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Post by karma67 on Mar 30, 2019 15:36:14 GMT
What a couple of days of ups and down,talk about coincidence. So heres the story,since seeing some NOS GEC KT88's at the audiojumble i told the seller if he still had them in a few months time id buy a set,as pay day was near i phoned him a few weeks ago to see if he still had them,he did but was going on holiday for 3 weeks. Ok i thought that gives me more time to save up,so wednesday evening i phoned him and arranged to come up today.All good so far,well it was up until last night when one of my sovetek kt88's decided to go bang,i lept out the sofa and flicked the off switch,just before i got there the sound went off :(bugger! As luck would have it the guy selling the GEC's was John Cresswell,an audio engineer based near woking,so with the thought of new valves taking a back seat i set of today to see what damage had been done. John gave the amp a good check over,it had one blown resistor and one fuse gone,after fitting new ones the amp was checked out of the oscilloscope,sadly all that was above my head but he confirmed all was healthy and it was putting out a clean 112 watts. So with that in mind i decided to try the supposedly top of the tree,nothing comes close GEC KT88's. Im listening to them now and yes they are better than the sovteks that were in there,i'll give them a few weeks of use to burn in (if that applies) to fully decide if the huge price difference is worth it :rolleyes:    |
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Bigman80
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Post by Bigman80 on Mar 30, 2019 16:26:57 GMT
That’s a lovely understated amp, Jamie. I have rolled valves a few tomes and never found it worth the money unless you’re using a different valve altogether. I hope your experience is better.
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Post by karma67 on Mar 30, 2019 16:35:09 GMT
i think the big gains are changing the pre amp tubes,i noticed a big difference when i did a few,these NOS kt88's are sounding very good,they have a lovely detailed mid range. at the moment im just glad the amp still works lol
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Post by antonio on Mar 30, 2019 17:50:47 GMT
Pleased your amp is working again, keep enjoying your new 'old' tubes.
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Post by alit on Mar 31, 2019 9:24:51 GMT
i think the big gains are changing the pre amp tubes,i noticed a big difference when i did a few,these NOS kt88's are sounding very good,they have a lovely detailed mid range. at the moment im just glad the amp still works lol Yes agreed, have found the same. |
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Post by Deleted on Mar 31, 2019 11:45:40 GMT
Nice amp and lovely set of tubes - congrats.
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Post by Deleted on Oct 15, 2019 17:36:20 GMT
The main advantage of NOS GEC KT88's would likely be much improved reliability over modern ones.
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Post by karma67 on Oct 15, 2019 17:49:58 GMT
yes i agree,so far no troubles at all
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Post by Deleted on Oct 15, 2019 19:49:12 GMT
Ive only ever bothered wth vintage valve amp. Totally did not like the sound of modern designs.. My fave tubes of all time were 'EL34' & 'ECL84'
The best sounding tubes i used for em were NOS Telefunken
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Post by Deleted on Oct 16, 2019 8:21:09 GMT
yes i agree,so far no troubles at all How are you getting o with the Stepped attenuator that you got for it? Anything of note? |
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Post by karma67 on Oct 16, 2019 15:47:53 GMT
yep i kike it much more than the alps blue for feel and use,i didnt have a night and day experiance though if im honest. the service was very good and quick postage so i would recomend gold point to try.
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Post by Deleted on Oct 16, 2019 16:08:22 GMT
yep i kike it much more than the alps blue for feel and use,i didnt have a night and day experiance though if im honest. the service was very good and quick postage so i would recomend gold point to try. Fair enough. |
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Post by Deleted on Oct 16, 2019 18:56:40 GMT
yep i kike it much more than the alps blue for feel and use,i didnt have a night and day experiance though if im honest. the service was very good and quick postage so i would recomend gold point to try. Strangely enough when I borrowed a Khozmo stepped attenuator I did find it a big improvement over an Alps blue Velvet! |
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Post by sq225917 on Oct 16, 2019 19:21:20 GMT
Jez I have a 10k remote control 64 step khozmo sitting doing nowt. Yours if you want to borrow it, needs 5v.
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Post by Deleted on Oct 16, 2019 19:29:42 GMT
yep i kike it much more than the alps blue for feel and use,i didnt have a night and day experiance though if im honest. the service was very good and quick postage so i would recomend gold point to try. Strangely enough when I borrowed a Khozmo stepped attenuator I did find it a big improvement over an Alps blue Velvet! Holy mother of jesus!!! Did I read that right lol!!! Jez, you are 100% spot on. The Khozmo is a beaut. |
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Post by Deleted on Oct 16, 2019 19:30:13 GMT
Jez I have a 10k remote control 64 step khozmo sitting doing nowt. Yours if you want to borrow it, needs 5v. Didn't this sell?? That was a bargain Price IIRC |
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Post by Deleted on Oct 17, 2019 13:46:56 GMT
Jez I have a 10k remote control 64 step khozmo sitting doing nowt. Yours if you want to borrow it, needs 5v. Ohhh.. I'm tempted. I've been meaning to design and build my own relay based attenuator with probably 256 steps for ages so I'll stick to the Alps for now thanks. Them round tuits are hard to find.... |
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Post by karma67 on Nov 4, 2019 19:00:12 GMT
some more rolling,this time the rectifier tubes,out goes the russian 6sn7's to be replaced by some rather lovely tung sol 6f8g's 
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Post by Deleted on Nov 4, 2019 19:32:16 GMT
6SN7's are a dual triode not a rectifier.
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Post by karma67 on Nov 4, 2019 19:35:58 GMT
6SN7's are a dual triode not a rectifier. ah ok,so what are the tubes called between the pre amp tubes and the power tubes? |
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Post by Deleted on Nov 4, 2019 19:44:54 GMT
No pre amp there... input stage would be a more accurate description. Depending on the design of the amp the valves immediate before the output valves ie driving the output valves, is either the phase splitter or the drivers.
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Post by karma67 on Nov 4, 2019 19:47:25 GMT
No pre amp there... input stage would be a more accurate description. Depending on the design of the amp the valves immediate before the output valves ie driving the output valves, is either the phase splitter or the drivers. cheers jez,could you tell from photo of the innards? |
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Post by Deleted on Nov 4, 2019 20:22:13 GMT
Sorry to go OT (slightly), well it's on topic with the subject... My amp has 2 x 6sl7, 2 x 6sn7 and then 4 xkt90. Obviously the KT90s are the output valves but what is the correct name for the other pairs in my case?
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Post by Deleted on Nov 4, 2019 20:25:23 GMT
No pre amp there... input stage would be a more accurate description. Depending on the design of the amp the valves immediate before the output valves ie driving the output valves, is either the phase splitter or the drivers. cheers jez,could you tell from photo of the innards? If it shows enough detail of the circuitry then probably yes. What are the input valves? |
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Post by Deleted on Nov 4, 2019 20:32:11 GMT
This is mine by the way :-)
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Post by Deleted on Nov 4, 2019 20:43:47 GMT
Not enough detail there....
A likely arrangement in both amps would be input stage amplifier followed by split load type phase splitter then 6SN7 as driver amplifier. Other arrangements are possible.
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Post by karma67 on Nov 4, 2019 20:46:39 GMT
cheers jez,could you tell from photo of the innards? If it shows enough detail of the circuitry then probably yes. What are the input valves? the are ecc801s's,then 6ns7 and then kt88's
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Post by Deleted on Nov 4, 2019 21:26:34 GMT
Again not enough detail but from what I can see it seems as I described above for other amp.
I have NOS Mullard mil spec ECC81's (CV4024) available BTW @ £10 each.
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