GAMMA 30 experiement
- Thread starter Adda
- Start date
Adda
Super Member
Yeah if done correctly, the VLD's really do like 3rd order filters.
So why the sudden change of tactics? I'm adding caps to my filter whats going on?
Well I still have less capacitance in my entire signal path then I did about a week ago.
I have increased the size of the output coupling caps in my Atoll DAC 100 from 2.2uF to 4.7uF, for better bass performance, as it is hooked up to a 10kohm input.
The Aragon 18k didn't need it's 10uF input coupling cap, since the Atoll has one on the output, so I bypassed it with a piece of wire.
The Perreaux E2 had a 3.3uF cap on the input, but it's input impedance is 47kohm, so 1.5uF is fine, so that's what I put in there in stead.
So I reduced the capacitance in my signal path by about half (incl. cap on the tweeter with 2nd order), so adding another 6.8uF isn't a problem.
So why the sudden change of tactics? I'm adding caps to my filter whats going on?
Well I still have less capacitance in my entire signal path then I did about a week ago.
I have increased the size of the output coupling caps in my Atoll DAC 100 from 2.2uF to 4.7uF, for better bass performance, as it is hooked up to a 10kohm input.
The Aragon 18k didn't need it's 10uF input coupling cap, since the Atoll has one on the output, so I bypassed it with a piece of wire.
The Perreaux E2 had a 3.3uF cap on the input, but it's input impedance is 47kohm, so 1.5uF is fine, so that's what I put in there in stead.
So I reduced the capacitance in my signal path by about half (incl. cap on the tweeter with 2nd order), so adding another 6.8uF isn't a problem.
Adda
Super Member
Disaster strikes, the peak I mentioned earlier, is centered around 7.8KHz, and is caused by the tweeters alone.
I set out to solve the problem, I checked all my (8) VLD's for the best parts, melted the wax to get the parts out, everything going well.
I saw that most of the transformers had started rusting, but I found two in a good state.
I had my VLD-13 style magnets out and ready to start assembling again.
SMACK!!!!
One of the VLD-13 type magnets collapsed, the pole plates had overcome the glue that holds the cast iron frame together, and no force in my possession will separate them again.
Thinking about what I had done before that point made me realize I had been both lucky and well had some bad luck too.
I had been taking stuffing out from between those magnets a few minutes earlier.
Had the magnets collapsed at that point, I might have lost my fingers!!!
Also, now I only have two VLD-12 left that are 100% functional and in excellent condition (VLD-12 type magnets, barely any surface corrosion on one of them).
I put extra stuffing in them so they are totally filled with the stuff, no empty cavities.
I have two others where the magnets are not perfectly parallel.
One with a collapsed magnet (VLD-13 style) :tears:, one with a weak magnet.
I have one perfectly good VLD-13 style magnet (still a VLD-12 but the lines are blurred between VLD-12/13/40), a chassis and transformer for it, I could assemble a good unit from this.
But the last one is a typical VLD-12 (holes in magnets) with a grimly transformer.
Will have to get another pair of VLD's of the same type, preferably VLD-13/40.
I also need some ribbon foil from Howard Dawson, the extra stuffing did nothing to remove the peak.
I can reduce it a lot of tightening the ribbon, but the peak comes back within hours.
If used as a super tweeter, my home made ribbons would probably be fine.
Edit: I think I nailed the crossover though, the 3rd order one (mkV) I posted above is really good!
I set out to solve the problem, I checked all my (8) VLD's for the best parts, melted the wax to get the parts out, everything going well.
I saw that most of the transformers had started rusting, but I found two in a good state.
I had my VLD-13 style magnets out and ready to start assembling again.
SMACK!!!!
One of the VLD-13 type magnets collapsed, the pole plates had overcome the glue that holds the cast iron frame together, and no force in my possession will separate them again.
Thinking about what I had done before that point made me realize I had been both lucky and well had some bad luck too.
I had been taking stuffing out from between those magnets a few minutes earlier.
Had the magnets collapsed at that point, I might have lost my fingers!!!
Also, now I only have two VLD-12 left that are 100% functional and in excellent condition (VLD-12 type magnets, barely any surface corrosion on one of them).
I put extra stuffing in them so they are totally filled with the stuff, no empty cavities.
I have two others where the magnets are not perfectly parallel.
One with a collapsed magnet (VLD-13 style) :tears:, one with a weak magnet.
I have one perfectly good VLD-13 style magnet (still a VLD-12 but the lines are blurred between VLD-12/13/40), a chassis and transformer for it, I could assemble a good unit from this.
But the last one is a typical VLD-12 (holes in magnets) with a grimly transformer.
Will have to get another pair of VLD's of the same type, preferably VLD-13/40.
I also need some ribbon foil from Howard Dawson, the extra stuffing did nothing to remove the peak.
I can reduce it a lot of tightening the ribbon, but the peak comes back within hours.
If used as a super tweeter, my home made ribbons would probably be fine.
Edit: I think I nailed the crossover though, the 3rd order one (mkV) I posted above is really good!
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Adda
Super Member
A picture of VLD-13 internals, probably applies to VLD-40 too.
This one looks grimly though, and the ribbon has scorched the fabric mesh beneath it.
Thread of origin:
https://bgaudioclub.org/showthread.php?12975-Информация-за-български-колонки
This one looks grimly though, and the ribbon has scorched the fabric mesh beneath it.
Thread of origin:
https://bgaudioclub.org/showthread.php?12975-Информация-за-български-колонки
Adda
Super Member
Ok, this thread will be slowing down compared to the pace it has been at since the 17th-18th of December.
I have finally managed to have something other then speakers on my mind!!!
Gotta' take this opportunity to do something else and sleep too, I don't even find music interesting these days.
No wonder, I have spent most of my waking hours listening to music, while tweaking my speakers, during the last couple of months.
I do have an update though, I'll be getting a pair of used VLD-40 tweeters, probably around the end of the month.
I think the 1.5uF cap I put in the Perreaux E2 has caused a reduction in bass, not sure why, it should be fine, but I probably missed something.
Swapping that cap didn't make much of a difference in sound anyway, the original cap must have been very good.
I will be putting the original 3.3uF back in there, once I pull my self together (!).
Oh well, the next update will probably be a pictures of a VLD-40's.
I have finally managed to have something other then speakers on my mind!!!
Gotta' take this opportunity to do something else and sleep too, I don't even find music interesting these days.
No wonder, I have spent most of my waking hours listening to music, while tweaking my speakers, during the last couple of months.
I do have an update though, I'll be getting a pair of used VLD-40 tweeters, probably around the end of the month.
I think the 1.5uF cap I put in the Perreaux E2 has caused a reduction in bass, not sure why, it should be fine, but I probably missed something.
Swapping that cap didn't make much of a difference in sound anyway, the original cap must have been very good.
I will be putting the original 3.3uF back in there, once I pull my self together (!).
Oh well, the next update will probably be a pictures of a VLD-40's.
Adda
Super Member
Just received my VLD-40's, and they look as trashy as any other VLD I have seen.
They need a bit of fixing up too, the ribbons are damaged and the terminals have come loose, I need to find replacement terminals or fix them somehow.
But as usual, we have plenty of deep scratches under the paint, the paint job is terrible, so is the quality of the cast.
But how do they differ form VLD-12's?
Well, they have a mounting mechanism for the ribbons, almost identical to the picture above, but as usual there are so many variations in the design of these things, you'd think they made them one at the time in separate factories.
They are all black.
But more interestingly, there is rubber lining around the bottom of the horn, framing the ribbon and funneling the sound out through the horn.
There is also felt like paper sandwiched between the horn and body of the tweeters.
VLD-12 owners might want update their VLD's with those modifications.
They need a bit of fixing up too, the ribbons are damaged and the terminals have come loose, I need to find replacement terminals or fix them somehow.
But as usual, we have plenty of deep scratches under the paint, the paint job is terrible, so is the quality of the cast.
But how do they differ form VLD-12's?
Well, they have a mounting mechanism for the ribbons, almost identical to the picture above, but as usual there are so many variations in the design of these things, you'd think they made them one at the time in separate factories.
They are all black.
But more interestingly, there is rubber lining around the bottom of the horn, framing the ribbon and funneling the sound out through the horn.
There is also felt like paper sandwiched between the horn and body of the tweeters.
VLD-12 owners might want update their VLD's with those modifications.
Adda
Super Member
It seems I need my old VLD-13 magnets, as one of the VLD-40's has a ruined magnet assembly (magnets not glued to cast iron frame).
The other one seems fine, just put ribbons in it and sound comes out, luckily this unit seems flawless.
The broken one will have to go on the toaster.
The other one seems fine, just put ribbons in it and sound comes out, luckily this unit seems flawless.
The broken one will have to go on the toaster.
Adda
Super Member
Huh what do you know, the two metal plates you see in the pic above, also shown in the pic below, that frames the ribbons (when one is mounted).
Those are not the magnets, the big huge thing below, that I thought was iron, that is the magnet!
The pole plates are barely magnetized.
Those are not the magnets, the big huge thing below, that I thought was iron, that is the magnet!
The pole plates are barely magnetized.
Adda
Super Member
I'm thinking that the best course of action may be to devise a pair of VLD's with external transformers, that uses the ribbon mounting mechanism form the VLD-40's.
It would be easy to assemble, and all the complications that arise from having built in transformers, would be eliminated.
I could swap transformer quickly and easily.
It would be easy to assemble, and all the complications that arise from having built in transformers, would be eliminated.
I could swap transformer quickly and easily.
Adda
Super Member
A picture of a VLD-40 ribbon and transformer assembly:
I would solder wires to the plates that sandwich the transformer flatwires and holds the screws holding the ribbon in place, I'd thread those wires out of the chassis and in to a transformer (after removing the transformer obviously).
Edit: on the other hand, to get a pair of magnets that look similar, I have to disassemble my two main VLD-12's, I don't want to do that.
I would solder wires to the plates that sandwich the transformer flatwires and holds the screws holding the ribbon in place, I'd thread those wires out of the chassis and in to a transformer (after removing the transformer obviously).
Edit: on the other hand, to get a pair of magnets that look similar, I have to disassemble my two main VLD-12's, I don't want to do that.
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Adda
Super Member
I think I have made a decision (at least a temporary one).
I have messed around with VLD ribbons a lot, my findings are that the quality is so poor that getting a good pair is a lottery.
I have a good pair of VLD-12's and I should keep using those until the PCB's are so grimly (it's close to that already) that I want them replaced.
When the time comes I'll replace the PCB's with parts from the VLD-40's and make the transformers external.
What's more interesting is that messing around with VLD's teaches you how to make a ribbon tweeter (VLD ribbons got Raven, Transmission Audio and Expolinear started), it is so simple so basic that you could train monkeys to do it.
The only problem is getting the right parts, proper magnets are expensive.
But I think I'll do it sometime, why not? I know pretty much exactly how I'd do it, and what I could do to voice them.
Yeah it's better to put my money towards home built ribbon tweeters, then play the lottery of VLD's or to pay quite a lot to buy new ones from Sweden (they cost almost four times as much as used ones (if I could get Bulgarian prices I would not hesitate I'd buy four on the spot).
I can use the transformers from VLD ribbons for my home made ones, or use Howard Dawson transformers, or make some my self, seems easy enough if you can make the required measurements, and have the parts.
I have messed around with VLD ribbons a lot, my findings are that the quality is so poor that getting a good pair is a lottery.
I have a good pair of VLD-12's and I should keep using those until the PCB's are so grimly (it's close to that already) that I want them replaced.
When the time comes I'll replace the PCB's with parts from the VLD-40's and make the transformers external.
What's more interesting is that messing around with VLD's teaches you how to make a ribbon tweeter (VLD ribbons got Raven, Transmission Audio and Expolinear started), it is so simple so basic that you could train monkeys to do it.
The only problem is getting the right parts, proper magnets are expensive.
But I think I'll do it sometime, why not? I know pretty much exactly how I'd do it, and what I could do to voice them.
Yeah it's better to put my money towards home built ribbon tweeters, then play the lottery of VLD's or to pay quite a lot to buy new ones from Sweden (they cost almost four times as much as used ones (if I could get Bulgarian prices I would not hesitate I'd buy four on the spot).
I can use the transformers from VLD ribbons for my home made ones, or use Howard Dawson transformers, or make some my self, seems easy enough if you can make the required measurements, and have the parts.
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Adda
Super Member
I have been doing even more thinking, and laid down some longer term plans.
Of cause I need to have my speaker boxes fixed up, it is way overdue and desparately needed, I also need a new pair of GAMMA woofers.
But what I really want to do is build a new magnet assembly for my VLD's.
The trail of thought that lies behind what I'll be doing is:
The primary problem with ribbons is the extremely low impedance, so either you need to put a transformer on them, or sacrifice a lot of efficiency and put a resistor on them (well unless you are transmission audio).
What can we do to improve that situation? the answer may be HORNS and Neodymium magnets.
I don't think a Neodymium equipped and horn loaded ribbon tweeter even exists, so why not make one?
Short ribbons with Neodymium magnets and transformers, tend to achieve an efficiency in the 90-94dB/w range, the radial horn from VLD's increase efficiency by another 5-6dB.
So using horns, it should be possible to make a ribbon tweeter with an efficiency in the 95-100dB/w range, if a transformer is used.
I only need an efficiency of 91-93db/w, so removing the transformer, and putting a resistor on them in stead, may end up being a viable option.
If I could make a VERY powerful Neodymium magnet assembly, that is compatible with the VLD chassis... :drool:
The making of this magnet will be quite a challenge, the magnets I need are so powerful that they can easily be considered hazardous materials.
Imagine having to glue several extremely powerful Neodymium magnets together in a "horseshoe" shaped assembly.
I need extremely strong glue, I need frames and "ramps" so that I can slide the magnets in to place, and keep them in place while the glue dries.
I have to be very careful, these magnets will be so strong that pulling them apart after they have come in to contact with one another, maybe be impossible.
If two magnets, or even two glued together clusters of magnets, come too close to each other, they will be sent flying through the air and slam together with enough force to shatter the magnets or even crush your fingers if they happen to be in the way.
I also need learn about simulating magnets, so that I can make an optimized topology, with the parts I have at my disposal.
I can't get Neodymium magnets "made to measure" I have to make due with what is available.
But the goal is to make a fairly efficient, horn loaded, true ribbon tweeter with Neodymium magnets and no transformer.
If I can't attain high enough efficiency, I'll have to find an amp that can drive very low impedance loads, so that I can get away with a smaller resistor on the ribbons, or go completely without a resistor.
This is my dream project, and I can't wait to get started, but it'll be a while.
I need to fix up my boxes and stuff, I really need a fully functional LF system to use with my ribbons.
It'll most likely end up being a GAMMA LA1231 (maybe a 4 ohm one not sure yet, but certainly a LA1231) in a 50-60 liter aperiodic box (nothing fancy, just a basic one).
I'll do a few mods to the LA1231's, I'll remove the dustcap and phaseplug them, like my BK3013A's.
I also want to dampen the basket with felt, and maybe add a thin coating around the middle of the speaker cone, as seen on one of the Bulgarian projects I showed earlier in this thread.
Of cause I need to have my speaker boxes fixed up, it is way overdue and desparately needed, I also need a new pair of GAMMA woofers.
But what I really want to do is build a new magnet assembly for my VLD's.
The trail of thought that lies behind what I'll be doing is:
The primary problem with ribbons is the extremely low impedance, so either you need to put a transformer on them, or sacrifice a lot of efficiency and put a resistor on them (well unless you are transmission audio).
What can we do to improve that situation? the answer may be HORNS and Neodymium magnets.
I don't think a Neodymium equipped and horn loaded ribbon tweeter even exists, so why not make one?
Short ribbons with Neodymium magnets and transformers, tend to achieve an efficiency in the 90-94dB/w range, the radial horn from VLD's increase efficiency by another 5-6dB.
So using horns, it should be possible to make a ribbon tweeter with an efficiency in the 95-100dB/w range, if a transformer is used.
I only need an efficiency of 91-93db/w, so removing the transformer, and putting a resistor on them in stead, may end up being a viable option.
If I could make a VERY powerful Neodymium magnet assembly, that is compatible with the VLD chassis... :drool:
The making of this magnet will be quite a challenge, the magnets I need are so powerful that they can easily be considered hazardous materials.
Imagine having to glue several extremely powerful Neodymium magnets together in a "horseshoe" shaped assembly.
I need extremely strong glue, I need frames and "ramps" so that I can slide the magnets in to place, and keep them in place while the glue dries.
I have to be very careful, these magnets will be so strong that pulling them apart after they have come in to contact with one another, maybe be impossible.
If two magnets, or even two glued together clusters of magnets, come too close to each other, they will be sent flying through the air and slam together with enough force to shatter the magnets or even crush your fingers if they happen to be in the way.
I also need learn about simulating magnets, so that I can make an optimized topology, with the parts I have at my disposal.
I can't get Neodymium magnets "made to measure" I have to make due with what is available.
But the goal is to make a fairly efficient, horn loaded, true ribbon tweeter with Neodymium magnets and no transformer.
If I can't attain high enough efficiency, I'll have to find an amp that can drive very low impedance loads, so that I can get away with a smaller resistor on the ribbons, or go completely without a resistor.
This is my dream project, and I can't wait to get started, but it'll be a while.
I need to fix up my boxes and stuff, I really need a fully functional LF system to use with my ribbons.
It'll most likely end up being a GAMMA LA1231 (maybe a 4 ohm one not sure yet, but certainly a LA1231) in a 50-60 liter aperiodic box (nothing fancy, just a basic one).
I'll do a few mods to the LA1231's, I'll remove the dustcap and phaseplug them, like my BK3013A's.
I also want to dampen the basket with felt, and maybe add a thin coating around the middle of the speaker cone, as seen on one of the Bulgarian projects I showed earlier in this thread.
Adda
Super Member
Here is where am at at this time, the ugliest testbed.
I have designated the baffle design the "boobaffle" for obvious reasons.
One of the speakers is very leaky as I have mentioned before, that speaker produces little bass below 100Hz, the other one is fine down to ~65Hz.
The not-so-leaky speaker is probably sort of kind of what I can expect from an aperiodic design, and I like it a lot, but I need more bass.
The positioning of the speakers and the room is all wrong here, everything has just been thrown in, I just moved and there is a lot to do (terrible floor, terrible walls, windows and a very wide radiator just outside the pic, to the right).
I have designated the baffle design the "boobaffle" for obvious reasons.
One of the speakers is very leaky as I have mentioned before, that speaker produces little bass below 100Hz, the other one is fine down to ~65Hz.
The not-so-leaky speaker is probably sort of kind of what I can expect from an aperiodic design, and I like it a lot, but I need more bass.
The positioning of the speakers and the room is all wrong here, everything has just been thrown in, I just moved and there is a lot to do (terrible floor, terrible walls, windows and a very wide radiator just outside the pic, to the right).
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