These are Q1-Q4 on the part lists. 1 of my 280s is a Rockford. Should I verify the PCBs for these 'superfets' (K147/J72)?
Hell ya! Who knows what you got. I have seen a few of the New Jersey babies go on eBay and it always makes me freak out that I cannot afford to collect them.
Every once and awhile, the seller puts up pictures of the amp without its top cover and you can always tell if it has 'superfets' by their tall profile.
Hafler apparently used whatever parts were available after the initial runs. One of my XL-280's has NEC fets, the other has Toshiba - but neither are the spec JFETs, the unobtanium 'superfets'.
My NEC JFET XL-280 is the reference because I purchased it original 20 years ago and the MOSFETS are stencilled heat grade originals. My other XL-280 has the heat grade written on by hand in marker - questionable originality, although they are Hitachis.
See what you got JFET-wise, the Arizona models rarely had the K147/J72 - those things are worth a pretty penny all by themselves if you have them...
Every once and awhile, the seller puts up pictures of the amp without its top cover and you can always tell if it has 'superfets' by their tall profile.
Hafler apparently used whatever parts were available after the initial runs. One of my XL-280's has NEC fets, the other has Toshiba - but neither are the spec JFETs, the unobtanium 'superfets'.
My NEC JFET XL-280 is the reference because I purchased it original 20 years ago and the MOSFETS are stencilled heat grade originals. My other XL-280 has the heat grade written on by hand in marker - questionable originality, although they are Hitachis.
See what you got JFET-wise, the Arizona models rarely had the K147/J72 - those things are worth a pretty penny all by themselves if you have them...
Thanks for telling, also very nice parts for pretty penny phono, in GR dress.
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knowing Jaccovitty - that's real deal , long ago unfortunate GB
he probably paid them few peanuts .......
having habit/hobby/curse/mania of buying bags of soon obsolete parts is ...... in his nature ;
he probably paid them few peanuts .......
having habit/hobby/curse/mania of buying bags of soon obsolete parts is ...... in his nature ;
Real McCoy.
I returned the GB ones to A'af long time ago, refund, what refund ?
Burnt myself a second time on a GB dually-V at the French HCFR forum, used a frighing hammer on those. Me has plenty A1349/C3381 by the cheapo, no need to scrape-off forgery labels.
(i keep little critter complementaries well separated in storage boxes, if a tall-hat jumps across the fence it's well recognisable, no chance to blend in with family members)
True, i've spent at least $1K a year on parts for the last 25, still bought too little.
I returned the GB ones to A'af long time ago, refund, what refund ?
Burnt myself a second time on a GB dually-V at the French HCFR forum, used a frighing hammer on those. Me has plenty A1349/C3381 by the cheapo, no need to scrape-off forgery labels.
(i keep little critter complementaries well separated in storage boxes, if a tall-hat jumps across the fence it's well recognisable, no chance to blend in with family members)
True, i've spent at least $1K a year on parts for the last 25, still bought too little.
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Perhaps it is wrong, but....
I have read that caps require a break-in period of seconds, not hours. This makes sense to me but many on the forums know much more than me. I think the speaker crossovers are the most likely culprit. I have a rather complex system of amps and dsp crossovers and they sound better than the passive ones without "breakin" (except for the speaker drivers) whether with the passive or the DSPs. Of course I am a skeptic about such things as cables (no evidence that an AC current, such as an audio circuit, has a preferred direction of travel) or other audio alchemy. Who knows though, maybe they open a rift in time that causes earthly physics to be different, sorry couldn't help that, I do like Dr. Who.
I have read that caps require a break-in period of seconds, not hours. This makes sense to me but many on the forums know much more than me. I think the speaker crossovers are the most likely culprit. I have a rather complex system of amps and dsp crossovers and they sound better than the passive ones without "breakin" (except for the speaker drivers) whether with the passive or the DSPs. Of course I am a skeptic about such things as cables (no evidence that an AC current, such as an audio circuit, has a preferred direction of travel) or other audio alchemy. Who knows though, maybe they open a rift in time that causes earthly physics to be different, sorry couldn't help that, I do like Dr. Who.
Jacco:
Surely you are trying to torture me, no?
That is the holy grail of JFETs, congratulations 😀
Surely you are trying to torture me, no?
That is the holy grail of JFETs, congratulations 😀
Checked my Q1-4 on all my amps.
2 Q1-4 have both type "superFETs," 1 has just the J72s, but not the 147. The "Rockford," as you predicted, has no "superFETs."
The other ineresting thing I noticed: 1 amp had "B" suffixed PCBs, the other 3 suffixed "D." The "B" had 2 caps on the opposite side of the PCB from everything else, the "Ds" had those caps on the same side.
Cheers tony
2 Q1-4 have both type "superFETs," 1 has just the J72s, but not the 147. The "Rockford," as you predicted, has no "superFETs."
The other ineresting thing I noticed: 1 amp had "B" suffixed PCBs, the other 3 suffixed "D." The "B" had 2 caps on the opposite side of the PCB from everything else, the "Ds" had those caps on the same side.
Cheers tony
Yes I had noticed that on earlier models they put the top middle cap on the back and maybe a few other differences.
The really interesting thing about the 280 is that I fell in love with its sound long before I knew anything of its construction. Upon learning about all the different variations in parts selection, I realize only now that I purchased a very, very special and unique amp 20 years ago.
As I mentioned, my amp had fairly unique NEC JFETs and came with higher-than-spec voltage Seacor film caps. I got IC electros where some got other brands. My second 'eBay' 280 is stuffed with many parts that are not the same as the first and it does NOT sound as impressive.
So I guess it was luck, the cool thing is I now have this great hobby in trying to meet or beat the original 90's 280 sound 😎
I'm thinking my F5 will give my 280 a good run....
The really interesting thing about the 280 is that I fell in love with its sound long before I knew anything of its construction. Upon learning about all the different variations in parts selection, I realize only now that I purchased a very, very special and unique amp 20 years ago.
As I mentioned, my amp had fairly unique NEC JFETs and came with higher-than-spec voltage Seacor film caps. I got IC electros where some got other brands. My second 'eBay' 280 is stuffed with many parts that are not the same as the first and it does NOT sound as impressive.
So I guess it was luck, the cool thing is I now have this great hobby in trying to meet or beat the original 90's 280 sound 😎
I'm thinking my F5 will give my 280 a good run....
I happen to be one of those that have had positive experiences recapping old components from receivers to amps to especially preamps, Hafler being among them, at the moment I have two DH-101's, one is all stock that I use for reference and the other I have upgraded caps, carbon resistors with metal film and lately I have been up grading the PS on it, when I do an A-B comparison the recapped pre wins hands down. Now when it comes to vintage tube stuff, the differences are huge after a full recap.
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Hi gil1,
I wish I could say the same. Though I still have something of a work in progress with my Hafler recapping, I can honestly say that none of my mods yet have made any of my equipment sound 'better'.
From my 110 pre to my 2 XL-280's, I have tried many caps, and I plan to try more. I am especially interested in bringing my 110 back to life as it is the 'heart' of my system. My 110 has ELNA Tonerex after the regs (sounded better than SILMIC II) but I think I have a lot of work to do ahead of the regs. It sounds rather lifeless at the moment.
One thing I found odd about recapping my 110 was that it seemed to change the gain for the lower. I checked supply voltages - they are rock solid at spec voltage. Weird.
Gotta get my Nichicon MUSE BPs in my 280's! Can't wait for that one...
I wish I could say the same. Though I still have something of a work in progress with my Hafler recapping, I can honestly say that none of my mods yet have made any of my equipment sound 'better'.
From my 110 pre to my 2 XL-280's, I have tried many caps, and I plan to try more. I am especially interested in bringing my 110 back to life as it is the 'heart' of my system. My 110 has ELNA Tonerex after the regs (sounded better than SILMIC II) but I think I have a lot of work to do ahead of the regs. It sounds rather lifeless at the moment.
One thing I found odd about recapping my 110 was that it seemed to change the gain for the lower. I checked supply voltages - they are rock solid at spec voltage. Weird.
Gotta get my Nichicon MUSE BPs in my 280's! Can't wait for that one...
HaflerFreak, I just noticed this thread goes back 3 years!
I have read that another worthwhile improvement is changing regulators from the fixed to adjustable, I have not gotten to that yet, I need to study a bit about that. Any recapping job that I have done has brought a subtle difference, some people call it the placebo effect, I have A/B to compare (with the DH-101)
Again, I have noticed the biggest difference with vintage tube gear.
Good luck and keep us posted.
I have read that another worthwhile improvement is changing regulators from the fixed to adjustable, I have not gotten to that yet, I need to study a bit about that. Any recapping job that I have done has brought a subtle difference, some people call it the placebo effect, I have A/B to compare (with the DH-101)
Again, I have noticed the biggest difference with vintage tube gear.
Good luck and keep us posted.
NEC "SuperFETs" etc
What would tell me I have NEC SuperFETs versus the parts list SuperFETs? Remember 2 '280s of mine, the Q1-Q4, are, per the parts list, what you described as SuperFETs.
Which are these on the parts & what would tell me I have these in any of my '280s?
What's an "IC electro(s)",
BTW I've replaced most of the wiring* in one my '280s w/SuperFETs. Previous owner not skilled @ soldering, tried to fix a couple things;cold solder joints.
* a little thicker wire in some places, a lot thicker in others! I'll gladly PM you the other reasons why I took the trouble to do this.
After I check & adjust the bias in both amps the same, I'll do a comparison. One channel in the rewired amp idles a bit warmee than the other. The "stocker" "idles evenly" though much warmer than the former.
Finally I think the XL-280 is Circa middle to late '80s
Cheers tony
What would tell me I have NEC SuperFETs versus the parts list SuperFETs? Remember 2 '280s of mine, the Q1-Q4, are, per the parts list, what you described as SuperFETs.
Which are these on the parts & what would tell me I have these in any of my '280s?
What's an "IC electro(s)",
BTW I've replaced most of the wiring* in one my '280s w/SuperFETs. Previous owner not skilled @ soldering, tried to fix a couple things;cold solder joints.
* a little thicker wire in some places, a lot thicker in others! I'll gladly PM you the other reasons why I took the trouble to do this.
After I check & adjust the bias in both amps the same, I'll do a comparison. One channel in the rewired amp idles a bit warmee than the other. The "stocker" "idles evenly" though much warmer than the former.
Finally I think the XL-280 is Circa middle to late '80s
Cheers tony
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