Messages

76

Reel to Reel Tape Machines / Re: newbee looking for direction on 15 ips recorders

« on: February 13, 2008, 06:54:50 PM »

Hi 'Stern':

Welcome to the forum.

Here is my take on some of the machines you're mentioning.
Without any modifications the B77 will give you the best audio performance but make sure it is a MKII. If you need balanced inputs and outputs you can certainly consider the MX5050 or the PR99, but you will have to compromise in audio performance in comparison to the B77MKII. The RS1500 beats all of the above mechanically, but the standard audio electronics are an abomination. You will see many people raving about the RS1500 in this forum, but mainly in combination with modified or external electronics.
The GX747 is in my view all looks but no guts. You will pay a lot of money for a stunning looking machine with only mediocre performance. I played with the N4522 a looong time ago and I remember that I was pretty impressed at that time, but I don't know if that would still stand today.

77

Reel to Reel Tape Machines / Re: Teac A-3340S and most likely the youngest person into reel to reel.....

« on: February 13, 2008, 06:07:39 PM »

David,


Welcome to the forum.
You can play two track tapes on your A3340S as long as you use the outer tracks (Channel 1 and 4). Mixing in the inner tracks will add about as much noise as signal, so I wouldn't recommend that. Playing a CCIR tape on a NAB machine at 15ips will put out 3dB too much signal above 4500Hz and you will lose some bass below 50Hz. That is all certainly audible, but no disaster. It can get you started while your tapes keep growing on you when you upgrade your playback system over time.

78

Tape Tech / Re: Inverse tape playback circuit

« on: February 10, 2008, 03:40:10 PM »

It will be several months before I can publish a derivative of my tube preamp that is sufficiently easy to build. At this moment the EQ is is switchable between 15ips IEC, 15ips NAB (which is the same as 7.5ips NAB) and 3.75ips NAB.

Eventhough it is easy to add, 7.5ips IEC and 3.75ips IEC seem fairly useless to me. Anyone who has a different opinion on that?

79

Reel to Reel Tape Machines / Re: which machine to get

« on: February 10, 2008, 03:31:25 PM »

The Telefunken M15a is a very nice machine, but I don't think John's $600 budget is nearly enough to pick one up in any acceptable state.

80

Prerecorded Tapes / Re: In the PINK floyd

« on: February 10, 2008, 03:26:24 PM »

Steve,

Is that 2 track 15ips of the Final Cut a one-off, or was it a limited release?
When the 'Pros and Cons' came out there were rumors of a limited release on 2 track 15ips tape. Those rumors silenced after a while and I have never seen anything happening.

81

Tape Tech / Re: Inverse tape playback circuit

« on: February 08, 2008, 06:41:38 PM »

I'm sure those Ampex and Studer flux-loops ended up in the garages of the engineers after they eventually all got sacked when Studer was sold and went digital and Ampex management decided that they could sit out the rest of their days only managing a rapidly aging IP portfolio.

In any case those guys had their tape heads pretty well characterized. If you are developing electronics for those heads, the best method is to just measure the EQ characteristics of the original machines and use that as a starting point for the EQ curves of your own design.

I currently have an unconventional tube playback design that works extremely well, but I cannot publish that very design for a few practical reasons. Over the coming several weeks I will be publishing some stuff that can help people to get a Tape Project compatible machine running fairly easily as long as they have some soldering skills. 

82

Tape Tech / Re: The speed of sound

« on: February 08, 2008, 12:53:35 PM »

Charles,

The main reason for running your tape at 30ips is an increased headroom at high frequencies. Depending on the construction of the heads you have to compromise a more or less significant part of the low end for that.

Back in the 50's and 60's that was certainly a trade-off worth considering, especially with live recordings where you never know in advance what's coming your way. However tape formula's from the 80's and later are dramatically better with respect to high frequency saturation levels, which makes it a whole lot less obvious to use 30ips and compromise your low end. Even in a live recording situation.

So, in my opinion 30ips is more or less an obsolete tape speed. (I'm sure that not everyone will agree with me on that point, though.)

83

Tape Tech / Re: Inverse tape playback circuit

« on: February 08, 2008, 12:34:12 PM »

Ken,

I've seen inverse RIAA filters that you can put in between your generator and the Device Under Test and I'm sure that there is test equipment around that has the inverted RIAA curve built in, but for tape EQ's it is less obvious because the characteristics of the heads play a significant role in the total EQ. Therefore the EQ curves you'll find in most record and playback amplifiers standalone appear to be slightly off-spec, especially for lower tape speeds.

So, a perfect inverse EQ filter to check your record and playback amplifiers wouldn't necessarily give you good results.

84

Reel to Reel Tape Machines / Re: Revox C-270

« on: February 08, 2008, 12:35:35 AM »

Paul,

You're right. My mistake, the reproduce head I wanted to refer to is the 1.116.027.00

85

Reel to Reel Tape Machines / Re: Revox C-270

« on: February 07, 2008, 04:16:19 PM »

Steve,

The A812 is basically a modernized version of the A810. The audio electronics are mainly the same and so is the transport from a mechanics point of view. If I'm not mistaken, the A812 uses the heavier spooling motors that are also used in the A807 and C270. That doesn't bring you anything other than faster acceleration and shorter breaking times. Very useful if you do some serious editing, but not really preferable if you only use the machine for listening, because these machines put quite a bit more stress on your tape during acceleration and breaking.
Furthermore the A812 has some more 'modern' control functions, again only really beneficial for editing.

In any case it is an excellent studio machine worth buying if you can find it for a good price.

86

Reel to Reel Tape Machines / Re: 810's organicity??

« on: February 03, 2008, 09:28:41 PM »

This is not a A810 specific problem. All electronic equipment, and certainly those build in the 70's and early 80's exhibit this 'organic' problem. The reason is that most electronic components have a specified shelf life of only 500 or 1000 hours, eventhough the operating life can be many 10,000's of hours. It is therefore recommendable for all your equipment to run it for a few hours every month. (I am doing that for my Revox collection and that keeps them in perfect working order.) An additional problem with the A810 is the back-up battery for the RAM of the microprocessor board. That is a NiCd battery that if it hasn't been replaced is most certainly worn out and won't hold any charge for more than a few days if you're lucky. Depending on the microprocessor board, it may also cause a problem during start-up with a completely depleted battery.

I have replaced the battery by a 1F / 5.5V back-up capacitor. Such a cap will live for many years without leaking like the battery. A leaking battery can also cause your microprocessor board to start rotting away. Definitely not very helpful to keep your machine running trouble free.

Arian.

87

Reel to Reel Tape Machines / Re: Revox C-270

« on: February 02, 2008, 06:27:27 PM »

finney,

My current tube head amp is rather unusual and I'm still refining it further. After that I'm planning to derive a version of the amp for publishing that is easier to build for others. That may take me a few month still. It can be used for all recorders that use the same head (Studer p/n 1.116.022.00), which are the A77, B77, PR99, A700 and the C270.

Arian.

88

Reel to Reel Tape Machines / Re: Revox C-270

« on: January 31, 2008, 12:44:41 AM »

Bob,

I have a C270 and it so happened to be the machine I've dedicated for the Tape Project. The Revox C270 was developed at the same time as the Studer A807 in the late 80s and was the last tape recorder developed by Studer Revox. The two machines therefore have a lot in common. Mechanically the C270 is one of the best recorders ever made, not in the last place because of the very smart use of the microprocessor in the tape transport.

There are a few practical drawbacks though. First, all C270s I came across are NAB, not CCIR. Second, there is a lot of (solid state) electronics in the signal path. The machine sounds good, but is limited by it's electronics. I have developed my own all tube electronics for this machine, which really brings out the superb capabilities of the C270. The audio performance surpasses my (unmodified) A810 by far. The third drawback of the C270 is that there are very few of them around. That means if it dies, it is most likely end of story, because the few available spare parts are horribly expensive. For that reason I'm currently retro fitting my A810 with my tube electronics. For the A810 there are plenty of spare parts.
On the positive side, since the C270 has been manufactured roughly between 1988 and 1996, all of them are using mainly Philips high quality components that are significantly more reliable than the components used in the early 80's and infinitely more reliable than the components used in the 70's. Therefore, if you can pick up any operational C270 for a reasonable amount (<$500) it will be a good deal. The EQ is sitting on separate PCBs and is very easily modified from NAB to CCIR.

Arian.