Klemt Echolette S

[Muesic]

Awesome thread! Some of the best echolette info I can find. So I just bought a rackmount Ng51. Which seems in decent shape on the inside. The most obvious issue is there is no mains transformer. Can anyone advise me on what I need to look for in a replacement? I see that the original had all the different settings for different countries. I'm not so concerned about replicating that unless I have to. Would it be possible to just wire it for use in the USA?

Other than that has anyone seen a rackmounted echolette before? I just thought it was too cool to pass up so a fun project to scratch my head over. I'll try to post a few pics and update as I progress.

[Kazooman]

There was a rack mounted echo on Ebay recently. Perhaps that is where you got yours.

I can't think of any reason why you couldn't wire the unit for US voltage only. The problem will be finding an appropriate transformer. There are three output voltages required. 6.3V / 1.5 A for the pilot lights and the heaters. 275V to go to the bridge rectifier. Finally, you need a 42V tap for the tape drive motor. You might have to settle for two transformers.

I can't tell from the pictures how the power supply is currently set up. You should install a three pronged plug to properly ground the unit. Be certain that you have a proper fuse in place. If it still has the original selenium rectifier you should replace with a modern silicon bridge rectifier before firing the echo up. When you have all of the power supply section repaired, I would recommend starting out with a lightbulb current limiter to see if there are any hidden problems. You can then check the DC voltages and adjust the values of the resistors at the filter caps if necessary.

[Mickey]

Power Transformer Echolette

Awesome thread! Some of the best echolette info I can find. So I just bought a rackmount Ng51. Which seems in decent shape on the inside. The most obvious issue is there is no mains transformer. Can anyone advise me on what I need to look for in a replacement? I see that the original had all the different settings for different countries. I'm not so concerned about replicating that unless I have to. Would it be possible to just wire it for use in the USA?

Other than that has anyone seen a rackmounted echolette before? I just thought it was too cool to pass up so a fun project to scratch my head over. I'll try to post a few pics and update as I progress.[ATTACH=CONFIG]31830[/ATTACH][ATTACH=CONFIG]31831[/ATTACH][ATTACH=CONFIG]31832[/ATTACH]

Hi, I know where you can get a power transformer albeit used. There is repair person who has one of the NG51s on his shelf which has been cannibalized ( the heads were faulty ), but I would think he would want top dollar for it. It would save you a lot of wasted time trying to locate one or more transformers. However if you go down the non-original replacement track you will require a transformer with a 270V AC winding at 80mA, a heater supply of 6.3V AC at 2.5A and a 42V AC at probably 1A. This latter winding I can confirm for you if you want to do it this way.
Before you start spending money I would check all heads for continuity and also the 48uf motor capacitor as well as visually checking the motor for any obvious overload signs. The pots are also problematic but with a little ingenuity these can be replaced with of-the-shelf ones.
I have never seen or heard of a rack mount Echolette NG51 so I hope you can get it back into a working state as it would be rather rare. It may however be a home made rack conversion?
Anyway good luck and don't hesitate to ask for assistance. Good luck, Mickey

[Muesic]

Ok thanks guys. I didn't buy it on ebay but it may have been listed on there. I just got it off of craigslist. It very well could be a home made rack. I can't really tell. The type on the serial tag is listed as ng51a. It seems in decent shape. I'll check the heads. The motor came unscrewed in shipping and looks to have frayed a few wires.

[Kazooman]

Ok thanks guys. I didn't buy it on ebay but it may have been listed on there. I just got it off of craigslist. It very well could be a home made rack. I can't really tell. The type on the serial tag is listed as ng51a. It seems in decent shape. I'll check the heads. The motor came unscrewed in shipping and looks to have frayed a few wires.

No concern where you got it! My comment regarding Ebay was just to note that I had recently seen a vintage rack-mount Echo. I think you have a real find. They clearly existed and they must be pretty rare as compared to the stand-alone units.

If you could post some pictures of the unit (inside and out, from all angles) we might be able to help you solve some problems. We can compare the guts to the Echolettes we have to see if the basic circuit is the same.

Keep posting on your progress, we would love to,help.

[Muesic]

I'm interested in the transformer. I sent you a pm but it's not In the sent box, so not sure if that worked. Pm me the details if you can. Thanks!

[Toxophilite]

I had a few of these and got them all working quite well a few years back
The fellow mention Bobby Staedal in Germany was hugely helpful, sent me a schematic and tutored me on many things
He specializes in these tape echos and has for years
One thing he insisted on was to recap the entire unit as ALL the caps tend to be leaking DC
Once you've done one or two you can graduate to brain surgery as it is not dissimilar
That was his recommendation. It worked wonders on one unit I had
He also sells tapes, pinch rollers etc etc

[notea]

Hello there,

I bought the NG51 few weeks ago, the preamp is working perfectly but the echo doesn't work at all.
the tape is rolling but the sound is not affected..
Is anyone came across this problem before?
I hope it's not a bad tapehead, apparently each should be 1.1k ohm but any idea how to measure them cause it's pretty hard to access..
Next step for me 'll be to build an audio test probe and trace the signal,
i 'll be grateful for your suggestions!
(sorry for the bad english i'm french..)

[Mickey]

Hi, does the visual indicator respond when a signal is applied, if it does I would check valves (tubes) 3 & 4. If the indicator doesn't show signs of signal then I would check valves 1 & 2. Rarely would all heads be that defective that some kind of echo signal isn't present at the output. The heads are problematic but don't rush in and start disconnecting things to measure the heads. Whatever you don't start turning pre-set controls. Check that both playback heads are "on".
Do you have a good multi-meter and a schematic for the item and make sure that the schematic is for the correct model.
Let us know what how you progress and also your level of electronic circuit knowledge.
Mike

[notea]

hello Mike, many thanks for your answer!

- the visual indicator does respond when the signal is applied also when the reverb button is on, but thanks to your method i noticed that nothing happened when i turned on the reverb control button. I mean the signal passes, but the "magic-eye" doesn't respond
- so i've replaced each tube with good ones (i didn't have a 12AT7 so i put a 12AX7 instead), now the visual indicator is responding i noticed that it's starts to make a hum when i turn on the reverb control button, the sound is pretty overdriven but still no echo..

my level in electronic is pretty low, i only know how to build pedal effect and look into an amp without dammage myself.
I doesn't feel confident with schematics, but if you or someone knows the NG51S well and could show me test points, i can do the job.
I only want to be sure to make everything is possible before taking it to the tech, thanks to you and other forumers.

Cheers Nick

[Mickey]

Hi Nick,
You can put that 12AT7 back as this is the bias oscillator which has less gain than a 12AX7.
With unit switched on I would check for voltage on pins 1 or 6 of valve 3. You can remove the valve to do this but remember to count the pins anti-clockwise when measuring from the top. This will give you an indication if voltages are reaching valve 3. Do this again for valve 4 but measure at pins 1 AND 6, you should read about 200 volts.
If there is voltage present at these pins then I would replace the valves and with a small metal blade screwdriver slightly touch the head gap of the replay heads after making sure the reverb control (nachallstarke) is fully clockwise. You should hear a noise through your amp when doing this. You can also go to the reverb duration control and touch the active side of the playback head 2 switch which must be in the on position. You should hear a loud buzz through your amp when doing this.
Now I assume that you have removed the chassis from the case and that you realize there are lethal voltages where the wiring is. Just be very carefull and work slowly and methodically. Let us know your findings.
Mike

[notea]

Hi Mike,
i measured the valves as you said and we have:
-valve 3 = 140V
-valve 4: pin 1= 196V and pin 6= 224V

next i touched the replayheads with reverb control fully clockwise, i got a slightly little "poc" very low on the first one on the left.
then i put the switch on and nothing happened with the playback head 2.Still got a lot of hum coming from de reverb control

sounds like dead tapeheads?..

Nick

[Mickey]

Hi Nick,
Well it appears that the power supply is functioning as designed.
If you can touch the input to valve 3 coming from head 2, that is the one that has a switch across it, which should be accessible from the connection on the switch located on the rear of the nachalldauer control. If you touch this with your finger via a screwdriver you should hear a loud buzz through your amplifier, and this would then indicate that that particular playback head is faulty. I would mention that playback heads are seldom faulty especially on "S" type machines unless of course they are just worn out from use. The early NG51 models had serious corrosion problems in the record heads and I believe that the large bias signal voltage played a part in their demise.
You can also trace the playback head wires to where they connect to valve 3 and again by touching the input grids of this valve you should hear a loud buzz through your amp.
I should have asked but does your NG51 have printed circuit boards or does it use point-to-point wiring? This differentiates the models.
Back to your problem, if there isn't a loud buzz then I would check valve 4 circuitry as the output signal is derived in part from this valve. Again try touching the input grids of valve 4 to see if a loud buzz is heard, making sure that the nachallstarke control is turned up fully. You could also remove valve 3 while doing this to stop any spurious signal from coming through.
My strategy is to trace the signal backwards from your amp back to the playback heads, if this proves to be OK then we move to the recording section.
Good luck, I look forward to your findings.
Mike

[oasisbluenose]

Great thread. I am in need of help too I'm afraid.
It's an NG51S my machine.
All three record and one of the playback heads were open circuit and have been replaced.
Bobby Staedel . What a great chap.
Power caps replaced along with the one electo in the case I can actually get at.New pinch roller.
The tape motor moves with no issues.There is a dry signal all the way through.
I can see a good bias and signal on my scope at each of the heads.
I have applied a signal at the playback heads and that shows through to the output.What I can't get is an echo.
The playback heads both make a noise through amp when gently tapped with screwdriver.I have tried un-soldering one playback head and attaching scope across it. Still no signal from tape.
I'm used to dealing with copicats but this one has me rather foxed.
Any help would be greatly appreciated.
Thanks.
Steve

[Mickey]

Hi Steve,
Yeah, Copicats are more easy to repair/restore except for one model which usually has a bias oscillator issue, but that's another story.
I agree with Bobby Staedel being a great chap but be aware (from personal experience) that his heads can still be faulty after his rewinding.
Long ago I made up a tape with 1Khz signal on it, easy to do on any working echolette by simply feeding in the signal and disconnecting the playback head, this used to be a great assist when I initially started to repair echolettes.
I would suggest that your issue is in the recording section and if you have a CRO you should be able to trace the signal to the recording heads which you state you can see, but can you see this on each of the three record heads?
I would probably select just one record head and check the signal is going to it and then ascertain if that signal is picked up by a playback head, again I would only use one playback head while doing this checking. You can have a good signal with bias at a record head but if the record head is defective then the signal isn't being transposed to the tape.
Unfortunately I don't have scan to email convertor on my printer but if I can locate a business or person who can email me my detailed NG51 schematic I will then forward that on to you but will then require your personal email address.
Cheers, Mike