Ampex 1100 Series Reel to Reel Check out

[DMcMahon]

1966 3 speed (single motor), 4 track stereo, 7" spools, solid state recorder, with internal power amps but no internal speakers.

It is dual capstan/flywheel with bi-directional playback/recording.

It is Export model 1163, I think it looks quite retro although I do not find it that attractive, overall pretty good condition for its age.

For Playback the special black metal Take Up spool does auto threading of the tape, which works well. For recording Ampex instructions say to use a standard spool for take up, I am not sure why this is ?

Brought this nearly 2 years ago, unlike the majority of my purchases this one worked very well straight out of the box with no faults/problems.

At the time did quick check out but have hardly used it so have been meaning for ages to check it out again. The only thing that I did not check out then is the auto reversal at end of tape. This is achieved by recording a short 20Hz tone (the recorder generates the tone) at end of tape (or anyway on the tape if required).

What prompted me now to check it out is that a friend of mine has just purchased a good condition 1968 Ampex Series 2100 (Export Model 2163) and he asked if I could check it out for him.

This is a very similar, slightly better version of my 1163, the 2163 was sold as requiring new belts (my friend reports that they have all turned to a gooey mess). So have been looking at mine to see how to replace the belts, looks like quite a strip down to replace the 2 main belts (counter belt is easy).

It looks like I may need a set of 3 belts also. My tape counter no longer works, not sure yet if actually the belt itself. The 2 lower speeds are very noisy now (canot remember it being that noisy when I originally tested it, but do remember thinking it was rather clunky during speed changes), looking at it now I can see that the belt from motor pulley that goes around the 2 flywheels is very slack on the 2 lower speeds but reasonably tight on the top speed (there is no belt tension adjustment). Can also see that this belt has lots of cracks in it.

David

[DMcMahon]

Originally Posted by DMcMahon

This is achieved by recording a short 20Hz tone (the recorder generates the tone) at end of tape (or anyway on the tape if required).

David

This is achieved by recording a short 20Hz tone (the recorder generates the tone) at end of tape (or anywhere on the tape if required to reverse at that point).

[Ted Kendall]

Originally Posted by DMcMahon

For recording Ampex instructions say to use a standard spool for take up, I am not sure why this is ?

If memory serves, only playback is bi-directional on this model, not recording.

[DMcMahon]

Yes you are correct Ted, bi-directional playback only.

So for stereo Record you have a standard spool on the Take Up position so that at the end of the tape you can swap the 2 standard spools over to do the other 2 tracks.

David

[DMcMahon]

Yesterday while checking playback found that both volume/line output controls were very noisy when adjusted so removed the cover off the amplifier unit to spray contact cleaner into the 2 pots.

Saw a folded piece of paper tucked into the top right corner, I thought initially it was maybe put there to insulate something, but upon removal and unfolding, found it was a faint typed note from a previous owner who had rebuilt the machine in 1993 and had done some audiophile mods in 1995.

Interesting to read this snippet of this work done then.

One of the wooden corner blocks in the case was split (quite large chassis screw fixes into it) so have glued and nailed it back together.

David

[Ted Kendall]

Wrong thread, sir...

[DMcMahon]

I don't think so. There is a label on the front of the machine saying it was rebuilt in 1993 and I can see some of the component changes referenced in the note

David

[ben]

That note just shows the delusional ideas prevalent in the audiophoolery world, with blanket cap changes, transistors 'sucking up' signals and 'low oxygen' wire. Not a single voltage measurement or other data in sight.

Interesting machine, I see what you mean about the looks - rather unusual, hard to get used to.

[TIMTAPE]

The "phoolery" type mods can also devalue in people's eyes those mods made by the skilled owner or serviceman which demonstrably result in better fidelity or greater ease of use of the gear. No surprise that manufacturers made modifications to their own designs in current or subsequent models, partly to maintain their competitive edge in the market.

The owner modification thing was perhaps more of an older tradition when gear was less capable but cost more in actual wages, and we both built and modified our own gear, whether from kits or from our own designs, partly out of economic necessity. I guess we continue that tradition today in forums like this. Another topic to explore perhaps.

[ricard]

Originally Posted by ben

...transistors 'sucking up' signals ...

I think it actually says 'mucking up' - not that it makes any practical difference.

I still find it very fascinating that there a) is a log of the mods made to the machine, which is useful if one wants to revert it to its original state, or wants an explanation for the change of wiring and caps, and b) the existence itself of this document, now being part of the machine's history and lending a personal touch to it.

I agree that the mods probably don't make a world of difference, but should be harmless if well done, on the other hand.

I remember seeing pictures of these machines in various books and magazines, I always thought it was rather ugly with the cover over the take-up reel, how does it actually work - does one run the end of the tape through the vertical slot and leave it there, and the auto loading mechanism takes it from there when play mode is engaged?

Does the cover (or covers) just cover the reel or do they have some function? I assume they come off easily if the idea is to replace the take up reel with a normal one for recording.

The styling of the machine to me looks influenced by computer magnetic tape drives of the era, the same goes for the 1960's style reels with small square-ish holes in the sides, rather than the much larger classic reels which were derived by cine spools.

By the way, is the large circular metal plate at the top of the machine on the internal rear view images a flywheel mounted on the motor itself?

[Ted Kendall]

The only sense in which I meant "wrong thread" was the extreme concentration of audiophoolery in the note. Credit to the guy for documenting what he did, and if the mods do no harm, might as well leave them be. Some of that effort, diverted to checking for duff electrolytics and the like, would have had more effect on performance - the main smoothing cap is prone to failure. Granted, the electronics of my 2100 look pretty ghastly, but then so do the insides of a lot of Stateside domestic kit of the time, and they function well enough.

The disc on the back of the motor is part flywheel, part fan.

[Uncle Bulgaria]

It looks straight out of The Italian Job! Have you checked it for traffic police conversations?

The previous owner certainly bothered to put time and money into it, however misguided he was. I think that's a pleasing addition to the story, and if it still works then so much the better!

[knobtwiddler]

Very few, if any, audiophool component substitutions will make enough of a difference to be successfully proven under A/B/X criteria when using modern DACs with their 115dB+ signal-to-noise. If you reduce that SNR to ~65dB, will they become any more audible, or just be buried under a blanket of hiss? This is one of the things that amuses me about cassette fanciers: the format has 60dB SNR (if tip-top, NR off), but some of them make out they can hear the difference between a discrete and a monolithic buffer

[DMcMahon]

Originally Posted by ben

Interesting machine, I see what you mean about the looks - rather unusual, hard to get used to.

I think my friends 2163 looks better in black.

David

[DMcMahon]

[QUOTE=ricard;1426681]

Originally Posted by ben

I still find it very fascinating that there a) is a log of the mods made to the machine, which is useful if one wants to revert it to its original state, or wants an explanation for the change of wiring and caps, and b) the existence itself of this document, now being part of the machine's history and lending a personal touch to it. Totally agree

I agree that the mods probably don't make a world of difference, but should be harmless if well done, on the other hand. Look well done


I remember seeing pictures of these machines in various books and magazines, I always thought it was rather ugly with the cover over the take-up reel, how does it actually work - does one run the end of the tape through the vertical slot and leave it there, and the auto loading mechanism takes it from there when play mode is engaged?

Exactly

Does the cover (or covers) just cover the reel or do they have some function? I assume they come off easily if the idea is to replace the take up reel with a normal one for recording.

The covers just hang on small pins so are very easy to remove, currently I cannot find the small cover. I think their only practical purpose is to keep the tape vertically in position prior to auto threading.

By the way, is the large circular metal plate at the top of the machine on the internal rear view images a flywheel mounted on the motor itself?

If the rear view then it is the capstan motor fan impeller.

David

[DMcMahon]

Originally Posted by Uncle Bulgaria

It looks straight out of The Italian Job! Have you checked it for traffic police conversations?

The previous owner certainly bothered to put time and money into it, however misguided he was. I think that's a pleasing addition to the story, and if it still works then so much the better!

Playback sounds very good to my ears, I doubt if the so called audiophile mods would have made any noticeable difference to the sound quality both on listening tests and on technical measurement tests. When I get my friends 2163 for belt changing it will be interesting to see if his sounds any different to mine, I somewhat doubt that it wil.

David

[DMcMahon]

Got the tape counter working by removing the counter belt and cleaning it, it was somehow catching up on the Supply table drive.

While trying to work out how to replace the 2 larger belts, I could see that the Fast Wind belt has at least 2 nasty cracks in it, so will need to be replaced as well as the Capstan belt.

Checking my spare belts I have none that are long enough so have ordered 2 belt sets from USA.

David

[DMcMahon]

Originally Posted by Ted Kendall

Some of that effort, diverted to checking for duff electrolytics and the like, would have had more effect on performance - the main smoothing cap is prone to failure.

Difficult to be sure but visually it looks like the main smoothing + 4 filter capacitors in the power supply section have previously been replaced, possibly in the referenced 1993 rebuild. In fact it looks like all electrolytics have been previously renewed.

David

[DMcMahon]

Tried to measure the various DC voltage supplies but just about impossible to get to the terminals on the 4 blue filter capacitors without a big strip down and extremely difficult to access/identify the relevant components in the encased pre-amplier electronics.

Measured the supply at the large yellow capacitor (I assume reservoir C353 10uF/150V) as +43.4V with 1.2V 10mS ripple.

Easily managed to access and measure the supply arriving at the power amp heatsink module (identified on schematic as D), +40.9V with 150mV 10mS ripple.

Assume these voltages are about right, the schematic unhelpfully shows no circuit voltages.

Apart from the power amp module this recorder is one of the most difficult I have worked on for monitoring the electronics, I hope I do not have to do any fault finding.

Cleaned the heads and tape path, was surprisingly dirty. Had to lift up the head assembly for better access. When refitting the head assembly noticed that the spring that sits above the black metal "Tape Take Up Assy" is not connected to anything at its top end, cannot see where it should go, thought maybe hooked under the right side of the metal plate but it is not keen to fit there.

David

[DMcMahon]

Have been doing various operational tests including playback, listening to the tape that came with it originally. One side of the tape is some lovely modern jazz and the other side a prog rock band that I recognize but struggling to put a name to, maybe Gentle Giant possibly. All the recordings are really good quality.

While listening, a horrible very loud noise is intermittently occurring on the left channel, most noticeably on the top speed of 7.5 ips and only on Forward Play not Reverse Play.

Difficult to describe the sound but it is a sharp rapid cracking sound as loud if not louder than the music playback.

The plastic take up spool at it rotates looks it is distorted/warped (or the spool carrier has a problem) with result that at times the top of the tape hits the top underside edge of the spool and this often co-incides with the noise. When the noise occurs it is easy to stop the noise by gently pushing down on the top of the tape so that it does not make contact with the top edge of the spool.

Assume this a static related effect, viewing it in the dark when the noise is bad there is no visual sign of any obvious static discharge.

The noise comes and goes to some extent (even though the tape still hitting the spool) but when present always can be made to go away by pushing the tape down.

Need to check it with some other spools, plastic and metal.

David