Stellaphone reel-to-reel tape deck
Philip Pemberton
> Philips model. And you might find it easier to get a service manual for
> the equivalent Philips machine -- if you can track down what it is. A
> quick look along my shelf off Poole&Molloy (Radio and Television
> Servicing) books didn't find any mention of this machine (there are
> plenty of other Stella models mentioned, all as being equivalent to a
> Philips machine). And it's not in any of the tape recorder repair manuals
> I've looked it.
What are the other Stella machines listed? The "upgraded" model of the ST 454
I have is the 455, only difference being that it has a speed selector. It's a
really nice machine and it works well. It's almost certainly pre-1960 and it's
possibly pre 1950 as well. I haven't used it much, and I've only got one
(ferric? it's dark brown in colour) tape reel for it. Once I glue the plastic
panelling back onto the wood case and clean it up with a bit of isopropyl,
it's going to go into general use. Anyone know how to get new valves or how
much it's likely to be worth?
If anyone has any ideas where I can get one of the fabled "service manuals"
for this thing, then speak up!
If you need it, the info off the metal plate in the storage area is:
Type: ST 454/01
50Hz, 60W
Nr.: 0225106
There's also a sticky label near the serial number plate that reads:
AH
OO 47/80 (not sure about the 8)
If it's any help, it's got a voltage selector, foot switch slot (with a metal
bar running through it that, when pushed up, will stop the tape) and a
superimpose button. It also has a track select switch (four track, I can
either do 1-3 or 2-4). I could scan in what little info I have, if it's any
help. I have a "product guide" leaflet for the ST454 and ST455. The 455 is
advertised as a three-speed equivalent to the 454. I could record the noise it
makes if it's any help. On page three of the instruction manual it says, in
these words, "In order to get the best results with your four-track tape
recorder we recommend the use of Philips Long-playing and Double-play tapes".
Thanks for the info, I'm off to hunt down some photos of the old Philips valve
recorders. Oh, yeah. While I'm on the subject of valves, it says the deck uses
(in unknown quantities) EF86, ECC83, ECL82, EM84 and EZ80 valves.
Thanks,
Phil.
Philip Pemberton
> are radio sets, radiograms, etc. Not that many tape recorders.
OK... That would explain the lack of info on the 454/455.
> However, after another search I have found the following Philips models
> that use valves similar to the ones you mention :
<snip>
> EL3515 (EF86, ECC83, ECL82, EM84, EZ80, single speed (3.75ips), 2 track)
Near perfect match there. Except for the lack of the track selector. My copy of the
leaflet says the ST454 uses a "fixed tape speed of 3(3/4)" per second". Here's a
like-for-like copy of the features list:
[<start snip>]
Push-button operation
Monitoring facility by headphones for radio, gramophone or microphone inputs
May be used as an amplifier for radio, gramophone and microphone inputs
Built in programme indicator [tape counter] with zero reset [via a small wheel]
Adaptable by means of the Stereo socket with additional suitable re-play amplifier
and loud-speaker for the reproduction of stereophonic tapes
Superimposing "trick" facility [turns off the erase head?]
Accidental erasure of tape prevented by safety interlock
Lockable tape 'pause' button
Takes reels up to 7" diameter
Fully tropicalised
[<end snip>]
So far I've re-oiled some of the mechanism with household oil (the little plate that
holds the tape against the head didn't move very well, due to it being full of
"rubberised grease"). I still don't know why it kept buzzing. Putting the drive belt
back onto the pulleys seems to have solved the problem.
I now need a 95mm drive belt, 2mm circular cross-section, to replace the one for the
tape counter that got snapped (courtesy of the fan and a slack belt).
When I've refurbished my machine, I'm going to produce a sort-of "unofficial guide"
to repairing them. Including diagrams and photos of my ST454. Watch this space!
(contributions needed - you will be credited if you help out!)
> EL3538 (EF86, ECC83, ECL82, EM81, EZ80, 3 speed (7.5, 3.75, 1.875 ips),
> 2 track)
Miles off.
> EL3542 (EF86, ECC83, ECL82, EM81, EZ80, 3 speed, 4 track).
Hmm... About the same amount off as the one above.
> The EM8x is the 'magic eye' recording level indicator. The EM81 and EM84
> have a totally different display pattern, so the difference between your
> model and one of these might just be in the case styling and minor
> changes in circuitry round this valve.
How rare is the EM84? And how reliable is it? If it's any help, the "magic eye" is a
horizontal bar style one that glows a rather nice blue-green. It has a red middle
section and the bar "grows" from the left and right, into the middle (red) section.
> FWIW the models I listed above are in the 1960-1961 volume of Poole&Molloy.
So perhaps my age estimate was a bit off... The plastic cloth around the speaker had
bubbled up a bit so I used my craft knife to cut a slither of plastic out of the
bubble and then I superglued it and smoothed it down. Looks just as good as new. I
also patched up an area that had begun to peel away from the wood. Cyanoacrylate
glue is too useful for words! And what it wouldn't stick stuck down perfectly with
hot-melt glue. The only major cosmetic fault is a fairly large crack on the lid, as
well as a brown foam-like appearance on the inside of the hinged cover. Not even
methylated spirit managed to remove it.
> : (ferric? it's dark brown in colour) tape reel for it. Once I glue the plastic
> : panelling back onto the wood case and clean it up with a bit of isopropyl,
> : it's going to go into general use. Anyone know how to get new valves or how
> : much it's likely to be worth?
> The valves are not that hard to find, actually. There's nothing
> particularly exotic in the line-up.
Hmm. I know of a company who go by the name of "The Chelmer Valve Company" who
specialise in, as their name suggests, valves. No problems there. The only problem
would be to get a magic eye in the UK. I'd really like to have a play with one and
hook it up to the output of my Sansui tuner amp - is this possible?
> : If anyone has any ideas where I can get one of the fabled "service manuals"
> : for this thing, then speak up!
> You might try a large public library (!). A number of them keep
> Poole&Molloy, which would at least give you circuit diagrams of the
> models above. Or maybe Mauritron could supply it (they supplied a copy of
> the service manual for the stereo Philips machine I mentioned in the last
> message).
No real large public libraries around here. The local library don't have many
service guides, and there's a charge of UK£1 if you need a book that's not on their
computer system (i.e. they have to get it in from another county). Pretty hefty if
you ask me.
> : If it's any help, it's got a voltage selector, foot switch slot (with a metal
> : bar running through it that, when pushed up, will stop the tape) and a
> That sounds like a standard-ish Philips footswitch 'connector'. The foot
> switch was entirely mechanical with a bowden cable to link it to the machine.
Hmm... Can you still get these footswitches? Or even a microphone? I don't mind if
it's used, I just need it to work!
> : superimpose button. It also has a track select switch (four track, I can
> : either do 1-3 or 2-4). I could scan in what little info I have, if it's any
>
> As you doubtless realise, it records on track 1 or track 3 with the
> spools one way round, then you flip them over and use track 4 or track 2.
I realise that.
> : these words, "In order to get the best results with your four-track tape
> : recorder we recommend the use of Philips Long-playing and Double-play tapes".
> Two points here. Firstly the 'stnadard' play tape was thicker and you
> didn't get such good head contact with it, which was a problem with 4
> track machines. Hence the recomendation to use the thinner long- or
> double-play tape.
Hmm. Live and learn. Kinda like the old problem with the Sinclair Spectrum computer
- it recorded onto tapes, but anything longer than a C60 would screw it up
(supposedly due to tape thickness, bandwidth, etc.)
> Also, the clear advert for Philips tape suggests that there was a
> connection between Philips and Stella :-)
Which would also explain the "cloning" of Philips machines by Stella.
> : Thanks for the info, I'm off to hunt down some photos of the old Philips valve
> : recorders. Oh, yeah. While I'm on the subject of valves, it says the deck uses
> Be warned that sometimes there were sometimes styling differences between
> the Philips and Stella models. Even though the electronics was very
> similar
I didn't find anything anyway. Just a copy of their logo and a piccy of an old
Philips tuner, circa 1979.
> : (in unknown quantities) EF86, ECC83, ECL82, EM84 and EZ80 valves.
> There seem to be 2 basic circuits used :
I now know the quantities - one of each valve. It's still running on the original
valves too. The filaments that heat them up are glowing a nice red colour. I really
must go round it with my fibre optic lamp and a camcorder some time!
> 1) : Record Play
> EF86 (Pentode) Microphone preamp Head preamp
> ECC83 (Double Triode) a) Radio/PU preamp Amplifier 3rd stage
> b) 2nd stage 2nd stage
> ECL82 (Triode Pentode) t) Output stage 4th stage
> p) Erase Oscillator Output stage/LS driver
> EM84 (Magic Eye) Level indicator -----
> EZ80 (Double Diode) HT Rectifier HT Rectifier
> OA85 (Ge diode) Level indictor rect. ----
Sounds like it. I'm off on a hunt for a germanium diode to confirm my theory :-)
> 2): Record Play
> EF86 (Pentode) Microphone Preamp Head preamp
> ECC83 (Double Triode) a) 2nd stage, PU in 2nd stage
> b) 3rd stage 3rd stage
> ECL82 (Triode Pentode) t) Level ind rect ----
> p) Erase oscillator Output stage/LS driver
> EM81 (Magic Eye) Level indcator -----
> EZ80 (Double Diode) HT Rectifier HT Rectifier
Not that one then. No EM81 (EM84 instead).
Thanks,
Phil.
Tony Duell
: > EL3515 (EF86, ECC83, ECL82, EM84, EZ80, single speed (3.75ips), 2 track)
: Near perfect match there. Except for the lack of the track selector. My copy of the
And apart from the fact that I can find no multi-speed version of this
machine listed anywhere (which is no proof that it didn't exist --
Poole&Molloy is not that good for tape recorders).
: leaflet says the ST454 uses a "fixed tape speed of 3(3/4)" per second". Here's a
: like-for-like copy of the features list:
Unfortunately, Poole&Molloy was written for service engineers who it was
assumed had the machine in front of them :-). In other words it's just a
schematics and brief alignment data -- nothing on the features of the
machine (well, 1 paragraph, perhaps).
: [<start snip>]
: Push-button operation
: Monitoring facility by headphones for radio, gramophone or microphone inputs
: May be used as an amplifier for radio, gramophone and microphone inputs
But I don't remember seeing a 'amplifier' mode switch on the circuit diagram
: Superimposing "trick" facility [turns off the erase head?]
Most likely, yes. May be fully mechaical (lifts the tape off the erase
head), but most of the Philips ones were electronic (replace head with a
dummy load). Again, I don't recall this being in the circuit I saw.
: > EL3538 (EF86, ECC83, ECL82, EM81, EZ80, 3 speed (7.5, 3.75, 1.875 ips),
: > 2 track)
: Miles off.
: > EL3542 (EF86, ECC83, ECL82, EM81, EZ80, 3 speed, 4 track).
: Hmm... About the same amount off as the one above.
Why do you say that? You mentioned a 3 speed version of your machine.
The only difference I can see in the valve lineup is the EM81/EM84
difference. Which actually isn't that much of difference...
A brief guide to decoding those numbers :
The first 'E' says that the valves have 6.3V heaters (filaments).
The next letters indicate the electrode structures :
C = triode
F = signal pentode
L = power/output pentode
M = magic eye indicator
Z = full wave (double diode) rectifier.
Where there's more than 1 letter, then it means there's more than one
electrode section. So CC = double triode, CL = triode and output pentode.
The '8' indicates that the valve plugs into a B9A (Noval, 9 pin
miniature) base
The last digit distinguishes valves that have otherwise identical
numbers. So an EF80 and an EF86 are both signal pentodes with 6.3V
heaters on B9A bases. But they have different charateristics (I can tell
you the EF80 is an RF/IF valve, and the EF86 is more commonly used as a
low-noise audio valve, but I can only tell you that because I have
databooks...).
Now, the only difference between the lineup in your machine and the one I
listed is the magic eye (EM81 .vs. EM84). The signal valves (amplifier
stages) and rectifier (EZ80) are the same, and could therefore be used in
very similar circuitry.
Now, I know that the EM84 and EM81 are totally different in appearance.
The EM84 has a fluorescent strip down the side of the glass envelope. The
pattern is illuminated bars (green/blue IIRC) at the ends of this strip
that come together as the bias is changed. The EM81 has a metalic target
inside IIRC which shows a 'fan-like' display -- 2 sectors that move
together or apart. I think that display is more green than the EM84 as well.
However, the valves are electrically fairly similar. It's possible that
the circuitry round them is much the same, just the cabinet styling
that's different.
My experience with repairing old machines like this is that unless you
can track down the exact model and get a copy of its service manual you
may have to make do with the details on a model with similar, if not
identical, circuitry.
: > The EM8x is the 'magic eye' recording level indicator. The EM81 and EM84
: > have a totally different display pattern, so the difference between your
: > model and one of these might just be in the case styling and minor
: > changes in circuitry round this valve.
: How rare is the EM84? And how reliable is it? If it's any help, the "magic eye" is a
Not that rare.
: horizontal bar style one that glows a rather nice blue-green. It has a red middle
: section and the bar "grows" from the left and right, into the middle (red) section.
The red section is presumably part of the casing, not the valve. I've
never seen anything red on an EM84
: would be to get a magic eye in the UK. I'd really like to have a play with one and
: hook it up to the output of my Sansui tuner amp - is this possible?
Shouldn't be _too_ hard. You'd need to provide power for the magic eye
(6.3V for the heater and about 200-250V DC for the anode and target).
There are a few R's and C's and a signal diode that you need as well.
With that, it should respond to a signal of a few volts peak-to-peak.
: service guides, and there's a charge of UK£1 if you need a book that's not on their
: computer system (i.e. they have to get it in from another county). Pretty hefty if
: you ask me.
You do realise that a service manual, if one could be found, would cost a
_lot_ more than that. I think I paid over \pounds 20.00 for a copy of the
manual for my Philips machine (I do not consider that to be excessive
either -- the manual contained full schematics, exploded diagrams, parts
lists, etc).
: > That sounds like a standard-ish Philips footswitch 'connector'. The foot
: > switch was entirely mechanical with a bowden cable to link it to the machine.
: Hmm... Can you still get these footswitches? Or even a microphone? I don't mind if
I've not seen one of those foot controls for _years_...
: it's used, I just need it to work!
What's so hard about the microphone? Don't Maplin still sell xtal units?
(I assume it's a crystal microphone you need).
: > : (in unknown quantities) EF86, ECC83, ECL82, EM84 and EZ80 valves.
: > There seem to be 2 basic circuits used :
: I now know the quantities - one of each valve. It's still running on the original
I guessed that. Mainly because that list of valves is roughly what's
needed for a tape recorder.
: > 2): Record Play
: > EF86 (Pentode) Microphone Preamp Head preamp
: > ECC83 (Double Triode) a) 2nd stage, PU in 2nd stage
: > b) 3rd stage 3rd stage
: > ECL82 (Triode Pentode) t) Level ind rect ----
: > p) Erase oscillator Output stage/LS driver
: > EM81 (Magic Eye) Level indcator -----
: > EZ80 (Double Diode) HT Rectifier HT Rectifier
: Not that one then. No EM81 (EM84 instead).
See above for why that might not be a problem!
-tony
Philip Pemberton
> : > 2 track)
> Why do you say that? You mentioned a 3 speed version of your machine.
Er... can I correct myself? The EL3538 seems to be a like-for-like copy of the ST455.
Instead of the EM84 used in the 454, the 455 uses an EM81. Add a track selection switch
and a fourtrack head and you've got a Stella ST455 equivalent. By the looks of things,
Stella only replaced the speaker (4" to 5"), improved the braking and clutching mechanism,
added an extra digit to the tape counter, added an automatic tape stop (one that used a
metal "switch strip") and added some form of mixer. It also cost a bit more.
> The only difference I can see in the valve lineup is the EM81/EM84
> difference. Which actually isn't that much of difference...
>
> A brief guide to decoding those numbers :
<snip>
> Now, the only difference between the lineup in your machine and the one I
> listed is the magic eye (EM81 .vs. EM84). The signal valves (amplifier
> stages) and rectifier (EZ80) are the same, and could therefore be used in
> very similar circuitry.
Hmm... I've just had a look at the ST455 - it has a separate magic eye meter that's on the
panel, instead of being embedded in the stop button (the stop button issue makes it a
bitch to replace). So it almost directly crosses over to that Philips machine you
mentioned.
> Now, I know that the EM84 and EM81 are totally different in appearance.
> The EM84 has a fluorescent strip down the side of the glass envelope. The
> pattern is illuminated bars (green/blue IIRC) at the ends of this strip
Correction - the EM84 has a green-blue main area and a red middle section. Or at least
mine has.
> that come together as the bias is changed. The EM81 has a metalic target
> inside IIRC which shows a 'fan-like' display -- 2 sectors that move
> together or apart. I think that display is more green than the EM84 as well.
OK...
> However, the valves are electrically fairly similar. It's possible that
> the circuitry round them is much the same, just the cabinet styling
> that's different.
So does the EM81 need more/less power/voltage than the EM84 or something?
> My experience with repairing old machines like this is that unless you
> can track down the exact model and get a copy of its service manual you
> may have to make do with the details on a model with similar, if not
> identical, circuitry.
Most of the problems with mine were down to lubrication problems. The play button kept
getting stuck because the grease had become extremely thick, almost like rubber. I used
some household oil to fix it and the buzzing seems to have stopped too.
> : > The EM8x is the 'magic eye' recording level indicator. The EM81 and EM84
> : > have a totally different display pattern, so the difference between your
> : > model and one of these might just be in the case styling and minor
> : > changes in circuitry round this valve.
> : How rare is the EM84? And how reliable is it? If it's any help, the "magic eye" is a
> Not that rare.
Hmm... I'll get in touch with Chelmer Valves and get a price for a few EM84s, an EM81 and
enough sockets for all of them. My Sansui tuner amp would benefit from a working level
meter. And my Rotel amp would too. I think LEDs look ugly as level meters anyway. But
that's my opinion.
> : horizontal bar style one that glows a rather nice blue-green. It has a red middle
> : section and the bar "grows" from the left and right, into the middle (red) section.
> The red section is presumably part of the casing, not the valve. I've
> never seen anything red on an EM84
It would be easy enough to do that. There's a small piece of plastic over the opening in
the stop button that looks like it had a coating on it. The colour of the magic eye seemed
a little uneven in the middle of the meter, too.
> : would be to get a magic eye in the UK. I'd really like to have a play with one and
> : hook it up to the output of my Sansui tuner amp - is this possible?
> Shouldn't be _too_ hard. You'd need to provide power for the magic eye
> (6.3V for the heater and about 200-250V DC for the anode and target).
> There are a few R's and C's and a signal diode that you need as well.
> With that, it should respond to a signal of a few volts peak-to-peak.
6.3V should be easy enough to get from a 6V transformer. As for the 250V, that would be
easy to get too - another 6V transformer, hooked up secondary to secondary (i.e. +6 on
heater 'former goes to +6 on tube drive 'former). I think Poptronix put a PDF of a simple
"magic eye" meter on the site. I'll have a look in a minute.
> : service guides, and there's a charge of UK£1 if you need a book that's not on their
> : computer system (i.e. they have to get it in from another county). Pretty hefty if
> : you ask me.
> You do realise that a service manual, if one could be found, would cost a
> _lot_ more than that. I think I paid over \pounds 20.00 for a copy of the
> manual for my Philips machine (I do not consider that to be excessive
> either -- the manual contained full schematics, exploded diagrams, parts
> lists, etc).
Hmm... £20 for that. The last time I tried to get a service manual was when our old Sharp
VCR died. I was quoted £74.82, provided they could find the manual. I had a look on
RepairFAQ.org, dismantled the mode switch in the VCR (coated with a nice thick layer of
corrosion), cleaned it, adjusted the spring tension and put it back together again. Worked
fine ever since.
> : > That sounds like a standard-ish Philips footswitch 'connector'. The foot
> : > switch was entirely mechanical with a bowden cable to link it to the machine.
> : Hmm... Can you still get these footswitches? Or even a microphone? I don't mind if
> I've not seen one of those foot controls for _years_...
Then I'll cheat a bit with a solenoid, a PP3 and a footswitch. Should be easy enough.
> : it's used, I just need it to work!
> What's so hard about the microphone? Don't Maplin still sell xtal units?
> (I assume it's a crystal microphone you need).
I said I built a microphone from parts I got from Maplin. It's sitting on my workbench,
hooked up to the Stella deck.
> : > 2): Record Play
> : > EF86 (Pentode) Microphone Preamp Head preamp
> : > ECC83 (Double Triode) a) 2nd stage, PU in 2nd stage
> : > b) 3rd stage 3rd stage
> : > ECL82 (Triode Pentode) t) Level ind rect ----
> : > p) Erase oscillator Output stage/LS driver
> : > EM81 (Magic Eye) Level indcator -----
> : > EZ80 (Double Diode) HT Rectifier HT Rectifier
>
> : Not that one then. No EM81 (EM84 instead).
> See above for why that might not be a problem!
Read it. The 455 and 454 seem to have identical valve lists, except for the magic eye
indicators.
Thanks,
Phil.
Philip Pemberton
could be causing the "warm-up buzz" problem? Whenever I push the RECORD and PLAY buttons
together (to record onto the tape), it seems to emit a buzzing/popping noise from the
speaker and I end up turning the thing off, waiting a bit and turning it back on again
just to get it to play again. Any possible suspects? Is it actually possible to test the
heater in a B9A-base valve with an ohmmeter?
Later,
Phil.
Tony Duell
: Just as a follow-on to mmy other reply - is it possible that a valve with a
: could be causing the "warm-up buzz" problem? Whenever I push the RECORD and
Very unlikely. This is much more likely to be a capacitor problem (maybe
a decoupling capacitor has gone low in value and there's thus a feedback
path). Screen grid decoupling capacitors on pentodes (like the EF86) have
been known to cause amplifiers to turn into oscillators if they lose
capacitance.
[...]
: to test the
: heater in a B9A-base valve with an ohmmeter?
Well, you can check it for continuity fairly easily, but that's not going
to help you here (I don't think one of the valves is failing to warm up).
I doubt if a normal low-voltage ohmmeter would detect a leak between the
heater and other electrodes, though.
The pins are numbered clockwise from the gap, looking at the base of the
valve. The heater pins are 4 and 5 for all the valves in your unit.
-tony
Philip Pemberton
Tony Duell wrote:
> Philip Pemberton (phi...@btinternet.com) wrote:
> : Just as a follow-on to mmy other reply - is it possible that a valve with a
> : faulty heater
> : could be causing the "warm-up buzz" problem? Whenever I push the RECORD and
>
> Very unlikely. This is much more likely to be a capacitor problem (maybe
> a decoupling capacitor has gone low in value and there's thus a feedback
> path). Screen grid decoupling capacitors on pentodes (like the EF86) have
> been known to cause amplifiers to turn into oscillators if they lose
> capacitance.
But it works flawlessly if it's given ten minutes to warm up. That's why I
thought one of the valves had a weak heater.
> : to test the
> : heater in a B9A-base valve with an ohmmeter?
> Well, you can check it for continuity fairly easily, but that's not going
> to help you here (I don't think one of the valves is failing to warm up).
> I doubt if a normal low-voltage ohmmeter would detect a leak between the
> heater and other electrodes, though.
Continuity wouldn't be the problem here anyway. A weak heater is hardly going to
show up on an Ohms test, least of all on my cheap Monacor DMT1010 meter.
> The pins are numbered clockwise from the gap, looking at the base of the
> valve. The heater pins are 4 and 5 for all the valves in your unit.
Thanks for that. Do you know of anywhere I could get an EM84 valve (used or NOS)
cheaply? I want to build a "magic eye" addon for my hi-fi. Just because I hate
LED/LCD/VFD meters. Especially considering the fact that my current hi-fi setup
doesn't include a VU meter.
Later,
Phil.