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Thread: Klemt Echolette S

  1. #1
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    Klemt Echolette S

    I would appreciate learning about any sites/vendors/etc who deal with the Echolette S tape delay machines.

    I just got a fixer-upper and I suspect I may need parts (rubber parts, maybe heads, etc).

    I apologize if this repeats an earlier thread - I looked and found one thread with the schematic, and several sites that sell the manual, but nothing too comprehensive.

    Bob

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    Welcome to the club! I have four Echolettes. I don't think that you will find anything "comprehensive". The manual does not have much technical information other than the schematic and you have already found that.

    Here is a place that can rebuild the rubber roller: Terry's Rubber Pinch Rollers & Wheels

    I do not know of a source for heads. You can buy tape loops on ebay or just make your own.

    These are very difficult to work on since the chassis is very crowded with parts. I have replaced all of the caps on two of mine to reduce some distortion and it is not an easy job. I still do not have what I could consider a properly working unit.

    Here's a pic:


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    Tnx - I found you post before. I think I can handle all the electronic issues (I've had lots of experience with analog tape recording), but, as you know, lack of mechanical parts can kill the whole project.

    I'll post again once I've had a chance to look it over...

    Bob

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    Quote Originally Posted by TransLucid View Post
    Tnx - I found you post before. I think I can handle all the electronic issues (I've had lots of experience with analog tape recording), but, as you know, lack of mechanical parts can kill the whole project.

    I'll post again once I've had a chance to look it over...

    Bob
    May be this link (Echolette documentation) will be useful
    Untitled Document

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    Chapter 2: I'm partway through, but I've learned some interesting things along the way so far...

    1. I took off the front panel and the underlying metal plate so I could get inside the chassis. Then I started tracing the circuit. I got through the input amp, record amp, and output mixing stage. The bias oscillator circuit (the ECC82) is behind the bias transformer, so I couldn't see it. Everything looks fine so far.
    2. There are only two electrolytic caps inside the chassis, both cathode bypass caps (c8/c30). One is easily accessible, the other isn't. I haven't replaced either yet.
    3. I plugged in the bias oscillator tube and slowly brought up the line voltage. I could see oscillations at the transformer and at the adjustment caps, and no smoke. There was bias everywhere, so I turned it off (Nachhall Aus switch).
    4. I changed input 1 and 2 to 1/4" jacks. Since the stage is grid-leak biased, you must wire the 25n cap from the input to the 10M resistor, then to the grids. The jacks should not be grounded to the chassis - use insulating resistors. The grounding scheme is a little strange - I measured 0.3V between the chassis and the internal ground buss. I also changed the output to 1/4" - again, do not ground the jack to the chassis. Also, I added the attenuator (200k/10k) so the output is low level.
    5. Next, I ran signal through it and got signal at the output and at the record calibration pots, but with very high 120Hz noise. I looked at the rails and saw over 25V p/p of nasty ripple. Subbing in a new cap, things looked normal. So, the filter caps were shot. I took them out (surprisingly easy) and mounted a couple of terminal strips next to the power transformer, then used regular axial caps to rebuild the supply filters. Fired it up again, and the noise is much lower.
    6. Next up, the playback chain. I'm going to inject signal at the heads and see what happens. If all looks good, as I suspect, the next step is to roll tape.

    More to come later...

  6. #6
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    Sounds like great progress. I know what you mean when you say that one of the caps is not easily accessible. Sometimes you need to lift one end of several components to clear a path to work in. Maybe we need some of those probes that arthroscopic surgeons use to repair knees through a tiny incision ;-).

    I have tried to find replacement cans for the filter caps without success. The only ones I have found are too large in diameter (Antique Electronic Supply). They might squeeze in but only after enlarging and moving the holes in the chassis. I did disassemble one of the original cans and pulled the guts out, but I haven't found any suitable caps that will fit in the can to keep the stock look.

    Keep us posted on your progress. I am very interested to hear how your project turns out.

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    Not much to report this week (I was busy editing my Guitar amp book for reprinting):

    1. I made some tape loops with prerecorded 500Hz/5kHz tones (at 3.75 IPS). Loaded one on, after cleaning and demagnitizing the heads and tape path. Pulled the bias oscillator tube so no erasure or recording. Does anyone know the tape speeds of the Klemt?
    2. The first thing I noticed was that the motor wouldn't start spinning without some help. I'm assuming the cap is bad (like the PS caps). Does anyone know anything about this cap (I'm assuming it's nonpolarized, since it handles AC). Maybe I can use 2 100ufd caps back-to-back.
    3. Then, no output. It seems to be the playback circuit. Unfortunately, that tube is way back in there and hard to get at.

    Anyway, my next step is to troubleshoot the playback circuit. Hopefully, next week.

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    All I can say about the cap is what I read off the can (and schematic). It is marked as a 48 uF 42V Bipolar cap. I am not an expert about this, but from what I have read about bipolar caps they constructed of two polarized electrolytics in series in opposite polarity. I would need to do more research on that before I actually tried it! A assume that they need to use electrolytics to get that high a capacitance and needed to go bipolar for the AC. It sounds like your idea to use two 100 uF caps in series (with opposite polarity) would work fine.

    Bummer on the no output.

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    Update: I'm still working on the playback circuit. I was able to inject signal at the inputs to the playback amp and see it at the output, but when I played the prerecorded test tape there was no output. I measured the resistance from the input cap to ground to see if the heads were ok: infinite resistance at both inputs. I moved the test point to the leads from the heads, and on one channel saw 1.1k ohms (seems reasonable) and on the other still infinite. So, in spite of the fact that everything looks ok, there's a break somewhere between the head and the input cap.

    My next step is to disassemble that part of the circuit and recheck the heads, then resolder everything and make sure the heads are really connected to the input.

    To be continued...

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    Looks like one of my playback heads is bad - I removed both, and one measures 1.1k ohms, which seems reasonable, while the other measures 1.5M ohms, so I'm guessing that head is more or less open.

    Kazooman, have you measured the resistance of your heads? The playback heads are the two on the left, and they connect at the lower RH corner of the back panel. You can clip on to the coupling caps and, assuming the caps are good, measure the resistance in-circuit. I'd be interested to know if your heads measure around 1.1k ohms...

    That still doesn't explain, though, why the other head didn't produce output. I'm on that next...

  11. #11
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    Hi guys,

    I'm also in the possession of a Klemt Echolette NG51S. Happily, I only had to replace a broken power supply. It sure looks like hell, working on this beast, it's very crowded inside.
    To be honest, the sound isn't excellent. But I notice a lot of trimpots on this machine, that I don't know the purpose of. (I count 9 of them) Do you guys have a manual of this machine?
    Another thing I'm curious about, is the Din connector for a remote control. What can be controlled with this? Only on-off?
    Also the output is pretty quiet. Could there be an impedance problem?

    TransLucid: if you could tell me exactly where to measure the first two heads, I would be happy to help you out. Is it possible to measure without taking this machine apart? (the big chassis is removed)

    Best regards!

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    PM me with an email address and I can send you the manual and schematic.

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    Aaaahhh, crap. Just bought a manual of ebay.
    Nevertheless, you can e-mail it to me; then I can start reading.
    Thanks

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    You will see the functions of most of the trim pots from the schematic. There are 3 records heads, each with its own bias and level adjustment (on the side panel). There are also a few other adjustments on the top (with the heads) and back (with the tubes). The ones on top are labelled, so you can find them on the schematic. The one on the back is echo/input balance, The internal pots are also on the schematic; I'd leave them alone, especially since some are in series with other pots.

    The DIN remote connector can switch the echo off (by grounding pins 2 and 3) or can mute the output (by grounding pins 1 and 2).

    There is a low level output (from pin 1) and a high-level output (from pin 3) of the output jack.

    The playback heads are soldered way inside the chassis, near V3 (the playback preamp). You can measure their resistance to ground there, but it's not easy to get to. The playback heads are the two outside heads; the three inside heads are record heads.

    I've got a new problem now - the unit passes signal, but the level indicator doesn't show any signal (the tube is good). Plus, the signal looks like the bottom part of the waveform is soft clipped. I'm going to fix that before moving on the the playback circuit...
    You need to adjust the bias for the tape you're using to get flat response, and adjust the record level trims for equal output from each head.

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    Thank you for this great explanation. I'm starting to think that this machine is just too complicated for me.
    I think that it's best that I don't open up this thing. Sorry.


    My main problem at this moment is oscillation. I know it's normal that these machines can oscillate; but mine starts when the "Reverb Control" is at level 1! Any idea how I can prevent this?

    Another problem: I think the levels of the 3 playback heads aren't equal. I suppose that when I turn the 3 knobs to level 5, there should be 3 echoes with more or the less the same volume?
    If I understand correctly, I can adjust this with the 3 trimpots at the right side of the machine?


    Thanks and good luck!




    Also Kazooman, thank you very much for the manual!!
    Last edited by carrejans; 01-15-2012 at 01:53 PM.

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    I haven't seen the oscillation problem you mention yet. Don't forget that there's a bias oscillator that turns on, so you may be seeing that, which is normal, when you start recording, if you're poking around with a scope probe. If it's audible, then it's not the bias oscillator.

    There are 2 playback heads and 3 record heads. The 3 volume knobs control the levels to the record heads. The output levels should be the same at the same settings of the control, and this can be adjusted using the level pots on the side (not the bias level pots).

    These machines are complicated and difficult to work on - I'm looking at it as a challenging and fun project, and when I get frustrated I put it aside...

    Bob

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    It's an audible oscillation actually.
    Maybe I can adjust it with the echo/input balance trimpot, you mention? (I have 2 trimpots on the back, between the tubes)
    Or maybe with the trimpot on top, behind the playback heads. (The right one has something to do with echo volume, I think) But that shaft has broken.


    Ok, so I will try to adjust the volume of the record heads. Which ones are the level pots and which one the bias pots? See my picture.

    klemttrimpots.jpg



    Thank you very much!!

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    Echolette stuff

    Looks like I picked a good day for my echolette to break (again). The volume trimmers are the black plastic guys on the side. Be gentle, they can break if you use tools on them. On mine the control for head number 1 works in the opposite direction of heads two and three. Also, to tame down the crazy osscillation turn down the reverb trimmer on the top of the unit.

    I just put a new tape loop in mine, only to find that the first playback head isn't working. The second one works, but pretty weak. I've worked so much on this thing, for this to happen now crushes me . Anybody have thoughts on my problem? Btw I have the older point to point unit ( motor dated 2 march 1961)

    Thanks

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    To add to Spider's description, the bias pots are the smaller variable capacitors.

    Spider - you can replace a head if you can get to the terminal strip way down in the inside corner, and can find a replacement. I bought a second unit for parts, but the real challenge is to disassemble the unit enough to get to the wiring and then be able to put it back together again. Also, the wires are very thin (although, to their credit, Klemt used very high quality wire).

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    TransLucid- I feel your pain on getting into the unit. The components are so tightly packed in there, it is downright amazing. Sadly, I don't think that my problem is the head/s. When I am in echo mode the output is a lot lower than it should be, if I go to nachhall aus the level is as it should be, gutsy and awesome. So, I feel that something else in the circuit must have gone. This started when I fired the echolette up, only to find that the motor wouldn't start without help (nothing new) I gave it a push and there was a terrible grinding sound. I found that the motor had slipped a bit from it's mount, and was grinding on the mounting screws for the vari/cap for head 2. I got the motor back in place, and this problem began. This is really killing me. I've worked so hard on this unit, everything was working great. BTW, the heads read about 1k, further making me think that they are ok. Any ideas?? I'd set this thing on fire if it didn't sound so good.
    thanks a million

  21. #21
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    The motor startup problem is most likely due to a bad cap. Mine did the same thing and changing the NP cap (it's a gold can) fixed it. The other two electrolytic cap cans were also bad, causing a lot of ripple in one case and causing them to overheat due to leakage in another.

    As for your level change, there is an adjustment (Nachhall Pegel) on top with the tubes. Did you try adjusting it?

    As for the heads, the play heads are the outside two, and the rec heads are the inside three. I measured one play head and (if I remember correctly) it was more like 8k ohms. 1k seems reasonable for a record head. Any reading at all means the head isn't open, which is the normal failure mode.

    Bob

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    I changed the volume of the 3 record heads, so they have +/- the same volume.
    The oscillation is not there anymore, either.


    The strange thing about this machine is, that everytime I use it, it has some other problems. ;-)

    - I have an annoying hum now, that I haven't had before. But this, I should be able to fix.
    - When I pull out the "Reverb Duration" pot, the reverbarations are a lot louder. (overdriven also)
    - Also the reverberations sound really chorus-like. Before I had nice clean reverberations... (has my tape become bad all of a sudden???)
    Last edited by carrejans; 01-16-2012 at 09:06 PM.

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    "As for your level change, there is an adjustment (Nachhall Pegel) on top with the tubes. Did you try adjusting it?"

    Sadly, I believe the top level adjustment is global, and applies to both modes. I did mess with it though, prior to posting. This is a pretty significant muting of the signal I'm dealing with. Roughly a 50 percent cut in level.

    "As for the heads, the play heads are the outside two, and the rec heads are the inside three. I measured one play head and (if I remember correctly) it was more like 8k ohms. 1k seems reasonable for a record head. Any reading at all means the head isn't open, which is the normal failure mode."

    well dang, it looks like one of my playback heads opened up after all. Dang dang dang dang dang dang dang. All of my heads measure out to 1k, with the exception of the one that measures 16.4 meg. Perhaps that one has a problem

    All this being said, I still don't see why I would experience such a great loss of signal in echo mode. This is vexing.

    Any guidance, good sir?

    thanks

    spencer

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    The reverb duration switch shorts out one of the playback heads in one position (I'm not sure which). When both heads are on, there are more repeats, which may account for the "chorus-like" effect you noted. This could mean that when to switch is in the other position, only the bad playback head is (partly) functional. On the other hand, if one head has no output, you should either hear no echos (if the bad head only is engaged) or longer echos (if the good head is switched in). If you can get to the head leads, you can try shorting out one or the other and see the effect.

    The duration switch also switches in an attenuating resistor (as best as I can tell) just after the Nachhalldauer control. Opening this switch could raise the level as you noted. This switch is open when the second playback head is shorted.

    I guess you'll have to do some more testing to figure out what's really going on.

    Finally, don't forget that the three record heads can create denser echos when used together. I'd start with only one record head functioning, then test both the playback heads, then repeat this with each of the other two record heads.

    Bob

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    I believe that Bobby Staedel rewinds Echolette heads. I have no idea what this would cost and you need to figure shipping to and from Germany. Here's a link to an English translation of his website:

    Google Translate

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    Quote Originally Posted by Kazooman View Post
    I believe that Bobby Staedel rewinds Echolette heads. I have no idea what this would cost and you need to figure shipping to and from Germany.
    kazooman, yes indeed. He is an awesome guy. When my echolette took a dive a few years ago he guided me through the process of fixing it. I think it was pretty exasperating for him, but in the end my echolette worked again (for a while). An angel really. I'm sending my heads to him, he does them for 25 euro a pop, plus shipping of course.
    Last edited by tboy; 02-25-2015 at 08:25 PM. Reason: fixed quote

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    Hi hope you guys still get this thread, i have an Echolette S it works fine for a while then it goes into this weird hum that kinda hard Oscillating noise it only occurs after about half an hour, it also is noisy when i turn on the Echo but i don't have any tape at the moment, any suggestions?

  28. #28
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    My first thought is your power supply caps are old and dry and start leaking after a while. Have you changed them?

    As far as noise when the echo is on, the playback amplifiers have a lot of gain, so any noise on the supply will be amplified.

    If you have a splicing block and tape you can make tapes easily.

    Cheers

  29. #29
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    Quote Originally Posted by TransLucid View Post
    My first thought is your power supply caps are old and dry and start leaking after a while. Have you changed them?

    As far as noise when the echo is on, the playback amplifiers have a lot of gain, so any noise on the supply will be amplified.

    If you have a splicing block and tape you can make tapes easily.

    Cheers
    thanks for the data mate, I'm sorry I'm really crap at this but id like to learn

    where are the "power caps" and what do they look like ?i don't have a manual, sorry to bug you!

    is there a PDF of the manual available?

    M

  30. #30
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    there are two aluminum cans on the back of the chassis (near the power transformer). One (gold) is for the motor, and the other (silver) is the power supply caps. The part is nearly impossible to find, so, if you want to replace them, you have to jury-rig something (I used terminal strips and radial caps).

    The manual is available, but pretty useless. The schematic is also available, and useful. You can find both on-line if you search for awhile.

    good luck

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    Bloke:

    Have a look at the picture I posted. As TransLucid said, the two aluminum cans to the right of the power transformer are the filter caps. Each can has two capacitors. There are two lugs on the bottom of the can and the housing is the common third (ground) terminal. There are similar cans available with the correct two caps in them, but the size is not the same (larger diameter). If you are going to replace the caps you have to be creative with terminal strips.

    As was also mentioned, you can easily make your own tapes. Here is a link to a source (one of hundreds) for tape and splicing kits.

    Splicit Reel Audio Products - reel to reel recording supplies

    You can buy tapes that someone else has made on ebay, but you will be ahead if you invest the small amount to get your own kit. The length of the tapes is not absolutely critical, since there is a tensioning roller, but you should shoot for 20 1/8".

    Note that when you power on the unit it acts as a preamp. When you press either of the buttons that activate the echo you do two major things. You turn on the drive motor and you energize the oscillator circuit. Either of these can generate the new noise you are hearing. You will need to track it down.

    If you PM me with your email address I can provide a copy of the manual and the schematic.

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    Thanks Guys i will take it on, awesome help its really appreciated!!

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    Hi,

    Can anyone tell me what is the actual dimensions size of an pinch roller for a Klemt echolette NG51S, the one on my device is missing and i think i've just found a suitable replacement, Thanks guys !

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    Hi,

    Can anyone tell me what is the actual dimensions size of an pinch roller for a Klemt echolette NG51S, the one on my device is missing and i think i've just found a suitable replacement, Thanks guys !

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    I just measured one, and as best as I can tell, the OD is 1.9cm, the height is 1.2cm (although this is not as important), and the inner bushing hole diameter is 6mm.

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