I need some help identifying pretty old amp.
Rear panel is quite simple and there is nothing more than :
COMMUNICATION & CONTROL ENG CO.
Park Road Calverton Nottingham,
England
Power Amplifier type 770/200M/A/382
and serial number, seems like this amps is manufactured in small quantities - maybe hundreds?
Is it the same company now?
COMMUNICATION & CONTROL ENGINEERING CO. LIMITED, DE21 6AW CHEQUERS LANE Financial Information
If i search this amp model from Google then there is nothing 🙁
If someone there maybe known this amps then it would be interesting to get some inormation.
I also add picture that show front panel and the amp interior itself. This is line amp and there is 2 big toroidal transformer, one, bigger is power supply transformer (split supply there, approx. 70VDC) and smaller are output transformer.
Rear panel is quite simple and there is nothing more than :
COMMUNICATION & CONTROL ENG CO.
Park Road Calverton Nottingham,
England
Power Amplifier type 770/200M/A/382
and serial number, seems like this amps is manufactured in small quantities - maybe hundreds?
Is it the same company now?
COMMUNICATION & CONTROL ENGINEERING CO. LIMITED, DE21 6AW CHEQUERS LANE Financial Information
If i search this amp model from Google then there is nothing 🙁
If someone there maybe known this amps then it would be interesting to get some inormation.
I also add picture that show front panel and the amp interior itself. This is line amp and there is 2 big toroidal transformer, one, bigger is power supply transformer (split supply there, approx. 70VDC) and smaller are output transformer.
Attachments
Yes, it is 100V PA amp
But 1980s i am not sure because some semiconductors (and seems that they are not replaced) dated as:
78week19 (older semic. what i get here) LM340CT regulator
85week22 (BFX85) transistor
88week43 (TDA2030) yes, this famous TDA2030 in pre-stage
one trimpot dated 85week12 and some components more dated 83 and 85.
I think this amp maybe 1989-1990 or even later manufactured.
This amp is working but 100V is not practical at home. I have 4 working unit and they are bomb-proof built. Output stage is the most interesting part - Hitachi laterals but sadly again, only N-channel 🙁🙁
But 1980s i am not sure because some semiconductors (and seems that they are not replaced) dated as:
78week19 (older semic. what i get here) LM340CT regulator
85week22 (BFX85) transistor
88week43 (TDA2030) yes, this famous TDA2030 in pre-stage
one trimpot dated 85week12 and some components more dated 83 and 85.
I think this amp maybe 1989-1990 or even later manufactured.
This amp is working but 100V is not practical at home. I have 4 working unit and they are bomb-proof built. Output stage is the most interesting part - Hitachi laterals but sadly again, only N-channel 🙁🙁
I would have a look at the output transformer primary.
They are often speaker type amplifiers with the transformer added for out door 100V speakers.
It might convert to switchable.
I have got a couple of 100V speakers waiting for conversion to 15 ohm in my workshop.
They are often speaker type amplifiers with the transformer added for out door 100V speakers.
It might convert to switchable.
I have got a couple of 100V speakers waiting for conversion to 15 ohm in my workshop.
I saw 8 primary wires which 4 are non connected. When i was looking right now, then it seems that maybe each arm two winding work parallel, i think 😕 It has no label, there is written manually: "S.I.G.A ET2531"
Secondary seems one winding - no multiple wires. Output transformer itself mabe are 300VA capacity (when compared to power transformers that same size).
Power transformer in this amp at a same size as 600-800VA toroidal today. Power transformer itself seems good, they are multiple primary - 110/130/150 and 220/240/260V~ and this is switchable rear panel switch, secondary Voltage is 2x50V if primary switch connected 220V and feed approx. 230V~. In this amp, secondary windings is connected to parallel to feed power stage +70Vdc, power stage consists 3 pair 2SK135, yes, only N-ch 🙁
I have 4 working unit (together 24pcs 2SK135 and some 2SK135 more which i get from friend) and i want to build complementary Lateral amp but i can´t find 2SJ49 or 2SJ50 🙁 . I know that there is some substitute (Exicon are wery good and i am previously buil amps with them and SemeLAB too) but i think that would be interesting to try old Hitachis 🙄
If i get time today then i try to measure this output transformer.
Last edited:
70 volts should give you 150 to 200 W into 8 ohms.
The output transformer will step it up a little bit to get 100V for the PA speakers.
It sounds like the phase splitting is done in the driver stage with bipolar transistors.
I would 1would a new amp if the phase splitting is to be done with P gate FETs in the output stage.
The output transformer will step it up a little bit to get 100V for the PA speakers.
It sounds like the phase splitting is done in the driver stage with bipolar transistors.
I would 1would a new amp if the phase splitting is to be done with P gate FETs in the output stage.
200W 8R seems little disputable. Maybe 4R?
6 output MOSFFETs and 200W to 8R? Of course, i have no experience with OT amps but i think only 70Vdc supply does not get 200W/8R 😕
If i find more time then i will try to redraw circuit from this amp.
And yesterday i studied the newest one which I have, component markings indicate that newest amp manufacturing date may be somewhere 1991 year end or 1992 beginning. When 3 amps which I have carry serial numbers 0009xx then newest one carry serial number 002386 and this amps interior is also a newer look - OT there is only windings which are necessary - no additional windings like older 3 amps OT, some additional capacitors added output FETs and little bit better construction too.
This amps previously used motocross track sound system in outside-forest region. Amps are not in use everyday and i get this amps maybe 5 or 6 years ago beacuse trackowner found that this amps are too old and looks ugly 😕😀 - what a statement !!!!
Since I saw that there is 2SK135 then I no longer think and grab this working "junk", maybe only thing what I misunderstood was the fact that 2SJ48, 2SJ49 or 2SJ50 is also pretty desperate to find 🙁
6 output MOSFFETs and 200W to 8R? Of course, i have no experience with OT amps but i think only 70Vdc supply does not get 200W/8R 😕
If i find more time then i will try to redraw circuit from this amp.
And yesterday i studied the newest one which I have, component markings indicate that newest amp manufacturing date may be somewhere 1991 year end or 1992 beginning. When 3 amps which I have carry serial numbers 0009xx then newest one carry serial number 002386 and this amps interior is also a newer look - OT there is only windings which are necessary - no additional windings like older 3 amps OT, some additional capacitors added output FETs and little bit better construction too.
This amps previously used motocross track sound system in outside-forest region. Amps are not in use everyday and i get this amps maybe 5 or 6 years ago beacuse trackowner found that this amps are too old and looks ugly 😕😀 - what a statement !!!!
Since I saw that there is 2SK135 then I no longer think and grab this working "junk", maybe only thing what I misunderstood was the fact that 2SJ48, 2SJ49 or 2SJ50 is also pretty desperate to find 🙁
Last edited:
- Status
- Not open for further replies.