@@Ari_Calamari a beautiful country. I have been to Oslo three times and each time just missed out on getting to the west coast. Bergen is still on my bucket list but I finished that engineering project.
Hi my name's Dave, I'm a new subscriber from Memphis Tennessee in the states. I have worked on three Dumbles in my life, every single one of them was different, and I don't mean a little bit. Every dumble amplifier sounds different because he generally made amplifiers based on what the customer that originally purchased it wanted. He didn't put out Mass Productions of the same circuit, he was a custom amp Builder. So when somebody says "that dumble sound", what they really mean is just a good sounding amplifier, with a lot of range. Not all of them are good Blues machines, some are more on the Marshall side.
Hi Dave. Yes, that’s what I’ve read about Dumbles, too. You’re very lucky to be in a country where three Dumbles have been on your bench. I don’t think there’s even one in Australia, so I’m happy just to get to work on the clone.
@@theguitaramptech they're just handmade, clones of Fender Marshall or Vox Style, with the greatest Quality Parts and great modifications to the original circuits. The steel string singer is based off of a fender circuit. Other models are of a different layout, down to ground reference points. When Alexander dumble started out he was just modding other circuits. So he chose to do fresh builds with the modifications he was doing. Growing up in Memphis Tennessee, being a music town, a lot of artists record here and in Nashville. That's the only reason why I've seen three in my life. You just need to see some reliable schematics, there are some real ones out there.
wow ...I had no clue that the Chinese had jumped onto the D-style amp 'clone' market ...the shoddy worj that I see in there really makes me happy that I went with Ceriatone for my D-style amp. Ceriatone use quality components, beefy Transformers, Teflon coated color coded wires, top notch Zinc plated Chassis. This amp looks like it's 2 minutes away from a nightmare! Great job sorting it out, and thanks for the excellent video! Subscribed!
Thanks Daniel. I very much appreciate your comments. Sadly, I agreewith you. Yes, it sounds great now, but I have my doubts about its long-term reliability, especially with the very high B+ for the EL84's.
@@theguitaramptech yes, agreed.maybe 6V6 outputs might have been a better option. And the JJ 6V6S tubes have a lovely tonal cross of the old school 6V6 & 6L6GC tubes.
Very detailed and interesting video Chris... Note: I saw Larry Carlton (my favorite guitarist) play live twice using the real Dumble amps. I took my mom both times as she loved Larry's playing also. It was at this small interesting venue in New Jersey called Club Bene (since torn down). You could either get concert tickets or have dinner w/concert tickets. If you did the dinner/concert combo you were there a few hours earlier and got great seats. We actually, wound up in the same seats both concerts (about a year or two apart) and were only about 12 feet from Larry on the stage. Larry was the best live and I am very glad I have those memories with my dear mom. She was the one who encouraged my music and also got me interested in jazz. Phil NYC Area (Jersey Shore)
Great memories of both your mum and Larry. After my show in upstate NY I stayed in NYC for a few days and got to see Larry. I got to speak to him after the show. Lovely man.
@@theguitaramptech Very cool Chris with you talking with Larry. I wish I knew you back then and I would have met you in NYC or invited you to come down to my recording studio for a beer and do a recorded jam session. (perhaps one night in NYC and the other on the Jersey Shore!). I am 1 hour from NYC by car and 40 minutes by ferry as going across the bay NYC is only 18 miles...To drive it it is 50 miles. I live right on the shoulder (as I call it) of New Jersey which is the start of the Jersey Shore....Thanks. Phil
400V on EL84s!!! Did you mention the screen voltage with the tubes in? I have several Leslie amps that used 7189s at 400V, but they are getting hard to find at decent prices. I've been hesitant to use my El84s. Even with a questionable circuit and design, if it's not melting down and it sounds good, you have a winner! You are right to question that bias circuit. Thank you for the video!
Thank you, Ronquest. Over 400v on EL84s! It's crazy. Even though I had the bias at a sane dissipation that amount of voltage on the plate and screen is questionable. But...it sure sounded good.
Great to have you along for another video Les. I hope you are getting something out of it. Yes, Harley is a gorgeous 41kg (90lb) of pure joy. I reckon he could start his own YT channel!
I have a 118 pound Anatolian Shepherd, a true gentle giant, and he melts women's hearts at 10 meters (see photo). I used to have a Shepherd/Dobie/Rottie mix who was 105 pounds; the smartest dog I've ever known.
@@theguitaramptech , we also had an elderly Cairn terrier ( only 25 pounds) who passed away recently, so we're looking to adopt another dog, probably a bit larger than the Cairn, maybe another small-ish female Anatolian, or a small German Shepherd, both of whom became available for rescue recently. We'll see how it goes!
The bias supply is also drawn incorrectly on that schematic, because the way they show it, if you turn the bias pot all the way to one side you will totally ground out the negative bias voltage. That can't be right; at least I sure hope its merely drawn wrong and not actually built wrong!
That's exactly right! I am very respectful about modding amps, but I ended up putting a resistor in series to give the bias cct some protection. I don't believe Alexander would have done something so stupid which is how I gave myself permission to do that change.
I agree. I worked on a Ceriatone DC30. The wiring was excellent quality, but I have to say Phil’s work on a Matchless is like a Mona Lisa. If I ever catch up on my repair work, I would love to put together that Ceriatone DC30 for myself one day.
You might be right about their thinking, SRT, but that approach would not work successfully. Have a look at the series of YT videos regarding SAG. In a nutshell, you never want your filtration to fall lower than your rectified voltage or you will expose the 100/120Hz ripple and the sound will not be good. A solid state rectifier will not sag, so you want as much rectification as you can on the first reservoir cap. That's why Marshall uses 100uF. If they wanted to simulate sag, the best way would be to install series resistors on the B+, much as Weber does in their excellent Copper Top s/s rectifiers. I would have used much bigger caps (80uf or 100uF) if I had the physical space.
Sometimes you just wind up getting what you paid for. The shortcuts and poor craftsmanship done on one of the more complex and layout sensitive circuits really showed itself this time. Frustrating to watch a tech have to correct all this stuff. Good work- not sure what you charged but add that to the cost and the customer could have bought a better built amp to begin with.
Gidday Chris! I hastily read the video title & got all crosseyed & giddy thinking I was about to have a once-in-a-lifetime look inside a rare, venerable work of art! Argh! No I'm not. It's cheap chinese cheat crap instead! Dangit. All those crappy, 4 stranded white wires remind me of old jag wiring. I didn't see the word - "Sprague" on any of those 'orange drop' looking capacitors. Looks like more chinese FAKERY again! As for the half-dozen or more errors on the circuit diagram...well I'm disgusted! This was obviously deliberately misleading MISINFORMATION! Who made this amp? What actual brand is it? Just so I'll know next time when I'm in the music shop & accidentally fall over & damage one of these amps or put a foot through the speaker that I won't feel so bad about it! The distortion you spoke of must have been caused by that broken wire do you think? - or because of a dead filter capacitor? That's some dispensation that it sounds great, but next time a wire falls off it may be a negative bias pot wire that will cook the EL84's. What a heap of cheaply made JUNK!
HAHAHA! I loved reading your comments. Hilarious! Let me address the most serious one first. I LOVE Jags. I’ve owned a Mark 2 and a S1 XJ6. Once you got to know where on the fuel pump to tap your mallet, it purred like a contented kitty. Yes, this amp ** was a knock-off. The owner couldn’t afford a real one. I know I can’t afford the even look at a real Dumble so I can’t say how close it was to an original. I will never know. I was disappointed in its construction and component choices, but everything is built to a price-point. Unfortunately, there have been too many repairs since I worked on this amp, so I can’t shed any more light other than the video itself. Please let me know if you ever get to see inside a real Dumble ODS. Send photos!
Thanks for taking the time to comment, spring bloom, but I’m not sure what you were referring to. The amp? It had bad raspy distortion when I got it, and to my taste at least, it sounded great at the end of the work. Where were you feeling misled?
@@springbloom5940 Hahaha! Not even a Mesa-loving metalhead would have liked this raspy noise. Thanks for clarifying your meaning. I would hate to be doing "Click Bait".
I’m annoyed that this channel wasn’t suggested to me by the algorithm until now.
Really enjoy this.
Thanks for that Ari. Well, we have now officially met. Where are you from in the beautiful world?
@@theguitaramptech I am from Norway. 🇳🇴 😎
@@Ari_Calamari a beautiful country. I have been to Oslo three times and each time just missed out on getting to the west coast. Bergen is still on my bucket list but I finished that engineering project.
Hi my name's Dave, I'm a new subscriber from Memphis Tennessee in the states. I have worked on three Dumbles in my life, every single one of them was different, and I don't mean a little bit. Every dumble amplifier sounds different because he generally made amplifiers based on what the customer that originally purchased it wanted. He didn't put out Mass Productions of the same circuit, he was a custom amp Builder. So when somebody says "that dumble sound", what they really mean is just a good sounding amplifier, with a lot of range. Not all of them are good Blues machines, some are more on the Marshall side.
Hi Dave. Yes, that’s what I’ve read about Dumbles, too. You’re very lucky to be in a country where three Dumbles have been on your bench. I don’t think there’s even one in Australia, so I’m happy just to get to work on the clone.
@@theguitaramptech they're just handmade, clones of Fender Marshall or Vox Style, with the greatest Quality Parts and great modifications to the original circuits. The steel string singer is based off of a fender circuit. Other models are of a different layout, down to ground reference points. When Alexander dumble started out he was just modding other circuits. So he chose to do fresh builds with the modifications he was doing. Growing up in Memphis Tennessee, being a music town, a lot of artists record here and in Nashville. That's the only reason why I've seen three in my life. You just need to see some reliable schematics, there are some real ones out there.
great work Chris.The amp is still going strong and sounding great. Thanks for all your help.
It’s a gorgeous sounding amp with incredible versatility, Eddie.
wow ...I had no clue that the Chinese had jumped onto the D-style amp 'clone' market ...the shoddy worj that I see in there really makes me happy that I went with Ceriatone for my D-style amp. Ceriatone use quality components, beefy Transformers, Teflon coated color coded wires, top notch Zinc plated Chassis. This amp looks like it's 2 minutes away from a nightmare! Great job sorting it out, and thanks for the excellent video! Subscribed!
Thanks Daniel. I very much appreciate your comments. Sadly, I agreewith you. Yes, it sounds great now, but I have my doubts about its long-term reliability, especially with the very high B+ for the EL84's.
@@theguitaramptech yes, agreed.maybe 6V6 outputs might have been a better option. And the JJ 6V6S tubes have a lovely tonal cross of the old school 6V6 & 6L6GC tubes.
Very detailed and interesting video Chris...
Note: I saw Larry Carlton (my favorite guitarist) play live twice using the real Dumble amps. I took my mom both times as she loved Larry's playing also.
It was at this small interesting venue in New Jersey called Club Bene (since torn down). You could either get concert tickets or have dinner w/concert tickets.
If you did the dinner/concert combo you were there a few hours earlier and got great seats.
We actually, wound up in the same seats both concerts (about a year or two apart) and were only about 12 feet from Larry on the stage. Larry was the best live and I am very glad I have those memories with my dear mom. She was the one who encouraged my music and also got me interested in jazz.
Phil
NYC Area (Jersey Shore)
Great memories of both your mum and Larry. After my show in upstate NY I stayed in NYC for a few days and got to see Larry. I got to speak to him after the show. Lovely man.
@@theguitaramptech Very cool Chris with you talking with Larry.
I wish I knew you back then and I would have met you in NYC or invited you to come down to my recording studio for a beer and do a recorded jam session. (perhaps one night in NYC and the other on the Jersey Shore!).
I am 1 hour from NYC by car and 40 minutes by ferry as going across the bay NYC is only 18 miles...To drive it it is 50 miles. I live right on the shoulder (as I call it) of New Jersey which is the start of the Jersey Shore....Thanks.
Phil
Very Cool, Thankyou. Nice Work. Not that I would work on my amps but found this very interesting and Entertaining. Cheers from Perth WA
Thank you so much, my fellow Aussie 👍
Hey Chris, another great video mate..Lots of info and tech ...Learning all the time, thanks for sharing..Lovely dog by the way..Ed..UK..😊
Thanks Ed. 🙏 How’s our beer count coming along?
@@theguitaramptech I'm in rehab .🍺😟
@@edwardhannigan6324 HAHAHAHAHA!
400V on EL84s!!! Did you mention the screen voltage with the tubes in? I have several Leslie amps that used 7189s at 400V, but they are getting hard to find at decent prices. I've been hesitant to use my El84s.
Even with a questionable circuit and design, if it's not melting down and it sounds good, you have a winner! You are right to question that bias circuit. Thank you for the video!
Thank you, Ronquest. Over 400v on EL84s! It's crazy. Even though I had the bias at a sane dissipation that amount of voltage on the plate and screen is questionable. But...it sure sounded good.
Another great video. I love the way you combine amazing knowledge with your sense of humour. OMG! Your German Shepherd looks huge! He is gorgeous.
Great to have you along for another video Les. I hope you are getting something out of it. Yes, Harley is a gorgeous 41kg (90lb) of pure joy. I reckon he could start his own YT channel!
I have a 118 pound Anatolian Shepherd, a true gentle giant, and he melts women's hearts at 10 meters (see photo). I used to have a Shepherd/Dobie/Rottie mix who was 105 pounds; the smartest dog I've ever known.
@@goodun2974 he sounds beautiful
@@theguitaramptech , we also had an elderly Cairn terrier ( only 25 pounds) who passed away recently, so we're looking to adopt another dog, probably a bit larger than the Cairn, maybe another small-ish female Anatolian, or a small German Shepherd, both of whom became available for rescue recently. We'll see how it goes!
@@goodun2974 it sure hurts when you lose a close friend like that.
The bias supply is also drawn incorrectly on that schematic, because the way they show it, if you turn the bias pot all the way to one side you will totally ground out the negative bias voltage. That can't be right; at least I sure hope its merely drawn wrong and not actually built wrong!
That's exactly right! I am very respectful about modding amps, but I ended up putting a resistor in series to give the bias cct some protection. I don't believe Alexander would have done something so stupid which is how I gave myself permission to do that change.
I was wondering if it was a Ceriatone ODS clone....until you opened it up. No way that kind of wiring would come out of Nick's shop.
I agree. I worked on a Ceriatone DC30. The wiring was excellent quality, but I have to say Phil’s work on a Matchless is like a Mona Lisa. If I ever catch up on my repair work, I would love to put together that Ceriatone DC30 for myself one day.
Good job!!
Thanks Peter!
Beautiful classic design tho
I totally agree! If it stays reliable, it will bring the owner much happiness.
Maybe they were trying to duplicate the sag of a tube rectifier, by lowering the reservoir cap value?
You might be right about their thinking, SRT, but that approach would not work successfully. Have a look at the series of YT videos regarding SAG. In a nutshell, you never want your filtration to fall lower than your rectified voltage or you will expose the 100/120Hz ripple and the sound will not be good. A solid state rectifier will not sag, so you want as much rectification as you can on the first reservoir cap. That's why Marshall uses 100uF. If they wanted to simulate sag, the best way would be to install series resistors on the B+, much as Weber does in their excellent Copper Top s/s rectifiers. I would have used much bigger caps (80uf or 100uF) if I had the physical space.
So, errors and crappy work aside, this amp seems designed to eat EL84s.
HAHAHA! It sure looks that way, Bladder. I am sure some people simply forget to look up the RCA tube manual when spec'ing a transformer.
What is the % of the green ‘alligator’ IPA? It must still work I guess if you’re using it😊
I think its about 65%
mr dumbledore
I felt more like Mr Grumblebum after that one, Ian.
Do you think there are any real Dumbles in Australia? I’ve never seen one.
Sometimes you just wind up getting what you paid for. The shortcuts and poor craftsmanship done on one of the more complex and layout sensitive circuits really showed itself this time. Frustrating to watch a tech have to correct all this stuff. Good work- not sure what you charged but add that to the cost and the customer could have bought a better built amp to begin with.
True words, Frugal. I hope it holds up for a few years now.
Gidday Chris! I hastily read the video title & got all crosseyed & giddy thinking I was about to have a once-in-a-lifetime look inside a rare, venerable work of art!
Argh! No I'm not. It's cheap chinese cheat crap instead! Dangit. All those crappy, 4 stranded white wires remind me of old jag wiring. I didn't see the word - "Sprague" on any of those 'orange drop' looking capacitors. Looks like more chinese FAKERY again!
As for the half-dozen or more errors on the circuit diagram...well I'm disgusted! This was obviously deliberately misleading MISINFORMATION!
Who made this amp? What actual brand is it? Just so I'll know next time when I'm in the music shop & accidentally fall over & damage one of these amps or put a foot through the speaker that I won't feel so bad about it!
The distortion you spoke of must have been caused by that broken wire do you think? - or because of a dead filter capacitor?
That's some dispensation that it sounds great, but next time a wire falls off it may be a negative bias pot wire that will cook the EL84's.
What a heap of cheaply made JUNK!
HAHAHA! I loved reading your comments. Hilarious!
Let me address the most serious one first. I LOVE Jags. I’ve owned a Mark 2 and a S1 XJ6. Once you got to know where on the fuel pump to tap your mallet, it purred like a contented kitty.
Yes, this amp ** was a knock-off. The owner couldn’t afford a real one. I know I can’t afford the even look at a real Dumble so I can’t say how close it was to an original. I will never know. I was disappointed in its construction and component choices, but everything is built to a price-point.
Unfortunately, there have been too many repairs since I worked on this amp, so I can’t shed any more light other than the video itself. Please let me know if you ever get to see inside a real Dumble ODS. Send photos!
Totally misleading title 🙄
Thanks for taking the time to comment, spring bloom, but I’m not sure what you were referring to. The amp? It had bad raspy distortion when I got it, and to my taste at least, it sounded great at the end of the work. Where were you feeling misled?
@@theguitaramptech
I was being snarky. Im a metalhead, so 'nasty distortion' sounded like a good thing. Interesting video, nonetheless.
@@springbloom5940 Hahaha! Not even a Mesa-loving metalhead would have liked this raspy noise. Thanks for clarifying your meaning. I would hate to be doing "Click Bait".