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EL34 vs 6550 vs KT88

#41
Wasnex said:
AFAIK these are not widely regarded as the best KT88. They are rather pricey though.
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Tried a quad of these in my Mother (DR201-based) and they didn't seem to like the high voltage. Lots of popping and crackling right out of the box. Went back to the Ruby KT88V STR set. The new sensor gold lions were happier in a friend's marhsall-based amp. I haven't tried many of the new sensor gold lion stuff, but it seems like whatever I have gotten in has been noisy. Haven't had much issue with some of the other new sensor brands.
 
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#42
coreyfyfe said:
Tried a quad of these in my Mother (DR201-based) and they didn't seem to like the high voltage. Lots of popping and crackling right out of the box. Went back to the Ruby KT88V STR set. The new sensor gold lions were happier in a friend's marhsall-based amp. I haven't tried many of the new sensor gold lion stuff, but it seems like whatever I have gotten in has been noisy. Haven't had much issue with some of the other new sensor brands.
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Yes there seems to be fairly widespread reporting across the internet that many of the New Sensor KT88 variants do not do well with high plate voltage. I have bought a couple of used amps loaded with EHX KT88s and the tubes all failed within a few months in variety of ways.

I do have a sextet of Sovtek KT88s in my Trace Elliot V6. The matching is not very tight, but they sound great and have not been doing anything weird. I think the Sovtek KT88 design predates New Sensor and has been discontinued...or perhaps just rebadged as Svetlana KT88.
 
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#43
My Sunn 2000S has a quad of Winged C 6550s and it has so much bass content, I have to go into the bright channel, keep the boost switch off and bass control around 3. It's prolly the voicing of the amp, but it's insane amount otherwise. I remember reading somewhere, that the 6550tubes were heavier sounding than KT88s, but it may have been referring to the old Tung-Sols or GE 6550As.---- My Reeves has a quad of TAD KT88 STR (Shauguang), and it is more neutrally voiced, but can get very heavy sounding. Again, it's prolly voicing. My 72ish V-4 guitar head has 7027As (original GE), and is more mid voiced, but can easily be dialed in for great bass.
NOW, I had 2 different Mesa 400+ amps years apart. The first one had JJ 6L6GCs and the last one had Winged C 6L6GCs. I think the first one had more bass content but could run out of steam too early (I was in a much louder band then). and the last one could not get very low. Don't know why. ALSO, I had a Peavey VB-2 with 6 EL34s, and I even swapped them out for 6CA7s, and for the life of me, could not get that amp to leave (guitar zone). It just wouldn't. I considered the idea that it had so much mid content that maybe I was blinded. NOT. PV gone > happy day.
 
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#44
my Traynor YBA 200-2 came with the KT-88's , but which power tubes would you suggest ?
i'm happy with the volume , but it has a lot of popping/crackling at first , then it seems to settle down a bit ...
:help:
IMG_2110.JPG
 
#46
Rockbobmel said:
I had good luck with these guys. CTech Electronics | eBay Stores . The TAD KT88s I have are holding steady.
Wasnex recommends JJs from (Eurotubes) only.
Are you sure its the power tubes?
Maybe it's just a dirty socket that is ok once it warms....??
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no , i'm not sure it's the power tubes , and actually the preamp tubes may be the problem after all ...
think i'll pull the tubes and clean the sockets , and give it another try !!
thanks for the heads up !!
:cool:
 
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#50
DaveDeVille said:
is compressed air ok ?
Click to expand...
I wouldn't. I believe you dab a tiny amount of deoxit DeoxIT® D5S-6, More than a Contact Cleaner on the tube pins and insert the tube in and out a few times. You can prolly do it without the cleaner first. It will just scrape the contacts. The tube pin clips inside the sockets can be tensioned as well, but I'll let someone else chime in here.
 
#51
Rockbobmel said:
I wouldn't. I believe you dab a tiny amount of deoxit DeoxIT® D5S-6, More than a Contact Cleaner on the tube pins and insert the tube in and out a few times.
You can prolly do it without the cleaner first. It will just scrape the contacts. The tube pin clips inside the sockets can be tensioned as well, but I'll let someone else chime in here.
Click to expand...
thanks for the info !!
:cool::cool:
 
#52
Rockbobmel said:
I wouldn't. I believe you dab a tiny amount of deoxit DeoxIT® D5S-6, More than a Contact Cleaner on the tube pins and insert the tube in and out a few times. You can prolly do it without the cleaner first. It will just scrape the contacts. The tube pin clips inside the sockets can be tensioned as well, but I'll let someone else chime in here.
Click to expand...

I use this on tube pins, and lots of other stuff too.
upload_2020-8-8_11-35-36.png
 
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#56
Rockbobmel said:
My Sunn 2000S has a quad of Winged C 6550s and it has so much bass content, I have to go into the bright channel, keep the boost switch off and bass control around 3. It's prolly the voicing of the amp, but it's insane amount otherwise. I remember reading somewhere, that the 6550tubes were heavier sounding than KT88s, but it may have been referring to the old Tung-Sols or GE 6550As.---- My Reeves has a quad of TAD KT88 STR (Shauguang), and it is more neutrally voiced, but can get very heavy sounding. Again, it's prolly voicing. My 72ish V-4 guitar head has 7027As (original GE), and is more mid voiced, but can easily be dialed in for great bass.
NOW, I had 2 different Mesa 400+ amps years apart. The first one had JJ 6L6GCs and the last one had Winged C 6L6GCs. I think the first one had more bass content but could run out of steam too early (I was in a much louder band then). and the last one could not get very low. Don't know why. ALSO, I had a Peavey VB-2 with 6 EL34s, and I even swapped them out for 6CA7s, and for the life of me, could not get that amp to leave (guitar zone). It just wouldn't. I considered the idea that it had so much mid content that maybe I was blinded. NOT. PV gone > happy day.
Click to expand...

That's interesting, my reading suggests people think the KT88 is more even and perhaps more bass heavy than the 6550. If you feel the 6550s are too bass heavy in the Sunn, try a different bias level.

I haven't ever played a Sunn, but AFAIK it's a fairly dark amp and the boost switch is pretty much unusable. Varying the bias can make subtle changes to the way the amp feels and also sort of works like a pivot EQ to balance the highs and lows.

That's a crude description of course. Try it; just make sure you don't set the tube current too high.

To me Hiwatt-style amps (Reeves 225) are a bit of an enigma. They are considered HiFi, but their frequency reponse is far from flat. With guitar, the voicing sounds warm. With bass the sound is sort of mid scooped with heavy, extended lows and aggressive upper mids.

Edit. Winged C 6550s where considered exceptional. I compared a quad to my JJ KT88s in my Aguilar DB359 and I could not hear any difference.
 
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#58
Rockbobmel said:
I had good luck with these guys. CTech Electronics | eBay Stores . The TAD KT88s I have are holding steady. Wasnex recommends JJs from (Eurotubes) only. Are you sure its the power tubes? Maybe it's just a dirty socket that is ok once it warms....??
Click to expand...

I do prefer JJ KT88s, but Shuguang would be my second choice. AFAIK TAD does a really good job of testing and matching tubes. They also charge a premium price. Pretty sure the TAD KT88-STR is made by Shuguang.

Older tubes sometimes make creaks and scratchy sounds as they warm up. Even some brand new JJs do this. If the sounds only occur during warm up, I would not worry as long as the noise is not super loud or sustained. If the sounds are continuous then you can try reseating the tube, cleaning the tube socket and retensioning the tube socket. Also move the tube to another socket to see if the problem follows the tube.

Hint: The noise will generally cause a small increase in cathode current that can be measured with a bias probe or multimeter. So if there is a way to measure the individual current in the output tubes you can identify which tube is making the noise. For example if the amp has bias test points for each tube, a cathode resistor for reach tube, or if you have bias probes that can be inserted between the tubes and the tube socket. I have also identified noisy tubes by pulling output tubes in pairs until the noise goes away. Of course you need to know how the amp is wired, so you know how the tubes are organized.
 
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#60
Groover said:
And here is my $1000.000.00 question, then I can live happily ever after..

So if I want to have nice fat punchy lows, strong low mids, decent highs but not extemely high (the crystal sparkle is too much for me), but obtain distortion without having to blow the roof off, what would be my best choice for power tubes on the SVT?

Sounds to me that the KT100 is still what I want, just not sure about the breakup/distortion
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The SVT is not the amp for distortion. They are built to sound clear at high sound pressure levels. The modern CL version can do some pre amp distortion, but the power tubes would not have anything to do with it.
 

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