Drops soon. This series will release once a month.

Try lower capacitance cables (shorter cables)

Yeah that's exactly the flaw the loop had. I fixed it in the end, but the amp in general sounds better with the stock values. THe mod that fixes the loop changes the sound of the amp a bit that I find is not better. I deleted the stupid loop in my Jet City all together.

Drop soon ! Series will be an EP a month.

Thanks !

I think I know the vid you're talking about. I saw one in my research where he explained that tubes were quieter back in the day, and that amps now need the DC heaters. I avoid NOS tubes, I jsut try to find a sound I like out of modern tubes, that way I can replace or recreate the sound I get. I take it this SLO30 uses full size 6L6's ? The tubes will still wear out if you run the amp regularly. Heat cycling from turning the amp on and off, and well, the small tubes are running hard regardless of volume. The power tubes will last longer, and lower volumes means they are less effected by microphonics. My best advice for long tube life, is to avoid turning the amp on and off a lot, and never used the standby.

@@DATT I only use the standby on start up for 10 to 20 secs and on shut down so it doesn't pop, a few secs. Old RCA tubes NOS are very consistent. But they are very expensive. If you can find them from a reliable source. And they are very durable. Much better made than modern tubes. They do something to the sound that is hard to explain. Nothing that can be heard in a YT video and barely in a good recording. But it is magic. They warm up the highs in a way that you can run the treble up and it doesn't get shrill. And that reacts with the mids. Hard to explain, but when you turn down the highs with stock tubes, the mids are also effected. The bass effects the mids too. The depth control is great as you can adjust for tone and up or down the depth to match it's output. Kind of the same with presence, though it does more and doesn't always work in that way. . It can though. And like I might have mentioned, the effects loop is amazing. I ran the wets through the front for awhile until I got the cables and what a difference. I believe it only goes through the power tubes. It came new with 5881's I think the tubes I put in are 6L6 I forgot what type Maybe Sylvanias from the 60's. More headroom and a better tone.

@@chuckyz2 Oh yeah, it's funny all there new amps running 30 watts but with full sized tubes. As I recall, just run them at lower voltage. I guess you're ok with 10-20sec of standby, I won't use it at all for startup to avoid inrush current. I haven heard of the "magic" of Nos Tubes, but it also makes me question how many diff types of fresh modern tubes have you compared in that amp ?

@@DATT I have a few other amps. And I have tried a few. 12ax7 JJ are ok. THey sound good to me. Close to the RCA. Electro Harmonics, ARS, Tung Sol. THe tung Sols are creamy but bland. They don't last. Early 50's RCA 6V6 in my Tweed Deluxe Clone They are amazing. All old RCA's in pre amp. I get the same results on the pre amp tubs in all my amps. The character of the tubes is there whatever I put them in. I thought the inrush of current on startup is bad for caps, but the SLO has over rated and it's not an issue. With my deluxe, it is an issue. From what I have heard the standby stops the spike. But it's not good to leave it on past that. The caps in the deluxe are rated like the originals. The voltage goes up way past that for a bit. Takes about 12 to 15 secs for it to settle. I have a pair Eurotubes bias probes I used to monitor the voltages and currents for biasing and checking to see the tubes are matched. Love those probes. I got all anal on this stuff when a russian tube went bad and took out my switching cip on the DSL15H. It was my first tube amp and I had a hard time finding a new chip. Even Marshall gave me the wrong part #. I bought another amp because I missed playing. I pulled the chip on that one and tested the 1rst amp to confirm it was the chip. I need to sell those because the Deluxe and SLO are all I use now.

For 12ax7 I like JJ for part of the preamp that generates distortion, but not phase inverter. TungSol's I like them of Phase inverter and buffers but not distortion generators. For Standby, Inrush happens more when you use the standby, you flick that switch it hits the caps, you turn on the amp with it already on, maybe a little less, but still hits the caps. Standby on when you turn the amp on, power starts to flow gradually as the tubes heat up. Turn standby on after turning on the amp with hot tubes, inrush hits the tubes. What happened was back in the day, when fender was trying to cut corners, they has cap rated like, lets say 450v in a 440v amp, but before the tubes were hot to flow current, it meant when you turned the amp on, before the load would drop to voltage, the caps would see too much voltage at first. Fender added a standby to work around that. Then, Marshal copied fender, and everybody else copied marshal, and we have a bad habit that has been passed down generation, and even to amp makers know better now, they add it because people expect it. On many new amps the Standby is a faux standby, and just a mute switch that doesn't actually cut power to the circuit or do any of the "standby" things. If you recal, your grandma radio and TV back in the day, had no standby, amps didn't have them till fender. You don't need it. Design manuals of the time say right in them, you don't need a standby, the only reason it comes up in convo because there are specialy commercial and industrial tubes back in the day that did need to be preheated, receiving tubes at they are called, do not need standby and can damage them as they are not designed to be hot without power applied, it can burn off coatings on the annode or something like that. Standby will also add heat cycles to your tubes if you use it like a "between set" mute like a lot of people do as the operating temperature of a tube, and the heat temp of a tube are far apart. I learned that about 10 years ago, I stopped using the standby, except for servicing, and I find my tubes have stayed sounding fresher and tighter longer, compared to back in the day, when I used to use it all the time I found tubes wore out even tho I hadn't played them that much.

Yeah, that's what they have here, for the FX loop Mod, those it's listed as 25 in this schem I think, same thing. I think i actually ended up with much more in the end.

Yeah I think I noticed that. Which sucks. Surely they must have another model ? Seems to be tricky finding rotary switches that have the ratings needed for a good speaker switch.

Oh well, hammond makes all sort of good transformers. The 300 series has universal primary, the might have a similar unit in the 200 series that is a bit cheaper. I'm not too worried about power transformers cause you can get away with a range. Like when I first got me Jet, it had a blown PT, I just jammed one from an old traynor in there and it worked. I havent' really payed attention to other transformer brands. The need for one doesn't come up very often, so I havent' kept on top of it, and when I haven't needed one, I just picked a hammond that I knew would work. Half the reason is they are Canadian, so I'll try to prefer them.

Yeah I don't know the tube shields are that important. Is yours a clone ?

@@DATT No it's an original, avenger though.

@@81giorikas Ohh, well that's going to be a different amp than this I think. Likely they updated the heater circuit.

The SLO choke is rated 10H 200ma, they don't list an impedance. I don't know that it has to be 200ma, that end of the circuit certainly doesn't consume that much. One could look at the 193J, or 193JP for matching specs.

@@DATT Thank you frend.

@@miguelrichartmellado2834 You're Welcome !

Unfortunately this kit was not from a company, and I don't know off the top of my head what companies make SLO kits. Some guy we found on Kijiji put it together using Ebay parts from Russia.

I will be making references to his page thru this series. Lots of good info on that site.

Hmm, maybe there are more differences on the MK2, or, is yours modded ? TBH, I didn't pay attention to the output impedance.

@@DATT Well it pretty much should be set from the master volume shouldn't it? Isn't that in series with the tonestack output impedance and it is a voltage divider all the time in the same time but it is the not grounded out that goes in the loop.

@@81giorikas I'm having trouble finding a schematic for the avenger to visualize it. The MV follows the tonestack usually. It's common in more modern amps, with proper FX loops that the loop follows the MV, usually there is a buffer of some sort. So the MV goes to a buffer stage that feeds the loop. Then there is recovery. I guess you could get away with MV direct to the loop out.

@@DATT The loop on the JCA 22H and SLO mk2 is pretty much the same, follows the master volume into a buffer as you said. BUT my question is when the master volume is low on settings, the output impedance going into the loop maybe closer hundreds of kohms...then even the buffer circuit may not prevent hi end roll off and is at a point of the circuit that is noticeable. On higher settings it shouldn't be as noticeable. You want (ideally) 10-20 times bigger input impedance vs the output impedance to prevent this. The avenger I was refering about the tube shields but you are right there are not many schematics on the net about the loop. I've traced mine and it is an anode out of the 4th stage, no cathode follower. That goes to a cap, voltage divider to drop the signal (220K/2.2K) and the output impedance is ok-ish at about 2 kohms. To boost the gain back up it uses the SLO return stage with cathode follower driving the stack but it has 22uf in that cathode bypass (2.2K resistor and 100K anode by the way vs the 220K anode on the SLOs). None of these damn loops works great in high volumes!!! In the studio the most ideal is to take the effects loop out and slave to another amp for the repeats only...

@@81giorikas I have to admit, I have trouble following this conversation without looking over schematics with a person in the same room as me. Also, I never really did much looking into the finer points of input and output impedance, so I'm not exactly sure how they work together. Part of me feels like Soldano didn't either and that why the loops have the flaws they did. But then, I feel like neither did Fender or Marshall. They just adjusted with formulas that they knew worked. If an output jack is connected directly to a volume pot, I would imagine the impedance would lower as you turn it down.

Rosamp ? is that a kit maker. Nothing to really compare, this kit was put together by a guy on Kijiji.

Ah no, V1 is def the most sensitive, by merit of the subsequent stages amplifying whatever it picks up. So, a 12ax7 has 2 gain sections, First section is the first stage of the preamp, the second is part of the "clean channel". With a 220k anode and 1.8k cathode, that first stage is about as high gain as it can get. It's "low gain" because it's not really generating any distortion, it's just taking the signal from your guitar, boosting it, and sending it down range. The signal it outputs is still relatively clean. The next few stages, like the cold clipper are actually generating the distortion. People often get distortion and gain confused. The cold clipper is actually the lowest gain stage in the circuit, kind of intended to normalize the internal levels, the stages before it can boost quite a bit, then the cold clipper brings the signal back down to a normal level that the rest of the circuit can handle. Eitherway, any noise the first stage picks up, will get exaggerated.

@@DATT thanks for explaining. What also should minimize noise would be changing the grid resistor to a metal film version wouldn’t it?

@@Johnsormani The grid resistor, you mean on the power tubes ? The power section is not that sensitive, hence they need a strong preamp signal to drive them, so they aren't that susceptible to noise. I choose metal films there more cause they are made to tight tolerances so I can make sure everything is balanced. Honestly, the best things one can do to make this thing quieter, would be to set it up with a DC heater supply on V1 and maybe V2, and if that doesn't do it, one might look at the ground scheme like I did, which is more complicated to do in an already built amp.

@@DATT no I meant on the grid of v1 first stage ( 68k)

@@Johnsormani Oh, you could but it might be negligible. If the resistors are creating noise, you'll won't even be able to hear changing just one, it's a cumulative effect. Replacing all the resistors on the amp might be noticeable. It'll also likely change the tone a bit because of stacked tolerances. IF I recall correctly more noise is generated by the capacitors. I'm not exactly sure which ones are quieter. IF the amp is noisy and you can to quiet it, me last comment about the DC heaters and Grounding still stand.