Klemt Echolette Showstar ...S40 series
This amp will be familiar to many musicians who worked in Germany during the sixties and it's still well worth a look.
In section 7 below there are some YouTube links showing Showstars on stage with some of the major bands of the time (and some that should have been). All of the clips were from the German TV show Beat Beat Beat with backline equipment supplied by the production company. These clips have now been released on a series of DVDs and on the Beat Club YouTube channel.
Go look !!
CAUTION
LETHAL VOLTAGES PRESENT THROUGHOUT THE CHASSIS
1. Introduction
Made by Klemt in Germany, the Echolette Showstar S40 series came in several versions. I've seen a valve (tube) rectifier model mentioned, but never come across one. All those generally available had solid state rectifiers. Early valve preamplifiers were eventually transistorised although mixers, phase splitters, vibrato circuits and output sections retained their valves. All produce 40watts rms from two EL34s into 5ohms (4-6ohms) or 20ohms (15-25ohms). Last-of-the-line amps lost the attractive, light-up, gold front panel and have unlit, half gold, half black panels.
I understand that Klemt merged with (or were taken over by) Dynacord at the end of the sixties and the Echolette name was eventually dropped. Dynacord themselves became part of Bosch Communications Systems.
The information below includes schematics plus German and English versions of the later (transistor) handbook. The German to English translation is mine so apologies if you’re German (or English come to that). Most of this stuff, including the original Klemt schematics, is available free elsewhere on the internet, but it can be difficult to read if you print at A4. The drawings below have larger text.
Although the schematics below are typical, there will be lots of variations. In particular, some units will have been altered to use ECC83 valves instead of the now very expensive ECC808. There's nothing wrong with this if it's done properly, but watch out for bodged wiring. Non working vibrato circuits can also be a problem. Lamps (L1) are available but it will be almost impossible to find a replacement ORP62 photoresistor. I can't find a data sheet for the B500C 400 bridge rectifier, but I'm fairly sure it's 1000V Vrmm, 500V Vrms and 400mA Id probably made by Iskra.
2. Valve Input Version With Solid State Rectifiers and Light-Up Front Panel. S40.
The early examples of this version had a one-piece, cream case with a trapezoidal ventilation grill on the top. It was later redesigned to have a separate black front panel surround, cream rear section and a rectangular top grill. Both had an all-gold front panel and cream (white) knobs, although black knobs with contrasting skirts were also used.
Photo of serial number 36147 with rectangular top grill courtesy of Jesper Karlsson.
Many thanks to Gérard Michaud of Gérard Michaud Électronique in Quebec, Canada for the following.
Hi Chris:
It seems that here in Canada, during the time those amps were imported (only a few years, I believe) only one version of Showstar got here: it has recessed front input jacks,with the fluorescent lights (with its on/off switch at the back), tubes on inputs, the .1mf vib.cap. (C32) connected to plate, no VDR, no heater fuse, and white knobs. Regards, Gérard.
Gérard has also provided some service advice which you can see in section 8 below.
Some of the circuit changes occurred gradually. The front panel lamp on/off switch, for instance, isn't shown on the early schematic but appears on some S40s. The S40 vibrato circuit also appears in some earlier S40Ls.
NOTE: There are definitely a number of variations in existence and you may need to mix-and-match both S40 and S40L schematics to find the right information.
By the time we get to serial numbers in the 29500s, a lamp switch and line grounding selector switch have appeared along with a new, rectangular ventilation grill in the top of the case. These features appear in the S40L version of the schematic but were obviously fitted to late S40s as well.
Many thanks to Jesper Karlson for photographs of an all tube S40, serial number 36147, above and right.
Speaking of leaving things off, the drawing below is now at issue 2. Issue 1 was missing a link between the 7v lamp winding and mains neutral ( 1 to I ).
PRINTING
Wix only provides webp images at the moment. To make a hard copy of a drawing :
-
Left click when the magnifying glass icon appears and wait for the picture to clear.
(On a touch screen, tap on the image) -
Right click and 'save image as' to somewhere as a webp file.
(On a touch screen, touch and hold down to view the menu) -
Open the saved file with 'Photos' (Windows 10) or whatever app works for you.
-
Use the print menu to print to A4 plain paper.
3. Showstar Loudspeaker Wiring.
The impedance values shown on the rear panel can be slightly confusing. The BV2890MD transformer has four identical secondary windings. In "5ohms" mode the windings are connected in a series-parallel arrangement, while selecting "20ohms" places them all in series.
The formula for an output transformer turns ratio is (NP/NS) = RL / RS where NP and NS are the number of turns on the primary and secondary, RL is the optimum anode load resistance of the output valve and RS is the impedance of the speaker.
In the 20ohms position there are, effectively, twice as many secondary turns as there are at 5ohms and so the turns ratio NP/NS is halved. The optimum load resistance RL is still the same and so the speaker impedance RS needs to increase by four times to keep the valves happy. 4 x 5ohms = 20ohms. Result!!
The Echolette handbook recommends a range of 4 to 6 ohms or 15 to 25 ohms. As the Showstar has a valve output stage, it would be quite happy with 4ohm or 16ohm cabinets. An 8ohm speaker probably wouldn't do any harm in the 5ohms position, but using load impedances above the recommended values can cause problems with excessive voltages around the transformer primary.
2
4. Transistor Input Version With Light-Up Front Panel. S40L.
This version normally has an all black housing**, black knobs and an all-gold front panel. The "Echolette" and "Showstar" graphics have now swapped sides.
Just to confuse things, Klemt made some chassis with transistor inputs and the older valve vibrato circuit. I don't have one to draw up so you'll have to look at both schematics.
** Just to show how confusing the case can be, Jesper has two S40Ls, one serial number apart, which have different coloured Tolex.
Next, a big thank you to Saverio Cardo for supplying the photographs below. They're from serial number 37449 which he was repairing and it's an interesting example of how the circuit evolved gradually. The input section is transistorised, but the vibrato circuit is still the older S40 version.
Left: One end of the front panel lamp holders.
Centre: Chassis from below, showing the long black light guide between L1 and Ph1.
Right: Chassis from above. The input transistors can be seen on the right of the pcb.
There are one or two later modifications to this particular unit, including a hard-wired mains cable and replacement power supply capacitors.
In the factory schematic below:
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There is a new on-off switch for the front panel lights and a line grounding system S6 and C37.
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The vibrato indicator GL1 is now also the standby indicator and has been moved across to the anode of V3A to maintain the correct logic. When the standby switch S3 is closed (amplifier on) and switch S2 is closed (vibrato off), GL1 will show a steady light since the anode of V3A will be high. If S2 is open (vibrato on), GL1 will pulsate in time with the vibrato effect. When the amp is in standby mode (S3 open), GL1 will be extinguished.
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The vibrato modulation has now moved from the grid of the mixer valve to the anode (plate) via a capacitor and the Intensity control is across the lamp rather than the photo-resistor.
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There are additional fuses in the HT and heater circuits and there is a voltage dependent resistor (VDR) across the 350V transformer winding.
5. Transistor Input, Valve Output, Solid State Rectifiers. No Front Panel Lights.
This model has no letter suffix on the front panel but is possibly an S40N. (Still trying to find out)
This version normally has an all-black housing, black knobs and a two-tone gold and black front panel.
The line decoupling (death cap) system has disappeared and the mains transformer is much simpler with no 7V windings for the front panel lights. Since the front panel doesn't light up any more, there's a Mains-On indicator lamp in the heater supply circuit.
6. User Handbook (transistor input).
The input sensitivity figures are only correct for transistor preamp versions. The valve preamp units have identical sensitivity on all inputs (if the factory schematic is correct).
Klemt Echolette
Verstärker S 40
Kurzanleitung zur Inbetriebnahme
1. Überprüfen der Anschlußspannung der Stromversorgung, danach eventuell Umschalten des Spannungswählers mit Gedstück oder Schraubenzieher und Auswechseln der Sicherung, wenn notwendig.
2. Anschluß des Verstärkers mittels Netzkabel an der Netzsteckdose und der Kaltgerätesteckerdose “Netz” auf der Rückseite des Gerätes.
3. Anschluß des Lautsprechers an der Klinkenbuchse “Lautsprecher” auf der Rückseite des Gerätes. Impedanze beachten.
4. Einschalten des Netzschalters durch Drehen nach rechts. Die dazugehörige Signallampe leuchtet auf.
Einschalten des Bereitschaftsschalters durch Drehen nach rechts. Die zugehörige Signallampe leuchtet auf.
Der Verstärker ist betriebsbereit.
5. Einstecken der abgesschirmten Instrumentkabel in die Klinkenbuchsen Eingang 1, Eingang 2 bei geschlossen Lautstärkereglern.
6. Einstellen der Regler auf die gewünschte Lautsrärke und Klangfarbe und Vibrato.
Klemt Echolette
S40 Amplifier
Quick Start Guide
1. Check the voltage of the mains supply, then adjust the voltage selector with a coin or screwdriver and replace the fuse if necessary.
2. Connect the amplifier from the mains inlet on the back of the unit to the wall outlet with the power cord
3. Connect the speaker to the "Speaker" jack on the back of the unit. Note the Impedance setting.
4. Turn on the power switch by turning it to the right. The corresponding indicator light turns on.
Turn on the standby switch by turning to the right. The corresponding indicator light turns on.
The amplifier is operational.
5. Insert the shielded instrument cable into the phone jack input 1 or input 2 with the volume control turned down.
6. Set the the volume, tone and vibrato controls as desired.
Daten
Ausgangsleistung: 40W Sinus Aussteurung
50W Spitzen Aussteurung
Klirrfaktor: 5% bei Nennleistung
Ausgang: 5ohm - 20ohm umschaltbar
Mischpult: 2 Kanäle mit je 2 mittel-neiderohmigen
Eingang 5mV und 100mV
Eingangsempfindlichkeit
Getrennte Lautstäre, Tiefen und Höhrenregelung.
Vibratokanal: Vibrato in Stärke und Tempo regelbar,
Durch Fußschalter abschaltbar.
Tiefen und Höhenregelung: Getrennt für jeden Kanal + 8dB
Brillanzregelung: +10dB
Signal stör spannungsabstand: Großer als 60dB
Betriebsspanungen: 50-60Hz,110V,130V,150V,220V,240V,250V
Leistungsaufnahme: Leerauf 100W, Voll-Last 200W
Röhrenbestückung: 2 Stück ECC808
1 Stück ECC82
2 Stück EL34
Transistoren und Halbleiter:
2 Stück BC113 Siliziumtransistoren
2 Stück BC114 Siliziumtransistoren
1 Silizium-Brückengleichrichter B500 C400
1 Selen-Gleichrichter E60 C45
Lampenbestückung: 1 Glülampe 48V, 0.02A
1 Glimmlampe mit Widerstand
1 Glülampe
Abmessungen: 490 x 165 x 275mm
Gewicht: 10.5kg
Data
Output Power: 40W RMS modulation
50W peak modulation
Distortion: 5% at rated power
Output: 5ohms - 20ohms switchable
Mixer: 2 channels with 2 medium - low level inputs.
Input sensitivity 5mV and 100mV
Separate Volume, Bass and Treble controls
Vibrato Channel: Adjustable vibrato Depth and Speed. Footswitch
Bass and Treble Control: Independent for each channel + 8dB
Presence Control: +10dB
Signal to Noise Ratio: Greater than 60dB
Operating Voltage: 50-60Hz. 110V, 130V, 150V, 220V, 240V, 250V
Power Consumption: 100W no load, 200W full load
Tubes: 2 x ECC808
1 x ECC82
2 x EL34
Transistors and Semiconductors:
2 x BC113 silicon transistors
2 x BC114 silicon transistors
1 x silicon bridge rectifier B500 C400
1 x selenium rectifier E60C45
Lamps: 1 x incandescent 48Volts 0.02Amps
1 x neon lamp with resistor
1 x incandescent
Dimensions: 490 x 165 x 275mm
Weight: 10.5kg
Bedienungsanleitung
Netzanschluß:
Auf der Rückseite des Echolette-Verstärkers Showstar S 40 befinden sich links übereinander angeordnet die Anschlüßbuchse das Netzkabel, der Sicherungshalter und der Netzspannungswähler.
Vor inbetriebnahme muß darauf geachtet werden, daß der Netzspannungswähler auf die gewünschte Betriebsspannung eingestellt ist. Bei Spannungen von 110 V, 130 V, 150 V soll die im Gerät vorhandene Sicherung 1 A träge gegen die mitgelieferte Sicherung 2 A träge ausgewechselt werden, da sonst eine Überlastung der Sicherung erfolgen würde.
Das Gerät ist vom Werk auf 220 V eingestellt.
Die Eingäng “Vibrato 1”, “Vibrato 2”, “Normal 1”, “Normal 2” auf der Leuchtplatte des Echolette-Verstärkers Showstar S 40 dienen zum Anschluß von mittel- oder niederohmigen Elektro-Gitarren oder Elektro-Baß-Tonabnehmer.
Auch Mikrofone können an diesen 4 Eingängen einwandfrei betrieben werden, wobei niederohmige Mikrofone zweckmäßig an die etwa 20-fach empfindlicheren Buchsen “Vibrato 1” und “Normal 1” angeschlossen werden sallen. Hochohmige Mikrofone oder Tauchspulenmikrofone mit Übertrager werden an die Eingansbuchsen 2 angeschlossen.
Die Kurzschluß-Eingangsbuchsen sind zur Verwendung von 6,35mm Klinken-Stecker Type PL 55 oder ähnlich vorgesehen.
Auf der Rückseite des Echolette-Verstärkers Showstar S 40 befinden sich rechts übereinander von unten nach oben angeordnet die Klinkenbuchse für den Lautsprecheranscluß, der Umschalter 5 ohm – 20 ohm für den Ausgang und die Klinkenbuchse für den Fernbedienungsschalter des Vibratos.
Inbetriebnahme:
Nach Einstecken des Netzanschlußkabels, der Anschlußkabel für die verschiedenen Tonabnehmer in die Eingangsbuchsen und des Lautsprecher-kabels in die Buchse “Lautsprecher” ist das Gerät einschaltbereit.
Der Echolette Verstärker Showstar S40 ist ein Spezial-Verstärker, besonders geeignet für den Betrieb mit Elektro-Gitarren und Elektro-Bässen, dessen Frequenzgang besonders auf die Eigenschaften dieser Instrumente zugeschnitten ist. Selbsverständlich ist trotz dieses speziellen Frequenzganges aufgrund der sehr großen Regelmöglichkeiten für die Höhen und Tiefen ohne weiteres der Anschluß eines niederohmigen Mikrofons bei ausgezeichneter Wiedergabequalität möglich.
Die Verwendung von zweistufigen gleichstromgekoppelten Silizium Transistorvorverstärken in den Eingängen sowie modernste Röhren ECC 808 in Gegentaktstufe mit EL 34 bei einer Spitzenleistung von 50W gestattet die Ansteuerung von beliebigen Lautsprecher-Kombinationen mit 4-6 oder 15-25 ohm Ausgangsimpedanze. Das eingabaute Kanal-Vibrato erlaubt eine schlagfreie Vibratomodulation, welche auch beim strengen studiobetrieb keine Beeinträchtigung der Übertragung hervorruft.
Schaltungsbeschreibung:
Je zwei, einem Kanal zugeordnete Kurzschluß-Klinkenbuchsen sind so geschaltet, daß durch eingebaute Spannungsteiler die Empfindlichkeit der Buchsen 2 etwa 20 mal kleiner als die der Buchsen 1 ist.
Vom Spannungsteiler gelangt die Eingangsspannung an die Basis des rauscharmen Silizium-Transistors BC 114, der als erste Stufe eines zweistufigen gleichstromgekoppelten Transistorverstärkers arbeitet.
Die Ausgangspannung gelangt zum Lautstärkeregler und dem Klangregelglied, welches in seinem Frequenzverhalten den Eigenschaften der Tonabnehmer von Elektro-Gitarren und Elektro-Bassen optimal angepaßt ist.
Von diesem wird die Spannung jedes Kanals den Steuergittern einer Doppeltriode Rö 1 zugeführt, welche zur Verstärkung und Zusammenführung der beiden Kanäl dient. Die in dieser Röhre verstärkte Ausgangsspannung steuert das Gitter einer 2. Doppeltriode Rö 2, welche als Phasenumkehrröhre für die in Gegentakt B-Schaltung arbeitenden Endröhren Rö 4 und Rö 5 dient.
Die Gitter-Vorspannung der beiden Endröhren kann durch den Einstellregler R 57 symmetriert und durch den Einstellregler R 63 auf die genaue Spannung eingestellt werden.
Der auf die Endröhren Folgende Ausgangsübertrager gewährleistet aufgrund seiner geschachtelten Wicklung einwandfreie Übertragung von 30 Hz bis 20 kHz.
Die Sekundärseite des Ausgangsübertragers kann von 5 auf 20 ohm umgeschaltet werden. Die geschaltete Ausgangsspannung liegt an einer Klinkenbuchse, welche zur Versorgung der anzuschließenden Lautsprecher dient.
Eine Anzapfung der Sekundärseite des Ausgangsübertragers dient zur Abnahme einer sehr starken Gegenkopplungsspannung, welche in die Kathode der Phasenumkehrröhre über ein regelbares Doppel-Glied zurückgeführt wird und zur Linearisierung des gesamten Frequenzganges dient. Das Doppel-T-Glied gestattet mit dem Regler “Brillanze” das Aufheben dieser Gegenkopplung in einem beschränkten Frequenzgebiet, wodurch bei Elektro-Gitarren ein stahlharter Klang erzeugt werden kann. Der Vibrato-Kanal wird nach dem Lautstärkeregler über das Potentiometer “Vibrato-Stärke” mit einem Photowiderstand Ph 1 beschaltet, der zur Erzeugung eines schlag- und geräuschlosen Vibratos benützt wird. Diese Vibrato-Schaltung wirkt wie ein sich im Takt der Vibrato-Frequenz verändernder Lautstärkeregler und erzeugt im Gegensatz zu anderen Vibrato-Schaltungen keine zusätzlichen unerwünschten Geräusche oder Beeinflussungen der Ausgangsspannung.
Der Photowiderstand Ph 1 wird über eine Lichtführung optisch von einem Lämpchen L 1 angeleuchtet, welches durch einen Multivibrator mit den 2 Triodensystemen der Rö 3 angesteuert wird. Das Lämpchen L 1 kann durch einen, an der Buchse “Fernschalter” angeschlossenen Schalter kurzgeschlossen werden, wodurch der Photowiderstand Ph 1 nicht mehr beleuchtet wird. Der Vibrato-Generator ist jedoch noch weiterhin in Betrieb, welches durch eine Glimmlampe Gl 1 angeseigt wird, die im Takt des Vibratos aufleuchtet.
Durch Anlegen einer negativen Spannung an eines der Steuergitter der Doppeltriode Rö 3 mittels des Schalters “Vibratostärke aus” kann das Vibrato abgeschaltet werden.
Das Tempo des Vibratos ist durch einen Regler “Vibrato-Tempo” zwischen 3Hz und 15Hz regelbar.
Der auf alle gängigen Spannungen umschaltbare Netztransformator besitzt die zur Anodenstromversorgung, Heizspannung und Gittervorspannung notwendigen Wicklungen. Die Anodenspannung wird durch einen Brücken-Silizium-Gleichrichter und die negative Gitter-Vorspannung durch einen Selen-Gleichrichter D 1 erzeugt.
Die Anodenspannung des gesamten Gerätes kann durch den Schalter “Bereitschaft” abgeschaltet werden.
Bei Umschaltung auf die Spannungen um 110 V ist die Sicherung 1 A träge, welche zur Absicherung bei 220 V dient, durch eine Sicherung 2 A träge auszuwechseln.
User Manual
Power Supply:
On the back of the Echolette Showstar S40 amplifier are located, one above the other, the power cord inlet, fuse holder and mains voltage selector.
Before use, care must be taken that the voltage selector is set to the desired operating voltage. At voltages of 110V, 130V, 150V, the 1A slow-blow fuse supplied should be changed to a 2A slow-blow or the fuse will be overloaded.
This machine is factory set to 220V.
The inputs "Vibrato 1", Vibrato 2", "Normal 1", "Normal 2" on the front panel of the Echolette Showstar S40 are used to connect medium or low impedance electric guitar and electric bass pickups.
Microphones can also be operated properly in these 4 inputs, with low impedance microphones connected to "Vibrato 1" and "Normal 1" which are, appropriately, about 20 times more sensitive. High impedance microphones or moving coil microphones with matching transformers are connected to input sockets 2.
The shorting input terminals are for use with 1/4" jack plugs type PL55 or similar.
On the back of the Echolette Showstar S40 are located, one above the other from the bottom up, the jack for the speaker connection, the 5ohms - 20ohms output selector switch and the jack for the vibrato remote control switch.
Commissioning:
After plugging in the power cord, the cords for the different pickups into the jack sockets and the speaker cable into the "speaker" socket, the unit is ready to turn on.
The Echolette Showstar S40 amplifier is particularly suitable for use with electric guitars and electric basses. it's frequency response being tailored to the particular characteristics of these instruments. Of course, in spite of this tailored response, it is still possible to connect a low-impedance microphone with excellent sound quality due to the very large treble and bass control options.
The use of two-stage, DC coupled silicon transistor preamp inputs and the latest ECC808 tubes, together with an EL34 push-pull output stage, produces a peak power of 50W into various combinations of 4-6 or 15-25 ohm speakers. The built-in Vibrato channel produces a smooth vibrato modulation, which causes no problems during studio operation.
Circuit Description:
Each channel has two short-circuit phone jacks connected so that, by built-in voltage divider, the sensitivity of jack 2 is twenty times less than that of jack 1.
From the voltage divider, the input voltage reaches the base of the low-noise, silicon transistor BC114, which works as the first stage of a two stage, DC coupled transistor amplifier.
The output from this section connects, via the volume control, to the tone stack which has a frequency response optimised to the characteristics of the pickups on electric guitars and electric basses.
From here, the signal from each channel is applied to the control grids of a double triode V1, which serves to amplify and mix the two channels. The increased output voltage from this tube controls the grid of a second twin triode V2, which acts as a phase splitter for the push-pull power tubes V4 and V5.
The grid bias of the two power tubes can be balanced by adjusting R57 and set to the exact voltage with R63.
The nested windings on the output transformer following the tubes ensures a smooth response from 30Hz to 20kHz.
The secondary side of the output transformer can be switched between 5 and 20 ohms. The switched output voltage is applied to a jack socket, which connects to the speakers.
A tap on the secondary of the output transformer is used to supply a very strong negative feedback voltage, which is fed back to the cathode of the phase inversion tube via an adjustable filter to linearise the overall frequency response. The double-T filter network allows the "Presence" control to remove the negative feedback in a limited frequency range, producing a harder sound in an electric guitar. The vibrato effect is regulated by the "Intensity" control with a photo resistor Ph1 used to create a powerful and silent vibrato. This vibrato rate is set by the vibrato frequency control and produces, in contrast to other vibrato circuits, no additional unwanted noise in the output voltage.
The photo-resistor Ph1 is optically coupled in a light guide to lamp L1, which is operated by a multi-vibrator formed by a double triode V2. The lamp L1 can be short-circuited by a footswitch via the "Remote Switch" socket, so that the photo-resistor Ph1 is no longer illuminated. The vibrato generator, however, continues to operate, indicated by a neon lamp G11, which lights up in time with the vibrato.
By applying a negative voltage to one of the grids of the twin triode V3 with the "Vibrato On/Off" switch, the vibrato can be turned off.
The speed of the vibrato can be controlled between 3Hz and 15Hz by the "Speed" control.
Switchable to all common mains voltages, the power transformer has the windings necessary for anode power, filament voltage and bias. The anode voltage is generated by a silicon bridge rectifier and the negative grid bias through a selenium rectifier D1.
The anode voltage of the entire unit can be switched off by the "Standby" switch.
If you change the mains voltage to 110V, the 1A slow-blow fuse which provides protection at 220V should be replaced by a 2A slow-blow fuse.
7. YouTube Links Including Showstars
All these (and more) now available on the Beat Club YouTube channel.
The Koobas - Daddy Rolling Stone
https://youtu.be/l5xhD5Ki58g?
Daddy Rollin' Stone, Somewhere In The Night
The Koobas on GermanTV Show "Beat Beat Beat", 1966 Pt.1
https://youtu.be/TzGmIl0KeJ4?si=kRKRulW503Nbz-RE
Shake, Take Me For A Little While
The Creation On German TV Show "Beat Beat Beat", 1966 Pt.2
https://youtu.be/VA6oJq4utGM?si=k-izf3gQF30jrDL6
That's How Strong My Love Is
The Move - Beat Beat Beat 1967
https://youtu.be/b6AA0qWI4dQ?si=7NTDqHzwmSHwd_Yb
Walk Upon The Water, I Can Hear The Grass Grow, Night Of Fear
The Spencer Davis Group On "Beat Beat Beat", 1966 Pt.1
https://youtu.be/rVr7RYxY6_0?si=zWS1nS4Eh5l0Almu
Somebody Help Me, Sittin' And Thinkin'
The Spencer Davis Group On "Beat Beat Beat", 1966 Pt.2
https://youtu.be/1Tm-s5sWJ4k?si=dv2e0PcYGnPVIvm7
Please Do Something, Keep On Runnin'
The Small Faces, German TV Show "Beat Beat Beat", 1966 Pt.2
https://youtu.be/sah6C87QsGo?si=FEAzY2q7nhgoUylh
What'cha Gonna Do About It, Sha-La-La-La-Lee
The Lords - Don't Mince Matter (1966)
https://youtu.be/B3qmLEJus90?si=2KY2zCzoP15648S-
Stay watching this one, it gets better. The Lords were a scream and well ahead of their time.
The Lords - Late Last Sunday Evening (1966)
https://youtu.be/j0JBfJTu1bQ?si=tSlRIa8goeDwu6SW
Nice shots of some early, valve input Showstars and a solo on a Burns Double-Six.
And last, but not least
The Monks Live In Germany - Monk Chant (1965)
https://youtu.be/3H-fmmNmrRs?si=HxB9nSlS0-zpO9Yw
Nothing to do with Showstars, but a brilliant band and an Echolette NG 51 (I think) being overdriven to #### in the organ solo.
8. Service Hints.
As mentioned above, this information was kindly supplied by Gérard Michaud of Gérard Michaud Électronique Inc in Victoriaville, Quebec, Canada. These are some of the problems you may come across.
(a) S40 and others that use ERO brand paper capacitors, replace all of those with Sprague orange drop, as they are usually leaky and cause many odd problems (do not forget the .1mf, c32 if any, of the vibrato circuit near the optocoupler).
(b) Resolder the small jumpers of the 2 small pcb's that connect to the main board (symptom may appears as scratchy pots).
(c) Replace all electrolytics with F&T brand (german made) or other good quality brand available in your country; the 32-32 mf can be upgrade to 50-50 mf or even better, 100-100mf.
(d) Since 1965, our ac mains went from 110 volt to 120 volt and this condition stresses the amp, so I always measure the 6.3 volt heater voltage: it may go up to 6.8v, and the plate voltages may stress the 32-32 mf cap. (I dont know if this condition exist in Europe). A bucking transformer(6 to 10 volt AC) has to be added for safety.
(e) Rework the gnd chassis connection near the 32-32 cap, it may be corroded and cause strange symptoms.
(f) Add a 5 amp fuse to the heater circuitry.
(g) Add an inrush current limiter (C60-11, 10ohms, 5A thermistor) to the primary of the power transformer.
(h) All of the above to be performed by a SKILLED technician ONLY.
Regards, Gérard.
9. S40 Rebuild by Jesper Karlsson
The amp is a valve input S40 in close to original condition. Photographs and text in italics are courtesy of Jesper.
Above Right: OEM hardware to bolt the head to one of Echolette's cabs
Above Left: Yep. The "death cap" switch. As can be seen someone installed a three prong wire but omitted to hook the last wire for ground up.
Above Right: Underside of main PCB. Mark the brass bracket for the vibratolight. The "tunnel of light" was missing in this amp. Fabbed one real easy by the use of some regular 6mm lexan,a straw from burger king, foil to wrap around the lexan rod and then sealed the entire thing off with electrical tape.
Above Left: Indeed. ECC808s. Marvelous flasks imo and as you can gather this amp has not been modded to take 83s. (Got me a stash of 808s around)
Above Right: Note the Faraday cage out of stainless for the small PCB for the tonestacks and volume pots. Stainless is used for the chassis throughout btw.
Above Left: This is about 1 litre of rubbing alcohol later.
Above Right: Yep. The OEM Siemens flasks from back in the day. Measure and work like new
Above Left: Caps of various forms was exchanged throughout. This then being one of two minor PCBs for the tonestacks/volume.
Above Right: Here some of the OEM caps. They ALL leaked like crazy. Every single one of them.
Left: Things started to come together.
Below: As stated someone had installed a homebrew setup for a three prong jobbie. Due to Swedish legislation these jacks were at the time not allowed (So called "S" marking rules). However i had one of these around from an approx just as old Dynacord...and it fit like a glove. It is however NOT the stock thing.
Above: Now we are starting to see results. Note the dual diodes though... Hm... It turned out that at first I just thought that this machine had a centertap and as such only sported two diodes. As I overhauled the machine however it would still compress like crazy at higher levels of power. I finally caved in and desoldered the HT wires from the PCB to do some measuring..and it turned out that them two diodes were all that was left of the original bridge!! Rendering a "zero" that was basically just floating around. As I swapped them diodes for 4pcs of regular N4007s...the whole enchillada indeed showed a different face.
Below: The offending setup.
Left: Here we see the aluminium block that holds the photoresistor bolted to the trem channels tonestack PCB to the left. On the right in turn is the brass bracketry for the lightbulb.
Right: Trem lightbulb. As can be seen it grounds direct to the PCB.
Below: Yep. Recessed jacks and all...
Below: My unit lacked the tube for the "tunnel of light" between the bung for the light bulb and the block for the photoresistor. As you might have gathered this whole thing with old tubers is a hobby of mine. What i do for a living is work on racecars. Got me a lathe so I turned some bungs to work as sort of "stoves" to fit the new tunnel. Worked out just fine. The bungs were made with an ever so small pressfit of 3/100 of a millimeter. Bought some 8mm lexan (polycarbonate)rod. This to work as a "spectre" within the tube,and hence enhance the job the bulb did.
So within...there´s approx 115mm worth of lexan rod. Shod with common oven foil...and in turn clad with common 9.5mm shrink sleeve that I heated for a snug fit. In turn two pcs of same shrink sleeve is used as a "slide fit" towards the two bungs. Whole thing works like a million bux.
Left: The PT.
Centre: Fabbed a fresh mesh for the cooling vent. Previously I had just stapled a mesh from underneath and that TBH first of all looked so-so and second of all the fit of the chassis vs the cab is so tight that it made it an enterprise just getting the chassis out of there.
Right: From an aesthetics POW it still needs work..but as is it´s at least in electric top notch nick.
Great job Jesper.