ELPICO TR400 - Reel to Reel - Low Volume on Playback

[nmiddlemass]

Hi..

I've been working on a lovely old Elpico BSR Reel to reel machine. I have replaced the belts and mechanically the unit is sound.

I have played a couple of tapes through this player and to me the volume seems quite low. When I've had different models they are quite loud, this is only a bit louder than the noise of the machine running.

I have hooked the outputs up to see if there was any difference but the volume again seemed low.

The solder joints on the head unit are good. When active the valves all glow although the ECC83 mounted on the orangey brown board doesn't seem as bright as the others.. My knowledge of the is limited.

I'm assuming there is an issue with the internal amp.

I have attached some pics..

As usual, any advice would be appreciated.

With Thanks.

Neil

[peter_sol]

The head may be worn or dirty
Have you tried cleaning it?

[ms660]

The amp looks ripe for an overhaul, Hunts, polystyrenes, resistors, switch contacts etc.

Might be an Elpico TR400?:

http://www.americanradiohistory.com/...h=%22elpico%22

Lawrence.

[Techman]

I was given a Elpico tape recorder with the TD2 deck sometime last year and it's probably the same or similar to yours and had exactly the same fault of low volume. As this is all 'audio circuitry' (other than the bias oscillator) it's true that ALL those brown Hunts paper capacitors will need replacing, and it's not often that I say something like that as I don't go along with replacing capacitors etc. for no good reason. I looked at the circuit and replaced a couple of what I considered critical ones and it made quite a noticeable difference. However, it wasn't until I'd replaced all of them that the performance came fully up to scratch. Actually, I've just remembered that I didn't have a circuit for it so I just used the valve data for the various valves and followed it through from there. I seem to remember that it's a bit of a time consuming game to get to the solder side of the circuit board, so if you didn't want to remove the board, you could cut the components out leaving enough of the old leads to be able to clean them up and solder the new components onto them. I think all the main paper Hunts capacitors are HT voltage rated 0.05uf types, so 0.047uf types, or even two 0.1uf types in series will work in each case, but do confirm that these are the actual values, as this is all from memory.

[nmiddlemass]

Thank you to everyone who has offered me advice, I am always grateful.

I have cleaned the head thoroughly, visually it looks sound.

It definitely is the TR400 Model

I think I will start off by replacing those brown HUNTS caps. It does look a pain to remove the board to get to the solder side so I will likely cut the components from the accessible side... However I don't have a schematic for this so unsure of the polarity of the Hunts Caps. Is there a way to identify this visually on the cap? Apologies if this is a silly question but I am only used to doing electrolytes.

Cheers.

NM

[teetoon]

Hi Neil. In my experience the resistors can go high, in particular the 220k and when replaced brings the volume back. May not always be the case of course but certainly worth checking.

My Dad had one of these Elpicos. It was his first Tape Recorder. I always thought they were a neat little machine.

Hope this helps. David.

[Radio Wrangler]

The brown Hunts capacitors aren't electrolytics. They aren't polarised. Inside they're just paper and metal foil, no electrolyte.

They work equally well either way round.

Some non-polarised capacitors have a marking band near one lead to say which lead connects to the outer foil. This makes a slight difference in some circuits due to stray capacitance to neighbouring components and wires. In this recorder you needn't worry, but it's good practice to see if the original component has a marking and if the replacement does, put them in the same way.

There are three groups of capacitors you need to be able to recognise:

1) Electrolytics. These are usually the largest value capacitors in a set and are mostly used as energy stores (reservoir and smoothing capacitors) and as low impedance signal coupling and decouplers for audio frequency circuits. Electrolytics can last almost forever under favourable circumstances, but heat tends to drive moisture out, drying their electrolyte so they get lossier and lossier. Electrically, they look like capacitors of reducing value, with an ever-increasing resistance in series with them. Electrolytics can degrade over years of dis-use, though many can be restored by a process called re-forming. They are the reason why long-unused equipment should be brought up gently, not plugged straight in. Replacement parts need the right voltage rating or more, and a larger capacitance is usually OK

2) General non-polarised. These are used for signal coupling, tone controls, filters and timing circuits. They aren't very critical on value. Paper or plastic films are the usual types. Paper ones take in moisture from the air and go electrically leaky. Some makes are renowned for this (EG Hunts) The electrical leakage can affect the bias on valves and cause damage much more expensive than the capacitor. Some plastic film types seem to last forever (EG Philips 'mustards') Go for the same voltage rating or more, you can often take liberties on the exact value.

3) Precision capacitors These are usually found amidst the coils and tuned circuits of radios. Most types are fairly reliable. Exact capacitance value is needed and re-alignment of the set is often needed after replacement. Stick to the same type or else you may get temperature related drift of the tuning. Generally these are left alone until it becomes certain that one has failed.

David

[camtechman]

Although it may not cure the problem a demag of the heads would be a good idea.

[nmiddlemass]

Thanks for the help. I suppose when something reaches this age it requires a proper overhaul of components.

I will certainly recap, check out resistors and demag the heads. I will update on progress.

With Hunts caps no longer being available what would be the best suitable alternative? I have read a couple of threads on this from a few years ago but would appreciate a view.

Thanks..

Neil

[Station X]

Originally Posted by nmiddlemass

With Hunts caps no longer being available what would be the best suitable alternative? I have read a couple of threads on this from a few years ago but would appreciate a view.

Thanks..

Neil

See here:-

https://www.vintage-radio.com/repair...apacitors.html

Scroll down the page. I use yellow polypropylene types, but it's a matter of personal preference.

[Steve_P]

Why not start by checking the HT line and the voltages on the valves?

Cheers.

Steve P.

[Edward Huggins]

A bit of an odd suggestion, but is the speaker intact? Those notorious 8" x 2.5" slot loudspeakers (designed mainly for TV use) have a perilously thin cone which may have become damaged.

[Techman]

Wow! there's certainly some 'night owls' replying to this thread in the early hours - and I thought it was just me that kept those sort of hours browsing the net and working on electronics etc.

There's also notably a lot of interest in this particular tape recorder by members - perhaps it's because of the Elpico name? My Elpico was borderline scrap when I got it, but I saved it because it was an Elpico model type. Someone will correct me if I'm wrong, but I think the 'Elpico' name can claim its fame due to one of the Davies brothers of the group 'The Kinks', who used an Elpico guitar amp and 'cut up' the speaker cone of this amp with a razor blade to make the first mechanical 'fuzz' sound before electronic fuzz boxes were invented, which sound is heard on the '64 hit 'You really got me', and is regarded as the first ever 'heavy metal riff' recorded onto disc. Actually, I think that the fuzz (overdrive) sound had been recorded electronically a bit earlier than this by Meek with his 'RGM sound', on the lead guitar of an obscure instrumental called 'Dodge City', but all this is getting slightly off topic for this Elpico recorder now.

My Elpico had a rather historically interesting tape with it, which had what sounded like a couple of teenage girls making recordings of themselves reading poetry and singing in their bedroom. On one side of the tape there's also a young lad learning guitar and the tunes are what would have been of the time that this recorder would have been new. One of the girls actually says her full name at one point. She's likely to be fairly old by now if she's still with us, and probably a grandmother or great grandmother even, her accent, I seem to remember, was from 'up north'. The recording was rather spoiled in a lot of places by what seemed like a bad connection on the microphone lead, with some intermittent loss of sound with loud 'hum' as the mic is being held and moved about. The person that gave me the recorder confirmed that the microphone did indeed have a bad connection in the phono plug, probably from being caught up and pulled, back when the girls were using it all those years ago, which he fixed and taped up. Unfortunately, he has recorded over a small part of the tape while he was testing the mic. From this I think it's likely that because of this fault, the tape recorder was put away when it was still quite new and never used again until it surfaced, probably at some car boot sale in the last couple of years or so. This recorder was another 'gift' from my CB/Ham radio pal who tends to give me items such as this in payment for various repair jobs - goodness knows where he gets some of this stuff from

It's a good suggestion as regards to checking voltages and also resistor values, although I'm gathering that the fault finding skill level of the OP is likely to be very limited, so if it does turn out to be anything more than replacing the paper capacitors, then a lot of careful guidance will be needed, and also a LOT of reading up on electronic theory by the OP.

In my recorder, the voltages were all around what would be expected. One thing that did happen while I was testing mine out was that the reservoir section of the double smoothing can suddenly failed open circuit (or lack of capacitance) resulting in sudden loud mains hum. A direct replacement of the correct size that will fit in the clamp is available at a cost of about £8, but for the time being I fitted a random single capacitor out of the parts box in place of the dud section and cable tied it to the can of the original and it does the job for now and got the thing working.

These recorders use an EZ80 rectifier (I see that the OPs actually has an Elpico branded one, whereas I think mine had a Mullard like the other two valves) which are nearly always OK in tape recorders. I have found completely dead EZ80s, but only in radios. Tape recorders don't give these valves the hours of of continuous use that a radio would, but still worth checking the HT voltage at the smoothing can. At least this recorder doesn't use one of those selenium rectifiers, otherwise I would have suggested taking a voltage reading in my first post on this thread as one of the first things to do.

Lastly, and no offence meant to the OP, but as the electronic servicing skill level of the OP is starting to become apparent (and something that I probably should have thought about in the first instance on this thread), is a WARNING about the dangers of HIGH VOLTAGE from transformers and stored energy in electrolytic capacitors - be careful, and if in doubt, ask. Also, do a search on this forum and take time out for some reading. It's all on this forum regarding electronic servicing and safety etc. Don't be put off, just be safe!

PS, My recorder is the same model as yours, and as shown in the link posted by Lawrence - they got it a bit wrong in the description regarding separate bass and treble controls, as it just has a tone control.

[radiotechnician]

If you own an audio oscillator, feed a 1 kHz signal
across the head, with no tape, on play, with a level
of 5 mV.

Then check the signal to noise ratio heard.

If loud and clear, then suspect the head.

You also could cross patch the head from your other working
vacuum tube BSR machine running a tape. This trick works both
ways for diagnostics. Needed is good test screened lead with
small alligator clips.


Years ago my firm sold an inexpensive BSR tape recorder, and
very many BSR record changers.

[Edward Huggins]

BTW Elpico has an interesting history which can easily be searched. They were very active from the late 1950s to late 1960s and made many (mid quality range) audio products with a range of brand names.

[nmiddlemass]

Hi Everyone,

Thank you for all the kind words of advice. I am grateful, especially so for the warnings and advice about safety and high voltage. It is heeded.

The good news is that this issue is now fixed.

I replaced all of those Hunts and that 220k resistor that was mentioned higher in this thread.

The volume is now as I would have expected to be

Funnily enough this also had a tape when I got it, it was made by a brother and Sister one Christmas Eve who were staying at their Grandparents house and speculating what Santa might be bringing for them. They also did some jokes and some singing before the inevitable arguments leading to the recording being stopped. Really interesting from a social history perspective.

Thanks Again

[dave walsh]

Excellent-that's one repair/restoration achieved and two vintage recordings saved by the OP [Middlemass] and Techman. The Kinks story re "mechanical" fuzz [p13*] is certainly true and it was Dave Davies, with the razor blade, who created that sound which led to the electronic fuzz box being all the "rage" [appropriate to the brothers who did a lot of fighting with each other]. Ray is sometime seen out and about here in Bexhill. I believe he has a daughter who lives nearby. Dave had a severe stroke in a lift at the BBC a few years ago but thankfully, made a recovery and played on stage again.

Jimmy Hendrix had a "secret" technician who developed specific electronic devices for him, particularly Wah Wah pedals and he may also have produced Fuzz Boxes but I'm not sure about that. I didn't know about the Elpico Amps themselves either!

Dave W

[Techman]

Well done for getting the tape recorder working properly again. I was 99% sure it was those capacitors from what you described. Coincidentally, the chap that I got my Elpico recorder from happened to phone me later the same day as I made my last post regarding another radio related matter. I told him that him and his old tape recorder were being 'mentioned in dispatches' on this forum (he's not a member and hadn't seen the thread), so he could have a look if he wanted. I asked him to remind me of the story of this recorder and he told me it was from a car boot sale and that other than giving the mechanics a bit of lubrication that when he plugged it in it worked perfectly. It was only after some time that the sound gradually died, as would be expected as the leakage of particularly two of those Hunts capacitors took effect. I haven't listened to the content of the tape for a very long time, so can't remember exactly what was on it, or the name of the girl mentioned. He also, couldn't remember the girls name off hand, but told me that at the time, he had tried to do a bit of research on the name, particularly on Facebook, but came up with absolutely nothing. When I said that if I had an on-line video hosting website that I would probably have uploaded the contents of the tape for interest sake, he told me that he had already done this at the time and it was via this very tape recorder, before it went wrong and was eventually given to me, so it's already out there.

After I mentioned about the Davies brothers and the Elpico speaker cone cutting, I did do a little bit of research, just to check that it was basically true what I'd said, and found that it was. Other than a previous dispute between them as to who actually did the damage (Ray or Dave) and whether it was a razor blade or a knitting needle, it seems that it was Dave's amplifier and it was him with the razor blade, and history was made.