joe-electro





Kenetek T4B Opto-Attenuator units for your LA-2A, LA-3A or similar projects. Available in 5 different speeds: Classic (Medium), Good Slow, Good Fast, Wayyy Slow and Stupid Fast. For overall general purpose work the Classic is your best bed. Use a Good Slow for bass and male vocals. Some people prefer a Good Slow unit on female vocals as well.  Good Fast units are best for drums, acoustic guitars, electric guitars, and up tempo music in general. Wayyy Slow is more like a leveler of the early to mid sixties.  Stupid Fast units are almost as aggressive as an 1176 with all four buttons pushed in.

Kenetek T4B's are the best selling T4B on the planet and are in use every day in studios all over the world making great music. Leading manufacturers including Warm Audio, Stam Audio, Serpent Audio and Skibbe Audio have all chosen Kenetek T4B's to ship with their new products.

Every T4B comes with a 3 year warranty and goes through no less than 5 quality tests before getting approved for shipment. Each unit comes with its own warranty certificate showing the date of purchase and serial number.

Matched pairs for stereo mix buss and mastering use are available, as well as Fast/Slow pairs for specialty builds. The T4B unit is the heart of the sound in an Opto-style compressor.  Your build deserves the best T4B you can get - a Kenetek T4B.

Order here:

https://www.gearslut.com/index.php?main_page=index&cPath=84

Thanks!!!
When I have money I buy gear. If there's any left I buy food.


ruffrecords

I thought labels that say "warranty void if removed" are either illegal or unenforceable.

Cheers

Ian
www.customtubeconsoles.com
https://mark3vtm.blogspot.co.uk/
www.eztubemixer.blogspot.co.uk


'The only people not making mistakes are the people doing nothing'

joe-electro

The FTC says you can repair your own things and manufacturers cannot force you to use their repair services.  Kenetek has in the past, and will continue to honor the warranty on all Kenetek T4B's unless there is obvious damage from misuse or abuse.

Thank you.

PS - Our return rate is less than 1 unit per thousand sold. That is, <0.1%.
« Last Edit: May 07, 2019, 07:53:44 PM by joe-electro »
When I have money I buy gear. If there's any left I buy food.

XAXAU


Kenetek T4B Opto-Attenuator units for your LA-2A, LA-3A or similar projects. Available in 5 different speeds: Classic (Medium), Good Slow, Good Fast, Wayyy Slow and Stupid Fast.

Hi this might be a stupid question but is it possible to have a slower attack and a more popping faster release built into these?
Or modify the resistance going into the cell to get a longer attack and use a faster cell?
Unsure how this circuit works to be honest!

Cheers

joe-electro

This is very difficult to do because the attack and release times are co-dependent. In other words, photocells with a slower release time also have a slower attack time.  Cells with a faster release also tend to have faster attack.  There is a wide variation in attack/release times between photocells within the same batch, due to the manufacturing process.  The photo-reactive material is mixed into a slurry and then sprayed onto the substrate, and not all photocells get the same density of material.

I can select out photocells that have a slightly slower attack and a slightly faster release, but this would be a laborious process. I would have to charge extra for the extra labor.

It's relatively easy to get photocells that have slower attack and release, or faster attack and release. These are what I call "Good Slow" and "Good Fast" T4B's, which you can specify when you order.   You might try a "Good Fast" and see what you think.

Thanks!!!

When I have money I buy gear. If there's any left I buy food.

XAXAU

This is very difficult to do because the attack and release times are co-dependent. In other words, photocells with a slower release time also have a slower attack time.  Cells with a faster release also tend to have faster attack.  There is a wide variation in attack/release times between photocells within the same batch, due to the manufacturing process.  The photo-reactive material is mixed into a slurry and then sprayed onto the substrate, and not all photocells get the same density of material.

I can select out photocells that have a slightly slower attack and a slightly faster release, but this would be a laborious process. I would have to charge extra for the extra labor.

It's relatively easy to get photocells that have slower attack and release, or faster attack and release. These are what I call "Good Slow" and "Good Fast" T4B's, which you can specify when you order.   You might try a "Good Fast" and see what you think.

Thanks!!!
Cheers

In most other comps  the attack and release can be altered, I understand that a slow cell is slow on bothe the attack and release side

But is there anything that can be done outside of the cell that will slow down the attack? Then pair that with a really fast cell?

joe-electro

Since the electroluminescent panel in a true T4B requires an AC signal, I don't know of any easy way of slowing the attack down without affecting other aspects of the sound that we want to keep intact (such as frequency response).  However, if you use an LED as your light source then you can use a nice sidechain circuit such as the Forrsell opto sidechain, which is very versatile and has a very effective attack control. Schematic can be found here:

http://www.forsselltech.com/media/attachments/SideChain_B.PDF

Thanks,

Bill
When I have money I buy gear. If there's any left I buy food.

XAXAU

Since the electroluminescent panel in a true T4B requires an AC signal, I don't know of any easy way of slowing the attack down without affecting other aspects of the sound that we want to keep intact (such as frequency response).  However, if you use an LED as your light source then you can use a nice sidechain circuit such as the Forrsell opto sidechain, which is very versatile and has a very effective attack control. Schematic can be found here:

http://www.forsselltech.com/media/attachments/SideChain_B.PDF

Thanks,

Bill
Cheers Bill

Back with another silly question

There´s 2 photocells in the t4b, are they both adding to the attack and release? Read something that said the t4b had 2 release stages, one that hits 50% GR in 60ms and the other 50% takes 1-15 seconds.

It got me thinking it could be modified if that was the case, like removing the ultra slow release stage, permanently or or with a switch. Then using a slower single cell to bring the attack from 10ms to 15ms and the release from 60ms to 90ms (or whatever).

Cheers

Rob Flinn


There´s 2 photocells in the t4b, are they both adding to the attack and release?

No.  One cell does the compression & the other cell controls the meter.
regards Rob

joe-electro

That's the way T4A and some very early T4B units were made 50 to 60 years ago, when LA-2A's were being used as levelers ahead of broadcast transmitters. All T4A units (that I've seen) and the very early T4B units (up until 1969 or so, coincidentally coinciding with the advent of the LA-3A) had three photocells in them. The third photocell, a Clairex CL705, had a very fast attack release time, and was placed in parallel with the CL505 cell in the audio path. It did indeed give those units a dual time constant, which might have been useful to broadcast engineers at the time. Over the next two or three decades, more sophisticated devices were designed (such as the CBS Audimax/Volumax combo, the Gates Sta-Level/Solidstatesman combo and Urei BL-40, not to mention all of the fantastic Orban units) which did a much better job of controlling both short peaks and average program level.

I have done quite a bit of experimentation with multiple photocells (with different time constants) and have come to the conclusion that there is not enough benefit to justify the additional cost for my production T4B's. In my experience, the overall response of the T4B is dominated by the response of the slower photocell.

That said, I have found that having the ability to switch between T4B's with different attack/release characteristics is very handy sometimes. A simple and inexpensive DIY solution can be found here:

https://www.gearslut.com/files/2xT4B_Mods.pdf

While I came up with this circuit in response to a question posed by someone building a Drip LA-2A, this circuit would work with any LA-2A work-alike.

I am also manufacturing a more elegant and flexible box that houses up to three Kenetek T4B's, and allows up to seven different attack/release curves, by switching in different combinations of T4B's. It also functions as a soft bypass, allowing you to hear the compressed vs uncompressed sound quickly. The box plugs into the existing T4B circuit and does not require any circuit modifications. However, if your T4B socket is located inside the enclosure you will have to come up with a way for the cable to enter the enclosure. The pics below show the prototype unit with a Kenetek LA-2X.  The production version of the box will not be as deep and the cable will be shorter. Please PM me if interested in one of these.





Hope this helps and thanks for reading!

« Last Edit: December 27, 2019, 08:23:23 PM by joe-electro »
When I have money I buy gear. If there's any left I buy food.


XAXAU

That's the way T4A and some very early T4B units were made 50 to 60 years ago, when LA-2A's were being used as levelers ahead of broadcast transmitters. All T4A units (that I've seen) and the very early T4B units (up until 1969 or so, coincidentally coinciding with the advent of the LA-3A) had three photocells in them. The third photocell, a Clairex CL705, had a very fast attack release time, and was placed in parallel with the CL505 cell in the audio path. It did indeed give those units a dual time constant, which might have been useful to broadcast engineers at the time. Over the next two or three decades, more sophisticated devices were designed (such as the CBS Audimax/Volumax combo, the Gates Sta-Level/Solidstatesman combo and Urei BL-40, not to mention all of the fantastic Orban units) which did a much better job of controlling both short peaks and average program level.

I have done quite a bit of experimentation with multiple photocells (with different time constants) and have come to the conclusion that there is not enough benefit to justify the additional cost for my production T4B's. In my experience, the overall response of the T4B is dominated by the response of the slower photocell.

That said, I have found that having the ability to switch between T4B's with different attack/release characteristics is very handy sometimes. A simple and inexpensive DIY solution can be found here:

https://www.gearslut.com/files/2xT4B_Mods.pdf

While I came up with this circuit in response to a question posed by someone building a Drip LA-2A, this circuit would work with any LA-2A work-alike.

I am also manufacturing a more elegant and flexible box that houses up to three Kenetek T4B's, and allows up to seven different attack/release curves, by switching in different combinations of T4B's. It also functions as a soft bypass, allowing you to hear the compressed vs uncompressed sound quickly. The box plugs into the existing T4B circuit and does not require any circuit modifications. However, if your T4B socket is located inside the enclosure you will have to come up with a way for the cable to enter the enclosure. The pics below show the prototype unit with a Kenetek LA-2X.  The production version of the box will not be as deep and the cable will be shorter. Please PM me if interested in one of these.





Hope this helps and thanks for reading!
Thank you for the answers and your builds look amazing, truly

My problem is thatI love the LA2A color and boxtone as well as the compression behaviour but it´s a bit limited for my uses
Sure I have synths to colour and drive, love smashing drumbusses in parallel and using it without compression on the 2 bus
But I can´t justify the price tag(s) of having 2 LA2A´s for those uses

I´ve looked at the 1176 schematic (and others) and it seems the attack and release circuits are separate yet still interacting with eachother
I have no idea how the LA2A is operating but isn´t there a way affect one and not the other?
Like having a stupid fast matched pair but messing with the attack portion to make it slower

I realize that messing with a gem of a circuit like this is silly but as I said I can´t afford a rack full of "one trick ponies"

Would like it to have a popping release but still let thru transients, I could have it needles barely moving but still, it would be nice to have a little bite if possible :)

Cheers