Hi!
I have a stereo receiver I use for listening only to vinyl that I was given as a gift by a relative. This relative built this amp from scratch. It sounds awesome and I love it, but today I started getting some hissing and high pitched noises, so I cooled down the 4 tubes, opened it up, turned it back on, taped the tubes with a pencil, and got lots of scratching and noise. I've had this thing for maybe 6 years and have never had an issue, so it made sense to me that the tubes might finally have gone.
When I opened it up, I saw 4 tall, slender tubes that I'd never seen before. I play guitar so I have minimal experience with pre-amp tubes for guitar amps, but these look nothing like them. The only marking on them is as follows:
Left Tube - Ge Electronic Tube - IN 188-5 (on the side)
Left Center - No markings whatsoever
Right Center - No markings whatsoever
Right Tube - GE Electronic Tube - EA 188-5 (on the side)
This amp is a completely DIY build and has no markings at all as far as company or parts. The green board where the tubes sat has markings but they see pretty generic. I'm gonna try to add some images below, sorry if they don't work, see Username.
At this point I just want to replace the tubes so I can use my amp again for tunes, but I've spoken to 4 different amp repair places and tube experts and they are just baffled, so i am turning to the forums here. Are there tubes that are readily available that can replace these? Just what the hell are these tubes? All help is greatly appreciated.
Thank you!
I have a stereo receiver I use for listening only to vinyl that I was given as a gift by a relative. This relative built this amp from scratch. It sounds awesome and I love it, but today I started getting some hissing and high pitched noises, so I cooled down the 4 tubes, opened it up, turned it back on, taped the tubes with a pencil, and got lots of scratching and noise. I've had this thing for maybe 6 years and have never had an issue, so it made sense to me that the tubes might finally have gone.
When I opened it up, I saw 4 tall, slender tubes that I'd never seen before. I play guitar so I have minimal experience with pre-amp tubes for guitar amps, but these look nothing like them. The only marking on them is as follows:
Left Tube - Ge Electronic Tube - IN 188-5 (on the side)
Left Center - No markings whatsoever
Right Center - No markings whatsoever
Right Tube - GE Electronic Tube - EA 188-5 (on the side)
This amp is a completely DIY build and has no markings at all as far as company or parts. The green board where the tubes sat has markings but they see pretty generic. I'm gonna try to add some images below, sorry if they don't work, see Username.
At this point I just want to replace the tubes so I can use my amp again for tunes, but I've spoken to 4 different amp repair places and tube experts and they are just baffled, so i am turning to the forums here. Are there tubes that are readily available that can replace these? Just what the hell are these tubes? All help is greatly appreciated.
Thank you!
They seems to be ECL86 / 6GW8 or PCL86 / 14GW8. Check the pinout and the filament voltage to be sure. Use the advanced editor and attach the pictures directly to your post. We can open your externally linked pictures only by manually pasting the url on the browser address bar, and this is very cumbersome to do on some devices.
Have you already tried to clean the tube pins and the sockets?
Have you already tried to clean the tube pins and the sockets?
Looks similar to 6BM8 also
Looks like this maybe
TubeDepot.com | Model K12G Stereo Tube Amplifier Kit
Found this in another thread
"10GV8 = LCL85. the 10GV8 and the 11MS8 (the tube that came with the K-12M kits) are functionally identical, so they should both work in the kits"
Looks like this maybe
TubeDepot.com | Model K12G Stereo Tube Amplifier Kit
Found this in another thread
"10GV8 = LCL85. the 10GV8 and the 11MS8 (the tube that came with the K-12M kits) are functionally identical, so they should both work in the kits"
Attachments
Last edited:
If the tubes are bad and you can't find 10GV8 tubes, the 9GV8 might be used with a small value dropping resistor. A 6GV8/6F5P might be possible with a larger dropping resistor, but I don't know if the power transformer is up to the task of twice the heater current. The 6GV8 could probably be used safely if the heaters were rewired from all parallel to a parallel/serial arrangement, but that would involve cutting traces and running jumpers, something that may be beyond your comfort level.
My apologies for the incorrect posting of the pics. I have not cleaned the pins and sockets, should I just use canned air for that?
Yes, unfortunately I am not up to the task of rewiring or changing anything. So I'll seek out 10GV8 tubes. Is that correct?
I use sandpaper (800 grit) on tube pins and contact cleaner spray on the socket. When the socket is exceptionally dirty, I also use a needle file (very gently). To remove the oxidation layer from tube pins, you can also scrape them with a knife.
Clean the sockets before you buy any new tubes.
"Tube Problems" That Aren't Tube Problems - Jim McShane - Tubes Asylum In particular, the first section.
"Tube Problems" That Aren't Tube Problems - Jim McShane - Tubes Asylum In particular, the first section.
Unfortunately the only markings on the tubes are the ones I listed, and 2 of the 4 tubes were completely unmarked, so I have no way of knowing what they are as I can't find anything about them anywhere online.
The print may have been rubbed off, but there still should be a visible type number on the tube.
Breathe on the tube so that your breath condenses on it, and as the condensate evaporates, look closely at the the tube for the type marking. Keep repeating this on different parts of the tube until you find the type number.
Probably 11BM8 tubes.
edit: about 7.75 seconds with Google revealed this page regarding the S-5 electronics Type M amplifier.
http://diyaudioprojects.com/Tubes/K-12M/audioXpress-review-of-S5-Electronics-K-12M-Tube-Amp-Kit.pdf
11MS8 tubes.
Breathe on the tube so that your breath condenses on it, and as the condensate evaporates, look closely at the the tube for the type marking. Keep repeating this on different parts of the tube until you find the type number.
Probably 11BM8 tubes.
edit: about 7.75 seconds with Google revealed this page regarding the S-5 electronics Type M amplifier.
http://diyaudioprojects.com/Tubes/K-12M/audioXpress-review-of-S5-Electronics-K-12M-Tube-Amp-Kit.pdf
11MS8 tubes.
Last edited: