EMI DLS-1 / EMI STD-373

[Goodizzy]

After three years of searching, I finally obtained a pair of EMI DLS-1 (US domestic REDD.36) studio monitors, complete with (2) EMI STD-373 amplifiers.  They have been stored for awhile and the amps will definately need some TLC, but otherwise they appear to be in good condition.

I am wondering if anyone has schematics for the amps?  I know radiomuseum appears to have some pictures and a possible schematic, but I do not have a subscription there.  If not, I plan on sketching out the schematic and measuring both transformers in the amps, as well as documenting the crossovers and speakers.  I would be happy to post my results here if there is interest.  This place has been a wealth of learning and knowledge for me and so this is the first "big" way I can give back.

I have included a few pictures.

 

[rock soderstrom]

I know radiomuseum appears to have some pictures and a possible schematic, but I do not have a subscription there. 

AFAIK, there is no schematic at radiomuseum.org.

 

[nashkato]

nope , no schematic at Radiomuseum

 

[scott2000]

nope , no schematic at Radiomuseum

I was reading that these were similar to some of the Leak amplifiers of the time...similar to this maybe?????

http://www.freeinfosociety.com/electronics/schemview.php?id=2357

... Maybe you can get some direction from schematics of those to make your tracing easier?????

I really don't know///// Just a thought.....

Good Luck!

 

[Goodizzy]

Thanks for the replies.  It's been awhile since I went to the radiomuseum page and you are both indeed correct- no schematic.  :-\

I must have been mistaking the page for another.  The pictures on the radiomuseum page also show a recapped/restored amp.

I have only pulled one amp so far as both cabs are very dirty and its going to take me a bit just to clean them up before I even begin soldering.  There is some corrosion, (rust) on the outside of the chassis, but thankfully everything underneath looks to be in good shape.  I'll be spending the afternoon finishing up cleaning the amps.  I'm unsure of how I'll proceed after, as I'm not keen on repainting the chassis.

I don't think tracing them out will be too difficult.  The layout and lead dress is more "professional" than any other UK gear I've seen during this period, besides some Vortexion stuff.  And I've already traced the PSU.

I own a REDD.36C modified Leak TL/25+, which were also found inside nearly identical speaker cabs.  The PSU is quite different, however.    I have documented all the changes made to that amplifier at EMI, which included- the addition of a type B jack and rotary switch for quickly reading all valve voltages, different values for output valve components, a modified octal umbilical socket and the mains fuse being used as the HV fuse.  From what I've gathered the amp would have been mounted inside another enclosure where the mains fuse, mains switch, and line transformer (?) were housed.

Thanks for that link, I will check it out.

The drivers in each cab consist of (1) EMI 92390G elliptical woofer and (2) GEC BCS 1853 tweeters.  The tweeters being an early version of the famed Celestion HF1300.  I haven't taken out the XO to inspect yet.

 

[warpie]

After three years of searching, I finally obtained a pair of EMI DLS-1 (US domestic REDD.36) studio monitors, complete with (2) EMI STD-373 amplifiers. 

Forgive my ignorance, but is there something special about these speakers?

 

[Goodizzy]

They were used extensively at EMI and Abbey Road as studio monitors from the mid-50s to early 60s.  They were then parted out and the drivers used to build the White Elephant studio monitor of Beatles fame until the mid-60s.  I don't know about "special."  I suppose that is subjective.

There are very few left, especially intact.  Like many other pieces of equipment here, they fit a nostalgiac niche. 

 

[warpie]

OK I see. Thanks for your answer. Good luck with finding the schematics!