TP-028, Nat Adderley's Work Song is now available

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - Tubes n tapes

Pages: [1] 2 3 ... 6
General Discussion / Holographic Imaging Process
« on: June 18, 2012, 10:10:26 PM »
Only partly related to R2R, but for anyone who is interested, Positive Feedback Online has published a short article from me about the SonoruS Holographic Imaging Process.

Events / SonoruS ATR10 at THE Show Newport June 1,2 and 3.
« on: May 28, 2012, 11:46:27 AM »
For those tape aficionados that are planning to come to T.H.E. Show in Newport Beach next weekend, SonoruS Audio will be in room 517 of the Hilton playing tapes on the ATR10 over the SonoruS directly driven transformerless ESL monitoring system. We will obviously be playing Tape Project tapes as well as tapes form other sources.

We will also be playing a variety of tapes recorded with the SonoruS Holographic Imaging Process. Come and hear for yourself how the walls of the room disappear.

The SonoruS ATR10 tape machine will also be used by On a Higher Note in the San Clemente room at the main exhibitors floor in the Hilton with Luxman electronics and Vivid loudspeakers, and by The Audio Salon in room 202 and 203 of the Atrium Hotel with Constellation Audio electronics and Magico loudspeakers.   

Events / Re: Subscriber event at Rocky Mountain
« on: October 12, 2011, 09:35:41 PM »
Philip O'Hanlon will also be rolling tape on the SonoruS ATR10 in the 'On a Higher Note' room on the mezzanine level.

Prerecorded Tapes / Re: yarlung records?
« on: September 01, 2011, 06:13:33 PM »
Grant, Those tapes will actually be 15ips/2track tapes on 10.5" reels with IEC EQ. However it is only a selection of the original album on one reel.

Reel to Reel Tape Machines / Re: Sonorus ATR10
« on: August 29, 2011, 03:31:06 PM »

For anyone looking for more information, I have uploaded the operating manual of the SonoruS ATR10, which also includes the specifications of the machine, on to the website.

Events / Re: California Audio Show July 15-17
« on: July 10, 2011, 06:33:24 PM »

For those who are planning to visit the California Audio Show next weekend, Philip O'Hanlon will be spinning several Tape Project tapes in the 'On a Higher Note' room (rm 434) on the new SonoruS ATR10 Tape Deck. This is a deck based on a Revox PR99, but with all new and redesigned electronics, including power supplies, tape drive electronics and audio circuitry. It features regulated tape tension, improved tape path and tube based playback electronics.

The system furthermore includes a Brinkman turntable, Luxman electronics and the remarkable Vivid loudspeakers.

For the rest, leave it up to Philip to put forward an impressive demonstration!


Events / Re: THE Show, Newport, CA June 3-5
« on: June 02, 2011, 11:51:48 PM »
Rick will be using one of my modified PR99 mkII's. The newly designed machine will only be demonstrated in the Sonorus room (#203)

Events / Re: THE Show, Newport, CA June 3-5
« on: June 01, 2011, 09:49:33 AM »
Rick Brown of HiFi One will also be spinning tapes in room 1004.

Here are some pictures of the ground up designed, PR99 based tape deck that Paul is mentioning:
On the show I will use a set of transformerless, directly driven electrostatic speakers combined with OTL driven woofer towers for the demo.

Hope to see many of you on T.H.E. Show.

Reel to Reel Tape Machines / Re: G36 reel holdowns
« on: June 08, 2010, 09:21:51 PM »
They will all fit on the G36 as long as you order them as a set with screw and spring.

Reel to Reel Tape Machines / Re: G36 reel holdowns
« on: June 08, 2010, 08:52:14 AM »

The thread is indeed M3.5. You can use any ReVox or Studer holddown on the G36. Either the plastic ones for the A77 and B77 or the metal ones of the PR99 or the Studers.

There are people selling them on eBay.


Thanks for the compliments on the article.

To retain the record function, one only needs to leave the components on the record boards and use new components for the modification described in the article.  The problem is that when the speed has been modified from 3.75/7.5ips to 7.5/15ips, the record adjustments and EQ are totally off, so you wouldn't be able to make any half decent recording with it anymore, even if the electronics are still in tact.

If the unit originally was a 7.5/15ips NAB machine, the record function at 7.5ips would still be valid. At 15ips you would record with an NAB EQ, but playback with IEC.

Tape Project Machines / Re: A Studer A810 playback head output mod
« on: December 24, 2009, 11:47:11 AM »
I have done a full tube repro on my A810 about two years ago. I did that same full tube repro mod on my Revox C270 six months before that.

That mod consists of a 23dB single tube flat gain stage built in the tape machine itself, connected to the heads by short cables.  The output of that stage is capable of driving a long cable so that the rest of the gain stages and the different EQs can sit in a separate external enclosure. The reason for that approach was mainly the fact that Studer heads don't do well with any significant capacitive loading, so the cables between the heads and the first gain stage need to be short. The output of the first gain stage has a fixed resistive output impedance and can easily drive a long cable without degrading performance.
The mod is permanent, but in order to keep the machine at least fully functional stand alone, the output of the tube gain stage also goes to a 23dB resistive attenuator and is then fed back to the original head preamp. That way I can take full benefit of the tube repro while the VU meters are still calibrated and the machine can still be used stand alone, without the tube repro.

The tube repro worked extremely well on the C270, so I thought: Let's do exactly the same thing on my A810. Only some small frequency curve corrections would have to be made in the gain stage to compensate for the difference in characteristics of the playback head in the A810 compared to the one in the C270. that way I could use the same back end amplification and EQs for both the C270 and the A810 without the need for adjustment.

The first gain stage in the C270 was placed behind the tape controls and counter. There is an unused slot that is reserved for a timecode card if I remember well. Unfortunately there was not such a nice location like that in the A810.  Since it is extremely busy inside the A810 there is only one spot with sufficient useful volume, which is on the left side of the middle towards the back. The only way to actually put something there is mounting it to the back plate of the machine. Inconvenient but feasible. That way the head wires could be kept under a feet. Making them longer will compromise the transparency of the sound.

So I built it up that way with the first gain stage built in an aluminum enclosure mounted to the back. After the success with the C270, my expectations of the A810 where very high. So the slap in the face was ever so more painful when I played the first tape. Somewhere between the hum and the noise there was also some music. I must have pulled the preamp out at least four times to double check the performance on the bench, which showed the same performance as the C270 preamp time after time.

To make a long story short, I found out the hard way why the head preamp of the A810 is sitting on the head block in a way that looks like an after thought and why there is so much shielding. The noise levels below the diecast chassis of the A810 are enormous. I could pick up volts over the ground lead of a shorted scope probe. The origin of some of that noise is the switch mode power supply for the 5V bus, but mostly the PWM regulated motor controllers. The designers made a well performing tape tension control, but clearly had no clue about EMI management.

I had to spend days to reduce the switching noise with at least 30dB to get the noise and hum of the preamp to a level that was sufficiently below the noise floor of the tape.

There is a happy end to the story in that the A810 now sounds better than anything that I have had the opportunity to listen to and that it has been my primary playback machine now for the last two years.

The moral of the story is: be very careful with running the un-amplified head signals through the machine. Long cables don?t work all to well with Studer heads, but if you want to do it anyway, my recommendation would be the run the head cables over the diecast chassis in the direction of the output plugs rather than under the diecast chassis.

Reel to Reel Tape Machines / Re: Revox/Studer A700
« on: December 04, 2009, 07:29:36 PM »
Hi Bob,

Welcome to this forum.
I own a Revox A700 (among several other machines). As a transport the A700 is one of the most interesting machines, shy of the large Studer's. The A700 shares its transport with the Studer A67 / B67. The interesting part of the transport is that it has regulated tape tension during play, FF and Rew, and during braking. Especially the last feature is quite unique outside the class of state of the art  recording studio machines. You can use a 5" plastic reel on one side and a 10.5" metal reel on the other side and the A700 manoeuvres flawlessly, even with triple play tape.

That was the good news, now the bad news: The audio electronics are quite terrible because of the use of very early opamps. Because of the pinout those early opamps cannot easily be replaced by modern ones. Also all the other components are of a typical early 1970s quality, which was not an era to be proud of in that sense. The result is that the A700 doesn't sound very good, not with playback and not with recording.

So I cannot recommend the stock A700 for high end audio. If you would use external audio electronics you would have a very nice tape setup with the A700 because the tape handling is quite unmatched and it uses the same high performance heads as the other Studer and Revox machines.


Reel to Reel Tape Machines / Re: Transports and tape handling
« on: December 01, 2009, 02:12:46 AM »
Because of this design, the reel motors need to have regulated tape-tension.  If they were un-regulated, the 10 gram differential could not be maintained, because tape-tension would change as tape-diameter changed.

I don't know about other members of the RS15xx series but the RS1520 reel motors do not have regulated tape tension. It is my understanding that the tape tension within the isolated loop assumes substantially the same tape tension that exist outside the loop due to a very small amount of tape slip when the tape tensions inside and outside the loop are not equal. A very even and well controlled tape slip is therefore of crucial importance with an isolated tape loop. The pinch rollers play the most important role in that process, which make pinch rollers on isolated loop decks much more critical than with conventional transports. Questionable pinch rollers on an isolated loop deck will diminish any benefit that the isolated loop initially may have had.

For an RS1520 with its unregulated reel motors the tape tension at the beginning and end of the tape is higher than in the middle. Still the tape tension will not vary as much as with a deck with a normal capstan arrangement and unregulated reel motors, which start with a low tape tension at the beginning of the tape and end up with more than twice the tension at the end.

Reel to Reel Tape Machines / Re: J-Corder decks vs. A810
« on: November 24, 2009, 04:53:47 PM »
Hi Doc,

I should probably clarify my PR99 / Studer remark. If you compare the transport mechanisms of the Studer B67 and A810 to the transport of the Revox A700, B77 and PR99 you'll see that they all share the same concept and manufacturing for the chassis, the motors, the head block and the pinchroller mechanism. The main difference between Revox and Studer is that the Revox machines are simplified to a bare minimum to reduce cost. Most other prosumer decks are cost reduced by compromising on construction and component quality.

The B77 and PR99 don't have regulated tape tension, which compromises the wow and flutter at the end of the tape and they don't have a scrape flutter roller, which I think was not a good cost trade-off, but they still have the same rigidity and stability of the mechanical construction and the same head performance as the Studers, which makes those little machines remarkably good performers, especially with updated audio electronics.

The absence of a scrape flutter roller is not very noticeable with Agfa 468 or Ampex 456, but with Quantegy GP9 and other 3M tapes it is certainly audible and measurable. I think they should have invested the extra $2 or so for a scrape flutter roller.

So to come back to the original remark. The PR99 is basically identical to the Revox B77, both mechanically and also with respect to the REC/Playback core. The PR99 was actually developed as a professional version of the B77, because so many B77s were used  professionally in the broadcast industry.

In Europe Studer/Revox was known for listening to the feedback of their customer base, hence the mkII and mkII evolutions of many of their machines. The PR99 was completely a result of that customer feedback on the B77. It was actually not at all an obvious product for the Revox brand back in 1980.

Pages: [1] 2 3 ... 6