Contrary to what I thought , I had too many pre-magnetization on the
three recording heads .
I inserted a 500k potentiometer between 60pf capacitor , 120pF and
220pF and heads, and thus I was able to adjust the pre- magnetizing
voltage applied to each recording heads .
It is true that these heads , instead of presenting a resistance of about
1,000 ohms are only 300 ohms , and I gather that the HF voltage that
was applied to them was too high.
So I consider that my problem is solved.
Sorry to have bothered you with my question ...
Hi Mecaso , no need to apologise , this is what this forum is for , if any apology is due it would be from me, for not replying to your question.
I'm glad you got it working , I thought the trim capacitors C14,15, 16 would have the range to adjust the bias.
I have thought about it and was going to suggest a reverse polarity on one or more of the heads as the heads I have seen have 3 wires + , - ,GND/shield.
Only other thing (other fault) I could think of was residual magnetism in the heads metal frame , which would need de-magnetizing like tape recorders do every now and then . Looks like a good bit of history you have there and if Klempt Echolettes could talk what an interesting story we could have !!
Hello, oc disorder.
Thanks for answer.
Yes, the trim capacitors C14,15, 16 would have the range to adjust the
bias, but, the resistance of my heads is only 300 ohms under DC, so, this
is perhaps the reason why capacitors are not sufficient.
With my potentiometers, i can adjust bias and my NG51S works
well,.........at my convenience.
It's again me.
To realize myself my tape-loops for my tape echos, you would have a brand
or a particular type of tape to be recommended to me?
If the rules of the forum does not allow it, you can maybe inform me in
On one of my NG51S, i suppose the previous owner has done a modification of the oscillator transformer.
Is somebody knowing how many turns of wire are wound on the circuit?
So, L1, how many turns?
So, L2, how many turns? And, too, what is the position of connect to the erase head?
(How many turns between the ground and erase head?)
Many thanks & greetings.....
Hello again Mecaso,
I don't know the answer to your question.. but it should be possible to calculate the inductance with the given capacitance to make the 17kHZ (or what ever it is)oscillation.
It also occurs to me that some of the early valve/tube tape recorders may have a near enough bias coil (although possibly a different freq) to replace the original.
That's just an idea ... I guess most of the old mono ones are very hard to find now but I imagine there are a lot more in attics and cellars (basements) in Europe than in Australia.
Maybe a quick trip to Great Britain too before they shut the door ??????
Hi guys, when you're talking about HF bias voltage for recording heads (60 -90 -120volts) do you refer to rms, pk or p-p voltage ?
Thanks in advance
I have 2 of these that need to be restored.
Is there someone that specializes in these that I can send them to.
I know one man who is able to repair your tape-echo ECHOLETTE.
He is a specialist worlwide known.
His mail address:
Last edited by Mecaso; 11-21-2016 at 10:06 PM.
Hi Kazzooman , and Bob Translucid , I have 4 Echolettes the early klemt 51 , on wich I have replaced all heads with Woelke Pro Studiorecorder halftrack heads , the set is working but I have to much noise even without echo or tape running .. so I will have to investigate the rest of the machine to find the noisy parts ... the heads I use work fine , I can adjust for bias to give a maximum on sound and that works satisfactory but next job is finding the noise in the machine , the mechanical parts are replaced , the plastic rollers are replaced by quality steel roller bearings like you find in Revox and Studer recorders , the pinch rollers are replaced by old but very good 8track pinchrollers .. you find them in the good old quality 8track tapes the inside diameter is to big but there is a possibility to pres in a 4 / 8 mm adapter in bronze ( bearings self made) some 8tracks have a plastic pinchwheel , that you can NOT use , but some have a synthetic rubber wheel and that's the one to use ! you can use pinch rollers from normal taperecorders also but still you will have to press out the inside bronze bearingbush and make your own , the old Klemts are running on 4mm axes the later Dynacords run 6mm shafts . so far some experience on these German machines , and yes it's a pain in the ass to get to the electronics . but they WORK HO SO FINE when totally in order .. :-)
keep posted , Ben
Bobby is agood , but there are other people too that can fix your Echolette .. I do .. :-)) in Belgium , and I can suply you with info , and pics ,and a set of heads and mechanical parts , pinchrollers , intermediate steel rollerbearings like on Studer and Revox recorders , Woelke Pro recorder heads for record and playback , only the eraseheads I do not have , but these are not going bad .
so keep in touch ;; Ben
Will try to put up some more images later , Cheers , Ben
just put 10 windings around the coil , measure and compare .. and you will know the ratio .. to your 10 windings :-)) easy job ??
Cheers , Ben
I just gave you the solution read my postings .. Cheers
Roller bearings are not a good solution if they are used before record
and playback heads.
It is the reason why Echolette use plastic rollers. You can use one
roller bearing only before erasing head, that is to say, after record &
play heads, that is to say between the last play head and the erase
I had the problem on a Dynacord S-62a, where a roller bearing added
noise, because roller bearings are made with magnetic metal.
And, too, do you are sure that your erase head works correctly and
erases well the track which is running in front of your record & play
Ho yes mister knowall ?? are you ?? I have three machines converted on roller bearings and they are running perfect without any unnecessary noise ,nor electric , nor mechanical, maybe you can tell me why is Studer and Revox , studio recorders fitted with roller bearings ??those Swiss perfectionists are maybe a bunch of stupidos?? And yes if you forget to demagnetize them and simply touch them with a magnetic screwdriver it could ad some noise , but most of the noise on recorders comes from bad tape , wornout tape, wrong bias what more ? noise in the amps , noisy transistors , leaking capacitors , magnetized heads from 'specialists ' who can not leave it to touch things with magnetic screwdrivers , same kind of guys that are bumping into speaker dustcaps with their fingers , Mechanical noise comes from dirty shafts , plastic wheels , washers that are touching tape while it revolves anything .. take a stetoscope and listen to the mechanics .. easiest way to find it .
Listen I am a newbee on this forum because I was looking for some more wisdom here , but I am 69 years old and about 55 years busy with all kinds of tubeamps , recorders and the like , so I am more or less aware of the stuff , but you never can say I know it all .. so I am waiting to learn some new tricks ..maybe .... or I can tell you a few .
No hard feelings :-)
I just have for the moment on one of my machines a litle problem that I am trying to locate .. don't worry ,I will find it , I have a litle birds-squeel after half an hour on a tapeloop and funny enough the same loop placed on my other machines is running perfect even for hours .. so I will need some time to find out why this loop is making the squeeling noise just on that machine. I will post you when I find it.
Cheers man.. I ll read you . :-) SEE REVOX B77 rollerbearing before and after heads and NO NOISE ! this is not a Toy but a Studio recorder
Last edited by staxmotownjunkie; 03-28-2017 at 11:48 AM. Reason: extra Revox picture
Hi Mickey , not a special problem , just a birds-squeel on one of my machines after 30 minutes about , same tapeloop runs perfect on my other machines , I will find it , don't worry
I have sent my answer to staxmotownjunkie by private message.....
You have something to say, you say it, period, no need to insult other Forum members.
Cool. Keep it that way.Listen I am a newbee on this forum because I was looking for some more wisdom here , but I am 69 years old and about 55 years busy with all kinds of tubeamps , recorders and the like , so I am more or less aware of the stuff
Welcome to the Forum.
Juan Manuel Fahey
Ok sorry guys , bad temper sometimes , but the it can happen .. so problem solved ; found the litle Tweety bird yes my friend ,Mecaso :-)
it was the Plastic idler .
just have converted the machine like my other Super 65's with a rubber idler on bearings .. FINI litle squeelly tweety bird , FINI ratlenoises .. just sweet running bearings no Mechanical noise no sound tapenoises , and running my own looptapes , I ll give you some pics now to prove my conversions , and yes... this machine runs on a Philips 1/2 track playhead .. and it's just putting out the same quality music echo like the original heads . 12 to 15 mVolts depending frequency 400 Hz or 1000 Hz and slow speed or fast but identical to original Dynacord head .
My looptapes ? made from Emtec ( Basf) Mastertape and some AGFA low noise tapes.. running perfect with minimal friction noises
In have another Echolette NG51 that is converted with Pro Studio Woelke 1/2 track heads , fully amazing quality !
pics from that one next time if anyone is interested .
Cheers ... Ben
Is somebody able to explain how , in 1960, a NG-51S was sold by
Dynacord as an ECHOCORD Super.
(Dynacord bought Echolette only in 1969, not in 1960.)
Please look at this link:http://www.el-me-se.de/old/pdf_files...OCORDSUPER.pdf
What was the factory who built all Dynacord & Echolette tape echoes
in the 50' & 60'?
I am curious to know that...!!!
The box of the Echolette NG-51S and the one of the Dynacord
Echocord super S-62a have the same dimensions.
The heads are the same, the motor is the same, the loop
is the same, just some differences between them.
I am quasi sure that the same factory was building them.
Who can explain that...????
Thanks in advance...
read the Klemt Story ..
it's about Klemt , Echolette and Dynacord .. also Winston .. Klemt speakers where mostly Isophon top of the range to be compafed with the JBL's 100 dB efficiency ! and very warm sounding ,JBL was more crisp in tone ( D130F) , Echolette build the famous Toneringboxes like Fender did .. later dynacord went to RCF and other cheaper manufactureres .. you can see how the quality of the gear went down .. music power and profits went up for Dynacord .. the old Klemt amps where technically fantastic but APITA to work on . especially the first Echomachines with point to point connections , and the first M40 amps .. later on they build Printed circuits .. Dynacord started Pushing EL34's over 100 watts for a couple at 750 and almost 800 Volts .. HT .. Crazy ! one of the best Amps from Klemt is the BS40 , and if you change the outputtransfo from that BS40 for the OPT from an M40 you have the nicest and most powerfull amp with just two El34's .. I modded these amps with two 6550's .. wow what a dynamic ! and no problems of noise from bad singlecoil pick ups .; Dynacord echos went also the cheaper way .. only one record head and 3 playbacks .. all plastic gear , motor with only one spead instead of the 2 speed 6 pole Papst, this in the Dynacord mixamp Eminent 100A the 100 type was an even cheaper version . compare the chassis with the early versions . and the Dynacord MiniEcho .. one playback head ..
About amps one of the nicest amps was also the M70 from Echolette let's say a slightly better version of the Golden M40 series and in a stronger Vynil housing. I have no idea who started first with the greeneye EM84 in the Echos , Dynacord had a greeneye in one of their 40 watt amps the frist Eminent
you can swop the EM84 for an EM800 and that's one straight green line instead of two smaller indicators coming together the EM800 is to find in NOS versions in Germany , and cheaper then EM84's
You can clearly see the big influence of the Klemt technicians in the first Dynacord amps .. this was the sixties area .. the most beautiful vintage stuff was build then everywhere , end of the 60's beginning 70's we got the printed circuit nightmare troubles, it all started in the radio and television branch , man what a lot of problems we got ! chassis tearing apart , bad solderings sockets getting to hot and burn out .. it was cheap to produce but it was the nightmare for most technicians , before we got the contemporary throw away electronics now ! I am over 50 years in the repairbussiness and if I see what is produced now .. my stomac turns around , I don't even want to open the new boxes anymore ! .. anyway ..
I own most of the early Klemt Echolette amps from M40 M70 M120 M150 the litle BS30 BS35 the Bs40 and almost all of the speakercabs ET1 Et4 etc.. got a big collection . and I like to play them . if you have a question and I can help , just give a shout .
Cheers , Ben .. staxmotownjunkie
Ok this is it then ?
I did this week a full restoration of 5 Echocords swerving around as boatancres ..
full restoration , means to me :
replace electrolytic cap 2 x 50 Uf with a 2 x 100 mF that fits in the same place straightforward . 10 Eu /pc
replace the selenium rectifier with a bridge rectifier 1000 Volts 1 Amp // 0.2 Eu piece
then remove all DC coupling anodecaps about 6 or 7 .. several sizes replace by polyestercaps 600 Volts not one Eu cost in total
then commes the shitty part : the heads and mechanical setup
replace open , and worn out heads , quit a few .. replaced by Woelke professional studiorecorder 2 track monoheads using only one track ( half the tapewidth = easy to adjust , just look for highest freq and max volume on scope , about 12 / 14 kHz will do fine at 10 /15 mV .the heads can be fixed on the original mountingplates from the Dynacord heads , need a skilled hand though and some clockworkscrews , NOS Woelke recorder heads are to find in Europe if you search
the mechanical setup is easy peezy .. the adjusting of the electronics is another piece of cake . the bias must be set accurately because bias from dynacords is much to high ( around 90 to 100 volts at 60 kHz ) Woelke recording heads are better running between 20 and 30 volts . if you know electronics , then you will know how to correct the bias . the LF signal needs to be a litle bit more then for the Dyna heads .. plenty of possibility in the Echocord
when your heads are done we start the mechanical job ;
the best pinchrollers are to find in old 8 track cassettes .. the good quality ones have a synthetic rubber wheel that is still soft and functional , only problem: the inside diameter is wrong at around 7,8 mm .. needs a bronze busch to run on the 4 mm axle of the Dyna .. again clockwork workbench turning the bushes on a litle lathe ( hope the name is correct ) and make the bronze bearings yourself because none are to find that fit correctly. ones the pinch roller is done leaves us with the rest of the ratling plastic wheels , I replace with precision metal bearings same system as you can find in the Revox B77 just different sized , in Europe SKF makes quality bearings that you don't hear running and that are dustprotected , not waterproof!!
the last wheel before tape passes the erase head is replaced with a rubber roller from a copymachine this to smoothen the tape-loops running .. this setup runs like a jewel ! amplifyer: the tubing is sorted for tested and noise free NOS Us 12AX7Wa tubes
the erase head is checked and cleaned , those very rarely go wrong
in the same time a 1/4 inch jack is fitted for instrument input and a different AC inlet , standard Euro 3 connections the ones you can find on all PC's and earth safety wire fitted to chassis
the green eye EM84 or 87 is replaced by an EM800 that I haveplenty of stock new ,it's a straightforward fit ,same pinning and connections , only difference . the EM800 is a one green line moving up instead of 2 lines coming together
so that's about last weeks work . just one problem on one of the machines .. A Papst motor 6 pole windings with one open winding I could make the motor running on 5 poles but won't start , so needs a fast start and then switch over to slow .; Im not telling how i DID it because it's a trick that is not correct for healthy repair. It's Ok for me because it is the echocord I am going to use my self . We needed 3 of them because we are playing oldschool 50's and 60 's and some Brian Setzer music .. Shadows , Spotnicks etc .. 2 for use an stage and one in spare incase , ... those over 50 years old boxes are out of warranty now .. I am glad I could make them back like new , in fact even better then new .
So If anyone has a project he cannot finish and he likes to get rid of it .. give me a shout I am desperately looking for a 2 speed motor , they are the same from Echolette 51 machines as from the Dynacord Super's . they can be used for eachother .
here some pics of the customizing job ;
Just forgot to say //
demagnitizing everything , very important !!
all screwdrivers you are using on tapemachines must be demagnetized .. as the heads , the screws anything to do with magnetic tape .. how I do it ?? simple ..
a very old Engel Loter soldering iron .. take out the soldering pin and install a coil wound from several copperwire windings ( 1mm wire , thick enough to withstand the current .. not very important how many windings as long as you can feel the demagnetizing job in your screwdriver , that you insert in de coil and activate the current .. then while still actived slowly remove the tool .. you can demagnetize the heads from the recorders with it ..
find yourself a secondhand soldering iron like these , penny's or for free .. if you find it . and make your own demagnetizing tool for peanuts .
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