Rick57,
I've seen mention on this board to using an output transformerless valve amp, and ditching the ribbons transformer aswell - apparently the tweets ribbon trans is there to change 'normal' amps impedance to one that matches the ribbon (high impedance I'm guessing
) this is also the same as the valve amps before it hits the output trans....
I'm sure someone with more knowledge will correct/elaborate, but if I was diy'ing an amp for this driver I'd be looking into this as a good option..
ps - I typed this after a few wild turkey's so forgive me if I'm talking rubbish
Rob
I've seen mention on this board to using an output transformerless valve amp, and ditching the ribbons transformer aswell - apparently the tweets ribbon trans is there to change 'normal' amps impedance to one that matches the ribbon (high impedance I'm guessing
) this is also the same as the valve amps before it hits the output trans....I'm sure someone with more knowledge will correct/elaborate, but if I was diy'ing an amp for this driver I'd be looking into this as a good option..
ps - I typed this after a few wild turkey's so forgive me if I'm talking rubbish
Rob
RobWells-
I'm thinking that with a thin foil element a couple inches long and say a quarter inch wide, the impedance has got to be really low (An ohm if you're lucky), and the matching transformer would be to step UP the impedance. So an OTL would be driving essentially a dead short and you'd need a LOT of output tubes.
Sheldon
I'm thinking that with a thin foil element a couple inches long and say a quarter inch wide, the impedance has got to be really low (An ohm if you're lucky), and the matching transformer would be to step UP the impedance. So an OTL would be driving essentially a dead short and you'd need a LOT of output tubes.
Sheldon
RobWells said:
Sheldon has this the right way around. The ribbon has a very low impedance, and this needs to be stepped up to present a reasonable impedance to the amp.
It is ESLs where the OPTs in a tube amp & the step-ups to the stats go in opposition and the possibilty exists to either direct drive the stats (SY is doing this) or to build a special "minimum turns" step-up for the tube amp.
dave
Re: Amp for Ravens (or ESg or CG)
I have a SA8535 planar tweeter, 103db sensitivity 1w/1m.
Works well when I connect
my 200w amplifier to it.....
...but...
also works well when I connect
my cheap Sony portable CD
player and driving it only with
my headphone jack
I bet anything is possible with
these high sensitivity drivers.
rick57 said:
I have a SA8535 planar tweeter, 103db sensitivity 1w/1m.
Works well when I connect
my 200w amplifier to it.....
...but...
also works well when I connect
my cheap Sony portable CD
player and driving it only with
my headphone jack
I bet anything is possible with
these high sensitivity drivers.
""Sheldon has this the right way around. The ribbon has a very low impedance, and this needs to be stepped up to present a reasonable impedance to the amp.
It is ESLs where the OPTs in a tube amp & the step-ups to the stats go in opposition and the possibilty exists to either direct drive the stats (SY is doing this) or to build a special "minimum turns" step-up for the tube amp.""
Sorry for confusing things guys! - I wasn't too sure when I posted..
Cheers
Rob
With a tweeter amp, I'd think that you could use almost any amp that you fancy.. - I'm hoping to build some tube amps for my tweets and mids eventually..
It is ESLs where the OPTs in a tube amp & the step-ups to the stats go in opposition and the possibilty exists to either direct drive the stats (SY is doing this) or to build a special "minimum turns" step-up for the tube amp.""
Sorry for confusing things guys! - I wasn't too sure when I posted..
Cheers
Rob
With a tweeter amp, I'd think that you could use almost any amp that you fancy.. - I'm hoping to build some tube amps for my tweets and mids eventually..
Decca DK30 Ribbons
To: Pjotr
I'd like to refer back to your posting on 3-16-03 of this thread. When you crossed over your DK30 at 2500 Hz, were you using them with the plastic Decca horns? Also, how steep slope crossover were you using? I have a pair of DK30s (used without the horns) that I have crossed over at 8KHz with 18 db/0 and with a different active crossover at 5KHz with 24 db/0. I've been afraid to cross over lower for fear of burning them out.
Thanks in advance for any info. pmt
To: Pjotr
I'd like to refer back to your posting on 3-16-03 of this thread. When you crossed over your DK30 at 2500 Hz, were you using them with the plastic Decca horns? Also, how steep slope crossover were you using? I have a pair of DK30s (used without the horns) that I have crossed over at 8KHz with 18 db/0 and with a different active crossover at 5KHz with 24 db/0. I've been afraid to cross over lower for fear of burning them out.
Thanks in advance for any info. pmt
Re: Decca DK30 Ribbons
Plastic? Any DK30 i have seen (n=1 set) had a metal horn. The Decca London's had a composite material horn -- i wouldn't call it plastic thou. Decca used the London down as far as 1k in at least one of their designs, but it was usually rolled off at 1.5k 3rd order.
With the tiny little horn on the current
Howard Dawson verison a minimum 3 kHz is speced. Given this, even without a horn, i would expect somewhere between 5-10k would be safe.
dave
pmt said:
Plastic? Any DK30 i have seen (n=1 set) had a metal horn. The Decca London's had a composite material horn -- i wouldn't call it plastic thou. Decca used the London down as far as 1k in at least one of their designs, but it was usually rolled off at 1.5k 3rd order.
With the tiny little horn on the current
Howard Dawson verison a minimum 3 kHz is speced. Given this, even without a horn, i would expect somewhere between 5-10k would be safe.
dave
Decca Horn Material
I believe you are correct - the horns may have been metal. What I was thinking of was the large plastic diffraction lens that could mount on the front of the horn. I bought them over 20 years ago mail order from some retail driver supplier in England. I never tried the horns or lens - went the purist approach.
A very good sounding tweeter, but I always wished I could use them about an octave lower. I agree with you that 5 - 10 KHz should be plenty safe. But that is why I was interested how Pjotr managed to use them at 2500 Hz and if they played very loud crossed over that low.
I believe you are correct - the horns may have been metal. What I was thinking of was the large plastic diffraction lens that could mount on the front of the horn. I bought them over 20 years ago mail order from some retail driver supplier in England. I never tried the horns or lens - went the purist approach.
A very good sounding tweeter, but I always wished I could use them about an octave lower. I agree with you that 5 - 10 KHz should be plenty safe. But that is why I was interested how Pjotr managed to use them at 2500 Hz and if they played very loud crossed over that low.
Dave is right, the DK30’s are made of cast aluminium and are very sturdy. It was once a fashion to cut down or to cut off the horn completely. That was a big mistake. Not only loads the horn the ribbon acoustically to 1kHz (and as such keeping distortion low), it also gives a wide dispersion pattern. Horizontally as well as vertically.
The Dawson ribbons are in fact a copy of the Decca’s with regard to the magnet system and the ribbon. Read the site of Howard Dawson about how to filter. It also depends a lot on how much power you intend to put at them. At domestic levels 3 kHz is safe. But below that frequency distortion will quickly rise without a horn.
I did filter de DK30’s at 2.5kHz with a 2nd order filter with a Q of 0.5 cascaded with a 2nd order butterworth at 1kHz. The B110 was filtered with a 2nd order filter with a Q of 0.5. The horn gives a delay of app. ½ wavelength at 2.5 kHz, so both speakers are connected in phase.
The Dawson ribbons are in fact a copy of the Decca’s with regard to the magnet system and the ribbon. Read the site of Howard Dawson about how to filter. It also depends a lot on how much power you intend to put at them. At domestic levels 3 kHz is safe. But below that frequency distortion will quickly rise without a horn.
I did filter de DK30’s at 2.5kHz with a 2nd order filter with a Q of 0.5 cascaded with a 2nd order butterworth at 1kHz. The B110 was filtered with a 2nd order filter with a Q of 0.5. The horn gives a delay of app. ½ wavelength at 2.5 kHz, so both speakers are connected in phase.
push-pull fully differential EL84/SV83 amp v gainclone for treble?
In response to: Suggestions for an amp to let the virtues of Raven ribbons shine through?
thylantyr said
>anything is possible with these high sensitivity drivers
Yes I know, but apart from sensitivity/ volume, ribbons are also very detailed and smooth.
You wouldn't want to lose this in a medocre amp
Planet 10 suggested:
How about a 4 watt class A push-pull fully differential EL84/SV83 amp?
I suspect this would be pretty damn good.
Any links?
For beginner/ intermediate/ advanced ?
Cost ??
(I'm looking at doing an active system with G1 s, croseed at 1.5 khz)
Anyone, where do you think a gainclone would sit on the detail- smooth spectrum, for 1.5 khz up.
In response to: Suggestions for an amp to let the virtues of Raven ribbons shine through?
thylantyr said
>anything is possible with these high sensitivity drivers
Yes I know, but apart from sensitivity/ volume, ribbons are also very detailed and smooth.
You wouldn't want to lose this in a medocre amp
Planet 10 suggested:
How about a 4 watt class A push-pull fully differential EL84/SV83 amp?
I suspect this would be pretty damn good.
Any links?
For beginner/ intermediate/ advanced ?
Cost ??
(I'm looking at doing an active system with G1 s, croseed at 1.5 khz)
Anyone, where do you think a gainclone would sit on the detail- smooth spectrum, for 1.5 khz up.
Re: push-pull fully differential EL84/SV83 amp v gainclone for treble?
I'm a beginneer (although i have studied alot). I am basing mine on this Vacuum State/Allen Wright design:
Using a pr of Dynaco SCA-35s i expect to be able to do a set of monoblocs for <$300 USD. I think Brett may have one actually running (he is far from a beginner).
dave
rick57 said:
I'm a beginneer (although i have studied alot). I am basing mine on this Vacuum State/Allen Wright design:
An externally hosted image should be here but it was not working when we last tested it.
Using a pr of Dynaco SCA-35s i expect to be able to do a set of monoblocs for <$300 USD. I think Brett may have one actually running (he is far from a beginner).
dave
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