Ferrograph 633H Recording Issue... - UK Vintage Radio Repair and Restoration Discussion Forum

untune87 · 23rd Dec 2012, 5:24 pm

Hi all,

I picked up a tidy and well looked after Ferrograph a few months back. It had been owned since new by the guy I bought it off and he clearly cherished it, I've no idea if it has had any kind of service over the last 50 years or so.

I've been using it to track audio to tape and use the preamp to add a bit of warmth and character to recordings. Today I came to record some stuff to tape to see what kind of an effect the tape saturation would give to different signals.

I recorded some drums a few months back and my friend did some guitar, and I've just been dropping it onto some EMI tape I got from this forum. The signal path has been from my PC audio interface (line out) to the Ferrograph line input which is then being recorded to tape, and sent back out of the line output which goes into a preamp and then back into the interface.

Listening back I noticed that I could hear what appeared to be a repeated/delayed signal, albeit much quieter than the actual signal itself, on the tape recording coming back into the computer. To see if it was something wrong with my setup - If I played a signal into the Ferrograph, switched to tape monitoring (as opposed to 'Original' which plays back the incoming signal via the output directly) WITHOUT the tape running/recording and then turned the input and output volume up I was hearing the signal, but obviously quieter and rolled off (tinny sounding). It appears this 'bleed' is only really audible if the input gain is pushed up, and turning up the speaker/monitor output makes it even more audible.

The problem is that in order to get a sufficient signal to noise ratio, even with the external preamp stage, the input has to be driven that bit harder to the extent that you can't avoid it. I was hoping to overdrive the input stage as an effect too, but this obviously makes things a bit difficult because it makes the problem worse.

Anybody have any idea what is causing this 'ghost' signal on the tape, is there any way around it? If it makes any difference, having the deck set to Fast Forward or Rewind quietens the noise down a bit, it's only when set to Rec or Play that it gets worse - but it is still there either way, just quieter.

Cheers

23rd Dec 2012, 5:24 pm	#1
untune87 Pentode Join Date: Oct 2010 Location: Greater Manchester, UK. Posts: 161	Ferrograph 633H Recording Issue... Hi all, I picked up a tidy and well looked after Ferrograph a few months back. It had been owned since new by the guy I bought it off and he clearly cherished it, I've no idea if it has had any kind of service over the last 50 years or so. I've been using it to track audio to tape and use the preamp to add a bit of warmth and character to recordings. Today I came to record some stuff to tape to see what kind of an effect the tape saturation would give to different signals. I recorded some drums a few months back and my friend did some guitar, and I've just been dropping it onto some EMI tape I got from this forum. The signal path has been from my PC audio interface (line out) to the Ferrograph line input which is then being recorded to tape, and sent back out of the line output which goes into a preamp and then back into the interface. Listening back I noticed that I could hear what appeared to be a repeated/delayed signal, albeit much quieter than the actual signal itself, on the tape recording coming back into the computer. To see if it was something wrong with my setup - If I played a signal into the Ferrograph, switched to tape monitoring (as opposed to 'Original' which plays back the incoming signal via the output directly) WITHOUT the tape running/recording and then turned the input and output volume up I was hearing the signal, but obviously quieter and rolled off (tinny sounding). It appears this 'bleed' is only really audible if the input gain is pushed up, and turning up the speaker/monitor output makes it even more audible. The problem is that in order to get a sufficient signal to noise ratio, even with the external preamp stage, the input has to be driven that bit harder to the extent that you can't avoid it. I was hoping to overdrive the input stage as an effect too, but this obviously makes things a bit difficult because it makes the problem worse. Anybody have any idea what is causing this 'ghost' signal on the tape, is there any way around it? If it makes any difference, having the deck set to Fast Forward or Rewind quietens the noise down a bit, it's only when set to Rec or Play that it gets worse - but it is still there either way, just quieter. Cheers