GSI laser tubes vs RECI

[Mike Lysov]

Hi guys,

I was wondering if the laser has been made to run with two 140W GSI tubes is it possible to use 2 x RECI(140/150W) tubes instead. Are they identical in length the tube diameter, all connections and power consumption?

Also does anybody know where I can find a price for a 140W GSI tube?
Does GSI sell them directly or they only can be ordered through the factory where the laser has been made?

[Mike Lysov]

I have to bring this thread to life again as it seems I have a dead GSI tube now.
http://www.sawmillcreek.org/showthre...-or-tube-fault

So if my tube is dead I have a few options:

1) Buy a new GSI tube. That would be the best option  but I am looking at least $9000 AUD expense without shipping(probably another $2000 on top). Considering I have just spent almost the same on repairing my Synrad tube it will probably kill me as a business financially. Or my wife kill me for sure.

2)Buy one Reci tube with the same or similar power rating and hope it will work together with another CGI tube that I have. Not sure how much they are for 150-180W tube but ebay says around $3000 AUD with a power supply and shipping included. I hope I won't need a new power supply as I still have two from GSI tubes and both working. I hope it would be ok to run RECI tube from the power supply I have as long as it has the same power rating. Am I right?


I do not want to change a power supply because then I need to do something with a laser control and I am bad at this stuff.

3)Buy two RECI tubes and try  to sell one working GSI tube. So it will be $6000 or less which will depend on how much I can sell the GSI tube for and whether I can run the RECI tubes from HVPSs currently used from the GSI tubes.

What would you do guys if it happened to you?
I can replace the tubes and realign them but that's just about it I can do. I do not think I will be able to replace power supplies mostly because apart from having wires for powering a tube they have some a DB15(may be DB21) connector attached to each HVPS and I have no idea what it is doing and how it is doing it. So even if there is the same connector on a RECI power supply it does not mean it uses the same pins or communication protocol.


in regards to the option 2 and 3 it does not have to be RECI tubes, anything reliable with 8000-10000h lifespan will be ok for me.

I totally understand if nobody can advise anything to me as it looks like I am the only one here with two tubes laser but I just hope somebody can have some advise on what to do.

[Mike Lysov]

There is also a fourth option to buy something like this https://www.aliexpress.com/item/CO2-...7-70d10fc15478

but I have no idea how reliable this multiple core tubes are.

Update: just to add a bit more details. GSI tubes I have are about 1600mm long and 80mm in diameter. It seems that similar to power EFR and RECI tubes are 250-400mm longer but I can try to add a metal enclosure for longer tubes.

CGI is changing business name all the time. It was JK laser recently not it seems they re-branded to something else(SPILaser or similar) and removed all tube details from their website. So it is very hard to find tech details for these tubes for power requirements.

My laser model also comes with 200W Synrad tube. I have just chosen one with two 140W CGI tubes because it was much cheaper than with Synrad. So I guess it is also an option to use 200W Synrad but it may require a lot of work and change in components, settings etc.

[Doug Fisher]

Check the RECI website for there requirements in regard to power supply and voiding their warranty. I think you need to have proof you are using an approved power supply.

You could get the specifications and drawings from RECI support and then hire an technician/electrician to look at your current setup plus the RECI documents to see if the swap would work. Then if it would work, make plans for that person to come back and do the install for you. It would be a worthy investment in your case as long as you took your time to find a competent person with a good reputation. Since you are in Melbourne, you should be able to find such a person.

[Dave Sheldrake]

Will write up a proper reply when i get to work mike, I have a 200 watt GSI SLC and have used (and still have) twin tube combined units

[Mike Lysov]

Thank you Doug, sure I will check all specs before buying new tubes. If it is Chinese and I decide to buy two of them I may even go for tubes over 200W if my power supply can power them without any issues.

I am in Brisbane now, not so many laser technicians around there. The company that has supplied my other laser(Spirit GX) has never worked with two tubes machine and I do not think they can be any big help with all this.


Thank you David, I will wait util you can reply.


I am really appreciate you guys trying to help. We have much smaller market here in Australia so there may be some knowledgeable guys for triumph and similar huge laser machines but it is really hard to find someone who can help with a small one. I have a friend who is very good with electronics and he can help me with power supplies and power testing but he does not have the same great skills with laser tubes.

[Dave Sheldrake]

Yup, you can use RECI or EFR tubes in place of the GSI, double check your frequency though, I'm not sure about the cheaper GSI's but the more expensive models like the SLC can have the frequency and PRF adjusted.

If you do want GSI tubes buy them direct, GSI's main manufacturing facility and head office is over here in London, the combiner unit doesn't need to be messed with really, unless you have a circular polariser or linear polariser on it, they won't work properly anyhows, to be set up properly the tubes have to be phase stacked and that requires a profiler at least (figure on $10k minimum for a cheap one of that power) badly set up, combined units actually lose power.

Avoid folded resonator glass tubes...they are rubbish...the twin core EFR isn't much better and suffers badly with overheating..If you want to go folded then RF is the only realistic way to go.

On a twin head the phase stacking issue doesn't matter, on combined beams it does...A LOT

[Mike Lysov]

Thank you Dave. I have SLC tubes. I was lucky to save JKLaser spec PDF for this type of tubes when they still had their website running.

My tube model is SLC140BP for both tubes and according to that PDF my tubes have linear polarization and waist location(not sure why it so important) is 1.15m from a tube output coupler. That PDF does not say anything about range of frequencies used for these tubes. see the link for it below
https://drive.google.com/file/d/0B1L.../view?ths=true

Now, if RECI/EFR tubes have the same type of polarization, frequency, power rating and the waist location they can be used with the same optical train including the Brewster window. Is it right or it is not that simple?

Unfortunately RECI website does not even say a word about their tube polarization type.

[Dave Sheldrake]

Reci are indeed linear (Random) polarisation but the problem is they aren't marked to show it or have locators. The issue will be stacking the outputs so you don't end up suffering with the cancellation effect (one beam cancelling the output of the other), for that you will need a profiler and a LOT of time to set it up.
Matched pairs tend to use either phase retarding mirrors (1/4 or 1/8th) to get the same effect or are built with the retardation as part of the way they are fitted in the casings

It might be worth calling GSI direct (they are over here in London) but they are expensive (the SLC 200 is $21,000 the last time I purchased one) have you looked at moving to an RF? OEM units if you buy from one of the Chinese bulk providers like Sintec Optronics (Ask for Pietro) aren't as bad as it first seems, from memory the 200 watt RF is around $13,000 and will easily keep pace with a combined dual 140

To be honest, I have 200's, 400's and well above and the dead space is the 180 to 400, lots more cost...not so much benefit on the return

If you want to keep costs down, my take would be go for a single EFR ZS2050, that's going to peak at 230 or so watts from a single cavity unit and no messing with combiners or folded resonators, direct they run about $2,000 a pop with the usual 10,000hr life

I must admit, I did prefer the ZX tubes but they stopped making them about 18 mnths ago even though they were more expensive

On polarisation and beam waist

Linear WWWWWW imagine it like that with the polarity staying in one plane compared to the output coupler (so the waveform is always, say Vertical) circular polarisation is the same wave form but rotates around the centre of the tubes centre line (the power distribution is more even around the form) but a lot harder to stack (the tubes lateral position becomes a lot more important)

Beam Waist is where the output coupler makes the beam at it's narrowest point >< in the case of yours , that's 1.12m away, when you move away from that it allows you to use it for a similar effect to a beam expander and mess with spot sizes without having to change optics, on an industrial laser or in a lab...great....on flying optics...not so much

Short version? it's a lot of fiddling if you want to swap to RECI or EFR twin tube setups and to do it right you will need a profiler at minimum and likely a decent power meter (as in the full monty not a wand) but will be cheaper for tubes, I'd go either single cavity (tube) big EFR or Syrad RF as the benefits of staying with twin tube GSI isn't really there in a flying optics set up used for cutting

[Mike Lysov]

Sorry Dave, I am not so good with all this. I watched some physic educational videos about polarization and I think I get it right but the rest things are very hard to understand.

When you say I need to stuck an output, why can I easily do it with my GSI tubes but you think it will be hard to do with RECI tubes for example?

I have all optics in place including a Brewster window. Is it some coupler optics on RECI tubes that won't allow me to do all the same with RECI tubes using the same optic train or something specific to a light profile for a beam coming from a RECI tube?

I do not mind it to be one single tube machine, but I want the same power(280W) or more and I want to spend as less as possible comparing to a double tubes laser.

I do not think it is going to work with a RF laser tube but I am also concerned on how I can implement a RF tube into all my current components I have. They are built for DC excited tubes for this model not for a RF tube.

I guess when my other laser model comes with 200W Synrad it is not just a power supply different from the one needed for GSI tubes. The model with Synrad tube have better drivers and motors, it can even engrave, cut thin metal and much faster than the one with 2x DC tubes.

As for GSI, they do not exist anymore. It was JKlaser for some time and you could still buy a new SLC tube from them. I even got a replacement tube from them where my new laser was delivered with a glass tube cracked inside back in 2012.

Then JKLaser was bought by a company called SPILaser and that new company focuses on Fiber Lasers only.

At least that what I was told yesterday by the guy who was a distributor for my laser machine brand in AU. They do not distribute this brand anymore but they are also a GSI distributor and deal with them regularly. This guy told me yesterday that SPILaser won't be making DC excited tubes anymore but promised to get more details about it later.
Today I sent an email to SPILaser asking for their advise but it will probably come to "Sorry we do not make these tubes anymore" and then I am just stuck and must find an alternative to GSI tubes anyway.

As for my laser machine MFG, they are in Taiwan and have only a couple of persons who can speak English. Every question to them can be sent over skype or email only and they are either ignoring them for a long time or they need days to reply to it.

[Mike Lysov]

My laser MFG confirmed yesterday that they could not supply GSI DC tubes anymore. So I have no choice but to find replacement for them from another supplier.

[Dave Sheldrake]

Cohernat do glass tubes of high quality, thing is they cost more than SLC's !

Binding two RECI's is going to be a PITA, lemme have a word with a friend at EFR and see if they have anything over the 260 watt Glass tubes and if reliability has improved

[Mike Lysov]

Thank you Dave, a coherent tube if it is more expensive not really an option for me. And it is till grey area for me whether their tubes can come in the same config as my GSI tubes. I am quite happy with something like RECI tubes as long as they can run up to 10000 hours. May be their 150-220W tubes can go up to $3000 in AUD but if they work at least I will have a source for replacement in the future and I should be able to get the same or even more power with them.

The fact that they are longer than my tubes is still ok with me, I can cut of a side of my machine and add a metal enclosure to cover longer tubes.

It is pity nobody makes a single core 300W or over DC exited tube. I have submitted a request for GSI tubes on alibaba but so far I got only sellers coming with their Chinese tubes.

The first seller to answer my request was a guy from a company that makes these multiple core tubes. If somebody would had tested them for a long time and says they are ok I would have tried them. However being the first one to try them for a few thousands dollars does not look good to me :-)

[Bill George]

Gee I did not know the Chinese made RF Tubes and then all you need is a Power supply > https://www.aliexpress.com/item/co2-...308.4.2.eoLvvk

What could be wrong with a tube from China?

[Dave Sheldrake]

Had a word with EFR, the F-220 has a peak of 270-280 watts but is dual core / single outer. That's as high as it gets until you go RF.

The power situation is a product of resonator length / diameter 80 watts per meter stable is about all you get