Hede Nielsen Loudspeaker info needed. - UK Vintage Radio Repair and Restoration Discussion Forum

parlourtw73vs · 27th Mar 2016, 11:07 am

Is there anyone out there who has any information or experience of a Danish manufacturer of loudspeakers called Hede Nielsen and particularly their HT 17 model. I'm particularly interested in their efficiency, the only real information I have is that they are of 4ohms resistance. I've seen a pair advertised and they appear to be from the late 60's or early 70's. A little digging appears to reveal that they were connected to Rank at some time and were responsible for some of their "Arena" branded products.Thanks in advance, this forum usually comes up trumps

Radio Wrangler · 27th Mar 2016, 11:46 am

4-Ohm speaker impedance was also a B&O quirk.

David

Edward Huggins · 27th Mar 2016, 12:22 pm

Yes, it's "impedance" not "resistance". What type are they - Reflex or Sealed ("Infinite Baffle") cabinets? Also, what is the output impedance of the amplifier you are using them with? Edward

parlourtw73vs · 27th Mar 2016, 1:31 pm

Apologies for mixing up resistance and impedance.There is very little information given in the advert other than the usual statements of "high end" quality and "superb sound" with exemplary cabinet work etc. The only guide is the attached photos which appear to show a sealed enclosure construction with the speaker leads emerging from the bottom rear of the cabinet. The vendor hasn't shown them with the fronts removed, either he doesn't wish to or maybe doesn't realise they may be removable, but they appear to contain a largish elliptical speaker coupled with a smaller tweeter. No sizes are given, but they are shown against a separate turntable and don't seem to be overly large, guessing at maybe 12" x 9" x 5". I only require one speaker to be used with my Deccalian 88 record player as discussed in an earlier thread. I've also been looking at an early Goodmans Maxim single enclosure, but when looking up its specifications it appears to require quite a bit of driving and I thought it may be too inefficient for my amplifier. I welcome any further thoughts on either unit.

Herald1360 · 27th Mar 2016, 1:34 pm

The output impedance is probably milliohms unless it's a valve amp. Also pretty much irrelevant unless you're concerned with speaker damping factor. What matters is the load impedance it's designed to drive, if it's higher than the speakers' it could be expensive.

Edward Huggins · 27th Mar 2016, 1:40 pm

A sealed enclosure is usually quite hard to drive. From your rough dimensions, it is unlikely that the elliptical speaker in this will be any bigger than the 8" x 5" in your Deccalian 88. I would suggest that if you bought this speaker, you would be dissappointed as to its sound and the power needed to drive it. I would recommend a Reflex type speaker, usually more efficient and will give more bass if the cabinet is larger. A used Tannoy "Eclipse" or "Mercury" would be ideal. Edward

Radio Wrangler · 27th Mar 2016, 2:03 pm

I've been doing a bit of research:

It looks like there was a Danish company called Arena Audio located in Horsens. It was founded in 1928 by Ove Hede Nielsen. The initial name was Herofon.

According to a very detailed post on Audiokarma by "the-real-mandak" in Copenhagen:

Sales reached 10,000 radios in 1939

In the 50's Nielsen changed the name to 'Arena' and started doing TVs, colour TVs in the sixties. In 1970 the factory burned down and Ove sold out to Rank-Murphy. The rebuilt factory operated as Rank Arena, until Rank closed it down in 1974.

Rank kept the Rank Arena name on products from other places until Rank sold off Rank-Bush-Murphy in 1978.

So if those speakers are post 1974, they may just be what J-Arfur attached to his better grade music centres.

If they'd been anything special, they'd have been better known.

David

P.Pilcher · 27th Mar 2016, 2:50 pm

Be advised that when a student in the mid 60's I ran a pair of Goodmans Maxim loudspeakers for a number of years. They had a nominal impedance of 15 ohms and my transistor Dinsdale home built amplifier giving a maximum output of 10 watts per channel (just!) ran them effectively.

P.P.

roffe · 27th Mar 2016, 3:28 pm

The HT17 measures 32x25x12 cm and has a Peerless 5x7in bass unit U570 and a Peerless MT25HFC.
16uF and a coil as crossover.
4 ohms system impedance.
One peculiar detail about the bass, is that it could be delivered with a lower resonance frequency (65Hz as opposed to 90Hz) for use in small closed boxes.
The box is completely full with Rockwool damping material and a sheet of cloth protects the drivers.

Radio Wrangler · 27th Mar 2016, 3:43 pm

Transistor amplifiers normally end with an emitter-follower stage, which gives them a fairly low output impedance. They also normally employ significant amounts of negative feedback, which acts to reduce their output impedance still further.

So the output of a transistor amplifier tries to act as a close approximation to an ideal voltage source. As Chris said above, they routinely have output impedances of a small fraction of an Ohm.

This isn't a match to a 4 Ohm, 8 Ohm or 15 Ohm speaker. But matching isn't needed, in fact it's usually inefficient. What we need is for the loudspeaker to present an acceptable load impedance to the amplifier.

At some instant, say on the peak of a waveform, imagine the input to an amplifier is +500mV and say the amplifier's gain (programmed by the choice of feedback resistors) is 20.

So the amplifier tries to make an output of +10 volts. It has a lot of loop gain and it will try harder and harder driving more and more current until it gets to 10v and the feedback balances the input.

If we connect a 15 Ohm loudspeaker, 10/15 = 0.666.. amps will flow into the speaker.
If we connect an 8 Ohm speaker, 10/8 = 1.25A
If we connect a 4 Ohm speaker, 10/4 = 2.5A
If we connect a short circuit by mistake 10/almost 0 = Almost infinite current!

Depending on how beefy the transistors and their power supply are, amplifiers are rated to drive some number of amps.

An amplifier designed for 8 Ohms load won't object to 15 Ohms at all, It'll think it's having a little holiday. It won't be able to drive as many watts out as it could into an 8 Ohm load, because it's power supply voltages will become a limiting factor.

An amplifier designed for 8 Ohms will find too much current is being taken if a 4 Ohms load s connected. Maybe the transistors survive, maybe they fail. Damage is possible. A short circuit is an absolute no-no.

So the general rule is to not connect a lower than rated load impedance to a transistor amplifier. You can connect higher values, but you won't get full power.

With valves, the situation is completely reversed. Valves have high output impedances, the output transformer reduces this somewhat, but it's still fairly high. They have small amounts of feedback (if any) so this doesn't produce much reduction (if any)

So they act more like current sources. Attach a short circuit and they're fine. The current is controlled, the voltage is tiny.

But attach too high an impedance speaker and the output voltage increases. Disconnect any load and the voltage goes much higher and things risk being damaged.

So the 4 Ohm Danish speakers will be acceptable to some amplifiers, but not to others. The only way to find out is to read the amplifier's specification. Plenty of Japanese amplifiers were designed for 4 Ohms so users could drive two pairs of 8 Ohm speakers at once.

David

Radio Wrangler · 27th Mar 2016, 3:59 pm

That looks to be a very basic speaker. The 2-element crossover isn't a crossover, it lets the full spectrum reach the bass driver and only protects the tweeter from low frequency components. In British terms, it's equivalent to what you'd get along with a Dynatron music centre (or mid range Sony for that matter) It isn't a Leak Sandwich or LS3/5A challenger.

David

parlourtw73vs · 27th Mar 2016, 4:34 pm

Excellent information, many thanks, especially to Roffe, the speaker you've posted is definitely the one that I've seen and has obviously helped the more knowledgeable to give an informed opinion. Thanks also to Edward for his helpful suggestions regarding the Tannoy models. I'm watching pair of Mercury M20's at the moment. The little Goodmans Maxim is going stratospheric with regard to price, I didn't realise they were so sought after, it's up to £160 now with hours to go so I think that's way too much to pay out to try and enhance the sound of my record player.

RojDW48 · 27th Mar 2016, 6:09 pm

I have just started reviving a Decca Deccalian Mk4 RP. I am pretty sure it has the same amp as yours (someone here will know if I am wrong!). It has different output levels for the internal and external speakers - viz 3.5W internal, 7W external. I tried the external into a Mordaunt Short Festival speaker and it sounded fine. The MS is a fairly typical 70s 2 driver setup with a decent crossover, so your RP should be able to drive a similar smallish hi-fi speaker from that era quite convincingly. Try your local auction rooms - I picked up the pair of MS festivals for £20. Those Nielsens look like rather typical Rank produce - built to a somewhat restricted budget!

27th Mar 2016, 11:07 am	#1
parlourtw73vs Pentode Join Date: Mar 2015 Location: Bolton, Lancashire, UK. Posts: 186	Hede Nielsen Loudspeaker info needed. Is there anyone out there who has any information or experience of a Danish manufacturer of loudspeakers called Hede Nielsen and particularly their HT 17 model. I'm particularly interested in their efficiency, the only real information I have is that they are of 4ohms resistance. I've seen a pair advertised and they appear to be from the late 60's or early 70's. A little digging appears to reveal that they were connected to Rank at some time and were responsible for some of their "Arena" branded products.Thanks in advance, this forum usually comes up trumps

27th Mar 2016, 11:46 am	#2
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,902	Re: Hede Nielsen Loudspeaker info needed. 4-Ohm speaker impedance was also a B&O quirk. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

27th Mar 2016, 12:22 pm	#3
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,338	Re: Hede Nielsen Loudspeaker info needed. Yes, it's "impedance" not "resistance". What type are they - Reflex or Sealed ("Infinite Baffle") cabinets? Also, what is the output impedance of the amplifier you are using them with? Edward

27th Mar 2016, 1:31 pm	#4
parlourtw73vs Pentode Join Date: Mar 2015 Location: Bolton, Lancashire, UK. Posts: 186	Re: Hede Nielsen Loudspeaker info needed. Apologies for mixing up resistance and impedance.There is very little information given in the advert other than the usual statements of "high end" quality and "superb sound" with exemplary cabinet work etc. The only guide is the attached photos which appear to show a sealed enclosure construction with the speaker leads emerging from the bottom rear of the cabinet. The vendor hasn't shown them with the fronts removed, either he doesn't wish to or maybe doesn't realise they may be removable, but they appear to contain a largish elliptical speaker coupled with a smaller tweeter. No sizes are given, but they are shown against a separate turntable and don't seem to be overly large, guessing at maybe 12" x 9" x 5". I only require one speaker to be used with my Deccalian 88 record player as discussed in an earlier thread. I've also been looking at an early Goodmans Maxim single enclosure, but when looking up its specifications it appears to require quite a bit of driving and I thought it may be too inefficient for my amplifier. I welcome any further thoughts on either unit.

27th Mar 2016, 1:34 pm	#5
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: Hede Nielsen Loudspeaker info needed. The output impedance is probably milliohms unless it's a valve amp. Also pretty much irrelevant unless you're concerned with speaker damping factor. What matters is the load impedance it's designed to drive, if it's higher than the speakers' it could be expensive. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

27th Mar 2016, 1:40 pm	#6
Edward Huggins Dekatron Join Date: Sep 2015 Location: Southwold, Suffolk, UK. Posts: 8,338	Re: Hede Nielsen Loudspeaker info needed. A sealed enclosure is usually quite hard to drive. From your rough dimensions, it is unlikely that the elliptical speaker in this will be any bigger than the 8" x 5" in your Deccalian 88. I would suggest that if you bought this speaker, you would be dissappointed as to its sound and the power needed to drive it. I would recommend a Reflex type speaker, usually more efficient and will give more bass if the cabinet is larger. A used Tannoy "Eclipse" or "Mercury" would be ideal. Edward

27th Mar 2016, 2:03 pm	#7
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,902	Re: Hede Nielsen Loudspeaker info needed. I've been doing a bit of research: It looks like there was a Danish company called Arena Audio located in Horsens. It was founded in 1928 by Ove Hede Nielsen. The initial name was Herofon. According to a very detailed post on Audiokarma by "the-real-mandak" in Copenhagen: Sales reached 10,000 radios in 1939 In the 50's Nielsen changed the name to 'Arena' and started doing TVs, colour TVs in the sixties. In 1970 the factory burned down and Ove sold out to Rank-Murphy. The rebuilt factory operated as Rank Arena, until Rank closed it down in 1974. Rank kept the Rank Arena name on products from other places until Rank sold off Rank-Bush-Murphy in 1978. So if those speakers are post 1974, they may just be what J-Arfur attached to his better grade music centres. If they'd been anything special, they'd have been better known. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

27th Mar 2016, 2:50 pm	#8
P.Pilcher Pentode Join Date: Jan 2010 Location: Lichfield, Staffs, UK. Posts: 150	Re: Hede Nielsen Loudspeaker info needed. Be advised that when a student in the mid 60's I ran a pair of Goodmans Maxim loudspeakers for a number of years. They had a nominal impedance of 15 ohms and my transistor Dinsdale home built amplifier giving a maximum output of 10 watts per channel (just!) ran them effectively. P.P. __________________ "Ohm's law rules here" - Oxygen free speaker cable not required! (Quote: Quad Service lab)

27th Mar 2016, 3:28 pm	#9
roffe Hexode Join Date: Nov 2003 Location: Linkoping, Sweden Posts: 493	Re: Hede Nielsen Loudspeaker info needed. The HT17 measures 32x25x12 cm and has a Peerless 5x7in bass unit U570 and a Peerless MT25HFC. 16uF and a coil as crossover. 4 ohms system impedance. One peculiar detail about the bass, is that it could be delivered with a lower resonance frequency (65Hz as opposed to 90Hz) for use in small closed boxes. The box is completely full with Rockwool damping material and a sheet of cloth protects the drivers. Attached Thumbnails

27th Mar 2016, 3:43 pm	#10
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,902	Re: Hede Nielsen Loudspeaker info needed. Transistor amplifiers normally end with an emitter-follower stage, which gives them a fairly low output impedance. They also normally employ significant amounts of negative feedback, which acts to reduce their output impedance still further. So the output of a transistor amplifier tries to act as a close approximation to an ideal voltage source. As Chris said above, they routinely have output impedances of a small fraction of an Ohm. This isn't a match to a 4 Ohm, 8 Ohm or 15 Ohm speaker. But matching isn't needed, in fact it's usually inefficient. What we need is for the loudspeaker to present an acceptable load impedance to the amplifier. At some instant, say on the peak of a waveform, imagine the input to an amplifier is +500mV and say the amplifier's gain (programmed by the choice of feedback resistors) is 20. So the amplifier tries to make an output of +10 volts. It has a lot of loop gain and it will try harder and harder driving more and more current until it gets to 10v and the feedback balances the input. If we connect a 15 Ohm loudspeaker, 10/15 = 0.666.. amps will flow into the speaker. If we connect an 8 Ohm speaker, 10/8 = 1.25A If we connect a 4 Ohm speaker, 10/4 = 2.5A If we connect a short circuit by mistake 10/almost 0 = Almost infinite current! Depending on how beefy the transistors and their power supply are, amplifiers are rated to drive some number of amps. An amplifier designed for 8 Ohms load won't object to 15 Ohms at all, It'll think it's having a little holiday. It won't be able to drive as many watts out as it could into an 8 Ohm load, because it's power supply voltages will become a limiting factor. An amplifier designed for 8 Ohms will find too much current is being taken if a 4 Ohms load s connected. Maybe the transistors survive, maybe they fail. Damage is possible. A short circuit is an absolute no-no. So the general rule is to not connect a lower than rated load impedance to a transistor amplifier. You can connect higher values, but you won't get full power. With valves, the situation is completely reversed. Valves have high output impedances, the output transformer reduces this somewhat, but it's still fairly high. They have small amounts of feedback (if any) so this doesn't produce much reduction (if any) So they act more like current sources. Attach a short circuit and they're fine. The current is controlled, the voltage is tiny. But attach too high an impedance speaker and the output voltage increases. Disconnect any load and the voltage goes much higher and things risk being damaged. So the 4 Ohm Danish speakers will be acceptable to some amplifiers, but not to others. The only way to find out is to read the amplifier's specification. Plenty of Japanese amplifiers were designed for 4 Ohms so users could drive two pairs of 8 Ohm speakers at once. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

27th Mar 2016, 3:59 pm	#11
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,902	Re: Hede Nielsen Loudspeaker info needed. That looks to be a very basic speaker. The 2-element crossover isn't a crossover, it lets the full spectrum reach the bass driver and only protects the tweeter from low frequency components. In British terms, it's equivalent to what you'd get along with a Dynatron music centre (or mid range Sony for that matter) It isn't a Leak Sandwich or LS3/5A challenger. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

27th Mar 2016, 4:34 pm	#12
parlourtw73vs Pentode Join Date: Mar 2015 Location: Bolton, Lancashire, UK. Posts: 186	Re: Hede Nielsen Loudspeaker info needed. Excellent information, many thanks, especially to Roffe, the speaker you've posted is definitely the one that I've seen and has obviously helped the more knowledgeable to give an informed opinion. Thanks also to Edward for his helpful suggestions regarding the Tannoy models. I'm watching pair of Mercury M20's at the moment. The little Goodmans Maxim is going stratospheric with regard to price, I didn't realise they were so sought after, it's up to £160 now with hours to go so I think that's way too much to pay out to try and enhance the sound of my record player.

27th Mar 2016, 6:09 pm	#13
RojDW48 Nonode Join Date: Jun 2014 Location: Bristol, UK. Posts: 2,074	Re: Hede Nielsen Loudspeaker info needed. I have just started reviving a Decca Deccalian Mk4 RP. I am pretty sure it has the same amp as yours (someone here will know if I am wrong!). It has different output levels for the internal and external speakers - viz 3.5W internal, 7W external. I tried the external into a Mordaunt Short Festival speaker and it sounded fine. The MS is a fairly typical 70s 2 driver setup with a decent crossover, so your RP should be able to drive a similar smallish hi-fi speaker from that era quite convincingly. Try your local auction rooms - I picked up the pair of MS festivals for £20. Those Nielsens look like rather typical Rank produce - built to a somewhat restricted budget!