Tannoy crossovers

I have tannoy 3808 drivers, 15", I understand from SRM (Super Red Monitor)

I dont have correct crossovers

Can anyone help with a circuit diagram or even the real parts !
A diy version without tone controls would be simplest and cheapest, probably sound best too.
Ive seen the diagram on here for the 12" version, I assume similar but not the same ?
 
NO! you Cannot live without the Autoformer.
Sure it will work well without it...
but not even close to what it should/could sound like.. Been there tried it.. Repeatedly.

Depends entirely on how high, or low, one sets one's personal acceptance bar :)

Having said that.. there are at least 2 bespoke makers who supply decent reproductions of the complete Crossover.. Not free though.
Google is useful.

The oem design autoformer is a' Reactive' component and the crossover circuit was Voiced with it. Substituting a simple coil produces audibly different result.. period.
But Hey! fill yer boots trying.. Many have :)
 
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Short answer: You don't.

Long answer: You'd have to have them custom wound for you. This will get expensive.

Alternative: Use the xover design from the Tannoy DC6000, which might well be somewhere in the file section of the Tannoy Yahoo group, as it does without the autoformer.
If it isn't on the yahoo group Roger of Lockwood Audio might be able to help.
Roger knows more about Tannoy DCs than Tannoy themselves.
According to Roger getting rid of the autoformer was a popular upgrade for these until nostalgia took over the market.

Lockwood Audio
 
Hello DIY community. This is one of my first posts here. Had an account and lurked for years, but haven’t posted much around here. Great forum though!
Anyway, I hate to resurrect an old thread, but I’ve seen a number of these threads without the info people are looking for regarding Tannoy Autoformers.
Firstly, I agree 100% with Bare. If you’re running vintage Tannoy, you NEED the Autoformers in the x-overs. As he explained they are a reactive component. You cannot simply replace with inductors and think it’ll be the same. It won’t. I’ve tried ad nauseam. Does it sound ok? Yeah, but why spend for vintage Tannoys and put a subpar x-over in?
Recap the originals if you must, but don’t ditch the autoformer. You’ll be sorry.
I realize tons of people sell Tannoy x-overs online without them, don’t waste your money. They are all a compromise.

To the point of my post. If looking for Autoformers for Tannoy. You will have to have them made. I went with J&K Audio, who make great transformers and have a custom autoformer made to the Tannoy spec. But far better made. There are 3 levels, permalloy core upgrade and potting available. I went with the permalloy and the potting. It isn’t cheap though. Expect close to $500 minimum with shipping. More for top levels.
They are amazing though! Incredibly well made.
I used a mix of Miflex copper foil pio caps and Jupiter VT foil and wax caps for all series positions in the high circuit. Jantzen Superior Z for the shunt in the low circuit. Jantzen copper foil and waxed litz inductors and Dueland silver and graphite resistors. These are all pretty high end parts. You don’t need to use parts that good. But get decent stuff.
All of the hookup wire is 16awg milspec silver plated copper with ptfe jacket. With some 18awg same type milspec in a few spots. For color reasons. It’s all I had. I’ll fix that when they are rebuilt in the finished boards/cases. All cardas solder.
These crossovers cost me $2,200 for parts and I made them myself.
Photos are of the prototype boards on Baltic birch. Now that I’ve tested them and they work. I will be making nicer boards and cases.
All components are based off of the Tannoy HPD 315 OEM crossover specs. They had it right, no need to adjust values. Just put better parts in.
I have the been running the factory crossovers for comparison. They are being used with Tannoy HPD 315s. Which I re-foamed.
I also had custom cabinets made, they are Tannoy Canterbury clones. Without the adjustable side ports. 150 liters. Without driver.
They were cnc made and are all 19mm Baltic Birch, with 38mm Baltic birch motor boards and bracing throughout.
I plan to experiment with ports, but tbh, they reach down very well right now and sound amazing sealed.
here’s a couple pics. Been working on this project the last 6 months
 

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Reminds me of the chat I once had with Roger Lockwood about autoformers.
According to him and I believe him because at that point he had specialised in Tannoys for over 50 years back in the 70s and 80s audiophiles would replace their xovers because xovers without autoformers sounded better!
 
Interesting Charles.

Far be it from me to argue with Roger from Lockwood. As you say, he was one of the foremost experts in Tannoy monitor drivers.
However, I have never seen him quoted anywhere saying this. I also humbly disagree with him whole heartedly. If that was what he said.
I have owned 15” and 12” Monitor Golds and 12”HPD. HPD are my favorite. In all of those cases, removing the autoformer and replacing with inductors and resistors did not sound anywhere near as good as the crossovers with autoformer. Both factory x-over and DIY “factory”.
it certainly sounded different, as it’s a different circuit, but not “better” in anyway. Def not an “upgrade” imo.
I suppose someone could like that way more? Though if tested against the factory crossover I’d be surprised.
Really the only way to know is to try it both ways. I have and my opinion is known. I’ve also read numerous other reports of the same. Personally, not sure why anyone would want to change the circuit Tannoy engineers decided on? It works great and sounds great in this case.
I’m curious what it is they like better? It would be easy enough to look deeper into what effect the mods have on the sound, if the values and changes being used were known.
To each their own, I suppose. All I know is that the replacement Autoformers from J&K are killer and sound amazing. Those looking for replacements should not hesitate.
 
It took the Tannoy engineers a couple of decades or so to figure out that xovers built on printed circuit boards and the switches sound bad (they only fixed those in the mid 80s) and that is not even up for discussion it is so obvious so they are probably not all that.

That said the lay out of the autoformer crossover is exceedingly cunning. The execution not so much until the very end.
 
I won’t argue the switch point with you. You’re correct. However those can be pretty easily replaced. Lorlin makes a nice drop in that works with the Tannoy pcb factory crossovers.
I used Lorlin in the above crossover for the prototyping. Ill be using very high end Elma rotary switches for my final version when I put them in cases.
Everyone should make sure their switches are up to par. No doubt. Someone could also use screw style terminals and eliminate the switches all together and still retain the autoformer. Though switches in working order won’t hurt the sound that much imo. I mean no worse than the cheap pcb traces.
Either way. I appreciate the conversation! Some good points.
 
Surprising.. Over the Decades (owned Tannoys since '72) I've heard Far too many self appointed Tannoy 'experts' tout their own horns/wares.

Typically Expensive 'improvement' variations. Most all do/did this for profit motives ;)
A very old phenomena that : Newer .. looonger.. looower, sales pitch.
Altruism had no part in this.

Naively , albeit decades ago, I Recreated a few of the loudest/more prominently shilled x over improvements.
In all candor.. to MY ears ALL proved inferior.. often Miserably so. An expensive lesson.. which even I, eventually learned.

Only thing more disappointing were /are the fanboys who continue bleat on loudly.. 'nuff said.

PS; Golds featured either pleated cone surrounds Or butyl rubber.
Both being Leagues superior to the Bio Degradable foam surrounds mandated by the Harmon International overlords in '74.
Golds X overs are point to point wired, phenolic boards are simply the mounting surface.
No poorly made PCBs there. (pre Harmon quality)
Inexpensive Tannoy fitted treble and energy switches are Far less problematic than typically claimed by those 'selling' something. .
Honestly.. how often does one fiddle with those settings ? Once maybe .. per decade or 2, If even that ?
I think I've fiddled those twice in Half a century of ownership
Quality contact cleaner is Easily as effective as a replacement minor upgrade quality switch.... Real life .
Only the Silly spring loaded speaker wire 'posts' are worth replacing out of hand.. IMO.
 
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I won’t argue the switch point with you. You’re correct. However those can be pretty easily replaced. Lorlin makes a nice drop in that works with the Tannoy pcb factory crossovers.
I used Lorlin in the above crossover for the prototyping. Ill be using very high end Elma rotary switches for my final version when I put them in cases.
Everyone should make sure their switches are up to par. No doubt. Someone could also use screw style terminals and eliminate the switches all together and still retain the autoformer. Though switches in working order won’t hurt the sound that much imo. I mean no worse than the cheap pcb traces.
Either way. I appreciate the conversation! Some good points.
The most common and usually advocated solution is to a) hardwire the crossover ie paralleling the pcb traces with cable and then to b) find the switch setting you prefer and bypass the switches in that position.
Total expenditure: Some of your time and a few pennies in wire.
 
Yep, I’m very familiar with paralleling the pcbs with solid wire. However, not everyone wants to destroy the originality of the Tannoy factory crossovers. I’m not sure many advocate doing that on original Tannoy crossovers anymore unless you don’t care about their value and/or have trace issues.
For those with good soldering skills, it’s not a big deal. However, It isn’t exactly easy for novices and they could quickly ruin a nice crossover or short two traces. Anyone that wants to tackle that, should be very comfortable soldering on old pcbs.
I did the x-over the way I did out of necessity. I used components that would not fit in the original crossover board. So made my own board, point to point hardwired with high quality wire. High quality switches and am very happy. I got to keep the autoformer too, which I am a fan of.
That was the point of my build. To make an external passive crossover that was point to point wired, with much higher end parts than original and a better autoformer.
I know all of the other choices regarding crossovers and mods and have pretty much tried them all pretty much.
I ended making what I like for my system. I am thrilled and don’t regret a thing.
Autoformer is a must for me. I have all the flexibility needed and am not worried about any loss of fidelity from switches or any other part of my crossovers. They sound great.
 
Best thing you can do to improve Tannoys is nix the passive xover altogether, and make it a 3 way active by adding an LF driver and remove the midbass from the coax cone. Works great for all of them and is a substantial improvement in every way.
 
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