Klemt Echolette E-51 trim pots and tubes location

[oc disorder]

hum....

I will need to have a look at mine, apparentely it doesnt do a thing,

Firstly I should acknowledge the site I found pictures and high quality schematics on

Echolette NG51 Tape Loop Echo | ReVamp Blog

Secondly Nisios thanks for your interpretation/opinion re the tunable capacitors it's starting to sink in ! :-)

Nisios re the hum , on the UK site Echolette NG51 Tape Loop Echo | ReVamp Blog

down the bottom he mentions this

On this last pic you’ll see a heavy twisted black and white cable. There’s a good reason for this, but you can improve matter just by tightening down bolts. The transformer is bolted to the main chassis and the main earth (ground) is connected to that. As the heaters have a centre tap to ground (via hum balance ) any problems with the chassis connection between the transformer (that’s the big brown thing on the left of the pic, with wires all over it) is big bad news for hum and background noise. The heavy black/white cable actually straps the main and the sub chasis’s together, so the electrical connection of the frames isn’t really important. If that’s not done, slacken the screws off to the transformer chasis, and then tighten them down again. It will shift any claggy accumulations and refresh the ground connection.

Sometimes I use emery paper and a squirt of deoxit where bolts hold chasis together.
This could be stopping the hum pot from "fine tuning the hum out" !!

And A.T. I was referring to the older Echolette so I'll get on the E-51... the right page now with the attached.
It appears Dynacord took over and redrew the schematic.. it seems almost identical ,well apart from the jacks !
R73/R72/R71 are the pre-sets see the attached.
Dunno why I thought a variable capacitor had a slug !
It appears all those "varicaps" are 150pF and the other values are ones the 150pF's are adjusted to.
What I thought was an AC sign is in fact a tilde ~ !!!!!!!!!!!!!!!!
" in mathematics the tilde mark used to indicate an approximate value"
Having 3 record heads that simultaneously record on to the tape I find a bit hard to get my head around !
The capacitance values appear to be multiples (i.e. freq doubling ?) I'm missing something.. perhaps it's my brain...!
What I am wondering is why they have to be set at different values. and suggesting maybe to do with the sound on sound approach..

[Audiotexan]

And A.T. I was referring to the older Echolette so I'll get on the E-51... the right page now with the attached.
It appears Dynacord took over and redrew the schematic.. it seems almost identical ,well apart from the jacks !

Nice to know!

R73/R72/R71 are the pre-sets see the attached.
Dunno why I thought a variable capacitor had a slug !
It appears all those "varicaps" are 150pF and the other values are ones the 150pF's are adjusted to.
What I thought was an AC sign is in fact a tilde ~ !!!!!!!!!!!!!!!!
" in mathematics the tilde mark used to indicate an approximate value"

Ok.. so nix the 'front panel' guess. TY for the pic! That tells a whole different story.

I had also wondered about the tilde, and was initially thinking "tune to" as well, but what made me 86 that idea was the top cap being ~200pf. You can't tune a 150pf cap up to a value of 200 that's outside of it's abilities last I knew. 150pf down to 120pf, np. 150pf down to 60pf fine. (Nevermiiiind. Forgot it's strapped to the other 150pf) 300pf down to 200pf...np! lol (Like a dog with a bone sometimes..."what do you mean there's another bone?!! I'm focused on the one in my mouth!")

So that's what made me guess that there might be an alternate mod/model issue. Wrong again.

Having 3 record heads that simultaneously record on to the tape I find a bit hard to get my head around !
The capacitance values appear to be multiples (i.e. freq doubling ?) I'm missing something.. perhaps it's my brain...!
What I am wondering is why they have to be set at different values. and suggesting maybe to do with the sound on sound approach..

2nd that question!

[nisios]

I biased the heads accordinf to the voltages Kazooman gave and i got the unit working great, i noticed that the frequency response is much better propperly biased. Man you can really put huge bias voltage on those heads in the order or 300/400V if misbiased, never ocurred to me you could do that without frying the heads or start arcing all over.

Now that everything is biased i just need to make a new tape loop, but i still have a Hum problem.

I thought the hum balancing pot was dead because it did nothing, so i changed it, easyer than testing in circuit in this case. The new one is the same, no effect on hum.

There can be two things happening, the hum is lo loud right now that i cant hear the balancing pot effect, wich is what i think is happening, or i have some problem on the balancing pot connection to the filaments (i dont think so, very simple fillament circuit...)

So i still have some more poking to do....

Anyone knows why do these guys make these units wich such high impedance allover? like every pot is 1M Ohm, resistors all really huge, 10M Ohm input impedance.... That makes the unit ultra susceptible to hum and noise....were these made to connect directely to the capsule of a condenser mic? Because huge input impedance is good for mic capsules because they are capacitive and it forms a filter, but with resitive inputs whats the point?

[Audiotexan]

I'm thinking your right OC...it's gotta be to do with the sound on sound aspect.

I kinda had inklings along those lines earlier as well, but had hoped someone would drop in on this thread and shed some light on the operational theory before I went off into left field with guessing. lol

[Mickey]

There is an article in "ReVamp Blog" Echolette NG51 Tape Loop Echo which advises how to adjust the hum cancel pot. You will need to have your amp turned up a fair way and all the controls on your E51 turned down. You should be able to hear the hum increase and decrease when turning R76.

[Mickey]

Thinking about sound on sound, it's not really that complicated as you would realize that multiple echos are just repeat recordings of the first echo. There would certainly be a deterioration as well distortion in all subsequent repeats (echos) but we are listening to guitar music not hi-fi audio.

[Mickey]

I find it easier to follow signal paths in the E51 circuit as compared to the NG51 & S. The layout of the E51 circuit diagram is more easy to follow.

[Mickey]

One thing that has always puzzled me is the nomenclature of the pre-set pots, especially R51, R52 & R46. It would make circuit description to lay persons a lot easier.

[Mickey]

E51 manual

The manual is on its way.

Hi, just wondering if you would be so kind as to send me the E51 manual? I have repaired quite a few of the Klemt tape echos both for personal use as well as for other guitarists and having compared them to quite a number of tape echo units I believe them to be both more versatile as well as better constructed than other European tape echos. Have not been able to compare them to the US made model but as these appear to be similar to an Echoplex I would think they would be rather limited in their echo capabilities. Cheers, Mike

[Kazooman]

Hi, just wondering if you would be so kind as to send me the E51 manual? I have repaired quite a few of the Klemt tape echos both for personal use as well as for other guitarists and having compared them to quite a number of tape echo units I believe them to be both more versatile as well as better constructed than other European tape echos. Have not been able to compare them to the US made model but as these appear to be similar to an Echoplex I would think they would be rather limited in their echo capabilities. Cheers, Mike

I PM'd you asking for an email address. Reply and I will send you the file I have. It is the NG51.

[Mickey]

Echolette manual

I PM'd you asking for an email address. Reply and I will send you the file I have. It is the NG51.

Hi, my email address is ju26284@gmail.com As I stated in my replies I have serviced/repaired quite a number of these as well as numerous Copicats. The Echolette tape echos are really straight forward in their design but very very difficult to work on. The pots on the circuit boards are a real pain and unfortunately they should be replaced as a matter of course when any work is done on these units. The volume and the tone pots are also troublesome but with a little ingenuity they can be replaced with readily available pots of the correct curve. Anyway I'll sop rambling and look forward to your information. Regards, Mickey

[echo]

You bias the heads by adjusting the variable capacitors located on the end of the chassis. You really should use an oscilloscope to do this since the oscillator runs at about 60 KHz. Heads 1, 2, and 3 should be set to 60, 90 and 120 volts respectively.

Hi, hello, I write from Italy.
Sorry if i recover this thread, but don't want to open another one with the (almost) same topic...
As for the bias tape voltage: where i have to measure it? I have not an oscilloscope (maybe later in time), can i do that with the meter and how?

Thanks a lot!

[oc disorder]

"As for the bias tape voltage: where i have to measure it?"
At the junction of the 100k resistor ,tape head and adjustable trim capacitor.

"can i do that with the meter and how?"
If your meter can read high frequency A.C. one probe on the chassis ground
and the other on the above junction.

As it is a high frequency A.C. (approx 60kHz?) average multimeters may not be able to read it.
There should be aprox 270vac on the oscillator coil and on the common to the adjustable
trim caps.

If you cant read that 270 , we have no way of knowing if the circuit is faulty or your meter
cant read the high frequency ac voltage.

[echo]

thank you so much oc disorder !!!
And yes, my poor wretched multimeter can't arrive at those frequencies, i checked before its specifications but I knew the answer ...
So it is better if i am looking a scope...
I'm passionate about Echo but now I'm starting to get interested also in how they are made .. and I don't understand why in this model (but also in the Dynacord Mini that I have here beside) there is only one cable for each tape head for play / rec (while the erase there are two) ... and by the way this cable seems a shielded cable, not the cable itself within ... arghhh! how much confusion that I have!

[oc disorder]