What type of preamp circuit would I need to add a 3th head to a tape deck for real time monitoring output? I'm not sure if some EQ curve is required like with turntable RIAA.
Equalization is essential also in tape recorder amplifiers.
Just copy the Rec/Playback amplifier that already is in your deck, with all it's switches set in PB mode. And try to get a dedicated PB head, as in most cases they've got narrower gaps than REC or combined heads.
best regards!
Just copy the Rec/Playback amplifier that already is in your deck, with all it's switches set in PB mode. And try to get a dedicated PB head, as in most cases they've got narrower gaps than REC or combined heads.
best regards!
I believe there are two standards, NAB or IEC.
Tape Recording Equalization
Your best bet would be to simply copy a preamp from a commercial deck. Often a 2 or 3 transistor circuit is all that is needed and that can powered from a single rail.
Just pull up some old service manuals and have a look 🙂
Tape Recording Equalization
Your best bet would be to simply copy a preamp from a commercial deck. Often a 2 or 3 transistor circuit is all that is needed and that can powered from a single rail.
Just pull up some old service manuals and have a look 🙂
Perhaps a better idea might be to just find a 3 head deck and fix it up. I'm assuming that this is reel to reel since adding a 3rd head to a cassette deck is near impossible.
Adding a 3rd head on an R2R is no walk in the park, the mounting has to be precise and azimuth adjustable and yet completely stable to work.
You also have to make sure that you get the appropriate head format, quarter track or half track (as already equipped on the deck) and note that head inductance will dictate the pre-amp design to a pretty significant extent.
EQ has to be correct both for speed and standard
New or NOS heads can be expensive, you might find a freebie or inexpensive 3 head deck for reasonable money. (Not to mention 2 head R2R usually have a single motor & lots of flutter / speed stability issues) No idea since you have not provided much information.
Adding a 3rd head on an R2R is no walk in the park, the mounting has to be precise and azimuth adjustable and yet completely stable to work.
You also have to make sure that you get the appropriate head format, quarter track or half track (as already equipped on the deck) and note that head inductance will dictate the pre-amp design to a pretty significant extent.
EQ has to be correct both for speed and standard
New or NOS heads can be expensive, you might find a freebie or inexpensive 3 head deck for reasonable money. (Not to mention 2 head R2R usually have a single motor & lots of flutter / speed stability issues) No idea since you have not provided much information.
Thanks for replies. Yes it's for tube R2R mono machine. I use it for mastering but want to add another head so I can monitor what's going on on the tape like defects and saturation. The master will be taken later of the original head later. So I don't need 100% reproduction quality just for monitoring.
Normally I use Aki GX 270D but for genuine vintage sound I use the mono tube R2R.
Normally I use Aki GX 270D but for genuine vintage sound I use the mono tube R2R.
You don't say whether you want a valve or semiconductor circuit, or what head you will be using. There are several circuits that I can think of that might give you a good starting point.
Valves - there is the Mullard tape-preamp circuit (circa late 1950s). Although designed for an earlier generation of tape heads, this gave me very good performance with 1970s (Bogen) heads. Built as a replay-only amp, it would be fairly simple, and give equalisation for 4 tape speeds. Supply requirement is 300V DC + heaters.
Semis - the Stuart circuits of early 1970s (Wireless World) gave very good performance with Bogen heads. A very simple i.c.-based circuit for the replay amp, needing a couple of 10V stabilised supplies. I thought it was probably about as good as tape circuits ever got. If you used this with a valve machine, you'd have to be careful with grounding arrangements. Far as I remember, Stuart gives information on calculations for head-impedance, etc. It's a really simple circuit that could be constructed on a small piece of perf board.
I have more details of both if you're interested.
Valves - there is the Mullard tape-preamp circuit (circa late 1950s). Although designed for an earlier generation of tape heads, this gave me very good performance with 1970s (Bogen) heads. Built as a replay-only amp, it would be fairly simple, and give equalisation for 4 tape speeds. Supply requirement is 300V DC + heaters.
Semis - the Stuart circuits of early 1970s (Wireless World) gave very good performance with Bogen heads. A very simple i.c.-based circuit for the replay amp, needing a couple of 10V stabilised supplies. I thought it was probably about as good as tape circuits ever got. If you used this with a valve machine, you'd have to be careful with grounding arrangements. Far as I remember, Stuart gives information on calculations for head-impedance, etc. It's a really simple circuit that could be constructed on a small piece of perf board.
I have more details of both if you're interested.
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