Hypothetical Amp Discussion

[Aiden101]

Hi guys,

This is my first ever post. This place is an information treasure trove. I've been so impressed by all of the amazingly cool stuff that people have built here. I've clocked up around 15 hours of reading here in the last 3 days alone—all of it well spent and genuinely fascinating.

Now, to my topic. I was having a conversation with a friend while setting up our pedalboards at a jam session, and the topic of amps came up. I was telling him about how I joined this site and how I'd love to begin building a Dumble-style amp at some stage this year.

We've both got the same amp at the moment, Marshall DSL40CRs, which have served us well so far, to be honest, but the dream would be to eventually get that final piece of the puzzle at some stage. Hopefully, I can build one.

Anyway, we got talking about how the DSL40's effects loop is digital rather than tube-driven. This sparked a conversation about creating the ideal tube amp with a dual series and parallel effects loop. The idea would be to have the best of both worlds: drives into the front of the amp, then the series loop could have modulation, delays, and an always-on reverb in it. The parallel loop could then have a more expansive reverb or some of the more crazy ambient effects I have, like a Chase Bliss Mood or Microcosm, etc., and I could blend them in nicely while retaining some clarity on my dry signal.

I already have something like this set up on an HX Stomp on my board at the moment, and it does sound great, but we started laughing at the idea of having both loops being tube-driven... And joked that we might as well throw in a tube-driven reverb tank in there too. That's a lot of tubes! 4 preamps, 2 power amps, 2 for each effects loop and (correct me if I'm wrong here) for reverb, do you need two tubes? One to drive it and one for recovery? So that would make 10 tubes in total???

I said I would post here and ask if anything like that has been done before?

I'd imagine that something like that would be incredibly power-hungry as well as expensive. I'm guessing that the circuitry would be very complicated as well.

Actually, I assume that cost, complexity, maintenance, size, weight, heat output, power consumption, and the fact that it would only appeal to a niche market would be logical enough reasons for not doing it. Obviously, not that many people would need a setup like that, but I think it would be cool all the same.

I’d love to hear some thoughts on this. Is there an engineering reason for why it's not really a thing?

Thanks,
Aiden

[TUBEDUDE]

One tube per effects loop. Maybe half a tube, if you can steal the drive signal from the signal chain. . And if using a 6AW8 It's the only tube needed for both reverb drive and recovery.
Anything can be done. To pull it off though you'll need a bit of experience. Have you built much, and have extensive soldering experience?

[Aiden101]

Hey, I haven't ever built an amp before but would love to try at some stage for sure.

Don't think I'll try one that complicated, it's probably too much for the first ever build, better to start with something simple and work my way up from there...

I have a lot of soldering and PCB design experience though. I've designed and built loads of stuff in the past, everything from LoRa radio network transmitters/receivers to home automation devices and even a quadcopter at one stage. I'll attach some pictures of a proximity tracking device I made.

Any advice on what would be a good starting point?

[Stephen1966]

Do you use the DSL40CRs dirty channel? Ever? The clean channel is actually not that bad with those amps but the onboard effects loop is a tone-sucker. Is it a pedal platform you are looking for?

I will elaborate on that. First, I should warn you, prototyping is an expensive business. Sometimes you aren't going to know a thing works until you try it and it will inevitably mean trying lots of alternatives. If you are any good with LTSpice you can model most things (more or less) but you will still end up forking out for things you will never use in the end.

4 preamps, 2 power amps, 2 for each effects loop and (correct me if I'm wrong here) for reverb, do you need two tubes? One to drive it and one for recovery? So that would make 10 tubes in total???

No. I'm not being funny, but think about it.

You have part of your hypothetical amp with the idea of the dual loops and a reverb. Why not try drawing up a block diagram of it? You are already half way there. Personally, I'm not really sure what you would hope to achieve with a loop into the front end. Maybe I misunderstood, but aren't you just talking about putting some effects between the guitar and the amp input! After you have the block diagram pencilled out you could figure where the drivers are, what tone stack you are going to use, if it will have a master volume and where that will be - pre or post phase inverter. For the headroom you want watts, lots of them so a LTP phase inverter. Then, you have to take a seat and make a bill of materials. You will need to sit down for that.

In the meantime, you need to start reading around and trying to understand what the Dumble amps are good at. The clean channel of an ODS can do a great job with pedals but you would never use the overdrive section, just like you probably never use the od of your Marshall now. The Steel String Singer comes closest to your pedal platform, high power/headroom requirements. That's like jumping in at the deep end and if you think it's going to be as easy as painting by numbers, prepare to be disillusioned.

Otherwise, yeah man! Go for it.

[martin manning]

I already have something like this set up on an HX Stomp on my board at the moment, and it does sound great, but we started laughing at the idea of having both loops being tube-driven... And joked that we might as well throw in a tube-driven reverb tank in there too. That's a lot of tubes! 4 preamps, 2 power amps, 2 for each effects loop and (correct me if I'm wrong here) for reverb, do you need two tubes? One to drive it and one for recovery? So that would make 10 tubes in total???

I said I would post here and ask if anything like that has been done before?

I'd imagine that something like that would be incredibly power-hungry as well as expensive. I'm guessing that the circuitry would be very complicated as well.

Actually, I assume that cost, complexity, maintenance, size, weight, heat output, power consumption, and the fact that it would only appeal to a niche market would be logical enough reasons for not doing it. Obviously, not that many people would need a setup like that, but I think it would be cool all the same.

Probably yes, people have tried just about everything.
Aren't you answering your own questions here? It would be difficult to get all of this dialed in, and you list some very good reasons for not going there.

Have a listen to the recent YouTube featuring Robin Ford's ODS 102. Different guitars, different players, clean and OD. https://ampgarage.com/forum/viewtopic.p ... 59#p466259

"Signal chain etc…
When Robben is playing, he uses three pedals. All into the front, no FX loop. Clean channel on the Dumble.
• Hermida Audio Zendrive
• Strymon TimeLine"

Allow me to quote from your signature: "Simplicity is the ultimate sophistication."

[Aiden101]

Do you use the DSL40CRs dirty channel? Ever? The clean channel is actually not that bad with those amps but the onboard effects loop is a tone-sucker. Is it a pedal platform you are looking for?

I rarely use it. Yeah, the clean channel is pretty good on it, I've always enjoyed playing it. The effect loop is a real tone sucker, especially with some reverb pedals. I actually put an Exotic EP Boost at the end of it to try and counter the volume drop.

Yeah, definitely looking for a pedal platform.

No loops into the front of the amp, I only have a tube screamer and a boost going into the front of the amp, everything else is in the effect loop.

I'll check out the steel string singer's.

As for building an amp, as I said, I'd like to try and build 'something' but need to be realistic in regards to complexity and also time.

I've two young kids so time is the biggest issue for me these days. It's not something I take lightly so when I start a project, regardless of it being short term or long term, I tend to properly prioritise time for it, otherwise it's unlikely to see completion and a waste of valuable and precious time.

What would you recommend as a starter amp? Would it be a better learning experience to start with a kit or with a full build?

[Aiden101]

Probably yes, people have tried just about everything.
Aren't you answering your own questions here? It would be difficult to get all of this dialed in, and you list some very good reasons for not going there.

Hi Martin, yes, I was just thinking out loud, apologies for the long winded post. Just thought it was an interesting discussion at the time.

That's a great episode of TPS, that amp sounds unbelievable.

As for my quote, I try and adhere to that principle at work and for the most part, it works very well but outside of that, I've yet to reign in the volume of pedals on my pedalboard. It seems to be ever increasing, both in number and complexity .

[GAStan]

What would you recommend as a starter amp? Would it be a better learning experience to start with a kit or with a full build?

Have you had a look at Rob Robinette's site? He has a lot of info on building amps, you might find a good first build there.

My first build was a kit from Mojotone, their Studio One Watt, rated "Easy". Nice little practice amp but IMHO may not be much of a challenge depending on your experience. I put together a pedal kit that was more challenging. There are several other kits that would definitely be more challenging, I'm just sharing my own first hand experience.

After that kit build I discovered this site and am on my 4th Dumble style build. If you decide to go this route I definitely suggest #124 because it's the best documented one.

[Stephen1966]

What would you recommend as a starter amp? Would it be a better learning experience to start with a kit or with a full build?

Only you can really answer that.

We know of quite a few amps that make good/great pedal platforms but the caveat is how much time, money and energy you have to invest. We also have no idea what you consider "complex". At the risk of sounding like my elders: "Remember! When you build something complicated, it can go wrong in complicated ways. "

On paper, a kit is going to be less bothersome because someone has figured out the main points of a build and has assembled (collected and supplied) all/most of the parts for you. They usually provide good documentation for the build and you will end up with a working amp you will feel immensely proud to have built yourself. You might not learn very much in the process though. If it's a working amp you want then maybe that's all you need. It can still be a vehicle for learning but you understand those who put these kits together are not necessarily trying to provide or obtain a learning experience as such.

If you really want to learn something though you can go the self-build route; start with the easiest thing you can think of and work up, from there. Making sure to understand everything or as much as possible as you go. Many people start with a Fender Champ. It's really a very simple amp with a handful of components. Or if it's something that you can gig with and that will take pedals nicely, there is the Tweedle Dee.

Honestly, there is a lot you can do, I personally went the self-build route and spent over a year on this site (more like two years actually) just reading and researching before I asked my first question.

Nothing ventured nothing gained as they say, but just ask yourself how far you are willing to go and what it is that you truly want.

[TUBEDUDE]

It looks like you have some soldering experience. A Champ is an easy build, but you might not really use it for much more than a training tool. A Deluxe might be of more use. It has a little more complexity. It might be a good starter for you as the circuit is push pull, like the amp you will finally create, has some usable power, and will be more of a challenge.