Tannoy Reveal 6D

[Valden]

Re: Tannoy Reveal 6D

Before I forget, Khron, thanks for your patience and assistance with this. It's been very good of you, to respond so helpfully to a new member's problem. I've really appreciated your advice and encouragement.

[Khron]

Re: Tannoy Reveal 6D

No worries, it's just "giving back to the community", as far as i'm concerned

Keeping information like this secret benefits noone, not even me

Attenuated tweeter, you say? In a pinch, you could fiddle with the trimpot that's on the output of the tweeter filter section (that's what it's there for, actually - fine-tuning the signal level at the input of the tweeter amp).

[Th3_uN1Qu3]

Re: Tannoy Reveal 6D

Now would be the time to install a signal generator app on that iphone and trace thru the signal path for the tweeter amp. I am sure Khron can help you with this more than i can, as i have never taken apart this model monitor.

[Valden]

Re: Tannoy Reveal 6D

Re the attenuated tweeter level, I had a look at signal strength at the voltage regulator on the filter board (the trim pot Khron mentioned) and compared the two monitors using the audio probe. The output from pin 14 of opamp 3 goes to pin 1 of the trim pot. With the good monitor the factory set output from the trim pot (pin 2) was a touch lower in volume than the input, to my ear. The trim pot appears to be adjusted fully clockwise, which appears to be fully attenuated, from fiddling with the one on the faulty monitor's filter board.

With the faulty monitor, the factory set position was also fully clockwise, but there was a big reduction in signal strength across the trim pot's pins. I found that in turning the fiddly adjustment screw through its 180 degree range, fully anticlockwise, that the output level came up, to equal the input, by ear. The trim pot is very intermittent during adjustment and has only two settings: fully loud at hard left and what sounds much the same in the middle.

Are these voltage regulator trim pots meant to be progressively adjustable, or do they have two or three settings? Would a drop of contact cleaner and some sweeping back and forth help?

FWIW I checked voltage levels with my POC meter (ain't got that Fluke or Gossen yet). The good monitor was steady at 3.8mV in and 1.2mV out, with an audible reduction in level from using the probe. This was measuring DC millivolts though. Wrong? Each time I checked the faulty monitor I saw readings of around 14 millivolts at pins 1 & 2. Que?? The opamps in both monitors appear to be working the same.

The outcome is that I'm now getting pretty good and reasonably balanced sound from the two monitors. The 'faulty' one might be a touch overdone in the high frequencies, but I'm not too fussed given where it's come from. I'll look into replacing that trim pot. I'll report on any markings I can find. Do we know the manufacturer and part number? I'm guessing a properly specced generic replacement would work?

[Khron]

Re: Tannoy Reveal 6D

Those aren't voltage regulator trimpots - they're just literally a volume control, for the tweeter channel

At least before bothering to source a replacement, sure, contact-cleaner's well worth a shot. Definitely can't hurt, anyway

Since they're trimpots, they're (obviously?) supposed to be continually-adjustable (as opposed to a multi-position switch). The schematic says that's a 1kohm trimpot, but you'd need (in an ideal case) to find one with a compatible footprint (ie. pin spacing, etc).

Then again, now that i read your message more carefully, they wouldn't necessarily need to be set to the same position, in both monitors. Mechanical things (ie. speakers) can easily have wider tolerances than electronics, so those levels should best be set using the actual tweeters, imho
Otherwise, even if you have the trimpots set the same, you're at the mercy of whatever sensitivity differences (dB per watt) the two tweeters might have...

[Valden]

Re: Tannoy Reveal 6D

It's not a voltage regulator? When I look at the schematic it's called VR1. And yes, it's rated at 1K (with no units, but Ohms it is! ). I'm happy to call it a trim pot, since that's what it's supposed to do.

Thanks for the advice on trying the contact adhesive. I have a can of CRC CO Contact Cleaner for such purposes. Expensive stuff! I've seen others using isopropyl alcohol.

I have to say, if I'd known that the main problem with this monitor would end up being the second surface mount component I lifted, I'd have been lifting them a lot earlier. Still, those days worth of looking at the boards and schematics and using my full powers of ESP paid off. It's surprising what can be achieved with the worlds crappiest multimeter. Sometimes when it's on the voltage setting it behaves more like a random number generator. Re those Brymen's, TME in Poland seems to be about the best source.

I have half a dozen supposedly failed negative voltage regulators on the desk, all of which test just fine. Oh well, spare parts.

[Khron]

Re: Tannoy Reveal 6D

Variable Resistor 1

Well, sometimes you get lucky :P

[Valden]

Re: Tannoy Reveal 6D

Ah, Variable Resistor! hehe.

Thanks.

[Khron]

Re: Tannoy Reveal 6D

Either way, congrats on the revival

[Khron]

Re: Tannoy Reveal 6D

Tiny update.

The other day, the tweeter in one of my Precision 6D's seemed to go out of commission.

Removed the back plate, cleaned off the speaker output connectors on the power board, removed the contacts from the tweeter connector housing, bent the "tongues" inside the contacts so they press harder onto the pins on the board.

Whaddya know - tweeter came back to life

Propped the speaker back to its rightful place, and guess what - woofer sound went away...

After some messing around, i figured i'd start flipping switches, and it turned out the 80Hz high-pass switch was the guilty party. A squirt of contact-cleaner and 20-30 operations later, all was well (and stayed that way)

Now, for a more long-term plan:
1) redesign the filter board - reusing the connectors, surface-mount resistors, film caps and DIP-switches; NOT reusing any of the ceramic, electrolytic caps or opamps (replacing them with either NJM2068's or NJM5532's);
2) redesign the power supply & amp board - "piggyback" / retrofit a stereo class-D amp (2xBTL) board; reuse the big fat electrolytics; change the power supply to be a full-wave rectified +39v only, for the power amp; add a 1A bridge rectifier & a pair of cap-multipliers to work as discrete regulators (bolted to the existing heatsink) to power the filter board

[Valden]

Re: Tannoy Reveal 6D

This is a fresh post to this very helpful thread, seeking assistance with identifying the thermoswitch on the power board of my Tannoy Reveal 6D monitor.

Diagnosis: The music was fading out in one monitor, which was the master of the S/PDIF pair. The other monitor kept playing, so I suspected a problem with the audio or power circuit in the problem monitor. Upon inspection, I found that the trace between the transformer connector's pin 3 and the thermoswitch was broken. Soldering in a jumper wire to replace the trace got the monitor working again - for about four minutes from a cold start, at which point the music fades with crackling over a period of about 10 seconds, to nothing. This replicated the fault I noticed before disassembly. If I jump the thermoswitch with a test lead, between that transformer connector pin 3 and the near side of diode 3, bingo, I've got music again (see pic below). That switch is looking guilty. :-|

Any info on what it's specs are, or might be? Sourcing a form/fit replacement could be tricky/expensive/slow, so I might use a switch with suitable specs, should one be available at the local Jaycar store. I'll mount it near the amplifier ICs, so it can feel the heat. Another option would be to just bypass the thermoswitch permanently, though I worry about the missing protection for the amps. From studying the power board schematic I gather that the thermoswitch works by muting the amps when it opens due to excessive heat. Upon opening, current flowing through the amp's pin 8 drops below 0.5mA, muting it, which stops it from operating and getting hotter. A point to note is that the amps (Texas Instruments LM3886) include built in thermal protection. They shut down at 165℃ and start again at 155℃. Not ideal, but an OK temporary fix. The heat sinks for the amps are quite substantial, after all. :-)

[Khron]

Re: Tannoy Reveal 6D

Slight update from this side as well.

It must've been a couple months ago that the tweeter output in my right-side Precision 6D died out. But since i hadn't done any mixing or critical listening, just watching YouTube and some series, it didn't bother me all that much. Not enough to take it off its place (bit uncomfortable to reach), crack it open and see what's what.

That is, until last night, when the left-side one went totally mute. Voltages looked ok, S/PDIF was locking on (LED on the back went from red to green), DAC-to-crossover-board cable was ok, power amps & drivers were ok (jiggling the switches made a bit of noise). So i "chiseled off" the black gunk off the ends of the cables, double-checked the speaker connectors, and it finally came good.

Mostly the same routine with the former (right-side) one as well, except without improvement. That is, until i decided to give the tweeter level trimpot a twist. And lo and behold, with some initial crackles, the tweeter came back!..

<sigh> I really gotta see when and how i can scrape together some cash, to finish my project to overhaul the electronics in these.
Got the two TAS5630 class-D amp boards almost fully populated, just gotta wind the output inductors (got the cores, need appropriate wire).
Got the little DSP boards pretty much designed (ADAU1701, tap off the I2S signals from the DAC board), still need to get the PCB's manufactured, plus the little adapter board for the DIY "USBi", and some panel-mount miniUSB's.

[Valden]

Re: Tannoy Reveal 6D

Hi Khron. The speakers on my Tannoy Reveal 8Ds have both lost their ‘spish-spish' highs too. Haven't managed to get them fixed yet. Hopefully it's the trim pots, which I have already had a fiddle with. I might just replace them.

My 6Ds are working pretty well at the moment. When the 8Ds crapped out a few weeks back I got serious about fixing the problem with the 6Ds reported in my last post. In that I thought the thermal fuse was playing up, but in the end I got the problem monitor working again by simply stripping it right down and cleaning all the sticky, gooey, crusty gunk off. Lo and behold, upon reassembling, it worked. As reported by others, it seems the gunk causes problems and should be removed as a first step. Hard to do, but having a variety of pick tools to hand helps.

Keeping these monitors working is worth it and not that hard to achieve. I have the schematics if anyone needs them. 🙂

[Khron]

Re: Tannoy Reveal 6D

The connectors to the speakers are wonky as hell too - on my left-side one, the spring-tongue broke off from inside the output line female side not long after initially fixing the electronics the first time around, so i ended up soldering that wire to the bottom of the board.

And earlier this year, the black gunk corroded the 7.5k resistor in the mute circuitry, which knocked out the auto-mute on power-up / power-down.

[bahudoord]

Re: Tannoy Reveal 6D

Hello
does anyone have the schematics for the Tannoy 8D

thanx
deep

[Khron]

Re: Tannoy Reveal 6D

The crossover section is, i would guess, pretty much identical to the 6D. The main difference is in the amplifier section, where the woofer gets a bridged pair of LM3886's.

How about you maybe try to describe the problem(s) you're facing, perhaps?

[240vchris]

Re: Tannoy Reveal 6D

ok here goes i got a pair of 66d's and one of them decided to give up. before searching online i took the whole thing apart and now i dont know how to put it back together

absolutely disgusted with the amount crap smeared around the pcbs. appears that all here are in agreement there?
powers up fine the led on the front switch works, on the signal input i got nothing the red green led o the backside any hints tips would be appreciated
schematics here ive downloaded, could but not wanting to crack the working one open (i will cry when i see more crap glue) and swap boards to narrow it down. but i am willing to upcycle the few bits that get metioned here more than once i.e the ceramic 5w resistors and some caps.
much love for this forum 240vchris

[waveform]

Re: Tannoy Reveal 6D

ok here goes i got a pair of 66d's and one of them decided to give up. before searching online i took the whole thing apart and now i dont know how to put it back together

absolutely disgusted with the amount crap smeared around the pcbs. appears that all here are in agreement there?
powers up fine the led on the front switch works, on the signal input i got nothing the red green led o the backside any hints tips would be appreciated
schematics here ive downloaded, could but not wanting to crack the working one open (i will cry when i see more crap glue) and swap boards to narrow it down. but i am willing to upcycle the few bits that get metioned here more than once i.e the ceramic 5w resistors and some caps.
much love for this forum 240vchris

In my case the digital board was causing some sort of short which caused no sound but my LED would go dim also.

I solved my issue by simply disconnecting the digital board as i never use the digital input anyway, and they're still fine to this day.

I would recommend starting by disconnecting that digital board first, put everything back together and turn them on again to see if it remedies the issue.
My original posts are on page 3 and 4 (with the default post amount setting per page.)

[240vchris]

Re: Tannoy Reveal 6D

In my case the digital board was causing some sort of short which caused no sound but my LED would go dim also.

I solved my issue by simply disconnecting the digital board as i never use the digital input anyway, and they're still fine to this day.

I would recommend starting by disconnecting that digital board first, put everything back together and turn them on again to see if it remedies the issue.
My original posts are on page 3 and 4 (with the default post amount setting per page.)

seems you could be right!
digital i.o disconnected after snapping a few cables on the connectors and replacing them i fired it up for quick hillbilly bench test. (see pics )

they popped and hissed a little. turned them off quick as they do get very warm turned them on a second time with a little wiggly waggle here and there i believe i also have another defect cable connector.
gotta find a replacement cable now or hardwire it?

might also place a new heatsink on the back and weld the 2 wire wound resistors on.
one step at a time
thx man

[micdim]

Re: Tannoy Reveal 6D

Does anyone have the actual schematic for the Tannoy Reveal 8D Bypass Switch. I'm told it's not on the schematics that were here. I downloaded those, but my tech says it doesn't show the Bypass switch specs?

I would very much appreciate it, and Thank you!