ok so what the heck can make the amp, solid state, 2008 Crate .... hum, cant hear it while playing but annoying after not playing. ......... Tried noise gat e but that chokes my guitar, but it does queten the hum. My guitar didnt cause hum on a different amp, so I dont think its the guitar.
Mine lost signal after a cap job I butchered, then fixed (put one cap in backwds and applied pwr; replaced it w/ a new one) Now nothing But it doesn't hum anymore!
Ha! You mounted the volume in the off set hole next to the jack! Right on! Sounds good! These are great little double ended amps. You can do a lot with the transformers if they’re totally rebuilt (the amp,not the trannies)as well. Not many 8-12 watt guitar amps out there with two output tubes! Here’s a couple different Ao44 “Spartacus” builds I did ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-P3JGK4jH-2I.html
I've got a 70watt version from 82 I picked up a few months back and use for bass. Perfect for nice gritty fat P bass tone in a blues power trio. However, I should have went through her first. Apparently the previous owner stuck a 3 amp instead of a 2.5 amp fuse in her and she cooked last night taking the tubes with her. Hopefully the damage isn't too severe. Gonna have to spend my Sunday going through her. Our drummer noticed the jewel power indicator light pulsing while I was playing. Any idea what might cause that besides an incorrect fuse?
Hey I found a late seventies Bassman 10 silverface combo at a music store is asking $426 for it. It's missing the grill cloth they said they just had it checked out by an amp Tech everything works. Is that a good price???
Super cool video, Mark. I'll review this lesson if and when my son's Fender stops working. His amp has been in our family, along with his Japanese Fender Precision bass for 30-odd years :) Both are still going strong.
Thank you HTA! I have one of these that has sat unused FOREVER. So for kicks and grins I pulled the fuse and found it was blown. So I have some 2.5 A 250V Slow Blow Fuses on the way from Amazon. I don't suspect it will be that simple. I have viewed this video several times in anticipation. Do you have any suggestions other than the thorough visual inspection for obvious defects and checking the pots, solder joints? Again thanks much for the video. It's really the only good look at one of these on YT!
String Bender, It's nearly certain that it won't be "that simple". Something failed in the amp and caused the fuse to blow. You should plan on replacing those big brown electrolytic capacitors in the power supply for sure. One of the power tubes could have shorted elements. There are dozens of things that could cause the problem .. and it's impossible to diagnose those in a YT forum. Your best bet is to track down a good tech and take to the shop. That's a valuable amp and worth maintaining IMO. Good luck.
Thank you so much for this video!!!! My Trace Elliot recently went down and most repair shops are tube snobs where I live in England so, VERY unhelpful! This made perfect sense to me thanks to you explaining it so clearly. Opened mine up, went through, found the issues....same problem! Cheap/shoddy jacks that had oxidised! Problems solved. THANK YOU SO MUCH!!!!!
It's a long shot, but with my solid state guitar head the light is on when it's plugged in (power switch on or off), and the power switch doesn't do anything, and it will not produce sound
Yep seen this problem before! Dont know how many peavey ive seen with this issue. Ive threatened to pull those cliff style jacks out and use regular old switchcrafts with leads down to the board but never actually have yet.
I have one of these, but it’s from a 1940s model my Dad got from some American soldiers in New Guinea during the war. It seems to be set up slightly differently from yours which I think is from the 1950s.
There's some junk in the pre-amp section that I usually strip out, and I add a fuse to the power line, and replace all the electrolytics .. other than that, it's mostly stock.
HammerToneAmps . Thank you for responding. so, I ask.. because I noticed you only had the ez81 and a pair of 6gwb's. iwas curious if you used tweed champ preamp or valco ? maybe your own design. Iam assuming you used the triode side for the preamp.
This one uses the existing triode arrangement in the amp which uses one triode section for a gain stage and the other for a phase splitter. The pentode sections are a push-pull output stage. If one were looking at the AO-44 schematic .. remove everything to the left of V1, except for R7. Wire an input jack straight to the junction of V1 pin1 and R7. I also remove R16, which is the feedback loop. I also recommend replacing the big electrolytic cap, which encompasses C11 thru C14.
This board looks similar to one of a GK700RB. I replaced a broken Input jack a few weeks ago. It wasnt easy because the board has tiny conducting paths on top and below which can be easy damaged. Replacement Jack: Neutrik NRJ4HF
I have just figured out why there are no skilled amp technicians or micro electronic hardware engineers making these videos, simply if they broadcast all the fixes for mediocre problems, they will be doing themselves out of at least $100 bucks, at least an hour,. It is frustrating, greatest respect to you sir, i simply wouldnt bother a little knowledge can be a dangerous factor. an exsasperated soundless solid state amp guy.
I was working on a Marshall VS100 with the same (real) Cliff jacks. During the diagnosis and cleaning I figured a lil' emery cloth would clean up the oxidized jacks pretty well. Amp owner told me a few days later he was looking online and read NEVER clean Cliff jacks with a heavy grit medium; it will take a "coating" off the metal contacts. Maybe he was trying for a discount... I donno, I was working for free anyway... and he helped me! New caps and the Marshall is screamin'! So scrape at your own peril. (Best just to replace.)
Actually made these from 67 to 77 (50 watt vers). I have a 72 that I use for guitar and it is the best sounding amp EVER!! It's the basic amp design (original Bassman) Marshall copied to make their first 50 watt heads. So it's basically a 50 Marshall head with built In 4x10 cab! Incredible amps!!
This was a really great video! I hope you are still making these! I'll try to find more after this post. I always enjoy watching someone's diagnostic approach to diagnose and repair circuitry; especially when they explain what it is that they are looking for, and what they expect to find at each point along the way. This demonstrates that you have a thorough understanding of the signal path. In my mind, this is the very best way to make any kind of tutorial. If all of your videos take this approach to diagnosis and repair, anyone with the interest in learning about audio amplification diagnostics would benefit greatly by watching your videos! This is the first video of yours that I have seen, and look forward to watching some more! Currently, I am diagnosing failure(s) in a Pioneer SX-1080 stereo receiver, and suspect parasitic oscillation as the primary cause of failure. I found this video while searching for some mixed frequency content injection techniques, as I am going to try to reproduce the oscillation (the oscillation is not present at idle, nor with a fixed frequency test signal (20-20Khz), incremental). Just my two cents : Anytime you can make a repair without the soldering iron is welcome! I will take those kinds of jobs anytime. That's always sweet. I have always preferred to remove the PCB; I have never used a mirror. But I must confess, a mirror could save a lot of time if it will fit! As far as the corrosion in the jack(s) is concerned (outside of ingress of a compound into the jack itself), the most likely cause of corrosion would be the metallurgical differences between the 1/4" male plug that goes into the contacts of the female jack (there could have also been some environmental issues at play as well). Almost all cheaply made jacks (especially these days) are made out of some really crappy (impure) metals, and will corrode when making physical contact with other types of metals. Especially when there are currents flowing through them. Thank you for making this video!
I read its just a pentatonic tuning... But seems very nice to me (although i didn't analyze any pentatonic tune up to now) plus... He likely learned this tuning from Gurdieff teachings... ...
Right away you should’ve tried patching the cable between the send and return of the effects loop as those normally closed jacks can often get dirty or worn to where they’re not making contact and passing the signal from the preamp to the power section anymore. When you were poking at them with the signal tracer and only getting signal on one side of the tip contacts that should’ve been a dead giveaway.
I just purchased one of these and replaced all the Electrolytic caps,anode resistors and resoldered with a 60w iron. Mine had been used by a piano accordion player since the late 80's and has a factory original cover. All speakers are good. I rewired the bias for individual control of each tube and bypassed the balance pot which I've seen cause trouble in other amps. My favorite tone is with the Studio Chanel set Bass 2 Mid 10 Treble 2 Volume 7 Master 5 Oh sweet Cheese's With my Gretsch Roundup rear pickup its a rock n roll machine. Still has all original tubes .
Great video, people should not go into virgin vintage amps without a videorecorder running. Thanks so much. Probably a grounding issue on the pots... Great you didn't change the capacitors. Next guys would have clipped them before anything. Please keep "um" coming!
Nice work. I'm diagnosing a Peavey Valveking 212 right now that has no signal on the lead channel. clean channel is fine. I was just about to type "buy some de-oxit" and as i was typing you mentioned it. LOL
Hi, could you please tell me about the socket savers you are using in this video and where you got them? I've never seen these with breakouts, great design to allow measurements from the socket side. This allows you to confirm voltages at the point of the tube pins vs. at the solder tabs inside the amp...especially the control grid. Great way to find intermitten connections in tube socket or loss of bias. Very cool, I need to get me some! Thanks for the nice video and any help on finding these sockets.
@ Blake I found all those on eBay by searching for "tube test sockets". "Back in the day" the primary manufacturers were Vector, Pomona, and CBS/Hytron. They're somewhat rare .. it took me several months to accumulate a usable inventory.
@Mark, thank you for the tip, I will try that out. I'm a little too young for those "days" yet most my interests lie in the "golden years" of tubes, test gear and guitar amps and especially Craftsmanship. Thanks again
