• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

GAMMA 30 experiement

It seems VLD-12 ribbon tweeters where sold in the UK under the name "Audio-Tronic".

So drivers made by Vissokogovoriteli, has been sold under the names, GAMMA, Jordanov, Expolinear, Giant and Audio-Tronic.
 
Last edited:
I have read that the Beyma 10LW30/N woofer might be usable without a low pass filter, this means I might be able to use it without any crossover network at all.
All I'd have to do is make a crossover for the ribbons, at around 3500Hz.
 
But it seems the Lambda TD10 series would be no less then perfect.
 
Last edited:
The BK3013A woofers needed further repairs.
The surrounds had gone loose in many places, but I have glued it down now.

Now they play louder before getting peaky, quite loud in fact, not party speaker loud though.
 
A picture of my ribbon material source, before butchering, well mostly.
Open it up by crushing the outer shell and removing the outer layer, use a nutcracker or pliers.

e2781f37_RibbonSource.jpeg
 
Hello from Germany!

Read your posts with Interest.
I have three pairs of VLD13. Two pairs "genuine" Jordanows and one pair Gamma.
I use them in several applications with success.
At this time they work together with Fostex fs21rp and two Jordan JX125 in 4 way active system giving a "fast" and clean sound.
In another application they run together with Markaudio CHR70 Gen3 in a 3,5 meters long basshorn.
Soundwise i would put the VLDs between Technics TH800 and TH1000 which i also own. A little less resolution than TH1000 but with wider frequency range than the both of the others. And what i like personally the most is: The VLDs are nearly unbreakable. If the ribbon breaks you make a new one for no money. Try this with the Technics ;-)

Together with the Fostex fs21rp i cross them at 4500Hz. With the Markaudios i cross them at 3500hz.
In both applications i dont use the horn for the VLD because i hear colorations in sound. In near future the horn will be needed because i bought four Dayton RS225 for the bass instead of the Jordan JX125 and i will use a Bandor 150 for lower mids. Then i will need every db i can get from the VLD. So i will begin with dampening the horn from the outside to get rid of most of the coloration.
I also thought of making a new horn out of Paper.

I use normal household foil for the ribbons. Sounds absolutely good but here or there are problems with a little hissing when playing louder.
Do you have a hint for me which caps use the right foil?
If the foil is too thin it looses efficiency.
 
speedgeil said:
Hello from Germany!

Read your posts with Interest.
I have three pairs of VLD13. Two pairs "genuine" Jordanows and one pair Gamma.
I use them in several applications with success.
At this time they work together with Fostex fs21rp and two Jordan JX125 in 4 way active system giving a "fast" and clean sound.
In another application they run together with Markaudio CHR70 Gen3 in a 3,5 meters long basshorn.
Soundwise i would put the VLDs between Technics TH800 and TH1000 which i also own. A little less resolution than TH1000 but with wider frequency range than the both of the others. And what i like personally the most is: The VLDs are nearly unbreakable. If the ribbon breaks you make a new one for no money. Try this with the Technics ;-)

Together with the Fostex fs21rp i cross them at 4500Hz. With the Markaudios i cross them at 3500hz.
In both applications i dont use the horn for the VLD because i hear colorations in sound. In near future the horn will be needed because i bought four Dayton RS225 for the bass instead of the Jordan JX125 and i will use a Bandor 150 for lower mids. Then i will need every db i can get from the VLD. So i will begin with dampening the horn from the outside to get rid of most of the coloration.
I also thought of making a new horn out of Paper.

I use normal household foil for the ribbons. Sounds absolutely good but here or there are problems with a little hissing when playing louder.
Do you have a hint for me which caps use the right foil?
If the foil is too thin it looses efficiency.
Click to expand...

Sorry I missed your post, welcome to AK, and thanks for sharing your experiences.

You really need to try some thinner foil, household foil sounds OK, but thin capacitor foil is much better.
If you compared the VLD's to those Technics tweeters, with household foil in the VLD's, well, then the VLD's will easily beat the Technics, if it got nice foil.

http://hd-audio.orpheusweb.co.uk/home.html sells prefabricated ribbons for VLD's if in case you can't find a suitable capacitor.

I recently found that it's good if the ribbons is quite taut, it reduces sizzle.

Also, if your VLD-12's was poorly assembled (about half of them are) you can rearrange the innards.
Take off the horn, and remove the ribbon, put the rest on a toaster, once the wax inside is molten, you can move everything around, or even swap components between units.
It is also easy to install a different transformer, if you should so desire, maybe Howard Dawson Audio knows how to make those.

Lastly, I just removed the dust caps from my BK3013A's, it definitely improved performance in the upper midrange, I'm closing in on being able to play these as loud as my old GAMMA 50's.

I think I still need to fix a slight but wide hump in the 2000-2600Hz range if I can.

I have decided to give GAMMA woofers another chance, phase plugs are the next step.

7758f522_AUT_7901.jpeg
 
Last edited:
So I have stuffed the bass relfex ports, to see how the BK3013A's do in a sealed box.
And they do fine, yet again (as with most other mods I have done) the upper midrange improved quite a bit, the speaker sounds more controlled and balanced.

Bass response i lacking though, it's fine down to 60Hz, which makes sense as WinISD tells me the same, using user user supplied T/S data for the AlNiCo LA1231.

However, specs for LA1231's seem to vary a lot depending on where you look, hifikit.se, Vissokogovoruteli and the guy from diyaudio who measured some, very quite a bit.
The "official" specs for BK3013A's and LA1231 haven't changed all that much over time though.

Anyway, I typed all the different LA1231 specs in to WinISD and tested, and well, using the "official" specs, yielded very nice bass response in a sealed box.
The user supplied specs yield what I hear from my speakers currently.

So my conclusion is that what I hear now is the worst case scenario, and that I will most likely get significantly better bass response using a new LA1231 vs. the older then me BK3013A.
It seems the magnets are indeed compatible between the two, so I'll try switching those over if/when I get LA1231's.
I'll see if it's possible to get some without a dust cap, so they are ready for phase plugs.
Also, I'm thinking about dampening the driver basket with felt.
Removing the barrel from the back of the woofer eliminated a cavity and increases box volume, but might reduce power handling, I use them without.

Lastly, I'm thinking of trying an Aperiodic box design, using metal mesh and coffee filters as a flow resistor.
Not sure if I'll take this route, I'm getting conflicting info from different sources.
Some say it reduces bass response, but reduces the impedance peak at resonance.
Some say it makes the box act as if it where bigger, as much as 20%, and reduces the impedance peak, giving more bass.

Does anyone here know anything about this?
Some say that increasing the Ql value in WinISD gives an idea of what a flow resistor does, it seems to extend bass response a little.

I think I'll go for a sealed box, I'll increase my box volume to 60 liters, add a lot of stuffing, to get the effective volume up around 80 liters.
And put new LA1231's without barrels and dustcaps, dampened with felt, and phaseplugs in there.

Should be fine, with f3 between 45 and 60Hz depending on what specs LA1231's actually have.
 
Oh forgot to mention, I hope to use the modded LA1231's without any crossover, if I can make them roll off in a smooth pattern, seems quite feasible.
 
Ok, I have supressed the hump between 2 and 2.4Khz, but got a small dip in the 1,6 - 2Khz region.

What I did was replace the 4.7uF camp in the high pass filter, with 2,2 and 1,5 uF caps in parallel for a total value of 3.7uF.

More testing is needed, I have to see what happens if I put a 3,3uF cap there in stead, to check if I should go fro a 3.9uF or 3.3uF next time I get caps.

Also, I should try a smaller coil in the high pass filter.

So the options I'm considering are:

Get a set of 3,3uF or 3,9uF caps, maybe a smaller coil (will be higher DCR though).

Or get two 3,3uF caps, and a 0,25mH (again higher DCR) coil and make the standard Audioscan 3.5Khz filter and adjust the lowpass filter to fit that.

Or I could just get 3,3uF caps, and mess with the lowpass filter again.

More thinking, first I should try moving that 3,3uF though.

Edit: I could also leave it as it is now, and put a smaller coil in the lowpass filter and see what happens.
 
Last edited:
If I put a cap with a value between 3.7 and 4.7uF in the highpass filter, in place of the 4.7uF cap, I should average out the situation, maybe getting a insignificant hump from 2-2.4Khz and a the same for the current dip in the 1.6-2Khz region.

Hmm, worth a try, I think I have the parts I need, at least for one speaker.
 
But then, the current situation is really good, the dip is very slight, I should go for 3,9uF caps and be done with it, I'm enjoying my speakers tremendously these days.
 
I got the 3.9uF caps and installed them, the result is exactly what I was looking for, the dip is all but gone, and the 2-3Khz region sounds smooth (tone sweep)

When playing music, it changes the voicing slightly, it's hard to explain.

So how do the GAMMA 30's sound at this time?

Smooth, flat and detailed with plenty of air but bass extension could be better.

I can now say that there are no problems with using the right 12" woofer as a midbass all the way through the midrange, just make sure to remove the dustcap and use a sealed or aperiodic box, open baffle should be great too.
 
I forgot to add that, I have barely been using my K240DF's lately, not for days untill last night.

When I put them on I expected what I usually expect in this situation, being taken away by the DF's great clarity.
But not this time, the GAMMA 30's do better in this regard, with a more natural presentation to boot.
 
Just put on the "Blade Runner" soundtrack for some quiet late night listening.

Damn this sounds good, so smooth, shiny and rich, these speakers are better then I had hoped for, I thought the 12" woofers would be a compromise, but not at all.

In listening position, the woofer and ribbon integrate seamlessly, this changes when listening at an angle though.
At an angle there is a noticeable disconnect between the drivers, and the 1500-2500Hz range gets suppressed a little.
This gives them a quite unoffensive and forgiving sound when heard at an angle, not bad for background music.
There will always be problems with speakers when heard at an angle, at the very least, you'll get stereo problems, so it doesn't bother me.
 
A few pics of what the good people of Bulgaria are doing.

This one was quite nice to find, someone else had thought of phase plugging the woofers, and gone ahead and done it.
It seems he gave the cone some coating around the voice coil, probably to increase the moving mass to compensate for the dust cap.
Might reduce breakup too, who knows.
100 liter sealed box.

Picture_218.jpg


This one seems to be based on a DIY kit sold in Bulgaria at some point in time.
Compact aperiodic box, no woofer mods.

IM0008981.jpg
 
You must log in or register to reply here.
Back
Top Bottom