Just found your channel and really appreciate your understanding of the high gain circuitry. Been playing for over fifty years, first amp an AC 30 followed by a blonde Tremolux to a Quad Reverb. Too heavy to carry and sold, looking for a 1x12 combo and got the 1x12 Soldano Astroverb combo. A really well built amp albeit PCB mounted valves but it sounds great. It will see me out for the rest of my gigging days.
That’s one of the downside to them. As long as the board isn’t too heat effected, cleaning the old crispy flux is a smart idea as it can exacerbate the issues.
The loop mod as shown on the most common SLOD schematic was engineered by me to calm the loop down from a nominal level of +10dbu to a more useable 0dbu. It is still a line level loop, but the original loop was 6-10db too hot for most line level gear. I can't tell if that added cap is an attempt to implement my mod, but I don't see the send level being attenuated. If done properly the loop mod will not significantly alter the sound or feel of the amp. The amp still won't work well with a delay in the loop, if you want to switch between channels, because the loop return level changes depending on where the Master Volume is set. Not a well designed loop imo.
So did Eric Clapton and Mark Knopfler. That’s what’s great about the SLO design, it’s not just a one trick fire breathing machine. It has its limitations, but it’s a great sounding amp across both channels.
@@drgearaustralia Exactly my thoughts. When I'm ready, I really want to build something on top of the SLO design but leaving the (highly inspirational!) monster channel and just have a clean and light/medium crunch on tap. Probably with separate volume pots to balance the gain jump on the crunch side. Not sure if that makes sense though but might be an interesting experiment. I wonder how the SLO clean compares to a Hiwatt one. I know the designs are totally different, and the tone control has different turning points but we'll see :)
Hello there! Nice video. I just build my first SLO and I’ve been looking for mods. I actually really liked a 12ay7 on v2. It makes the gain knob much more usable. Before it would get muddy after 11 o’clock. I get it that’s a high gain amp and all, but for instance why is there a 22nf decoupling cap on v2 plate instead 2nf? That would make the drive channel less muddy.
Every amp tech loves to talk crap about the previous tech. I'm guilty of this myself but... just know that the next tech will be talking crap about you. And it doesn't matter if you've done a great job or not, it's an ego thing. None of us are immune.
I only talk crap when the "other tech" does crap work. And then only to other techs who will "get it". I was taught never to talk bad about my competitors to my customers. It just makes you (me) look bad. I will talk about design errors and things that affect tone, and offer to make it better. I will also point out when the work that was previously done is going to raise the cost of repairing an amp because of damaged traces, burned insulation, sub-standard soldering etc.. It is our duty to report the condition of an amp to the customer. Telling the truth is not "talking crap".
Ah funny you should ask, the next video contains info about how to bias an amp using a multimeter and some measurements to get an accurate plate current without exposing yourself to massive high voltage.
I have a soldano lucky 13 100watt combo. Trying to track down the source of some hiss and noise. I replaced all the 12ax7s and still has it. Would you happen to have the schematic for it?
I noticed the transformers are all on the same plane. Does their proximity negate the issue a Marshall would have with power and output transformers directly next to each other?
There’s a lot of factors that go into transformer placement to minimize cross talk and whatnot. Some Marshall’s were placed incorrectly and coupled, especially the 30th Anniversary 6100 models.
What are your thoughts on PI tubes. Do you think the triodes need to be perfectly matched, or is there an acceptable range you think they can be out from each other?
Matched PI tubes aren’t really a major concern in most guitar circuits and in fact, having it slightly unbalanced results in some excellent 2nd order harmonics.
@@drgearaustralia Oh okay, ya, thats cool you say that, because I was having a conversation with a buddy, and he was saying tat too, so Im actually like I hope someone else confirms this lol. Thanks brotha!
I've always thought that while you're working on an amp, the repairs should make the amp look like it hasn't been touched, i.e. the repair work should not look very obvious.
That’s generally the idea, however sometimes it’s impossible to avoid and sometimes circuits need some work that is apparent. Mesa Mark V and Fender Hotrod Deluxe amps come to mind when talking about apparent repairs to fix design faults.
@@drgearaustralia Those Fender HotRod Deluxe amps do suffer from their fair share of design flaws too, I've never really liked the sound of them, the cleans sound fine, but the overdrive always did sound a bit harsh and grainy to me, and no guesses as to where the tone-stack is placed in them...right after the first gain-stage before the signal goes to the second gain-stage, the basic flaw with that design is that no matter how you tweak the tone-stack the signal coming out of the second gain-stage ends up as a heavily clipped waveform, that's why Mesa/Boogies and Fender HotRod Deluxes sound the way they do, too much bass going into the second gain-stage which leads to horrible-sounding blocking distortion, which causes the "Fartyness".
@@simonkormendy849 This is not a rule of thumb. First of all with marks, you obviously tailor the bass going in with the tonestack. Secondly there are designs like CAE, brunetti, bogner with huge bass caps between the gain stages and they sound great with no blocking distortion. It's the whole circuit and amp and cab that plays a role. Thirdly even in the hot rod deluxes, you can just boost from the front and get a lot of mileage.
@@drgearaustralia I kind of skipped through the first part. What mods did they perform. There are like a million of small things you can do in this circuit.
I totally agree 100% about what you said about Mesa/Boogie amps, and Mr Randall Smith has the hide to charge 5-grand plus for his badly designed high-gain amps.
Nice to know that there's someone else who agrees with me that Mesa/Boogie put the tone-stack in the wrong place in their amps, I once tried playing through a Mesa/Boogie Nomad 45W amp, the one with 4 10inch speakers, I could get a reasonably good clean tone out of it, but when I tried dialling-in a good overdrive tone, all I could get was a very harsh, cold and farty sound out of it, and Mesa/Boogie say in their ads tone Tone TONE....if harsh, cold, and farty is their idea of great guitar tone there must be some pretty tone-deaf people working for Mesa/Boogie, and I'm a monkey's uncle.
It’s a hallmark of the Mark series amps and their derivatives. Very early eq and gain controls with little other stage filtering, so you’ve really gotta pull the eq in line with the rotary controls. Of all the things to take umbridge with on Mesa products, it’s definitely the least problematic. You know, compared to their awful PCBs, lack of service documentation, terrible lead dress, propensity for noise and insistence on using 400v caps in crucial circuit blocks that see over 500v. There shall be many a Mesa rant on this channel as time goes on.
@@drgearaustralia Yep, I agree, there's one amp tech on youtube, The Guitologist, who has serviced a few of those Mesa/boogie Mark series of amps and he always complains about the circuit boards in them, I've read/heard stories about Mesa/Boogie deliberately introducing errors into their schematics as a way to protect their intellectual property, when you really look at the design of the Mark series of amps, there's nothing really special about them, they are really just hot-rodded/modded Fender amps, I've also heard/read stories about Mesa/Boogie stealing/copying amp design ideas from Mike Soldano, the Dual Rectifier circuit looks a lot like the Soldano SLO 100 circuit to me, I really don't know why Mesa/Boogie are going to great lengths to protect their intellectual property when a lot of the design ideas they use are actually standard electronic design ideas, Mesa/Boogie always make it very hard for non-Mesa/Boogie amp techs to get the service info they need to fix Mesa/Boogie products, Mesa/Boogie also used to get very narky about criticism of their products too.
Yeah I take anything he says with a spoon of salt as he’s incredibly hit or miss and there are many more techs I look up to who’s opinions I take seriously. The rectifier/SLO/5150 debate is silly as there’s very little original in guitar amp design, and every time something new is created, elements of it are taken. That’s the core of electronics and engineering. There are big differences between the SLO and Rectifier circuits, however they share comparable topologies including things like the cold clipper stage that adds so much of the tone.
I'll give you a nickel's worth free advice don't shit talk those who were there before you. It just makes you look petty and really doesn't serve any purpose.
Good thing the advice is free because it’s worthless. If someone does bad work and rips off a customer to the tube of several hundred dollars, they deserve to be called out for it and for an explanation given to to customers so they might avoid a similar situation in future.
@@drgearaustraliaThen call them out. We don't know if this was Bell Labs or some poor guitar tech in a Siberian hotel room with the owner screaming at him to do anything to make it work. It is not like a customer would never lie to you to make himself not look so stupid.
Except, if you watch the video carefully you’ll notice I say something to the effect of their being a video of him repairing this amp on RU-vid. So there’s receipts for the work and the statements I made. I assume by your use of Bell Labs as an example that you’re from the US and have a very different culture when it comes to faux neutrality and ‘civility’. Here in Australia, we don’t believe in any of that.
It's a bit sad how you have to slag off the competition like you are the only one who knows shit. Replacing the transformer because it's 10 years old WTF? Caps maybe if it has very high hours. I remember when I was selling boutique Virgil Arlo pickups for $1000 and you slagged me off "ridiculous! just some wire and some magnets" and now you sell $1000 Custom Shop SD pickups. Rubbishing early Mesa amps! Hilarious!
Whatever dude. You obviously didn’t watch the video or listen to anything I said so there’s nothing else to say. Besides, I can see old conversations we had several years ago and you’re not worth taking seriously and have no real standing for any criticism.
If you have some secret way of making low volume products at a similar margin to high volume products, I’d love to hear it. Some products are over priced for sure. However, whenever you make limited runs of a product with high quality components that aren’t bought in quantities of thousands, custom fabbed transformers and offer customization for orders, then much of it can be explained by economies of scale. Paying $6K for another clone of a Fender Deluxe or Dumble style circuit? Pointless to me. However, an amp like a Soldano is using an original circuit, high quality components inside and out, incredibly thick chassis steel and those Deyoung transformers wouldn’t be cheap. If you only make a few hundred amps a year, unless you’re making large margins on them, you’re not gonna be in business long. I’m sure if they made 10,000 a year and made 15% profit on them and got parts at top buy in quantities, then yeah they could bang them out for cheap in the same way Jet City did or Behringer still do, but that’s not how these are done.
@@drgearaustralia You hit the nail on the head. "Margins". How much profit margin is enough? And what is the profit margin? Should you make 100% profit margin? Or maybe 50% is enough? Some of these guys are making 400% profit margin. That's BS to me. Not just the boutique builders, but the big name mass-produced stuff too. That stuff is made in 3rd-world countries with slave labor, and cheap parts. But they still charge a lot of money for them. It's a scam. People are waking up to it.
@@TheCyberMantisa small boutique amp builder just makes a small amount of amps per year and still has all the overhead of running the business, marketing etc. So they need more than 50% or 100% of profit to keep the company afloat. Then there is also the international distributors that take a share and,of course the dealers. Soldano had some,product they made only 200 pieces of and had to develop them anyway. It’s also a choice of the owner to scale up and predict if the amp would sell 10000 pieces a year at a far lower price ( probably not) , in the end earning the same profit
Given their broad appeal across artists as diverse as Clapton, EVH, Killswitch Engage and more, I’d say they’re pretty damned solid and sound good. Usually comes down to the musician though.