How to use GP9 tape properly

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martin 204

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Hello,

I aquired a Revox B77 mk11 awhile back to record a friend on 'ruined piano' - using 2 x Nady Ribbon mics in Blumlein confuguration. My knowlede is abysmal but we have got good results.

I learnt the hard way about sticky shed after buying a carton of new pancake 456 on ebay. After searching the net for anwers to the mystery malady I ended up here. Lots of good stuff in the archives.

Anyway thats all behind me - I am now proud owner of a stock of Quantegy GP9 on beautiful red anodised reels.

But now I am in doubt whether I am set up to use GP9 tape at all. I read that it is hot tape - but what does that mean in practice? - does one need to adjust anything to use it? Or does it just mean more head room (as I assumed)?

I seem to get some hiss on the low passages but much greater dynamic range. When the meters have gone over on record my playback system explodes with ruined chords :-).

Grateful for any advice on how to use GP9 properly.

Thanks,

martin
 
You have to adjust the bias on your machine any time you change tape types.
 
If the bias is set for 456 you will have more non-musical distortion using GP9, so you definitely want that changed. As far as levels, you can hit GP9 well into the red, but your playback level will be too hot and overload the electronics casuing distortion. That has to be set as well.

I'm not familiar with the capabilities of the B77, so I don't know if the circuitry can setup to GP9 or not. It has to be able to bias up, and level up without causing overload in the electronics. Some machines can't do it. For some of these older machines - 70's/80's 456 was considered a hot tape.

GP9 is a super tape if your machine can pull it off.

The down side is higher cost, increased head wear and it can't be used interchangeably with 456. You will have to decide which tape to use and stick with it.

-Tim
 
Last edited:
martin 204 said:
Hello,

I aquired a Revox B77 mk11 awhile back to record a friend on 'ruined piano' - using 2 x Nady Ribbon mics in Blumlein confuguration. My knowlede is abysmal but we have got good results.

I learnt the hard way about sticky shed after buying a carton of new pancake 456 on ebay. After searching the net for anwers to the mystery malady I ended up here. Lots of good stuff in the archives.

Anyway thats all behind me - I am now proud owner of a stock of Quantegy GP9 on beautiful red anodised reels.

But now I am in doubt whether I am set up to use GP9 tape at all. I read that it is hot tape - but what does that mean in practice? - does one need to adjust anything to use it? Or does it just mean more head room (as I assumed)?

I seem to get some hiss on the low passages but much greater dynamic range. When the meters have gone over on record my playback system explodes with ruined chords :-).

Grateful for any advice on how to use GP9 properly.

Thanks,

martin

GP9 is great tape. However, you have to get your machine biased and the tape tension set to avoid the increased head wear. The real drawback is if your machine can erase GP9. Some older decks (pro and non-pro) don't have a strong enough erase current to completely erase the previous material. This is something you will have to find out for yourself if you can't find the specs for your machine. If the machine is set-up by a pro then there are no drawbacks to using GP9. The problem comes when the tape tension is overlooked. If the tension is not set correctly, then the GP9 will have too high of a tension on the heads and the heads will wear faster.

The GP9 has a very low noise floor and non-existant shedding characteristics. It is the de-facto standard in today's pro studios (the ones who still use tape). You don't have to run it into the red to get low noise tapes, but it does like it.

Running 456 is certainly easier, but if you are willing to have a pro set the deck up for GP9, the benefits are definitely there.
 
GP9 tape

Thanks to all for advice - I have taken the Revox to a pro tech to align. Tim Gillette in Perth Oz - if anyone round here needs contact details email me.

martin
 
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