Dalesford D50/200 replacement

Hi there,
I picked up a nice looking pair of RAM Electronics 100 Monitors the other day for £30 (£15 after refund). I soon discovered that one of the bass units (Dalesford D50/200)was dead. No sign of damage and the cone moved smoothly and quietly. Not sure what its fate was.
Anyway, I need a repalcement and my initial thoughts were to get Kef B200 units. I initially thought SP1014's which are quite easy to get. Then I found a link on Falcon Acoustics who have an interest in that company. The chap there suggested I should be getting the large magnet variety SP1039 or SP1054. Pricier and harder to find it seems. No mention made of the SP1022.
I wouldn't say that the D50/200 is a large magnet type, but the design is clearly B200 related but with inverted rubber diaphram. It weighs 1.67kg. The large magnet Kef's are about 2.7 to 3kg. The regular ones around 1.47kg.
I then wondered if I am better just going for a pair of new Monacor SPM-205/8 units?
Any advice. I want to keep any work low cost or else I will just sell for parts.
I think the one remaining D50/200 may help fund the unit purchase a little as they are quite uncommon.
Cheers
 
Hi Peter,

I came to this thread via a random Google as I was interested in in exactly this issue although I'm coming from a post-restoration perspective having replaced a pair of Dalesford D50/200s already and was wondering if I'd made the correct choice. I thought I'd post as even if you've moved the project forward it might be useful to someone in the same position in the future.

First off congratulations on the RAMs - an absolute steal and a great pair of speakers. I hope you managed to coax them back to life. I love vintage speakers from the golden era of small manufacturers (especially the three-way "BBC" lineage) and recently had a pair of Keesonic KRFs restored. These are wonderful monitors with a fantastic mid-range which used a pair of Dalesford D50/200s as woofers much like most vintage RAM models. In this design they're paired with a Peerless mid-range and silk-dome tweeter.

From reading around I think the common consensus from people who experienced them first-hand were that Dalesford drivers were generally inferior to KEF and not finished to quite the same standard. That doesn't mean they were bad drivers per se - they're actually very good when correctly implemented (and the highly respected RAM range is testament to that) but they should be viewed as a separate entity and careful selection is needed in swapping them for a KEF counterpart.

Hidden away at the Falcon site is a data sheet for the common Dalesford drivers of that era:

https://www.falconacoustics.co.uk/downloads/Dalesford%20Speakers%20Datasheet.pdf

Here is the same for the different variants of the KEF B200:

TL Links

And finally, the Monacor SPM-205/8:

MONACOR - Products - SPM-205/8


In the end I opted for the Monacor drivers - they sound fantastic and it's hard to imagine anything sounding any better they're so smoothly integrated. My reasoning was that although not an exact match they are close enough and as close as any of the KEF equivalents (which, by purely looking at the specs on paper, I agree the small magnet type would be closer fit to me, not to disrespect your previous advice which may come from experience) while also being very competitively priced and subject to modern quality assurance rather than gambling on a vintage pair.

Hope you made the restoration and found a happy match - if anyone else needs to find a replacement i'd recommend the Monacor units in a heartbeat but do check over the T/S parameters above as each speaker design will have different tolerances.

Finally - a couple pics of the restored KRFs which are sounding terrific and in daily service.

krf1.jpg


krf2.jpg


krf3.jpg