NOTE: This kit is for the professional Studer machines model A807 1/4" machines that require a variable number of playback chain calibration tapes corresponding to the the various speeds and equalisation options. The A807 had a great many possibilities from 2 and 3 speed as well as single or dual equalisations and NS (normal speed) and HS (high speed up to 30 ips).
NAB Equalisation always applies to 3.75 "/sec and AES equalisation to 30 "/sec. So for these there is only 1 speed / equalisation. For the speeds 7.5"/sec and 15"/sec you can have either NAB or IEC (CCIR) equalisation.
HS versions will have 10.5" tapes
Some variation combinations may not be applicable and a price will not be shown and you wont be able to select it for purchase.
Nagravox Setup and Calibration kits include:
• Playback calibration tapes for each speed and equalisation.
• New fresh record setup tape for calibrating the record chain
• A set of detailed instructions, explanations, required equipment (which are not too onerous nor expensive), diagrams and check sheets SPECIFIC to your particular model machine. These are based on Revox Studer manuals, Factory Tech Bulletins, industry best practice and Nagravox’s own experience repairing, updating and restoring tape machine’s.
You need to decide:
• Speed version - 2 speed or 3 speed in NS normal speed to 15 or high speed HS to 30
• The tape type and formulation you will be using to set the machine up for. We recommend SM900 but can accommodate SM911, LPR35, LPR90, ATR Master and ATR MDS36. (All currently manufactured new tape).
The playback calibration tape/s are long length on a 7" special somewhat 'ugly' blue reel (so it cant be mixed up or easily recorded over in error) and includes a plethora of appropriate length tones (the important ones are in minutes not seconds!) at calibrated levels with full commentary and explanation. Everything on the tape relates back to the calibration manual notes and explanation. 30"/sec playback tape are on a 10.5" plastic reel
The Record chain tape is a brand new full length 7" tape of the type you will set your machine up on. For HS versions the record tape is a 10.5" pancake.
Instruction Manuals are requested and sent to you via a download service as a pdf.
Do you want add a second machine model or equalisation speed or want to set up on multiple tape types? We offer extra add-on kits for purchasers of this full kit which provides additional options and usability to this base kit in an economical bundle. (some variations (there are many) may not be applicable)
SOME GUIDELINES ON TAPE TYPE
- SM900 and ATR Master are durable studio grade mastering tapes able to handle up to +6 to +9 Db saturation with minimal increase in distortion.
- SM911 is a max +3 Db tape. This 'over drive' is not the only difference but I am hesitant to pass comment on nebulous terms such as 'warmth'. You just need to try and decide for yourself. Certainly be circumspect in being guided by www forum hot air and nonsense.
- LPR90, LPR35 and MDS 36 are thinner commercial grade tape with similar (but not exactly the same) magnetic characteristics as their standard play cousins. Their main advantage is economy in that you get 44% more tape and time on a reel. However you dont get something for nothing and lifespan is reduced.
- SM900 (std play) and LPR90 (long play) have similar but not exactly the same magnetic properties despite what the manufacturer implies. Similarly for SM911 / LPR35 and ATR Master / MDS 36 . So setting up on one and using the other could mean a variation of 0.75 - 1.5 Db difference in level between std and long play and the optimum bias will also not be the same.
- How critical is it that I use the exact tape formulation all the time? You can use any tape formulation on any machine no matter what it has been set up on and it will work OK but not optimally. You wont break anything! The key here is 'optimal'.
- How many times can I re record over and play tape. I suggest the following rough use guidelines.
- Re-recording over SM900 / SM911 - 15x LPR35/LPR90/SM468 8x
- Playing pre-recorded. This is dependent on machine but generally I would apply the following based on tape tension and spooling speed / handling:
- Revox 36 series & machines with basic tension control 300 - 400x
- Revox A77, B77, PR99 400 - 500x,
- Revox C270 & A700 and all Studer machines 200 - 300x
Test Instrumentation and leads / adapters required for calibration
Our service manuals detail the typical instrumentation you need for calibration. Here is a summary.
- Millivolt meter - analogue not digital ( definately NOT your digital multimeter!)
- Signal Generator - required for inputting record chain pure sine waves at various frequencies and amplitudes. Digital or analogue OK.
- Adapters and cables - quite a few including dummy loads
- Oscilloscope - although not absolutely essential, an oscilloscope is really fabulous to visualise and understand what's happening. Modern ones are mostly really good, not very expensive and boast a range of useful functions such as auto setup and measurements of frequency and amplitude.
Have a look at what we have listed here:
These are nice to have but not really necessary as you can accomplish much with what's already listed.
- Frequency meter
- Wow and flutter meter