8mm Forum: Bell & Howell 644 (641/642/643 et al) - External Speaker Connector Type

This is topic Bell & Howell 644 (641/642/643 et al) - External Speaker Connector Type in forum 16mm Forum at 8mm Forum.

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Posted by Steve Withnell (Member # 5495) on August 22, 2016, 05:26 AM:

I had thought the speaker sockets were DIN types - but it appears they are something else, a bit odd ball like the power connector.

Anyone know what the make/model of the matching speaker side plug is?

TIA

Steve

Posted by Maurice Leakey (Member # 916) on August 22, 2016, 06:12 AM:

The speaker plug for this range of projectors has two pins for the speaker wiring and a larger plastic pin. When connected the large pin mutes the projector's internal speaker.

Posted by Paul Mason (Member # 4015) on August 23, 2016, 12:10 PM:

The old Bell & Howell cabinet speakers are fairly common on Ebay so these would be a good source for the plugs.

Posted by Maurice Leakey (Member # 916) on August 24, 2016, 06:10 AM:

It should be noted that the speaker plug to which we are referring was only used between 1961 and 1969 beginning with the 641/642/643/644.

The British made 601 was introduced in 1947 and was based on the pre-war American design. It was in a wooden box often referred to as a "blimp". It used a two-pin plug somewhat similar to the much later DIN plugs. The models ceased in 1957 with the 640.

In 1961 the models 641/642/643/644 were introduced and used a new type of plug which included a large pin which muted the projector's internal speaker when a separate external speaker was used. These progressed to the TQI which came out in 1969. These still used the same plug.

Things changed when the TQII model was introduced in the 70s. This used the standard 2-pin DIN plug which continued when the TQIII came out in the 80s.

The TQIII series eventually changed to using the ELC lamp and about the same time the speaker plug became a Post Office type 2-ring quarter inch jack plug.

I say all this to point out that 12" Bell & Howell extension speakers through the years came with plugs which fitted the then current projectors, so it is very important to verify that a speaker comes with the plug that you want.

The most simple way to connect a speaker is to just insert the two bare wires into the two small holes, and to use a matchstick in the upper hole to mute the internal speaker. A suitable speaker should be 16 ohms for a valve based amplifier.

Not all green TQIII models had a DIN socket, some American versions for the UK market came with a socket for a jack plug.

Posted by Paul Mason (Member # 4015) on August 25, 2016, 05:13 AM:

Here is a link to a 1960s speaker on Ebay of the type used with the 641 series. Note the Bell & Howell "overlapping squares" logo:

http://www.ebay.co.uk/itm/Bell-Howell-Speaker-for-B-H-Filmosound-16mm-Projector-in-original-case-/252508060380?hash=item3acaa73adc:g:n1AAAOSwGIRXZEuN

The TQII projectors appeared in 1973 which were superseded by the TQIII series from 1976.

Posted by Steve Withnell (Member # 5495) on August 26, 2016, 03:44 PM:

Thanks guys. I think I might swap the connectors out for a current standard.

Steve

Posted by David Guest (Member # 2791) on September 05, 2016, 05:08 AM:

I have these jack plugs for this machine in stock

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