The Tangents I have (possibly Model 300?) sport passive radiators. They are a little aggressive at the high end, so I've been meaning to crack them open and look at the crossover, but I haven't done it yet.
Maybe Tangent 500, as they have what looks to be a 12" passive radiator. Sensitivity on that speaker is supposed to be 97 dB/W.
The 300's are equivalent to KG4's. And the 500's are equivalent to Forte's. If they have a 12" woofer and passive, then likely they're 500's.
My usual practice when bringing home used speakers is to run an impedance sweep with a DATS V3 to see if there is anything amiss. Well one of my 400's impedance curves was almost double what it should have been and slightly off in other ways. So I proceeded to pull each driver and run sweeps on them. They all checked out ok, so I pulled the crossover. And that's where the problem was. There was a crack in the PCB running from the edge to one of the pads of the electrolytic in the low pass. And somehow the sides of the crack had become misaligned, so that the bottom of one side was at the top of the other side. Try as I might, I could not get them realigned by force. Then I tried to heat the solder pad of the electrolytic and realign them. And that did the trick. The solder on the pad wasn't cracked. I have no idea how the board could have broken, become misaligned and be held in place by the solder. The crack only ran through the (-) of the low pass circuit so I scraped away some of the masking and soldered across the crack to help hold it in place and provide a stable electrical connection. I never listened to them before I fixed the board, so don't know it's effect on the sound. But maybe they sounded off because of this and that's why I got them so cheap. Anyways, it was an easy, free fix for a great pair of speakers.
My usual practice when bringing home used speakers is to run an impedance sweep with a DATS V3 to see if there is anything amiss. Well one of my 400's impedance curves was almost double what it should have been and slightly off in other ways. So I proceeded to pull each driver and run sweeps on them. They all checked out ok, so I pulled the crossover. And that's where the problem was. There was a crack in the PCB running from the edge to one of the pads of the electrolytic in the low pass. And somehow the sides of the crack had become misaligned, so that the bottom of one side was at the top of the other side. Try as I might, I could not get them realigned by force. Then I tried to heat the solder pad of the electrolytic and realign them. And that did the trick. The solder on the pad wasn't cracked. I have no idea how the board could have broken, become misaligned and be held in place by the solder. The crack only ran through the (-) of the low pass circuit so I scraped away some of the masking and soldered across the crack to help hold it in place and provide a stable electrical connection. I never listened to them before I fixed the board, so don't know it's effect on the sound. But maybe they sounded off because of this and that's why I got them so cheap. Anyways, it was an easy, free fix for a great pair of speakers.
They sound OK to me, certainly sensitive enough and with sufficient low end to keep me happy. The only down side is a slight tendency for high end stridency at high volumes, possibly due to the high side compression driver you can't get away from with those Klipsch speakers. I'm currently driving them with a 20W/ channel class A of my own design, basically all current mirrors. I'm curious to see what a little triode power will do for them, even if it's with somewhat compromised output transformers (Hammond 125CSE). I'm thinking of retrofitting the "Mighty Mite" amp with a pair of the Musical Power Supplies "Hi-Fi" 5k, 10W transformers to see if there will be any improvement in audible performance, as those transformers will likely trounce the Hammonds.
Here's the thread to the amp I'm currently using to drive the Tangents:
https://www.diyaudio.com/community/threads/le-mutant-class-a.191986/
Here's the thread to the amp I'm currently using to drive the Tangents:
https://www.diyaudio.com/community/threads/le-mutant-class-a.191986/
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Only one channel of the refurbished Mighty-Mite amp is working, though it seems to be able to drive at least one of my Klipsch living room speakers with authority. I'll have to pop it open and check the connections - I suspect one of the input leads came loose.
The small hammonds are not bad transformers if you use as much of the secondary as you can. If you have ever seen the freq curves.
I'll be rooting around in the guts of the "Mighty-Mite this weekend to see if there is a loose connection somewhere. While I'm at it, I'll tighten the nuts on the output binding posts. First step will be to power up with both tubes in place to see if there is current flow in both the output sections. I put a 10 ohm monitoring resistor in series with the cathodes of both output stages for good reason.
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Just for curiosity's sake I hauled one of my early version Edcor GXSE transformers in to work to check it out on my bench setup. Driven with a 50V, 300 Hz sine output, the turns ratio was pretty much spot on at 5k:8. The primary inductance is a touch on the skimpy side at around 16.9H. I'd be curious to see how the newer GXSE transformers with end bell construction test out. I bought mine back before 2010 when the only option was open frame construction. I definitely got more bass extension when I replaced the wimpy XSE transformers in my early "Shrine" hybrid SE ultralinear amplifier with the physically larger GXSEs. The transformer in question is the GXSE15-8-5k, manufactured in 2008, according to the date code.
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The next constructional stage up at affordable expense just to provide that little extra power into lowish efficency speakers with the ECL82 group, is the 7W Mullard P-P version, which is an excellent sounder; however, I found the topend rather mellow, though it suited then 1950-60´s record player and tape cuts. In subsequent years I modified the original design many times in an attempt to get it sonically to fit my ears, but it is a very economical amp to build and run; currently my day to day listening amp using fixed bias which gives 9.5W+9.5W using paralled ECC88 phasesplitter cathodyne and pentode front end. I use a multisectioned Sowter output transformer with 43% & 20% UK taps. . I scrapped the triode sections in the original design, as by today´s standards even with GNFB applied it was a highish distortion contributor.
In the DIYforum there is a an old reference type; in search box, copy paste ECL82 PP "reference" amp and it comes up with a pull-down list.
On a more experinced note, it´s great to tinker on these easy relatively low Bmax designs when compared to my quad 250W KT90 class which uses a SMPS power supply at 600V at several amps, riddled with watchdog circuits for protection as one false move there is no compromise; a misprobe creates destruction and a mighty bang en-masse.
Build carefully and one will be rewarded.
Bench Baron
In the DIYforum there is a an old reference type; in search box, copy paste ECL82 PP "reference" amp and it comes up with a pull-down list.
On a more experinced note, it´s great to tinker on these easy relatively low Bmax designs when compared to my quad 250W KT90 class which uses a SMPS power supply at 600V at several amps, riddled with watchdog circuits for protection as one false move there is no compromise; a misprobe creates destruction and a mighty bang en-masse.
Build carefully and one will be rewarded.
Bench Baron