Grundig C100 cassette 'mods'

[Martin Bush]

Hi all

I have a nice Grundig C100 DC International machine and cassettes which I acquired from a forum member.

It's now got a set of batteries in and plays very nicely.

I have a few cassettes and one looks slightly dodgy, which is fine as I want to try something out.

I believe that tape from a normal Compact Cassette will work in a DC machine as it is the same width. So my idea is...

Compile some content in Audacity
Change the speed and record the sound onto a Compact Cassette on my Yamaha deck
Transplant the tape to a DC shell and hubs (keeping the old tape safe).

I have two questions:

I think I will have to slow down the music in Audacity so that when it plays at the higher speed employed by DC it will be correct - what percentage do I need to slow it by (I have done a calculation, but maths is not my strong point). I need to get this right as I won't be able to test it until I have loaded the tape into the DC machine.

Will a stereo recording play properly in a mono machine? Or should I make the content mono to start with in Audacity?


Martin

[Analogue man]

As tape speeds are all multiples of each other (e.g. 1 7/8, 3 3/4, 7 1/2, 15 IPS) the reduction in speed needs to be 50%. Yes a stereo tape will play ok through mono heads although you may experience a little phasing occurring if the same sound appears on both channels but one being slightly out of time with the other.

[Martin Bush]

I thought DC international was 2ips?

As I say, I have done my own calculation, but this has involved converting inches to cm and, with me being someone who struggles with maths, I wanted to check.

[Ted Kendall]

If you pitch the file up by 6.6%, that should be right for 2 ips. I think DCI reads the lower half of the tape, so you should be all right there. Best to apply the same signal to both sides of the recording machine, although differences in azimuth may cause loss of top.

[Martin Bush]

Well, 6.6% is what I got too! That's a first

But would it be pitch up or down. If I pitch it down, record it at 1 7/8ips, when played at 2ips that will be right won't it?

Of course the more I think about this, the more confused I get.

[Ted Kendall]

Fair point - the signal going onto the tape at 1.875 should be pitched down 6.6%. Then the tape will be at correct pitch when played at 2 ips.

Sorry about that...exits stage left seeking wet towel.

[Martin Bush]

Well, you say that @Ted_Kendall, but the more I thought about it I was able to make both speeding up AND down work in my mind.

But yes, I think slowed down then played at the faster DC speed is the right way

Of course some may wonder why I don't just record on the Grundig using a DIN to RCA lead. I could do this, but I know that my Yamaha records well - I have no experience with the Grundig as yet.

[ricard]

Does the C100 not have record capability? Or are you hoping for higher fidelity with the Yamaha deck?