Klemt Echolette E-51 trim pots and tubes location

[echo]

thanks again oc!
In your pic seems there are two cable for the tape head (not the erase).. the red one and the black.. is correct? Or you would tell me that in one cable that seems "only a shields cable" there is an another cable inside?
however when i look the rec/play tape head on Echolette i see only one cable (shields ..) for each tape
Where am I wrong?

[Mickey]

The cable to the record/playback heads are shielded cables so it appears there is only one cable but in fact the active lead is shielded by (usually) a woven outer covering which also acts as the head signal ground path.
Exactly what are you trying to achieve? Could you please describe the faults you are experiencing with the Echolette.

[echo]

Hi Michey,
i've just replaced tube and tape for echolette. The problem is that when the echo effect is bypassed the sound is clear and beauty, when i switch (fast or normal) echo the sound is distorted.
So i think that the cause is an wrong bias setup for this kind of tape? Is possibile?
And so the questions i've written above are to known next steps for bias setup.

[Mickey]

Hi,
When you say the sound is distorted do you mean all of the sound or just the echo sound. You have three echo recording level controls, so if you turn them all down is the sound still distorted and when you increase the levels one at a time is the distortion more evident in one recording head?
Do you have the correct schematic for the echolette? If so we can then go discuss each stage at a time so that you can understand what is going on in the circuit when the echolette is operating.
Cheers, Mickey

[echo]

Hi,
is distorted only the echo sound (the "bypassed" sound is ok, clean). If i turn down all the three control of echo recording level the sound is clean. If i increase every control one at time it seems to be that the distortion is the same on every head.
The schematic is the same that oc disorder posted above on 07-16-2014 (Echolette S Type NG51)
Thanks again Mickey, too kind (and all the others) !!!

[Mickey]

Hi, you have checked that there is a ECC81/12AU7 used as a bias oscillator (Ro 5) , now check that you have about 300volts at the bias oscillator transformer also on pins 1 & 6 of the oscillator valve. If this all appears as it should then I think you will have to buy,beg or steal an oscilloscope to measure the voltages going to the heads, where you will be looking for 60V,90V & 120V on heads 1,2 & 3 respectively.
Before attempting the above you could check the voltages on the playback valves, pins 1 & 6 of Ro3 & Ro4. Approximately 90-100Vs on Ro3 & LHS section of Ro4 and approximately 200V on RHS of Ro4.
Let us know what you find.
Cheers, Mickey

[echo]

Hi,
thanks again Mickey!
Today i'll check the voltages who don't need a scope... then, when i'll buy a scope (a few days!!! ) i'll do all the other check and i'll write you!!
Cheers from Italy

[echo]

Hi Mickey,
First i've checked the voltage of Ro5 valve and it's 286 Volts...
Now i have two questions (it's not too strange, no?
1) when i have to check (whit a scope) the voltage of the three heads i put the one tip on the chassis, the second in the point shown in the pic? (for every head obviously). It's possible that if i check this three voltage the sum of their is higher than 270 V? Mmm...


2) For the voltages on the playback valves... really i don't understand what pins in each valve i have to test.. (LHF and RHF it means left and right, i hope!). Do you mean for example pin 1 of Ro3 and pin 6 of Ro4, or Pin 1 and 6 of eache valve, or other... ? Sorry for misunderstanding! Among others thing what a mess to move in the middle of all those wires / components!

Have a good weekend!

[Mickey]

Hi,
The voltages to the heads are not summed, they have to be 60, 90 & 120 volts as from head 1 to head 3. The bias oscillator voltage from the oscillator transformer would probably be 250 volts but remember we are talking about AC volts at 60Khz. You have to realise that when reading voltages in the bias oscillator circuit (Ro5) there are DC voltages coming from the power supply and AC voltages generated by the oscillator circuitry. The AC voltage is necessary to energise the recording heads so that the signal being recorded on the tape is not distorted. Very difficult to understand so do not worry to much at present about the principles involved in recording heads.
Again if you have approximately 60, 90 & 120 volts going to the record heads then I would think that everything is OK in that part of the circuit.
Yes LHS means "left hand side" and RHS means right.
Again pins 1 & 6 of both valves (Ro3 & Ro4). They are the anode pins of these valves and if you look at the schematic you will see that these anodes are all connected through resistors to high voltages.
Now if you think about the circuitry of the Echolette, the signal comes in through the input jacks to valve Ro1 from here it goes to valve Ro2. Some of this signal goes directly to the output, and you say that the dry (direct) signal is not distorted.
Some of the signal from Ro2 goes to the recording heads via R29 etc and is mixed withe bias oscillator signal via C14 etc. Now if the signal going on to the tape is not distorted and of required level (60, 90 .....) then the distortion will probably be introduced in the Ro3/Ro4 circuitry.
Signal on the tape is picked up by playback heads 4 & 5, this then flows through Ro3 & 4 and is mixed with the dry signal from valve Ro2 so that you hear the dry signal and the echo signal in your amplifier.
Hope that you can understand what I'm trying to say and that this explanation is of assistance.
Mickey

[echo]

Mickey you are the number one!
Too kind and clarifier!
Thanks a lot for the explanation of signal behavior!
Another strange clue.. When i insert the echo effect the signal on the magic eye indicator seems too high (you know, the two "opposing lines" become very close and they "intersect" immediately) and so get this sound distorted ... it's the effected signal too high and goes to overdrive too soon?...

[Mickey]

Hi, with regard to the the indicator valve Ro6 closing on echo setting, could be that one or more of the pre-sets have been tampered with or resistors have changed in value allowing the output signal or echo signal to feed back into Ro6 circuitry.
Now be aware that those pre-set controls are very fragile, so before adjusting any have a very close look at each one to see if they may have been re-adjusted at some time.
The pre-sets to look at are R41 (nachhall pegel/echo level pre-set),R52 (in series with nachhalldauer (echo duration).
You could also short the nachhall aus (echo off) switch when in echo mode. This switch shorts to ground any echo (or other signal) when the echo effect is not being used. But by shorting it to ground with a jumper lead while the switch is in the "echo on" position you should remove all echo signal going to Ro6 and should stop the overload (distortion) visible on Ro6.
A little note: when The Rolling Stones released the song Satisfaction the guitarist in the band I was playing in turned up the input volume on his Echolette to obtain that distorted lead guitar sound. His Echolette was the first one that I serviced and scrutinised when I was about 19 years old.

[Mickey]

Hi, if you can email me your name and email address by Private Message I can then send you some more information on Klemt Echolettes. Regards, Mickey

[echo]

PM sent, thanks!

[Souleyman]

Hi guys,
What the resistance of the record head should be? Are they different with NG51?
My own NG51 heads have about 1k-1.2k (and playback ones too) but I've met the same view about 500 Ohm too.
Which is a properly resistance of record head?

Thanks for any answers!

[Mecaso]

Hello

I have just bought an ECHOLETTE E51 on eBay It was in defect order (no

heads, no motor, no tubes....)

I have installed heads, motor, tubes and now it works. But.....the direct and

echo sounds are with distorsion. I have look at voltages, all resistors and all

capacitors. All seems perfect.

If somebody has an idea of the problem.......????

Thanks & regards....

Bernard (as Mecaso)