Tape Cartridges (4-track tape in upper left for size reference)

Following is a description of the various cartridge/cassette formats commonly used in tape delays, as well as information on the Univox / Melos EM-200 magnetic discs. Notably absent from this page are the Echoplex cartridges (mainly because I don’t own an Echoplex).

On this page you’ll find:

• The Sony RE Series circular cartridges (RE-4, RE-5)
• The Apollon / Dictaphone cassette
• The 8-track cartridge
• The Univox / Melos Echo Tech EM-200 magnetic disc

Sony RE series

These peculiar circular cartridges were probably used for answering machines, prerecorded message playback or similar purposes. It’s doubtful Sony would have designed a tape cartridge exclusively for tape delays, especially since the company never manufactured such devices.

There are different lengths of tape available, the most common being the Sony RE-4 (46 meters tape length) and the RE-5. The cartridges were used on the first generation of Roland Space Echo models (RE-100 and RE-200), before the company moved to free running tape transports on the classic RE-101 and RE-201 models. They are found on many other Japanese-designed tape delays of the era: Ace Tone, Elk, Guyatone, Pax Echo Dek (aka Hohner Echo Plus), etc.

RE-5 cartridge fitted in the ELK Echo Machine transport

These cartridges have become hard to find. The easiest way to procure one is probably by buying a tape delay that comes fitted with one of them. Sony RE cartridges do occasionally appear on online auction sites as well.

Although at first glance the cartridges look somewhat unreliable, the technology is actually fairly solid. After hours of use on ESTECHO machines, no broken or jammed tapes have occurred. On the downside, the system has a lot of mechanical noise, especially compared with the much more silent free running tape transports.

RE-4 original box

The biggest advantage of delays using the RE series is the length of the tape: compared to free running or tension loop transports, it can be more than 10 times as long, which means less wear and fidelity loss over time, because a section of tape doesn’t travel as often across the heads. The biggest drawback, in the 21st century, is the rarity of the cartridges. There are probably other weaknesses (which might explain why Roland decided to drop the cartridges on their Space Echos), but scarcity is most definitely the worst.

It’s most probably possible to replace the tape inside a working cartridge, by cutting the existing tape, splicing the new one on the “going in” end, then running the tape through the machine slowly until the whole tape has been replaced. Due to the rarity of these cartridges, the most precious part is probably the plastic casing itself, which obviously can’t be replaced as easily as the tape. It’s also possible to splice back together a broken tape, fairly easily if both ends are sticking out of the cartridge.

8-track cartridge

There is a surprisingly big number of tape delay units designed around the 8-track cartridge, particularly in Japan, were these (mostly) budget units are easy to find and relatively cheap. Being low budget machines (often used to provide basic vocal echo for the karaoke market of the seventies), they come with limited features and fidelity. On the other hand, they are small and lightweight compared to full-featured, professional models and, contrary to the other cartridge types on this page, replacement tapes are easy to find. Any 8-track tape in good condition will do, even prerecorded tapes. Guyatone and Kastam are two of the well-known brands with 8-track units, many of which having been rebranded numerous times for sale in various territories worldwide .

On some occasions, consumer 8-tracks not sold specifically for tape delay use need to be modified in order to function properly. This is mostly due to the presence of an extra head; 8-track players/recorders for the home stereo market have a combined read/write head, while tape delay units must have separate read and write heads to provide the desired delay. Consequently, it is sometimes necessary to remove parts of the plastic casing, freeing up the required space for proper cartridge contact with the heads.

In the above image, the white cartridge (designed specifically for use on this unit) fits snugly, but the red one had to be modified to enlarge the far right side, which was extending much further towards the inside, blocking one of the heads. Another piece towards the middle was removed as well.

The back padding also had to be replaced. Over the years, the foam padding that pushes the tape against the heads often turns into a messy goo, rendering it useless (and potentially dirtying the inside of any machine it’s used in). This is more often than not the cause of weak, or absent, delay signals. Replacement foam backings for 8-track tapes are easy to find on the internet.

In order to replace degraded foam padding, it’s often necessary to open up the cartridge. This is easier done for some brands than others: some have screws which can be easily removed, others are held in place by plastic pins that need to be snapped. (An excellent reference on this topic is available here.)

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The biggest limitation of the 8-track delay system is the very short distance between the read and write heads, which means that only short delays can be produced. At the longest delay setting, the tape runs very slow, resulting in a very noticeable drop in sound fidelity. Of course, if fidelity isn’t what needed, and one is looking for new and surprising ways to morph sounds into something organic and unpredictable, this lo-fi transformation might be just what is needed. For example, ESTECHO’s music often uses lo-fi delay signals as a sound texture and/or special effect, which can be heard on many tracks.

On the other hand, running the tape at full speed with the output 100% wet (ie. delay signal only) and zero feedback means that one can play “through” the tape almost in real-time, which makes for very interesting effects, provided one can adjust for the few milliseconds delay between finger movements and the sound. The result is a lo-fi carbon copy of the dry signal that went through the machine’s preamp and tape before being heard.

A big plus with 8-track delays is the very limited wow and flutter, due to a very steady tape speed. The most common reliability issues come from a bad contact between the tape and the heads due to a misaligned cassette or worn out padding. Next in line is a worn out or loose drive belt in the unit itself.

Apollon / Dictaphone

The Univox EC-80A & EC-100 units are very common tape delays in North America, showing up regularly on auction sites, and have probably spread much frustration over the years due to their notorious unreliability. The two EC-80A units owned by ESTECHO, although very appreciated when in working condition, are a maintenance and reliability nightmare. Compared to the similar 8-track devices, the Univox units are extremely finicky; tapes need to be adjusted, wiggled, shimmed, and the electronics sometimes fail as well.

The two models I know of: Apollon and Dictaphone

This is a very uncommon cassette format. The Dictaphone company sold some, which probably means they were used for answering machines, and maybe also jingles/commercials for radio. Many Univox / Unicord units come with an Apollon tape, an obscure Japanese company that seemed to be the “official” tape supplier for these machines.

The cassettes are very similar, if not identical, to an obsolete consumer audio format called the “Playtape”, which was sold in mid to late sixties. It has been reported reliably that Playtape cassettes can be used in the EC-80A and EC-100 units. Although this hasn’t been tested on ESTECHO’s two units, the two format seem identical enough. Some parts of the plastic casing most probably need to be removed in order to provide space for the separate read and write heads.

Much like the 8-tracks, the main reliability problem with these cassettes is worn out padding behind the tape. There is also an issue with the Dictaphone tapes, whose casing isn’t exactly the same as the Apollon. The front part extends a little bit more forward, although the tape and pinch roller are in the same relative position in both cassettes (see below).

The two cassettes are slightly different at the tip, as can be seen here.

What needs to be done to ensure that the Dictaphone cassette fits snugly is to file or break off a small part of its casing, a similar procedure to what must be done on many 8-track tapes as well. Although most of the front end of the Dictaphone extends further than the Apollo, not all of it needs to be filed off, just one area. The picture below shows a modified Dictaphone cassette, a regular Dictaphone, plus an Apollon cassette for reference.

Left to right: modified Dictaphone, regular Dictaphone, Apollon. The critical area is at the bottom of the image.

Univox / Melos EM-200 magnetic discs

The original magnetic discs for the Univox / Melos EM-200 are very hard to come by these days. This is probably the most difficult to replace magnetic support of all tape delay units (with the exception perhaps of the Binson magnetic drum). This should be considered before investing in a Melos / Univox EM-200 unit.

Replacement disks for the EM-200

Reports of using the inside of a modified 5 1/4 floppy disc as replacement have cropped up on the internet. This could potentially work, but hasn’t been tested by ESTECHO. Problems that could arise are: inadequate or different frequency response, increased wobble and bad contact due to the central hole in the disc, and premature disc wear leading to dirt/residue on the heads.

Following is a copy of the original disc replacement instructions (click to enlarge), for those lucky enough to have a replacement: