'Tube'-ing a reel-to-reel player.

[percy]

I am sure this has been done before but just want to throw this out and see what more information I find on this.

I am thinking of taking up a project to add a tube-preamp to a reel-reel deck.
I would like to disable/bypass all the audio circuitry and substitute with a tube pre-amp i.e. take the signal straight off from the tape heads. All other 'control' electronics can stay as-is.
If you have done such a project or atleast aware of one I'd appreciate if you could share some details.

I haven't picked a reel-reel player model for this yet but I am open for suggestions.

 

[dnsey]

You'll need to decide which replay curve(s) you want to implement, and design your preamp accordingly.
Don't forget to use bias traps.

 

[percy]

both good points. I didn't realize tape decks needed an equalization compensation curve like turntables(RIAA).
hmm..looks like I will have to delve further into the reel tape recording process to completely understand these two (recording bias and eq). I guess there must be standards for tape recordings (like riaa for vinyl). Can you point me in the right direction ?
Thanks!

 

[percy]

Aha!
http://www.bottlehead.com/et/adobespc/Seduction/bottleheadtapeheadpreamp.htm

 

[powertriode]

This could be what you're after.

 

[wa2ise]

The Dynaco SCA35 intergrated tube amp has a "tape head" input, along with "phono". The selector switch switches out the RIAA circuit and switches in the NAB? equalization circuit for tape heads. Uses the same preamp tubes. You could hunt down a schematic and reverse engineer what they did. Or find yourself an SCA35.