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Do you recognize this (most likely Australian) vintage tube amplifier?

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DarekWawa

DarekWawa

Member
Joined 2020
#1
Do you recognize this (most likely Australian) vintage tube amplifier?
I found it on a Polish advertising website.
The front appears to be stereo, but when viewed from above, two identical output transformers are missing. The current owner has no idea what this design is or whether it works. The amplifier has a strange plug and we don't even know what the mains voltage is

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#3
It is a bit of an enigma! There are what look to be connectors for 4 seperate connections from that front section. Could it be the front panel was for driving 2 PAs, and this is just one channel? The loudspeaker that could be the other OPT is the same make and there are no signs of different holes on the chassis.

The new plug is Swiss, but I don't think that old lead is a Swiss plug?
 
#4
Certainly appears to be aussie made, given the A&R output and power transformers. The output stage valves appear to be 6GW8, which were very common in the 1960's, and the amp style is likely based on a magazine project - like a Playmaster. The 4-pin interconnect McMurdo plug/sockets were very commonly used. You'd have to inspect the wiring to see if it was a UL PP amp. The knobs are also quite commonly used, but I haven't come across that style of chassis and front panel before. A lot of such amps were DIY kits. The A&R output transformers were quite good for hi-fi, although it seems one has been replaced - hopefully with an equivalent.

Ciao, Tim
 
#7
Wzmacniacz wyceniono na około 280 euro. Niestety nie ma go w moim mieście ani w pobliżu, żebym mógł go zobaczyć osobiście. Sądząc po treści ogłoszenia wnioskuję, że jego właściciel ma niewielką wiedzę na temat elektroniki. Napiszę do niego i poproszę o dokładniejsze zdjęcia (łącznie z wnętrzem) żeby zobaczyć jaka to zabudowa i czy warto negocjować cenę.
 
#9
DarekWawa said:
The amplifier was priced at around 280 euros. Unfortunately, it is not in my city or nearby, so I could see it in person. Judging by the content of the ad, I assume that its owner has little knowledge of electronics. I will write to him and ask for more detailed photos (including the interior) to see what kind of construction it is and whether it is worth negotiating the price.
Click to expand...

English please

dave :cop:
diyAudio moderation team
 
#11
I am not familiar with the A&R transformers but some of the Australian made transformers have a very good reputation.I own a pair of Trimax A54 B monos [Mullard 520 design]that sound beautiful.They were also made in Melbourne.Modern push pull amps I have tried sound quite poor by comparison.I also prefer them to the Radford STA25 although they also sound excellent.
 
#12
So far I've only assessed an A&R OT 896 (15W +/-1dB 30Hz to 15kHz ‘High Fidelity’ range) in a PP pentode mode circuit, where I had to limit global feedback to 12dB to maintain unconditional stability, and it was flat to 30kHz. A&R had a higher fidelity range 40xx using grain-oriented laminations, and I have a few but not yet tested for hi-fi performance. One of those transformers above looks like the 4005, which was 7W rated, and didn't come with bell-ends. The other output transformer (with bell-ends) could have been a replacement, as there are no visible mounting holes to suit bell-ends around the other transformer. There is a 1965 A&R stock catalog on-line, and RTV&H magazine has many adverts scattered over a decade or two. For Hi-fi, they mainly catered for the Playmaster and Mullard project amps, with UL variants, through the 1950-60's.
 
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