Romy the Cat wrote:

I used my typical “flash” techniques and discovered some leeks in that 50 years old enclosure. Sure it the leaks were there then it would be no “acoustic suspensions” and the driver would run further. So, fixed the box with the liquid wood and the problem with the Red’s “sinking” is gone.

Romy the Cat wrote:

The dynamics is an extra subject. The HF driver does surprisingly OK in terms of dynamic. The LF driver is another story. The Reds in a right “untreated” box do their typical “primary resonance spreading” and it certainly do not give an impression of dynamics in the terms as we use to…

Romy the Cat wrote:

BTW, it is interesting that you find the Golds and DMT's tonally challenged compare to Reds. Can you elaborate on it? The Golds need >150W to drive them….

samuel33 wrote:

Can you explain Roomy your points ? Because you say all the time what should be an intresting path but you never tell why. Why high efficiency mid driver would be an improvement? why higher effeciency would increase the sound quality? Can you develop, because reading you saying X or Z is great without developing is quite boring. Are you here to develop ideas ? you never finish what you start to say....you just throw couple of ideas and after you make a post on another subject and again and again... I have a deep feeling of emptiness after reading your statements : even a 14 years old pupils have a more constructed way of arguing than you. Sorry but it'is so annoying ... at first i thought that you create your website to share, ok your very funny when you criticize other manufacturer but there is a deep lack of consistency.on the other side...and i regret it. Which concept of electrodynamic speaker have you in mind ?

Romy the Cat wrote:

...To substitute SL600 original tweeter with anything else, would it be Revelators, Diamond or made from Faberge Eggs is like to make a movie with Humphrey Bogart and ask busboy form a nearby Chinese restaurant to re-record the Bogart’s dialogs. The SL600 tweeter with pure copper dome and phenolic suspension was probably the most perfect tweeter even was made (sonically), with only disadvantage in sensitively department.

I use the SL-600 as my summer monitor, driving it with 100W A/B amp and I do like it all around balance, size and many other factors.  The SL-600 has beautiful cupper tweeters, phenomenal in my view but the circumstances of my habits made me to look somewhere else. The SL-600 has second-order 12dB/octave slope at 2.3kHz but…. the SL-600 has sensitive in low 80s and I'm keep destroying those tweeters. I have burned 6 of them. Not truly burned but afar a few months/weeks/days of use I hear that the tweeters got changed and do not sound as good as initially. I understand that my barbaric Macondo-spoiled habits with high dynamic range are to blame and I do admit that I drive the SL-600 much harder that I shell. But it is what it is and I am not willing to moderate my listening habits.

Here is the question. The SL-600 is old speaker and many people might went over the same dilemma. So, is any tweeter out there that would work well with SL-600, would not require a lot of modification and would tolerate abuse well? I am not intend to make long experiments and rather am looking for a plug-and-play solution. I am sure somebody out there, and most likely the Brits, have already off a shelf solution.

manisandher wrote:

Hi all, This thread has been a facinating read for me, and has prompted me to resurrect my old Celestion SL600 speakers. But their copper dome tweeters are looking (and sounding) rather worse for wear. Does anyone know where I could source them from? Any help you could provide would be really appreciated. Mani.

Thanks for the advice Romy.

But actually, I may not need new tweeters after all (for the time being, at least, until the dreaded 'Autumn Sound' arrives).

You see, when I connected them up, I didn't really think too carefully about the speaker wires I used and connected them to the amp (an old Plinius 8150 integrated I had knocking around) with 'bell wire' - the only stuff I had lying around at the time. Not surprisingly, they sounded awful.

But having replaced the 'bell wire' with thicker cable (just cheap multi-stranded copper stuff), they sound much more believable.

I take your point about the quality of the amp driving them. I think the Plinius is a pretty good amp. The only other one I have stored away is an old Pass Aleph 4. I might try this one at some point and let you know how I go.

What were your experiences with SL600/cable combinations -any insights you could share?

On a slightly different note, I was talking to a 'high-end' dealer over the phone about a certain pre/power amp combo (retailing for around £10K here in the UK). When I mentioned that I was looking to use it to drive my old SL600 speakers, I could hear the 'disgust' in his voice. He was adamant that I would need a pair of speakers substantially 'better' than the SL600s, costing at least £7K, to match this pre/power combo. To his credit, he did say to bring the SL600s in and compare them to a £7K pair he stocks. And I probably will. But unless they're IB with 1st order XOs, I doubt I'll be satisfied.

Any thoughts on why dealers think a pair of speakers should cost the same as an amplifier in order to be a good match?

Mani.

Romy the Cat wrote:

They need a LOT of very good power, preferably in class A to sound the best and then will not last long with a lot of power. The caT

Do not even try your tube amps with SL600!

The SL600 is very low sensitivity and if you drive it with more or less powerful SET amp then you will ruin SL600. I have destroyed 6 (six) of SL600. A 5 minutes  of driving SL600 with 8W-10W SET as reasonably high volume and you will never get proper HF from SL600.

What happens is that low power SET will unavoidably clip driving this type of load. Even if some people can’t hear the negative auditable consequence of clipping but the act of clipping itself creates a huge amount of HF harmonics (over auditable range). Some tweeter and crossover can hold it but the SL600 can’t. No, you will not burn you tweeter but you will overheat it once and then the speaker will always gave a very idiosyncratically -bad HF.

What you drive SL600 then stay above 80-100W into 8R. If you drive SL600 with an amp over 2W and sub 50W then NEVER make SL600 to play loud.

manisandher wrote:

As I alluded to before, I'm at risk of becoming a DSET convert - it's all very well having a nice low-powered amp, but what the hell do you use with it? Are there any decent high-sensitivity FR speakers out there? Or is this simply physically impossible?

I do not know. My local guy told me initially that Zu Druids are 110dB sensitive and high impedance. Hearing it I lent to him my full-range Melquiades to try. He has a few other PP and SET amps, so I thought with 110dB sensitivity and high impedance my no-feedback Milq will be running the show. He kind of liked Milq initially but what he reported was not what I expected and it in my view it was confusing.  Another day I visited him; we did some changes in Zu Druids (more need to be done) and tried a few different amps. It was clear the Milq was not the best candidate as it was dynamically straggling to drive Zu Druids. He has some kind of 30-40W tube PP that did much better job. That made me to do only and to learn that Zu Druids are 101dB. In really it might be even less as those hi-fi companies lie for am few dB and it become a common practice. Furthermore in LF the Zu Druids have perhaps 90dB efficiency as then use port and what the port begin to become affective the no-feedback SET would die.

I still, can’t figure out Zu Druids. I would heavily highpass it to use with SET or drive it with 50W SET, preferably with feedback. Something the level of Lamm ML1 might be a good candidate for them to try. If you look out there then you will see anybody promote Zu Druids as some kind of wonder that might be perfectly used with flea-power amp. This is why people attracted to them I guess. However, I do feel that it is a bit stupidity to promote Zu Druids as a SET friendly loudspeaker. It might be a good speaker for the money but not for use with SET. In 2006-07 the industry whores created a lot of hype about Zu Druids. I do not know if it was worthy or not but I know that fact that they were pushed as “$3000 solution that can be driven by SET full-range“ was very inaccurate.

Romy the Cat wrote:

I still, can’t figure out Zu Druids. I would heavily highpass it to use with SET...

manisandher wrote:

Do you think 150Hz is too low with a 7W SET? In all honesty, I think I was heavily influenced by the Zu Druid 'hype' myself. I had bought the Berning (without really thinking too much, really - it seemed like a good idea at the time!) and was then stumped as to what to use with it. I didn't have space for horns (although I do now), and the Druids seemed, from what I had read, to fit the bill. But now that I've got the Berning and the Druids, I feel obliged to at least try making them work together...

I do know, Mani, it is hard to say. My crossover strategy is not to cross where is it necessary from logical point of view but where it necessary from sonic point of view. In practical terms it means that you need to look at the quality of you complimentary upperbass section and to listen what acoustic system and amplification cases the octaves of your interest better. Also, you have that freaky Berning  Siegfried. I mean “freaky” because it is not a regular amp that is more or less predictable to a degree but Mr. Berning‘s own OTL switching creation. It is god or bad – it is know only for the people who use it – and it is much unknown to me how it behaves driving the Zu Druid’s port. I have local guy with Berning  amp but he has a conventional  non- freaky Berning. In your case it is hard to predict anything.

OK, I see.

Actually, I was planning on using the Druids with their ports sealed. Bad idea?

FWIW, I have a pair of Wilson Benesch Chimera speakers (the UK-based manufacturer, not to be confused with the 'famous' US one) that I'm hoping to use for upper and lower bass duties, i.e. disgarding the HF driver (and the built-in passive x-overs). I've just got a feeling that the ABR-loaded upper chamber might work very well from 70-150Hz or so. I intend to block the downward firing ports of the lower chamber, and push these drivers 'hard' <70Hz.

The Chimeras have average sensitivity, so I'll use the amplifiers that I currently have knocking around - a Pass Aleph 4 for upperbass and a couple of Hypex class D amps for the lowerbass.

Hopefully, I'll manage to get something half-coherent coming out of this hodgepodge. If not, DSETs and horns will be on the agenda sooner rather than later.

Mani.