Hartley-Turner Amplifier - UK Vintage Radio Repair and Restoration Discussion Forum

klystron84 · 19th Sep 2018, 4:11 pm

I have recently acquired a Hartley-Turner Power and Pre Amplifier, output stated to be 20W peak. Unfortunately there are no model numbers available. The output stage appears to be Class AB, based on the CV124 with associated transformer, in addition to a main transformer supplying the pre and power amplifier. The length of spindles together with a giveaway selector switch for gramophone suggests this equipment started life in such a device, though other than the company name on the faceplate that's all that I can see.
From research it seems to date from the late 1940's since the company name did not change until around 1950. It is in excellent original condition and in construction seems to pre date a Leak amplifier I have from the 1950s for separate tone/pre amp stages and the main power amplifier.
So far I have been unable to locate a circuit diagram or indeed any Hartley-Turner diagram of this period?
I appreciate Hartley went on to write several well known works in the Hi-Fi field and there may be references there to part of the circuitry that I'm not aware of. But apart from a grainy picture of a similar amplifier and also the famous "Boffle" loudspeaker which Hartley exhibited in 1952 at an American exhibition, I've come across little of substance.
Could any more knowledgeable Member point me toward ideally a circuit diagram or any information still available on similar amplifiers or gramophones they were fitted into?

Many thanks

Edward Huggins · 19th Sep 2018, 4:40 pm

It's a long time since I have seen Hartley-Turner referred to. In the early 1950s my Father used to service touring Fairground PA/Music systems and these tended to use energised 12" or 15" H-T speakers. Later on, he himself he used them in his own PA system for Fetes and Dances complete with a (pre-Disco) twin 78 turntable. He had a home-built amp of two PX25s. I used the change the records and fade them in and out. I still have all those (mainly Decca, Regal and Parlophone) 78s. They very soon bring a tear to my eye when I play them now....

Herald1360 · 19th Sep 2018, 5:09 pm

Well, the CV 124 is better known as the "bomb proof" 807.

If the amplifier is at all reasonably laid out build wise, it shouldn't take long to reverse engineer, except maybe for any equalisation components wrapped round selector switches (if applicable).

Any p-p 807 amp circuit would be a good starting point except perhaps for the (in)famous zero bias class B job!

Here's one I found with a quick goggle:

https://www.google.co.uk/search?q=80...AbTxWOdoVBQDM:

Synchrodyne · 24th Sep 2018, 8:38 am

The book "Audio! Audio! listed a Hartley-Turner 20-watt mono power amplifier as having been available in the period 1950-55. No valve information was provided.

There was an (apparently corresponding) Hartley-Turner Tone-Control unit available 1950-54, with a "Super" control unit available 1954-55.

The manufacturer was given as H.A. Hartley & Co. of Hammersmith.

Cheers,

wd40addict · 24th Sep 2018, 1:21 pm

Anything like this one?

https://www.worthpoint.com/worthoped...mono-245241920

Hartley and Turner fell out quite early on in the company's history, but the name was well established so Hartley kept it. I think ultimately it did get shortened.

klystron84 · 27th Sep 2018, 10:40 pm

Thank you and yes pretty much identical to this one, though as I mentioned in addition there is a pre amp which this does not appear to have. My understanding is that Turner died in 1943 and the company's efforts during the war were to support the war effort. Hartley kept the company name until 1947 before changing it. Although the company was sold in 1953 the US branch was sold separately in 1952 and I believe is still very much in business producing loudspeakers.

Thanks for this information, I have recently come across a circuit diagram pretty much identical to mine though sadly lacking component values. As you say it is possible to reverse engineer but I was rather hoping to avoid this. It seems a fascinating device so maybe I shall just have to do this.

19th Sep 2018, 4:11 pm	#1
klystron84 Diode Join Date: Sep 2018 Location: Cardiff, Wales, UK. Posts: 2	Hartley-Turner Amplifier I have recently acquired a Hartley-Turner Power and Pre Amplifier, output stated to be 20W peak. Unfortunately there are no model numbers available. The output stage appears to be Class AB, based on the CV124 with associated transformer, in addition to a main transformer supplying the pre and power amplifier. The length of spindles together with a giveaway selector switch for gramophone suggests this equipment started life in such a device, though other than the company name on the faceplate that's all that I can see. From research it seems to date from the late 1940's since the company name did not change until around 1950. It is in excellent original condition and in construction seems to pre date a Leak amplifier I have from the 1950s for separate tone/pre amp stages and the main power amplifier. So far I have been unable to locate a circuit diagram or indeed any Hartley-Turner diagram of this period? I appreciate Hartley went on to write several well known works in the Hi-Fi field and there may be references there to part of the circuitry that I'm not aware of. But apart from a grainy picture of a similar amplifier and also the famous "Boffle" loudspeaker which Hartley exhibited in 1952 at an American exhibition, I've come across little of substance. Could any more knowledgeable Member point me toward ideally a circuit diagram or any information still available on similar amplifiers or gramophones they were fitted into? Many thanks

19th Sep 2018, 4:40 pm	#2
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,327	Re: Hartley-Turner Amplifier It's a long time since I have seen Hartley-Turner referred to. In the early 1950s my Father used to service touring Fairground PA/Music systems and these tended to use energised 12" or 15" H-T speakers. Later on, he himself he used them in his own PA system for Fetes and Dances complete with a (pre-Disco) twin 78 turntable. He had a home-built amp of two PX25s. I used the change the records and fade them in and out. I still have all those (mainly Decca, Regal and Parlophone) 78s. They very soon bring a tear to my eye when I play them now.... __________________ Edward.

19th Sep 2018, 5:09 pm	#3
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: Hartley-Turner Amplifier Well, the CV 124 is better known as the "bomb proof" 807. If the amplifier is at all reasonably laid out build wise, it shouldn't take long to reverse engineer, except maybe for any equalisation components wrapped round selector switches (if applicable). Any p-p 807 amp circuit would be a good starting point except perhaps for the (in)famous zero bias class B job! Here's one I found with a quick goggle: https://www.google.co.uk/search?q=80...AbTxWOdoVBQDM: __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

24th Sep 2018, 8:38 am	#4
Synchrodyne Nonode Join Date: Jan 2009 Location: Papamoa Beach, Bay of Plenty, New Zealand Posts: 2,944	Re: Hartley-Turner Amplifier The book "Audio! Audio! listed a Hartley-Turner 20-watt mono power amplifier as having been available in the period 1950-55. No valve information was provided. There was an (apparently corresponding) Hartley-Turner Tone-Control unit available 1950-54, with a "Super" control unit available 1954-55. The manufacturer was given as H.A. Hartley & Co. of Hammersmith. Cheers,

24th Sep 2018, 1:21 pm	#5
wd40addict Octode Join Date: May 2009 Location: Stevenage, Herts. UK. Posts: 1,518	Re: Hartley-Turner Amplifier Anything like this one? https://www.worthpoint.com/worthoped...mono-245241920 Hartley and Turner fell out quite early on in the company's history, but the name was well established so Hartley kept it. I think ultimately it did get shortened.

27th Sep 2018, 10:40 pm	#6
klystron84 Diode Join Date: Sep 2018 Location: Cardiff, Wales, UK. Posts: 2	Re: Hartley-Turner Amplifier Thank you and yes pretty much identical to this one, though as I mentioned in addition there is a pre amp which this does not appear to have. My understanding is that Turner died in 1943 and the company's efforts during the war were to support the war effort. Hartley kept the company name until 1947 before changing it. Although the company was sold in 1953 the US branch was sold separately in 1952 and I believe is still very much in business producing loudspeakers. Thanks for this information, I have recently come across a circuit diagram pretty much identical to mine though sadly lacking component values. As you say it is possible to reverse engineer but I was rather hoping to avoid this. It seems a fascinating device so maybe I shall just have to do this.