Messages

31

General Discussion / Re: The SACD vs Tape Challenge

« on: April 05, 2009, 07:40:02 PM »

I have certainly not heard every DSD recorder and player, so it may very well be the case that the Korg MR2000S lifts DSD to a new level.

That said, as far as I know nobody has heard a true DSD decoded audio stream because DSD cannot be converted to analog as it was originally intended (One of the several inherent flaws of DSD). As far as I have been able to find all DSD DACs use a questionable digital filter with a conversion to some form of PCM at the end. If anyone is aware of the existence of a true DSD DAC, I am very interested to learn more about that.

The best DSD DAC I have used is the EMM Labs DAC6e. Good as that unit is, it could not reach the level of my modified Luxman on high res PCM, especially on the HRx material.

But as I mentioned before, SACD has become a niche format for serious audio and I really appreciate that, especially for multi channel. So if anyone can help me find a significantly better SACD player or DSD DAC, I am very interested.

32

Reel to Reel Tape Machines / Re: Library wind on Studer Revox C270

« on: March 28, 2009, 04:03:21 PM »

Hi Christopher,

I think the development of the library wind feature on the C270 was never really finalized. It is partly functional, though.

First, you need to toggle S3 before you switch the machine on. The microprocessor apparently only reads the dipswitch settings during the initialization of the software. After you have done that, the library rewind mode is always enabled. That means that whenever you rewind it will do so at a slow speed. As far as I have been able to see there is no library wind mode for fast forward.

You can still rewind at full speed if you use the zero locater or the auto locater.

Furthermore, RA4 should adjust the tape tension in library wind mode. As far as I can see, the software doesn't switch over to RA4, but stays at RA6, which is the normal rewind tape tension. At least in the software revision I have RA4 doesn't do anything.

So all in all not a very fantastic feature, but it can be used. Probably the reason why it is normally dissabled.

Hope this helps.

Arian.

33

General Discussion / Re: SOLID STATE AND ZOMBIES

« on: March 05, 2009, 06:57:44 PM »

Coloration comes in many shapes and forms. Harmonic distorsion is only one of them which by itself is quite easy to remedy. The most important audible coloration that does not show up as measurable harmonic distortion is caused by the fact that many parameters of components change as a result of the actual signal going through it, especially when it is a very complex signal like music. This happens a little in passive components and a lot in active components.  Transformers and inductors are the worst passive components in that area but all active components exhibit that problem to an even greater extend.

The parameters affected in tubes and transistors are similar in several areas, but they differ in others. Especially the number of parameters that show a modulation effect in transistors is much higher which makes it much more difficult to deal with. Tubes have a stronger tendency to modulate their own working set points. This is audibly perceived as a warmth in the sound. Transistors do the same, albeit in a lesser degree, but the transistor circuits that are used nowadays take a lot of that effect out.

The single ended triode circuit makes 'optimum use' of these modulation effects both in the tubes and the transformer which is for a significant part the reason why they sound so warm and natural, even if the distorsion is low. In fact if you use the same single ended transformer coupled circuit design with a transistor a similar warmth and naturalness appears but also a significant amount of solid state coloration due to the other parameters that are modulated by the signal.

A push pull design takes out even harmonic distorsion and also some of these parameter modulation effects, but by far not all of it.

So the bottom line is we like our tube colorations large or small but we hate SS colorations even if they are real small. As for tubes conserving information that gets lost with SS, I haven't been able to systematically detect that in any way. SS tarnishing some of your low level information where tubes do not, certainly.

But when you compare a very well designed tube system with a very well designed SS system, the differences get pretty small and what remains is the recording and the music. (But if push comes to shove I would still go for tubes......n tapes)

34

General Discussion / Re: SOLID STATE AND ZOMBIES

« on: March 05, 2009, 11:24:59 AM »

Great story Mark.
In my experience you have to do a really large investment to get SS gear that comes alive.  I've not heard any SS gear that is completely free from the typical SS coloration, eventhough in some (expensive) cases it is very tolerable.

I have done a lot of designing with tubes and solid state, and I have to say that only in the case of tubes have I been able to get to a point where the electronics are acoustically almost fully transparent. Therefore tubes still have my preference.

However the tube story is also far from clean. The very vast majority of tube gear out there adds significant coloration to the original recording. The difference with solid state is that we tend to like the tube coloration while the solid state coloration is normally perceived as annoying. That makes all that tube gear a lot more tolerable and pleasant, but not necessarily better. In practice more often than not the tube lover likes his colorations more than the reality of the recording. Unfortunately those pleasant colorations very often degrade the really well done recordings.

So in my opinion complete transparency should still be the ultimate goal and until now tubes can still get closer to that ideal than solid state can. It doesn't show very often in the audiophile world, though.

35

General Discussion / Re: The SACD vs Tape Challenge

« on: February 19, 2009, 03:41:14 PM »

Making a comparison between analog tape and SACD wouldn't be very intersting. DSD is an inherently flawed system that was really proposed by Philips and Sony with the intention to significantly reduce complexity and cost on the playback side. Unfortunately that didn't practically work as expected, so the playback became actually more cumbersome than CD.

With the right effort SACD is capable of very good sound, but in reality it is as uncontrolled and subjective as any analog medium. The fact that it is also a multi channel medium is for me the most attractive aspect of SACD. For those few labels that are still producing them: Please keep on doing it! I'm a fan!

But back to the subject, a comparison between tape and high res PCM would be more interesting because high res PCM is by nature a much better defined and controlled medium than DSD.
The good news with respect to this subject is that Reference Recordings has the Exotic Dances available in HRx 176kHz/24bit. Now we are talking about an interesting and reasonably objective digital vs analog tape comparison.

36

Reel to Reel Tape Machines / Re: Butterfly heads.

« on: January 29, 2009, 01:06:15 PM »

John,

The main difference between butterfly heads (CCIR) and the 'normal' heads (NAB) that you find on most machines is the gap between the two tracks on the tape. NAB heads have 2mm spacing between the tracks where butterfly heads have 0.75mm spacing.

Butterfly heads only make sense if your tapes are recorded that way or you record them yourself with these heads. If you play a tape back that is recorded with NAB heads, like the TTP tapes, you will lose about 1.5dB of signal to noise ratio. There may also be the risk that your butterfly heads pick up unerased crap from the 2mm gap of an NAB tape, such as a time code signal. (Not with TTP tapes obviously, since they are recorded at on new tape stock) There is however no real penalty if you play back a CCIR tape on NAB heads.

So, in summary, don't spend a lot of money on butterfly heads unless you do some recording of your own.

A different question: Is the capstan of your C270 completely silent or can you hear some whine of the motor? My C270 is a bit noisy in that regard, even though it doesn't show in the W&F spectrum. I have not been able to find any reference whether that capstan noise is normal or not. For me it is just a little bit too loud, which makes it sometimes annoying.

37

Reel to Reel Tape Machines / Re: Hagerman Bugle

« on: January 28, 2009, 06:02:04 PM »

Xavier,

The corner frequencies for NAB and IEC are mentioned in my NAB to IEC converter article on the LAOCAS website.

http://laocaudiosociety.net/tech/NABtoIEC.pdf

Maybe that is of some use for you.

38

Prerecorded Tapes / Re: Yellow "Stereotape" Labels On Reels in Factory Boxes...

« on: January 25, 2009, 10:51:29 PM »

I spent the first 30 years of my life in Europe. Unlike here in the US, R2R was not a popular medium for music albums at all in Europe. It was mostly vinyl or otherwise cassette tapes of very mediocre in quality. Therefore you won't find very many prerecorded tapes from Europe.

39

General Discussion / Re: Ron Welborne's A810

« on: January 22, 2009, 12:00:36 PM »

That really looks like a nice set up.

The A810 is switchable between NAB and IEC playback and is therefore immediately ready for TTP tape playback and pretty much every other possible 2track tape playback. Direct from the head playback from an A810 is possible but poses some challenges.

40

Reel to Reel Tape Machines / Re: Calling all Pro's

« on: January 21, 2009, 10:04:13 PM »

Steve,

Mike is right. The A820 would always be the right choice, because it is pretty much the absolute mechanical reference in analog tape recorders. It doesn't come cheap, though.

The A810 also winds a very neat pack using the lower of the four spooling speeds. But if you use a lot of acetate tapes, I indeed wouldn't recommend the A810. A better choice would be the B67 in that case, which does have controlled tape tension during breaking. Not as good as the A820 obviously.

An A80 is always a very good choice as well. Not as cool as the A820, but more friendly to your wallet.

In all cases the main question will be whether you have the possibilities to restore/maintain the machines yourself. If not, you need to get it from a proven source, because any of these machines you buy cheap on ebay will have some issues, big or small.

41

Reel to Reel Tape Machines / Re: Calling all Pro's

« on: January 21, 2009, 11:21:11 AM »

John,

I double checked with the A810 manuals, just to make sure I wasn't talking rubbish. The A810 indeed accelerates and brakes with the peak torque of the spooling motors. According to Studer you can set that peak torque for anywhere between 3 and 6N. (The normal tape tension during playback and spooling is 0.75N). You can set it even lower but that is apparently not recommended and the machine becomes quite sluggish in that case. In practice the peak torque is not regulated by the tape tension arms but preset on the spooling motor driver. That is why the stress on the tape with small hub 7" reels is really high even with the minimum recommended peak torque.

The stretch on a 3600' 1 mil tape wouldn't really be measurable on the counter because the actual stretch is only a few percent and happens only during the short length of tape during initial acceleration and braking. The effect will be more on a 1800' tape on a 7" reel. (That stretch slowly recovers over time, so it is not a disaster)
It has to be said that I have the peak torque adjusted close to the maximum for fast maneuvering with 10" reels. If I use a triple play tape on 7" reel, it will dramatically stretch the tape when you stop at the end of the tape or it pulls the tape in between the pancake and the reel. Ugly in both cases. At the minimum peak torque, that may not be the case.

In any case, my original post was intended to describe the basic difference in philosophy between the Studer recording studio machines like the A80 and the A820 and the Studer broadcast machines like the A810, and also the A807 and the Revox C270. But unlike the latter two which have some additional compromises, the A810 is substantially the same in almost all its parameters to the A820 during recording and playback and that makes it in my opinion one of the most interesting machines to get.

42

Reel to Reel Tape Machines / Re: Calling all Pro's

« on: January 20, 2009, 06:46:15 PM »

That's interesting, John. Your A810 apparently has a setting or software release that I haven't seen yet. My A810 (which is very well adjusted) and the handful that have passed through my lab all were not regulating tape tension during braking, but were braking at maximum reverse torque. (Great for fast editing). All clearly intentional because it nicely stops very controlled with the tension arms in the correct position again. The tape tension setting for FF and REW you are referring to only adjusts the tension during actual FF and REW, not during acceleration or deceleration. You can adjust the peak torque on the motors to a lower level, but that doesn't fully mitigate the mechanical stress for thin tapes on small hub 7" reel like the Revox A700 does for instance. Again the large stress only happens during braking and to lesser extent during acceleration, but not during actual FF, REW or PLAY. Any stretching over the full length of a 1mil tape won't therefore be measurable with the tape counter.

If there is a software version or a dip-switch setting that enables tape tension regulated braking, I an very interested to learn about that.

Anyway it was not at all my intention to pull the A810 down. Quite to the contrary, it is a great machine and it is my favorite machine in many ways, the accurate counter being one of them. I mainly use it with 1.5mil tapes and occasionally with 1mil tapes. Double play tapes and certainly triple play tapes, I play back with my A700 because of the tension controlled braking of that machine. The sound quality of the A700 is pretty mediocre but so are all those double play and triple play tapes anyway.

Fred's comments about the state of many A810s is very valid. There are many A810's around, which is a good thing, but if you can't restore them yourself, it is better to buy it from a qualified source, because they are quite complex machines. That is not gonna be cheap but compared to modern audiophile pricing it is always a bargain.

43

Reel to Reel Tape Machines / Re: Calling all Pro's

« on: January 20, 2009, 12:50:35 AM »

I fully agree with John. The Studer A810 is a very good choice. The commercial machines from Technics, Teac and Akai indeed look like toys in comparison. The A810 is in many ways identical to the A820 in that it uses the same heads and the same audio plug in boards. The audio performance of both machines is substantially the same.

The main difference between the two machines is the application. The A810 was targeted for broadcast use and mobile recording. The A820 was targeted for recording studio use. So, the main difference between the machines is that the A820 is optimized for a tape handling that has the absolute minimum of stress on the tape under all conditions of use. Keep in mind that the original mastertapes of so many iconic albums constitute an enormous value and need to be handled in the most gentle way. The A820 has no stationary surfaces touching the magnetic side of the tape other than the head surfaces during playback and record. During FF and REW there is no friction on the magnetic surface at all. The machine furthermore keeps the same tape tension under all circumstances including braking.

For the A810 the situation is different. The practical application is broadcast and mobile recording. Speed of use is the predominant factor for this machine. During record and playback the A810 also only has the head surfaces as friction points as well as an excellent tape tension regulation just like the A820. However, as soon as you go to FF or REW, the situation is very different. The tape is lifted immediately from the heads with stationary tape lifters and the machine will literally give 'full throttle' to accelerate as fast as possible. The tape tension will be as high as the motors can generate. During breaking it is even worse, it will brake at its very maximum power by applying both the mechanical brakes and 'full throttle' of the motors in the reverse direction at the same time.
If you switch from FF or REW to play, it will brake very fast until the tape reaches the play speed and immediately switches to play without having the tape come to a stop first. That is really cool by the way and incredibly fast.

So, to make a long story short, the A810 will give you virtually the same playback performance as the A820, which is probably the best R2R ever made. Your tapes will, however, see dramatically more mechanical stress. For normal 1.5um tapes (Agfa 468 and Ampex 456 etc.), that is no problem. For 1um commercial tapes (long play) it may stretch your tape, especially with 7" reels. Double and Triple play tapes will be transformed into a wire after a braking session.

Another option worth considering, for normally not too much money, would be the Studer B67. This machine uses constant tape tension during braking as well and has nice playback electronics, similar to the A80, but not quite the same mechanical performance.

Just my 5 cents worth.

44

Prerecorded Tapes / Re: CROSS TALK WITH 4 TRACK TAPES

« on: December 18, 2008, 01:21:46 PM »

Another point worth mentioning is that if you run a 4 track tape over a 2 track recording or playback head, the magnetic 'conduction' of the two track heads will spill some of the information of the outer tracks of your 4 track tape into the center tracks and vice versa. This is especially true when the 2 track heads are butterfly heads. So running your 4 track tapes over a machine that has both 2 track and 4 track heads on the same head block will, to a certain extent, permanently increase the cross talk between the forward and the reverse tracks.
Not a major deal, but it is noticeable.

45

Suggestion Box / Re: Beatles "Love"

« on: December 03, 2008, 11:44:53 AM »

Tom,

I fully agree. I have 'Love' on SACD and play it through my own Virtual Surround processor back in two channels. What stands out in this release is the exceptional quality of the original recordings. I have not heard an original Beatles release that brings out that quality. From that point of view it would be great to have it on tape.

I'm sure that this remix is not to everyone's liking, even though if you allow the time it indeed grows on you.

Furthermore, I don't think that George Martin will be jumping at the bit to support the initiative and I expect that the 'Love' album is mixed in the digital domain, which disqualifies it for TTP.

In any case it's a great album.