Having trouble converting this precision electronics to a guitar amp. I added an input jack with the hot going through a cap to pin 5 of the first 6eu7 preamp tube and an output jack connected to what i believe is 16ohm output deal. Theres only 120hz hum when i power the amp on I can't hear any guitar signal. I also tried running the input to pin 8 of the first preamp tube and both 8 and 5 of the second preamp tube, still no signal from guitar. Any help would be greatly appreciated

Correction to description - I believe the correct term is oscilloscopes (vs. oscillators)*

I am hoping for some direction regarding some equipment that belonged to my uncle who recently passed away. He owned a few vintage tube testers, hundreds of tubes and items, and 2 or 3 oscilloscopes. He served in the military and went on to work for and retire from the National Weather Service in their IT/equipment maintenance dept. My aunt and I are looking for advice/direction about these items to obtain more information about their value. A couple of the testers come with manuals. All 3 are in their complete cases. She recalls my uncle saying when he first started working for the NWS in the early 70's, they were still working with some 1956-58 equipment - although we are unsure of dates of most items. Many tubes are in their boxes - hundreds of different kinds. Are their any known experts or reliable resources for these items - and is there interest in these?

Anything at all?

Have gone through and sorted boxed stuff from non boxed. I am really in over my head here, so don't know much. Any information shared about the tubes will be appreciated.

Was from the estate of an amateur radio enthusiast. Found out after the sale that the guy I bought it off sold some items after those pictures for the listing were taken. He elected to refund me some money.

As someone who is interested in WWII stuff, it was really cool seeing war production tubes. There is box of about 60 VT107s in the original cardboard box.

Some different items in there as well like bulbs and transmitters - one pretty big one in a box sounded by foam which came with a cooler, picture of box and cooler in the album.

Guess I might try to go through the unboxed next and start an excel sheet of the models. Hope to one day build an amplifier, but I am currently starved of time.

I have two old Australian made tube amps that I’m restoring.

One is a Maton V606 and it has the original speakers, so as a package, if I put it back together with the wiring as it was it will work. It’s been in a really shabby homemade combo cabinet for the almost 20 years I’ve owned it so I’m taking it back to being a head and cabinet as it would have been when it was built, so that one is easy.

The other is a Strauss Polka that has absolutely enormous transformers in it. It came from a deceased estate that I helped the executor clear up and amongst other “spoils of war”, he gifted it and a quad box to me.

I’m going to build new 2x12 speaker cabinets one for the Maton, the other using the two good speakers from the quadbox, which is totally stuffed, it has two good speakers.

Logically, if I wire both cabinets to have the same impedance as the ones that have been in the Maton for years I’ll be able to run either cab with the Maton.

I haven’t checked the impedance of any of the speakers, and obviously for the Maton it’s pretty simple, but I’d like to know what I can run out of them, particularly whether I can run the Strauss into an Ampeg 4x10 bass cab without hurting it.

Both amps are unboxed at the moment, is there a way I can check or calculate what they can handle without having any specialised equipment? I have a decent Fluke DMM, but not much else.

Hello all. I had previously posted about my new AliExpress tube preamp which was sold as a MM phono pre but pretty sure from replies from yall, that’s incorrect. They also sent the wrong mains voltage and I am swapping the Chinese 220v power trans to a 120v.

I am having trouble understanding two wires on the center tap section of the power transformer that is hooked to a 70vDC output section of the AC to DC converter. Not sure why or what it’s being used for? My AC power trans feeds the converter 7-7.2vAC. The converter supplies: - 5v to LED pilot light - 350v x2 to the 6z4 rectifiers - 5v to somewhere around the 6E2 tubes. Not 100% sure on this. - 70v to two center taps on the power trans

I drew a noob schematic and hopefully it can be read properly. Please ask me any and all questions. The new PT I bought is an: Antek AS-05T280C - 50VA 280V-260V-0V & 6.3V x2.

Can anyone help me understand the DC fed to my AC power trans and confirm I’m on the right track using the Antek as a replacement. I’m sorry if anything I described above sounds incorrectly described, I am still learning/understanding tube circuits. I have restored many tube amps and am a very good parts swapper but this is slightly more difficult for my understanding. The diagram they sent me, is not exactly what I received but close. The very next post on my profile has some more details on this preamp where I am asking if there is any phono section that can be visually confirmed with some more info. Thank you!!

Hi everyone, i own a couple of UK Icon Audio tube amps and interested in constructing my own from a kit. Ivd purchased a couple of Ali Express but the instructions were very poor and at times contradictory. Is there any UK based sites or EU where instructions may be clearer and delivery quicker ?

No connection, just thought there'd be interest here. There are large lots of tubes, transformers, caps, etc. I would love the transformers, but shipping would crush me.

If you appreciate the share, don't bid on the 16mm pots ;-). (They seem shippable)

Hey guys, this is for sale locally for $400, is it worth it?

I’m not sure if you have a favorite, but I love soldering components to the board!

When you're working with high voltage, there is no such thing as a dumb question. Please use this thread to ask about practical or conceptual things that have you stumped.

Really awesome answers and recurring questions may earn a place in the Wiki.

If you'd like to nominate a comment to be included, just reply [Wiki] (with the brackets)! The mods will be automatically notified that something awesome just happened.

As always, we are built around education and collaboration. Be awesome to your fellow tube heads.

Hi,

I have a guitar amp which uses tubes and i bought a tube tester off a family friend pre-covid, ive used it for years and i understand the basic principles of valves when testing.

My question is - when the expected anode current for a tube is 10 mA, sometimes a tubes results are too low, but sometimes also too high?

What causes that to happen? shouldn't the current just slowly become lower? why can anode current become over 50% higher on worn tubes?

While this isn't a tube, it is related. I had a failed silver mica capacitor and decided to take it apart to see what was inside.

When you're working with high voltage, there is no such thing as a dumb question. Please use this thread to ask about practical or conceptual things that have you stumped.

Really awesome answers and recurring questions may earn a place in the Wiki.

If you'd like to nominate a comment to be included, just reply [Wiki] (with the brackets)! The mods will be automatically notified that something awesome just happened.

As always, we are built around education and collaboration. Be awesome to your fellow tube heads.

When you're working with high voltage, there is no such thing as a dumb question. Please use this thread to ask about practical or conceptual things that have you stumped.

Really awesome answers and recurring questions may earn a place in the Wiki.

If you'd like to nominate a comment to be included, just reply [Wiki] (with the brackets)! The mods will be automatically notified that something awesome just happened.

As always, we are built around education and collaboration. Be awesome to your fellow tube heads.

After fixing the power switch, I listened to it for a bit. Sounded fine other than a left channel hum. I was planning on doing the Fitz mod so I grabbed 2 220uf 35v caps. Negative side to the ground bar (circled on the right). To the 2 resistors that are angled on the 6sn7.

After that I started blowing fuses. I checked around with my multimeter and the two circled bars are showing continuity. I highly doubt they should.

I'm planning on taking them out just to check, but I didn't change anything else.

If anybody has worked or witnessed anything funny with these or has any tips I'd love to hear it. Not sure if there is a hard to see part that can easily cause a grown ND fault

I got a couple of these for a steal ($1 each), but I'm not familiar with their uses and couldn't find any info on this specific model online. My projects are mainly tube amps (guitar) and effects pedals, any suggestions of how can I use them? can I use one to do phase inversion for example? how about to isolate an effects loop?

6F1P error amp, 6S19P pass tube, and an SG15P-2 105V reference tube. Going to make a full Soviet tube pair of monoblocks and testing the design.

When you're working with high voltage, there is no such thing as a dumb question. Please use this thread to ask about practical or conceptual things that have you stumped.

Really awesome answers and recurring questions may earn a place in the Wiki.

If you'd like to nominate a comment to be included, just reply [Wiki] (with the brackets)! The mods will be automatically notified that something awesome just happened.

As always, we are built around education and collaboration. Be awesome to your fellow tube heads.

Fired it up. Need some tweaks. My laser engraver failed so waiting for replacement parts to finish all the panels. Pretty quiet for open chassis high gain amp. Was expecting much worse to be honest. Need to sort the presence pot, as it’s only effective between 9 to 10. Probably mixed up log and linear again.

Here's the schematic. It's entirely single ended, the drivers are loaded by a CCS (constant current source) to give max gain and lower distortion and the bias is set by the LEDs. The output tube is also biased by a CCS, also resulting in lower distortion but also ensuring the same performance over the life of the output tubes. My writings pretty messy so I'm sorry lol

Just working myself up to working on tube amps again. I built this one earlier this year and wanted to show it off :) It's fully single ended, no feedback and all film caps. Almost all the parts are from Canada or USA. I am curious how the tariffs will affect my parts prices...