Messages

451

Tape Project Machines / Re: reverse RIAA and IEC adapter to use phono stage as head amp

« on: September 27, 2008, 11:48:44 AM »

How is the Seduction as a phono stage for the price?
I have not constructed my kit which I have had for 3-4 months so far.
 I know it is more complicated switching, but has anyone managed to build one as RIAA phono, then another set of jacks and switch IEC and NAB for tape heads. Would putting that much stuff in there destroy the sound from the careful component placement and signal path length or make it have more noise etc? I don't want to destroy it's performance.

452

General Discussion / Re: Subscribers, speak your peace

« on: September 24, 2008, 12:36:01 PM »

Actually, I completely agree with everything you said.
 If everything is absolutely "right" with a tape system by spec and by ear, it should theoretically be the most neutral and the best sound. At least with Tape Project tapes it is a bit closer to the source. But see the threads on the ambiguities of alignment tapes and response curves with IEC  with various heads  elsewhere on this forum. These things apply in any analog tape duplication process and I am sure it is one of the major things (getting and keeping it right) that keeps the Tape Project from being a massive product-out-the-door-as-quickly-as-possible affair.
However, this pales by comparison with the idiosyncrasies of  vinyl disc mastering and playback. Being an electromechanical process, it is far more subjective in it's trade offs and spec wise (again in general) can't touch even 15 ips. 1/4"  stereo tape. Yet it can sound wonderful as you stated. In the 60s with the home playback technology then available, R2R was considered even in its 7.5 ips. 1/4 track prerecorded form to be superior to vinyl.
The point being that even now in the 21st century, a system optimized or "voiced" to use your term, for vinyl playback with a specific cartridge and its related arm, table, cables and phono stage and all other factors in a "mature system " as outlined above and carefully auditioned, may not be so neutral with regard to both R2R tape or for that matter high bit rate digital - let alone normal CD.
If the opposite is done, making the system sound best by ear with the most potentially neutral source(s), then optimizing the vinyl playback equipment to that, a more balanced system that sounds the most musical for all sources may result.

I do not list what I am listening to on my profile because I am far more of a tinkerer/collector than an audiophile in the sense of having big $$ to spend on cables and equipment. I am listening to some of that 70s-80s mid fi equipment with inexpensive speakers I have modified, and tri-amplified, all with solid state amplification which do not show that flat of response with an RTA in my listening space. I have compromised between tuning via RTA and by ear and on good sources of all varieties its sounds remarkably good to me. But, because it isn't really that accurate, it is subject to sounding variously better or worse depending on the particular program material in whatever format. Then I am tempted to re-tweak it for that particular source, typically with either the crossover settings or even the evil tone controls. But I have to go back to a more "reference setting" for the best program sources.
If this is true in my budget system, it is true but in a more nuanced subtle way even in a great system like Larry's.

453

General Discussion / Re: Subscribers, speak your peace

« on: September 24, 2008, 12:40:11 AM »

Back to Charles (Stellavox) comments which I was responding to, it is a bit of a slippery slope when you subjectively tune by ear a system to optimize vinyl playback, then introduce another source (R2R) that theoretically can be better, but in actuality might just be better in some ways. There are certainly many variations that can be introduced from tape head design and it's interaction with playback electronics.
The tape might come off as inferior if the system has been subtly tweaked for vinyl with a specific turntable setup. In the realm of what Larry listens to these are subtleties, but might influence the most critical listeners one way or the other.
 As I said, and I think many are saying similar things, we should not consider that one demo session a default judgement forever on the quality of TP tapes vs. vinyl. What if you tweaked a system for ultimate Tape Project playback and then hooked up a generally good cartridge/arm/turntable and phono stage. Would the advantage then go to the tape because the system was not optimized for use with that turntable system ? There always have been complimentary components (bright cartridge/dull speakers etc.) and components considered "better" for one kind of music or another. Mechanical transducers typically are the hardest to make right and not add their own coloration.
And phono cartridges are mechanical transducers. Nobody would say they sound identical any more than 2 types of speakers.
Hopefully, we try for flat and low distortion with our specifications but we know our ears tell us things the specs don't measure very well or we would all be listening to those Japanese receivers from the 80s with tons of negative feedback and ".0000000001 % distortion".
Probably Larry will now need to consider what happens with his speakers and other components when trying to now optimize his wonderful system for best sound with both vinyl and tape.

454

General Discussion / Re: Subscribers, speak your peace - OK, how Playback Equipment "quality"

« on: September 23, 2008, 01:01:00 AM »

  Apparently, the host had a modified 1500 recorder and some version of a Seduction preamp.

I was there. The owner of that system posts actively on this forum. He was a wonderful host and can speak for himself here. For the record, (sorry) it is a Technics with the full tube Bottlehead Repro Amp - not the smaller Seduction unit. I don't think it was unanimous by any means that the vinyl bested the tape. To be sure there were some differences noted between the 2 with various records vs. their Tape Project counterparts. In all fairness, the level of quality was so high it was more like slightly stronger attributes in one area vs another sometimes for the tape and sometimes for the vinyl. I would say subjectively that the dynamics, especially on high frequencies were a little more open with the tape. There were a few glitches with both the turntable and system grounding which did produce some unwanted side effects such as some low level noise and hum on the tape side. I would not call it the "ultimate shootout" between vinyl and tape sources.
In general I was astounded at the sound quality in all respects from either source such as imaging, transient response, transparency etc.

455

General Discussion / late 50s HiFi through Ampex speaker

« on: September 15, 2008, 01:29:16 PM »

Yes this is only slightly tape related.
I have been having fun listening to vintage HiFi (and not so HiFi) mono records (don't have any mono pre-recorded tapes) through one of a pair of Ampex (that's the tape related part) powered tube speakers. These really sound great for what they are. An 8" JBL driver in a portable case run full range with compensating EQ driven by a built in 10W. amp using 6V6 output tubes. These were built as monitor speakers for Ampex portable tape machines. I am using one (they have a standard RCA line in) to supply amplification for a portable Rek-O-Kut turntable in a case, made for I don't know what. It has their 3 speed Rondine table and a GE arm where only the headshell pivots vertically with a GE variable reluctance magnetic cartridge with Lp and 78 styli and the matching 1 tube preamp with switchable record compensation curves all built in the case with a cover. It was all reasonably good stuff when new. I would say that it still provides pretty good sounding mono audio from vintage mono 78, 45 and Lp records. Not really the same as listening to the same records on modern equipment and in some ways better.

456

Reel to Reel Tape Machines / Re: Adapters for Otari MX 5050

« on: September 13, 2008, 10:32:53 AM »

OK, just took the side panel off of my older 4 channel MX-5050. I see a hole where one can axcess 2 allen head metric 3mm screws that hold the turntable on the motor shaft. On mine, this is the same size as the hex key that and holds the side cover on. These loosen counterclockwise as normal.
AFAIK, you just loosen them if necessary and move the turntable in or out on the shaft to center the tape between the flanges for both a 10.5 reel and a 7 reel with the small hub (using spacers)  then re-tighten. If your unit has any other damage or other parts have internally shifted all bets are off. Do the turntable shafts appear to be straight and not bent? If you rotate them do they wobble or run true?
The noise if there is a whine might be from the idler to the left side of the head block which might need lubrication for it's bearing.

457

Reel to Reel Tape Machines / Re: Adapters for Otari MX 5050

« on: September 12, 2008, 11:07:47 PM »

Could it be a shipping thing - that is the spindles took some end shock from improper packing and the tables moved on the shafts?
In any case, as long as the motors are not physically damaged and the tables can be set to the right height so the tape winds between straight reel flanges without touching either side, you're good.

As to your other question, compared to the rest of the audiophiles on here I listen to absolute junk, so I added that phrase to the bottom of my profile where the rest of you put your mega $$$ or home hand designed and tweaked equipment.

Just think 70s -80s mid-fi with a few odd twists. I am a collector more than an audiophile. I can listen to about every recorded format from 78s through wire to most reel formats, cassette and 8 track, all the common tape and disc quad fromats from the 70s up through modern digital HD stuff.
If you really need to know more I will tell you in an email or PM.
 

458

Tape Project Albums - general / Re: When will the tapes which were ordered at 22nd Aug be shipped out? Order 242570

« on: September 10, 2008, 12:09:02 PM »

Look at the statement on the home page.
I can't speak for the people running this, however
I would probably expect you need to be a LOT more patient than that.
Remember these are being duplicated at realtime speed with strict quality control.
Not pumped out like some cassette product. I just know it takes a LOT of time to do this right.
I would expect more like a YEAR !
I think that lower charter subscription #  members are getting priority to complete their library with the last of the catalog releases as it states on the home page.
Then selective subscription people like me will get more tapes when they go back and begin duplicating more of the lower catalog #s again.
Then probably the people who just ordered one or two with no subscription.

I have 2 tapes so far (TP-001 and TP-002) and I am serial # 111 having joined in March this year 2008.
My last tape was shipped in July.
If you got the full charter subscription, you may well get the last titles being done now before I get any more because I ordered  TP-001,2,3,4,5 and 7 and not 8,9 or 10

459

Tape Project Machines / Re: The Seduction Repro Amp Project

« on: September 06, 2008, 01:36:34 AM »

I THINK I am beginning to get it now. I have read some of what Jay said regarding eq vs. tape/head design on the MRL website.
So part of what I hear you saying is that head as well as tape design has really marched on. And so modern tapes and head design no longer fit what was needed in the NAB curve as it was compensating for more limited frequency response in the heads and lower output tape.
So for the truly best from the TP tapes one needs state of the art heads and the CCIR eq. curve they are recorded with of course, and all that with the properly recorded high output modern tape gives extended frequency response and S/N ratio.
So, even though the seduction is a tube design that does not mean it will mate best with and give really extended response with old tube era heads no matter what kind of shape they are in or if they were state of the art in 1960.
To put it another way, they really had to work to coax reasonably flat response to 15k with Scotch 111 by use of the NAB curve on the pro recorders back in the day.

460

Tape Project Machines / Re: The Seduction Repro Amp Project

« on: September 05, 2008, 12:36:21 PM »

While we are visiting this subject (gain etc.),
What effect does head inductance and impedance have on gain and frequency response for the tape-modified Seduction. I have both newer machines with heads designed for solid state head preamps and older ones that were designed for use with tube head preamps. The first photo in this thread shows the Seduction being used with a machine that obviously is of the tube era head design, while the majority of (tape) users are using it with the Technics (or Otari) heads, or some similar spec. aftermarket replacement for same.

461

Reel to Reel Tape Machines / Re: Adapters for Otari MX 5050

« on: August 30, 2008, 11:40:12 PM »

On the subject of cables vs an active (or transformer) box to convert from XLR pro studio machine line out to typical HiFi gear tape in, make sure of your connections when making (or buying) direct  XLR to RCA cables. When you un-balance the line, the common thing is pin 2 hot, but some are pin 3 hot. Some designs like you to common the "neutral" or signal low balanced side of the line with pin 1 ground, others want you to take the ground of the RCA to ONLY pin 1 or ONLY to the low side of the balanced line. It sometimes depends on whether the tape machine has output transformers (older ones) or op amps for it's balanced line out. And there are various schemes if you are using 2 conductor shielded cable vs. single conductor with a shield. Rane Corp. had some good notes on their website about various balanced to unbalanced and vice-versa cable assemblies. It will not load the tape deck down in the sense that the input impedance of most unbalanced inputs is way higher than 600 ohms. A greater concern is that the signal will be too "hot" for a typical line input, and overload it causing distortion on peaks. Many recorders have output level controls and you can use them to drop the level to that which is typical of your other sources.
Consumer unbalanced "line level" varies quite a bit but is considered to be in the ballpark of 350mV to perhaps 750mV across 10,000 ohms
 - around half a volt give or take.

As for the Otari NAB hub adaptors, the older machines (not just Otari) lacking the pull and turn spindle locks on the small hub spindle, could still be used with non-clamp type NAB hub adaptors with an appropriate collet type clamp to hold them tight. That is what is built into the Otari adaptors. Whatever it is, must be tight enough to prevent the NAB hub adaptor from working its way loose on the shaft and slipping or worse yet, allowing the reel to become loose. Some NAB hub adaptors depend on the shaft tension to hold the adapter in the reel and pin it against the turntable, while other designs clamp the reel firmly with their own spring tension and have a backing flange, relying on the small shaft hold down only to hold the hub adaptor engaged on the drive of the spindle and keep the whole NAB reel/hub adaptor from coming loose. 

462

General Discussion / Re: Heads- Pt.3 Other formats

« on: August 28, 2008, 11:46:07 AM »

On one of the Technics machines (which playback in 1/2 and 1/4 track stereo) it depends on which model (1500 or 1506) on which head playback is first and which is last. A 1500 records in 1/2 track stereo and plays back in 1/2 and 1/4 track stereo. Once again the old rule applies. Erase>Record>Playback. If it records in 1/2 track stereo than the 4th head "must" be the 1/2 track playback head. If it's a 1506 which records in 1/4 track stereo, than the 4th head "must" be a 1/4 track playback head.

This feature of the Technics is atypical of multi format decks, in that the 4th head is in the main format of the machine and the opposite format head precedes all the others. As in 1/4 track play then 1/2 track erase, record, play. In most other dual format designs the opposite format additional playback head is after the primary format playback head.
 As in 1. 1/2 track erase, 2.  1/2 half track record, 3. 1/2 half track play, 4. 1/4 track play.

463

General Discussion / Re: Beginners Guide to Tape Recorder Basics

« on: August 28, 2008, 10:38:57 AM »

Not to devolve too far into head trivia, but there is a class of consumer machine that people may frequently encounter that is NOT compatible with TP tapes. This is the 2 head 1/4 track format where the record and play functions are in one head as you described in "sync" playback using the record head in the last post. In fact some Tascam multitrack (8, 16) use this design too so the signal is always  in sync. It's just harder to optimize record play frequency response and impossible to monitor what you have just recorded on the fly without rewinding with a 2 head (erase, record/playback) system.

As an aside,
yes trivia buffs, that is what the "tape monitor" button is for on many many pieces of audio equipment. It continues to send the program signal to the tape output jacks while allowing you to hear the tape recorder output that can then be switched between tape and input to compare recorded quality.  Some may have forgotten or be too young...

But I digress.

I have also seen auto reverse 2 head designs that play and record both directions. These would have (from left to right) reverse record/play, reverse erase (remember, the tape would be moving the other direction), forward  erase, forward record/play.

And I own a semi pro 2 head design  2 track 15 ips. (inches per second since we are explaining things here) old tube Crown recorder. So at least one 2 track stereo machine is not 3 head !

464

Tape Project Albums - general / Re: Need some help - please!

« on: August 23, 2008, 09:08:59 PM »

Just shooting from the hip. From the words used to describe the problem, sounds like a playback head misalignment problem.
I would try a record / play cycle with known good material  on a new good blank tape and see if it can make a tape that sounds pretty much exactly like it's input source. If so, perhaps the tech didn't align it to a "real world" standard but it is only aligned to itself. I would try another 2 track stereo tape like an older pre-recorded one if you or your friends have one. Although not to the standards of the TP tapes, it should exhibit proper channel balance and not sound dull or like there is a phase issue. Mono parts should be clean and centered in the image. You could consider playing part of your TP tape on another 2 track stereo machine. If it only has NAB EQ it will not sound quite like the right frequency balance but still not dull or phasey.
It is hard to tell subjectively whether the problem was subtle - on the order of a different phono cartridge, or gross - as in no highs at all and/or channels wandering in and out. Improper threading might cause improper tape to head contact, or as was suggested, the machine might have been jarred from proper alignment when in transit. Did you get the Tape Project alignment tape? Could a local tech help you use that to check the alignment?

465

General Discussion / Re: Newby, here, with a few questions...

« on: August 21, 2008, 10:56:12 AM »

You asked -

1.  "Can the appropriate TEAC machine (2T, 10 1/2" reels, 15ips, etc.) be modified to support the IEC equalization curve?"

I am not the expert here, in general I would like to know too, but for older tube machines like I have.

I think, but am not sure, that one would have to change various capacitor and resistor values to change the time constants in the head preamp eq circuit. Just adjusting won't make the slopes occur at the correct frequencies. There are component changes for the Seduction Bottlehead for NAB vs. IEC (vs. it's original RIAA phono) so why not the same in the Teac's (or any) solid state head preamp. Anything is possible as far as a redesign of the head preamp eq circuit, but is it easy? Do I know actual R/C values and what to replace???? No.

If it IS just a mater of adjustment, or this is true of some designs, I would like to know too.


2.  "Can either the Revox or TEAC machine be modified to utilize the Bottlehead electronics?"

I gather that it has to do somewhat with head impedance. The Technics and Otari are similar and that is what the circuits in the Bottlehead have been designed for. Perhaps the (some?) Teac heads are also close. Revox - I have no idea, except as tape head and electronics technology progressed from tube to solid state, head impedances (inductance?), in general, dropped. So, the typical Revox is more of the right era, but European design. Don't forget some Revox machines have CCIR eq which is what is needed out of the box.

As far as getting the wiring out to the external preamp, again, anything is possible but as with the Technics some methodology has to be developed to not have crude wires springing from your head block.