• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

SP-70 Dead Tweeters

Mr_Mustrd

Mr_Mustrd

AK Subscriber
Subscriber
I've picked up a pair of Sansui SP-70 in excellent condition but both tweeters don't work. I've measured them seperated from the crossovers and i'm getting OL, even disconnected the woofer to see if the tweeter would play and no go :(. Any suggestions on a good replacement that I can use in the mean time while I wait for for 2 T-1001 tweeters to pop up? It's going to be very difficult to find two of them at a good price.
 
Register to hide this ad
That's a tough one. The tweeter is really what gives the SP-70 it's characteristic sound (or more specifically what distinguishes it from other Sansui speaker models of the era, most of which used horn tweeters) so changing it is a crap shoot in terms of how close it will be to the original sound.

A decent soft dome, mylar dome or titanium dome tweeter - of identical physical size - at 8 ohms would work without butchering the baffle board, and perhaps be perfectly satisfactory. Because the specs (other than impedance) of the T-1001 are unknown, it isn't possible to try and match it exactly.

I'll add that these tweeters seem to be very highly failure prone. Whether that is due to design and age, or previous abuse of the speakers with excessive power levels isn't known, but I've had similar issues with numerous other Sansui drivers going open on multiple other models made between 1969-1973. Mostly tweeters and mids, no woofers so far other than those that were clearly physically damaged by puncture or water.

It's a shame, because the SP-70 in particular is one of the better efforts Sansui made in speaker design as a simple two way setup, and with a dome tweeter, which was unusual for them at the time. The T-1001 was used only in the SP-70 and SP-1001 (which was it's original application, hence the designation T-1001).
 
mikenelson said:
Here is a single unit for sale

Sansui SP-70 tweeter T-1001 8 ohm 1 inch dome

https://www.ebay.ca/itm/125530661204?epid=2121325565&hash=item1d3a35e154:g:DuYAAOSwJE5imB2a&amdata=enc:AQAHAAAAoBPk2RUnOYdXOYAy9NRJcWyVdVKDjc4eXRPc7f+c3vGh5G/ZdoiTJ8B/EpnG8WLNT+aJu/2OZ9s6Vyym8DKiZN5q0FekTMmzTCvEMYYfqIeun8Li9n7XMphZKfZeesYVxgkCh2TqB9sKGNIwzHC7bIaySPvLnWnY2ZeatysX8Sa4HJnoxjFxLri59WauqgTXztQPtTFzCWoHik3qKE8Ubm8=|tkp:Bk9SR97MlLfNYQ
Click to expand...

Yeah that is an option, I could buy that now and then wait for another one to pop up. I did just find a pair of SP-70 local for $70 but it's a really old post and good chance they could be gone.
 
Another option, the owner of Alloy Music in Victoria Canada successfully repaired the voice coil of one of the midrange drivers from my set of Pioneer hpm 200's about 9 years ago and it is still sounds like it should. You may want to contact him about repairing your mids he is very experienced at repairing hard to work on drivers.

https://www.alloymusic.ca/alloy_music_inc
 
Sansuiman said:
That's a tough one. The tweeter is really what gives the SP-70 it's characteristic sound (or more specifically what distinguishes it from other Sansui speaker models of the era, most of which used horn tweeters) so changing it is a crap shoot in terms of how close it will be to the original sound.

A decent soft dome, mylar dome or titanium dome tweeter - of identical physical size - at 8 ohms would work without butchering the baffle board, and perhaps be perfectly satisfactory. Because the specs (other than impedance) of the T-1001 are unknown, it isn't possible to try and match it exactly.

I'll add that these tweeters seem to be very highly failure prone. Whether that is due to design and age, or previous abuse of the speakers with excessive power levels isn't known, but I've had similar issues with numerous other Sansui drivers going open on multiple other models made between 1969-1973. Mostly tweeters and mids, no woofers so far other than those that were clearly physically damaged by puncture or water.

It's a shame, because the SP-70 in particular is one of the better efforts Sansui made in speaker design as a simple two way setup, and with a dome tweeter, which was unusual for them at the time. The T-1001 was used only in the SP-70 and SP-1001 (which was it's original application, hence the designation T-1001).
Click to expand...

I've read that the tweeters are very delicate, do you think that just transporting them could have damaged them? I had to drive over an hour to get them, and if they did get damaged on the way, that could mean just buying a replacment on ebay they could arrive damaged again. Was very excited to get these and to find out both tweeters are out is very disappointing, but what can you do, it comes with the territory of buying speakers that are close to 50 years old. I'll take a look at some possible tweeters and see what is out there. Thank you!
 
mikenelson said:
Another option, the owner of Alloy Music in Victoria Canada successfully repaired the voice coil of one of the midrange drivers from my set of Pioneer hpm 200's about 9 years ago and it is still sounds like it should. You may want to contact him about repairing your mids he is very experienced at repairing hard to work on drivers.

https://www.alloymusic.ca/alloy_music_inc
Click to expand...

Thank you! I'll reach out to them and see what they say
 
Another company to talk to is The Vancouver Audio Speaker Clinic, ask for Tibor, they just reconed a set of Panasonic SB-400 tri ampable speakers for me and they have been around since the early 70's and have a large stock of NOS parts for a huge variety of speakers. Very knowledgeable about speakers

https://www.vancouveraudiospeakerclinic.ca/
 
Problem with both of those companies they are located in Canda and I'm in the US, so shipping would be pretty wild, but thank you for the suggestions! I'll still shoot them an email and see what they might charge
 
I don't think merely transporting them would've killed the tweeters. Did you verify they were fully operational before hauling them home?

As to the linked specs, that is helpful in as much as you now know the crossover point is 6kHz, so any replacement driver selected must cover the range of 6-20kHz. As well, the specs show a sensitivity of 92dB, so you would not want a tweeter that was more (or less) efficient than that or the balance in sound levels between the woofer and tweeter will be wrong, and probably noticeably off.
 
Mr_Mustrd said:
Problem with both of those companies they are located in Canda and I'm in the US, so shipping would be pretty wild, but thank you for the suggestions! I'll still shoot them an email and see what they might charge
Click to expand...

I know what you mean, When I have parts shipped over the border I just keep reminding myself how good the equipment will sound when the parcel arrives.
 
Could either one of the below be a possible fit? The shape looks to be a close match so I wouldn't have to cut into the cabinet.

Goldwood GT-525 1" Soft Dome Tweeter $13 ea

Cone / Dome Diameter 1"
Cutout Diameter 2.88
Overall Outside Diameter 4"
Depth 1.13"
Tweeter Type Soft Dome
Power Handling (RMS) 100 Watts
Impedance 8Ω
Frequency Response 3,000 to 20,000Hz
Sensitivity 92dB 2.83V/1m

https://www.parts-express.com/Goldwood-GT-525-1-Soft-Dome-Tweeter-270-182?quantity=1

Dayton Audio DC25T-8 1" Titanium Dome Tweeter $16 ea

Cone / Dome Diameter 1"
Cutout Diameter 2.76
Overall Outside Diameter 3.92"
Depth 1.08"
Tweeter Type Metal Dome
Power Handling (RMS) 50 Watts
Impedance 8Ω
Frequency Response 3,000 to 20,000Hz
Sensitivity 93dB 2.83V/1m

https://www.parts-express.com/Dayton-Audio-DC25T-8-1-Titanium-Dome-Tweeter-275-045?quantity=1
 
Electrically speaking, it looks like either one of those should work fairly well, though I might go with the Goldwood based on its sensitivity rating, assuming it fits physically into the cabinet opening.

Good news is that they're both fairly inexpensive, so if you end up finding original tweeters later on, you aren't throwing out a substantial investment on these as a temporary replacement
 
Sansuiman said:
Electrically speaking, it looks like either one of those should work fairly well, though I might go with the Goldwood based on its sensitivity rating, assuming it fits physically into the cabinet opening.

Good news is that they're both fairly inexpensive, so if you end up finding original tweeters later on, you aren't throwing out a substantial investment on these as a temporary replacement
Click to expand...

Thank you! I was leaning towards the goldwood as well due to the silk dome tweeter. Hopefully they'll sound good but I'll find out soon enough.
 
I'm thinking the Goldwood soft dome might be a little more relaxed sounding than the titanium dome Dayton. Which probably makes it closer to the original tweeters in characteristic sound. Will be interested to get your assessment of them once the new tweeters are in.
 
Sansuiman said:
I'm thinking the Goldwood soft dome might be a little more relaxed sounding than the titanium dome Dayton. Which probably makes it closer to the original tweeters in characteristic sound.
Click to expand...

Perfect! Hopefully one day I'll get my hands on a working pair of sp70s and can AB test them to compare.
 
Reflow all of the solder first,then check the caps..seems odd that both are down.
May be worth looking at the selector switch also.

I know the wherabouts of 4 tweeters 2 in my Sp-70's and 2 spares that i've been eyeing up
Not in the US though.
 
Trw said:
Reflow all of the solder first,then check the caps..seems odd that both are down.

I know the wherabouts of 4 tweeters 2 in my Sp-70's and 2 spares that i've been eyeing up
Not in the US though.
Click to expand...

I agree, it does seem unlikely and that's what I thought as well but I'm not getting any reading when testing it when it's disconnected from the crossovers. But when I replace the caps I'll try testing it again in hopes that it does work.
 
You must log in or register to reply here.
Back
Top Bottom