I am currently using an OP275 to drive my integrated 6V6 CCS PP amp.
(gain set for 101)
( http://pbpix.com/amp/6v6%20pp%20amp%20change%20hw.png )
(My latest integrated 6V6 PP amp)
The Vcc for the OP275 is +/- 20v and I can only drive the 6V6 grids with 34v PP.
I've been looking at the OPA604AP with a higher Vcc of +/- 24v.
But it's only single-amp per chip
I see there exists a OPA2604AP dual version but I cannot find any available at the normal authorized US distributors. I do see them being sold via Ebay from Asia. But I cannot trust that Asian counterfeit chip community.
Why is it that these OPA2604AP chips don't seem to be available here in the US yet they're all over the place by Asian sellers?
The only other option is to get the single/amp OPA604AP and try to buy some of those single-to-dual chip socket adapters.
Any answers, thoughts or ideas?
(gain set for 101)
( http://pbpix.com/amp/6v6%20pp%20amp%20change%20hw.png )
(My latest integrated 6V6 PP amp)
The Vcc for the OP275 is +/- 20v and I can only drive the 6V6 grids with 34v PP.
I've been looking at the OPA604AP with a higher Vcc of +/- 24v.
But it's only single-amp per chip
I see there exists a OPA2604AP dual version but I cannot find any available at the normal authorized US distributors. I do see them being sold via Ebay from Asia. But I cannot trust that Asian counterfeit chip community.
Why is it that these OPA2604AP chips don't seem to be available here in the US yet they're all over the place by Asian sellers?
The only other option is to get the single/amp OPA604AP and try to buy some of those single-to-dual chip socket adapters.
Any answers, thoughts or ideas?
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The status of OPA2604AP may be active but the lead time for through-hole parts is more than 6 months. Because you would have to order a commercial quantity (as in a minimum 150 to several thousand parts) it means they are virtually unavailable for DIYs though. If you look at what is being supplied in Ebay kits that claim to use OPA2604 now, they are mostly SMD type mounted on DIP8 adaptor boards. However, examples of these that I have twice bought from Chinese Ebay stores seem to work fine on 20V supplies and otherwise measure as genuine parts as far as I can tell.
I suggest, even looking at the laser etching quality on new DIP8 chips now being offered by Ebay stores (they can't seem to get the BB logo right and should by now be TI branded anyway), that those are mostly fakes of one type or another. Don't risk it.
I suggest, even looking at the laser etching quality on new DIP8 chips now being offered by Ebay stores (they can't seem to get the BB logo right and should by now be TI branded anyway), that those are mostly fakes of one type or another. Don't risk it.
The OPA2604 DIP8 is available through trusted sources such as Mouser and Element14( formerly Farnell) but currently seems to be only in bulk quantities. MOQ 150.
You might have to search for online hobbyist stores instead.
A quick search came up with a 4 piece listing that's based in the US. But I have never used them nor know anything about them. So please use discretion.
4 X Burr Brown OPA2604AP OPA2604 - Free Shipping - | Reverb
Or an Amazon based seller :
Texas Instruments OPA2604AP (Pack of 1): Amazon.com: Industrial & Scientific
You might have to search for online hobbyist stores instead.
A quick search came up with a 4 piece listing that's based in the US. But I have never used them nor know anything about them. So please use discretion.
4 X Burr Brown OPA2604AP OPA2604 - Free Shipping - | Reverb
Or an Amazon based seller :
Texas Instruments OPA2604AP (Pack of 1): Amazon.com: Industrial & Scientific
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^This ,
TI should have some
consider re-design
OR keep a personal stash of the old original workhorses or PMI Op-27, 37,
Linear Tech Corp LT1028
Duals like OPA2134 , could be an option
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I would recommend a rail-to-rail FET opamp like the OPA1642---will take a +/-18v supply and swing to +/- 17.65 volts---giving you a 35.3 volt peak-to-peak swing; it's also a much better chip.
Thank you.
I'll take a look at that one too.
Right now the op275 can do 34pp out with a +/-20v and it has a max of +/-22v which gives me just under 40vpp out.
I wonder if there's a Jfet input-chip as good as the op-275 or the opa604 etc that also might have a really high output swing of at least 50v PP or better ...and a great freq response @ a gain of 100
As was mentioned in another thread, the LME49860 is a 44V-validated LME49720. So you could put it on +/-22V rails and it'll swing pretty close to the full range.
Thanks for the links:
So I took a look over at Amazon for the opa2604ap and found a few from suppliers at prices from $5 to $12 or more. It was hard to determine if these are US based or "authorized" re-sellers.
So I sent an email to the lowest priced seller first. He shows a BurrBrown logo on the chip. ( TI acquired BB 7-8 years ago)
So I asked that guy if the chips were real or counterfeit and here's his reply:
"Sorry, for this next question ,
We need confirm from our supplier 1st.
So, please don't buy them.
Thank you,"
So I'll see if they get back w/an answer.
Then I'll go to the next vendor in line.
I spoke w/Mouser today and they will check w/TI to determine availability of the opa2604, of if BurrBrown even actually ever produced an opa2604 back when TI acquired them 7-8 years ago.
Be very careful where you source the OPA2604 from.
I hadn't realised they were back in production following the issues from a couple of years ago where I believe the dual version was pulled due to production line problems and the devices deteriorating and falling out of spec when used at supply voltages toward their maximum rating. The single version was not affected.
I didn't think they would be reinstated, but it does indeed say 'active' on the current status.
I hadn't realised they were back in production following the issues from a couple of years ago where I believe the dual version was pulled due to production line problems and the devices deteriorating and falling out of spec when used at supply voltages toward their maximum rating. The single version was not affected.
I didn't think they would be reinstated, but it does indeed say 'active' on the current status.
Wow... thanks.. I didn't know this.
So.. I guess it would NOT be wise to buy any of the opa2604 with the Burr Brown logo that are shown online for sale currently.
... as TI bought them over 7-8 years ago. Right?
Best to wait for a new TI version of the opa2604.
Thank you
Definitely best to buy either from TI direct or from an authorised distributer. UK suppliers aren't listing these as currently available fwiw.
Unless you can be sure the BB types are original old stock from years ago then I would avoid. Its just not worth the risk.
Unless you can be sure the BB types are original old stock from years ago then I would avoid. Its just not worth the risk.
I knew I had seen an official version of what happened somewhere. Read the pdf in post #1
OPA2604 is dead
OPA2604 is dead
OPA453 comes closest to what you're after - not quite as wide bandwidth as OPA604 but does swing 50V p-p easily at 20kHz. While the DS doesn't mention it, it does look from the input bias current spec that its some kind of FET input, either JFET or MOSFET.
TI did post an alternative part to the 2604. Have to look up what that was, but it is hopeful that the 2604 is back again. The replacement BTW had lower distortion... worth considering.
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