CJ
Well-known member
The HA-100X has four metal tubes that are welded inside the can. They are partially treaded for # 4 screws ata each end to allow for different mounting options.
All things LA2a related
- Thread starter Scenaria
- Start date
Help Support GroupDIY Audio Forum:
EmoRiot - I know about the Sifam but the Surplus Sales site is handy. Maybe some good meters there for the SSL compressor as well. Thanks.
But I still have no clue on VU meters ?
Besides the Sifam ones can we get one of those Weston vintage ones that pop up on eBay from time to time?
If they are not exactly the same as Sifam will they function as replacement or will we have to adjust something like a resistor value?
I know how to select resistors, capacitors and most components but am totally ignorant when it comes to selecting the correct meter (besides the Sifam one)
Jim
But I still have no clue on VU meters ?
Besides the Sifam ones can we get one of those Weston vintage ones that pop up on eBay from time to time?
If they are not exactly the same as Sifam will they function as replacement or will we have to adjust something like a resistor value?
I know how to select resistors, capacitors and most components but am totally ignorant when it comes to selecting the correct meter (besides the Sifam one)
Jim
EmoRiot
Active member
Bluzzi,
I'm going to try a new strategy in getting someone who actually knows the answer to respond. I'll give you completely wrong information and hopefully someone will correct us. :wink:
:wink: :wink: :wink: Uh... yeah, I think you can put any meter in there! In fact, a little known trick is that if you wire the meter directly to the incoming AC current, you'll get a better read on the meter. There's 3 resistors that need to go sequentially after the meter, but they can be absolutely any value of resistor made! If you can't afford a meter, a classic trick that was even used in the revision 3 of the LA2a was to attach a rubber band to a paper clip and wrap it around a deck of cards. That will meter correctly too! But you have to find the right tension of rubber band. That's the only trick with that one. :wink: :wink: :wink:
What do you say guys? Anyone want to step in and correct us before we're hooking rubber bands up to our AC current?
Bluzzi just wants to know if he can use any vanilla variety of VU meter? Help! :shock: :?: :?:
I'm going to try a new strategy in getting someone who actually knows the answer to respond. I'll give you completely wrong information and hopefully someone will correct us. :wink:
:wink: :wink: :wink: Uh... yeah, I think you can put any meter in there! In fact, a little known trick is that if you wire the meter directly to the incoming AC current, you'll get a better read on the meter. There's 3 resistors that need to go sequentially after the meter, but they can be absolutely any value of resistor made! If you can't afford a meter, a classic trick that was even used in the revision 3 of the LA2a was to attach a rubber band to a paper clip and wrap it around a deck of cards. That will meter correctly too! But you have to find the right tension of rubber band. That's the only trick with that one. :wink: :wink: :wink:
What do you say guys? Anyone want to step in and correct us before we're hooking rubber bands up to our AC current?
Bluzzi just wants to know if he can use any vanilla variety of VU meter? Help! :shock: :?: :?:
EmoRiot - Don't worry about it. The guys here are very helpful and generous with their time and knowledge. Its a big forum and they don't necessarily see or have time to answer all questions. Sometimes I think they want guys like me (more assemblers than electronics engineers or gurus) to learn some things on their own. Its not a bad idea to seek some info by ourselves in books etc. I know a little about electronics but not enough to make decisions on design (especially on a classic design such as the LA2A).
I'll ask my tech resident electronics genius. I just thought some that have built the LA2A clone using an alternate meter would know.
I'll call him tomorrow and get back here with an answer hopefully.
Jim
I'll ask my tech resident electronics genius. I just thought some that have built the LA2A clone using an alternate meter would know.
I'll call him tomorrow and get back here with an answer hopefully.
Jim
EmoRiot
Active member
Definitely,
The guys on this board are the coolest and most selfless/giving people I've seen in the audio biz. :thumb: The amount of hours spent by some to make sure that everyone's coming along well in their projects and that the DIY community, as a whole, is progressing in collective knowledge is really mind boggling. My humor definitely wasn't driven by an ungrateful expectation to get free help from geniuses.
I think you're right. We'll take this as a challenge to learn on our own. I've bought a couple of books on electronics so that I can finally start learning not just the "how" of building stuff... but the "why."
If you figure it out, let us know what you come up with.
The guys on this board are the coolest and most selfless/giving people I've seen in the audio biz. :thumb: The amount of hours spent by some to make sure that everyone's coming along well in their projects and that the DIY community, as a whole, is progressing in collective knowledge is really mind boggling. My humor definitely wasn't driven by an ungrateful expectation to get free help from geniuses.
I think you're right. We'll take this as a challenge to learn on our own. I've bought a couple of books on electronics so that I can finally start learning not just the "how" of building stuff... but the "why."
If you figure it out, let us know what you come up with.
> Anyone want to step in and correct us before we're hooking rubber bands up to our AC current?
It will be a lot more exciting to stick the paper-clip in the wall output.
Kids, don't try this at home!!! Go to the neighbors house and try it.
> no clue on VU meters?
All true-VU meters are interchangable. It is a Standard, as far as electric and dynamic response goes. Mundane non-audio details, like mounting and lighting, are at the maker's discretion, because they don't matter to the audio function.
But there are a lot of fake VU meters. From 1938 through the 1970s, anything that looks like a VU probably is. But a lot of cheap recorders appeared in the 1970s: VU-like meters from old Akai and Sony consumer recorders won't be true-VU, and may be very un-VU, needing extra drive power and having odd dynamics.
> can we get one of those Weston vintage ones that pop up on eBay from time to time?
Weston made a lot of true VU; I think the Standard is based on a Weston design.
But before 1938 there were other Standards. I have a lovely pair of pre-1938 Weston audio meters with internal rectifiers and scales like a VU, but much slower and calibrated to different level. I was in the right place at the right time: it is unlikely you will find anything like that.
> will they function as replacement or will we have to adjust something like a resistor value?
When you hang a VU meter across an audio circuit, it really needs to be very much like a VU meter. Lesser meters will load and distort the signal. The rise of fake-VU in the 1970s is because buffer amps became cheaper than good meters: they could use a lame meter and buffer it off the audio path.
Also a true-VU always has an internal rectifier. When you hook it to an audio output, it gives a reading related to signal. But a basic meter is DC-only: on audio it just waggles a little on bass-hits, does not read level. The true-VU rectifier is specialized: in the 1970s it became cheaper to use generic rectifiers in the buffer-amp on the PCB, and use a common DC meter.
The Sifam is almost certainly fake-VU, but apparently close enough that it can be used in place of a true-VU without recalibration. The dynamics would not fool an old VU-watcher like me, but you are not using it as your main system level indicator.
It will be a lot more exciting to stick the paper-clip in the wall output.
Kids, don't try this at home!!! Go to the neighbors house and try it.
> no clue on VU meters?
All true-VU meters are interchangable. It is a Standard, as far as electric and dynamic response goes. Mundane non-audio details, like mounting and lighting, are at the maker's discretion, because they don't matter to the audio function.
But there are a lot of fake VU meters. From 1938 through the 1970s, anything that looks like a VU probably is. But a lot of cheap recorders appeared in the 1970s: VU-like meters from old Akai and Sony consumer recorders won't be true-VU, and may be very un-VU, needing extra drive power and having odd dynamics.
> can we get one of those Weston vintage ones that pop up on eBay from time to time?
Weston made a lot of true VU; I think the Standard is based on a Weston design.
But before 1938 there were other Standards. I have a lovely pair of pre-1938 Weston audio meters with internal rectifiers and scales like a VU, but much slower and calibrated to different level. I was in the right place at the right time: it is unlikely you will find anything like that.
> will they function as replacement or will we have to adjust something like a resistor value?
When you hang a VU meter across an audio circuit, it really needs to be very much like a VU meter. Lesser meters will load and distort the signal. The rise of fake-VU in the 1970s is because buffer amps became cheaper than good meters: they could use a lame meter and buffer it off the audio path.
Also a true-VU always has an internal rectifier. When you hook it to an audio output, it gives a reading related to signal. But a basic meter is DC-only: on audio it just waggles a little on bass-hits, does not read level. The true-VU rectifier is specialized: in the 1970s it became cheaper to use generic rectifiers in the buffer-amp on the PCB, and use a common DC meter.
The Sifam is almost certainly fake-VU, but apparently close enough that it can be used in place of a true-VU without recalibration. The dynamics would not fool an old VU-watcher like me, but you are not using it as your main system level indicator.
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PRR - Thanks for the clear explanation on VU meters. I am expecting a few from eBay soon. Is there a way to test if they are good?Can I just use a line level to drive thm directly or could that damage the coil? From what you said it would seem that they can take line level.
Jim (next I get two T4B)
Jim (next I get two T4B)
CJ
Well-known member
The old vu's are like a swiss watch. Took one apart the other day. Copper oxide diodes are spring loaded in a tube. Little round pellets. Pretty weird.
Thanks for the Weston tip. I've got 6 Weston's coming from eBay! I think I have enough for now!
I'll be ordering 2 T4B next.
On another note.....
I just bumped into a friend of mine that makes signs etc. Well I asked her about engraving and although she doesn't do that what she does do that may be something to look into is this.
She has a computerized plotter/Cutter that will do up to 24 inch wide and any length precise cutting of adhesive backed vinyl. So the letters get cutout and anything underneath then shows through. This vinyl comes in any colour.
So I thought I could do 2 things.
One is to do a sheet with all the lettering cutout so that the metal colour comes through for the letters. Of course one could also paint those areas.
Juat stick the sheet to the faceplate.
The other is what she suggested. Stick the sheet to a plexiglass sheet that is then held to the faceplate by the switches and pots and mounting screws ( the exact same cutout for the faceplate but in plexiglass. This would protect the vinyl and faceplate from eventual scratches.
If I decide to do this I'll advise if its worth it. Up to today I wasn't going to do anything but anodyse the faceplate (and only because its free).
Jim
I'll be ordering 2 T4B next.
On another note.....
I just bumped into a friend of mine that makes signs etc. Well I asked her about engraving and although she doesn't do that what she does do that may be something to look into is this.
She has a computerized plotter/Cutter that will do up to 24 inch wide and any length precise cutting of adhesive backed vinyl. So the letters get cutout and anything underneath then shows through. This vinyl comes in any colour.
So I thought I could do 2 things.
One is to do a sheet with all the lettering cutout so that the metal colour comes through for the letters. Of course one could also paint those areas.
Juat stick the sheet to the faceplate.
The other is what she suggested. Stick the sheet to a plexiglass sheet that is then held to the faceplate by the switches and pots and mounting screws ( the exact same cutout for the faceplate but in plexiglass. This would protect the vinyl and faceplate from eventual scratches.
If I decide to do this I'll advise if its worth it. Up to today I wasn't going to do anything but anodyse the faceplate (and only because its free).
Jim
QNote
Active member
Hi all!
[In the middle of the Bloo kit project...]
Which pots are ya'll using for this project (Mouser/DigiKey part numbers would be nice). The log types in the needed values appear to be rare. I rather not purchase "cheap" ones, unless that is what everyone is going with.
I have some of the older Allen-Bradley pots, but they appear to act a little "dirty"--rather not use them.
[In the middle of the Bloo kit project...]
Which pots are ya'll using for this project (Mouser/DigiKey part numbers would be nice). The log types in the needed values appear to be rare. I rather not purchase "cheap" ones, unless that is what everyone is going with.
I have some of the older Allen-Bradley pots, but they appear to act a little "dirty"--rather not use them.
EmoRiot
Active member
::Which pots are ya'll using for this project::
I was wondering about the Precision Electronic pots used in the UA reissue. They're 10% tolerance, instead of the Allen-Bradley's 20%, but I don't know if this makes a difference.
I was wondering about the Precision Electronic pots used in the UA reissue. They're 10% tolerance, instead of the Allen-Bradley's 20%, but I don't know if this makes a difference.
QNote
Active member
I don't think the tolerance is such a big deal. I would be looking for a "quality" pot at a reasonable cost. Longevity and reliability are the most important factors for my choice potentiometers. Pots from "the shack" are not going to give many years of trouble-free operation.
Which pots are going to be the best value given this criteria?
Which pots are going to be the best value given this criteria?
cannikin
Well-known member
Quick Question:
After linking pins 1,2,4,6,8, on the T4B.
Do connect them to ground?
After linking pins 1,2,4,6,8, on the T4B.
Do connect them to ground?
QNote
Active member
[quote author="EmoRiot"] ... I was wondering about the Precision Electronic pots used in the UA reissue. They're 10% tolerance, instead of the Allen-Bradley's 20%, but I don't know if this makes a difference.[/quote]
I checked these out. Digikey carries them for a very reasonable price. I will be purchasing these, myself. I already have the linear taper pots (Clarostat) for the rear panel.
I have also ran across a ton of NOS resistors that have never been opened (it appears) until now. The labels on the box say they were purchased in 1965. These are a rare find. There is Ohmite, AB, and many others, in MANY different values from 1/4 watt to 10 watt--all with the MIL part numbers! I'm hoping everything is here that I will need, as far as resistors. There were also some "goodies" in the box! You'll see them in the pictures once I near completion of the unit.
I will also be using "vintage" wire, as well (mainly for the vintage look). All of the wire is NOS, including twisted pair and some small shielded cabling, as well. Some of the wiring has the older "cloth" type sheathing--very neat looking. It appears to be in great shape, too.
Things are getting exciting. Now off to place a tube order...
I checked these out. Digikey carries them for a very reasonable price. I will be purchasing these, myself. I already have the linear taper pots (Clarostat) for the rear panel.
I have also ran across a ton of NOS resistors that have never been opened (it appears) until now. The labels on the box say they were purchased in 1965. These are a rare find. There is Ohmite, AB, and many others, in MANY different values from 1/4 watt to 10 watt--all with the MIL part numbers! I'm hoping everything is here that I will need, as far as resistors. There were also some "goodies" in the box! You'll see them in the pictures once I near completion of the unit.
I will also be using "vintage" wire, as well (mainly for the vintage look). All of the wire is NOS, including twisted pair and some small shielded cabling, as well. Some of the wiring has the older "cloth" type sheathing--very neat looking. It appears to be in great shape, too.
Things are getting exciting. Now off to place a tube order...
G
Guest
Guest
are there any sugestions on setting the stereo adjust /limiter response
c4/c14 ? (once the compressor is built)
is using a spectrum anilyzer the best ?
what are good values to replace c4 with , since that ****** just sits
there once it is set.
could the stereo adjust /limiter response be replaced with
fixed resistors , or do units vari too much , to use a standard
value , (i.e testing the factory setting on ua reissue pot and using that.)
wouldn't that just be a range between 1-1meg @ 1/2 watt ?
(not sure the actual wattage of those pots)
anyways i don't like those pots , their mean , and i promise there
gonna get it.
c4/c14 ? (once the compressor is built)
is using a spectrum anilyzer the best ?
what are good values to replace c4 with , since that ****** just sits
there once it is set.
could the stereo adjust /limiter response be replaced with
fixed resistors , or do units vari too much , to use a standard
value , (i.e testing the factory setting on ua reissue pot and using that.)
wouldn't that just be a range between 1-1meg @ 1/2 watt ?
(not sure the actual wattage of those pots)
anyways i don't like those pots , their mean , and i promise there
gonna get it.
JerryPbury
Well-known member
Finished up my first kit. AC is exactly 120V.
AC transformer is putting out 550VAC (+50). All my test points are +25vdc to +60vdc except for the neon (53.5) and T4B which is at spec. I have not run a signal through it. Come to think of it all of my tube projects over the years have always run higher voltages than spec. Any thoughts?
Thanks,
Jerry
AC transformer is putting out 550VAC (+50). All my test points are +25vdc to +60vdc except for the neon (53.5) and T4B which is at spec. I have not run a signal through it. Come to think of it all of my tube projects over the years have always run higher voltages than spec. Any thoughts?
Thanks,
Jerry
For now I will be buying 2 T4Bs but I would like to experiment with making my own.
The LDRs are no problem but Iam wondering about the EL panels. They are expensive and some have made T4Bs using LEDs or other EL material available much cheaper.
Can anyone give their opinions if EL other than the LSI ones can result in quality units. By that I mean "sound" as good or better.
Just wondering if its worth it to experiment.
Thanks.
Jim
The LDRs are no problem but Iam wondering about the EL panels. They are expensive and some have made T4Bs using LEDs or other EL material available much cheaper.
Can anyone give their opinions if EL other than the LSI ones can result in quality units. By that I mean "sound" as good or better.
Just wondering if its worth it to experiment.
Thanks.
Jim
the EL thing has been done over and over..
simple fact... though the EL's seem expensive ($30 does some rediculous) it is what works and has been tried and tested.
how much could you really save? $20 $25? if your only making one or two then wouldnt that amount be worth the satisfaction of knowing your using what was originally spec'd?
simple fact... though the EL's seem expensive ($30 does some rediculous) it is what works and has been tried and tested.
how much could you really save? $20 $25? if your only making one or two then wouldnt that amount be worth the satisfaction of knowing your using what was originally spec'd?
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