Redgum is an Australian brand I really wanted to be able to write great things about when I repaired and serviced this Redgum RGi120 integrated amplifier.

Being completely independent and running a website entirely without advertising means I always say exactly what I think. I’m not swayed by anyone else, I don’t owe anyone any favours and nor am I impressed by the paid-for-by-advertising mainstream media who’ll say anything for a dollar.

Sadly, despite wanting to, I couldn’t find much good to say about this Redgum RGi120 integrated amplifier. Angry fanboys and pitchfork-wielding evangelists notwithstanding, I posted the truth about what I found inside this Redgum RGi120, as Liquid Audio customers and visitors expect. Read on to see what I found.

Updated for 2019 and 2022: A couple of people did come after me, but with the typical emotion-rich and evidence-poor responses we see in such cases. You can read some of them and my replies in the comments below.

Disclaimer

Everything in this article is based on my objective examination of this Redgum RGi120 amplifier. I am not paid or sponsored by anyone. This article presents my opinions and experiences, from the perspective of a specialist hi-fi electronics repairer. They do not purport to represent all Redgum products, other Redgum products may differ and things may have changed since this unit was manufactured.

Article Goes Crazy

Someone mentioned this article on a local hi-fi forum and things went crazy. I received over 600 hits in one day, my greatest to that point. The manufacturer even responded, stating that using better parts would not make any difference, an extraordinary claim and one that is factually incorrect. Redgum stated that they use the lowest quality parts they need, to build the amplifier and have it function, hardly a shining endorsement of their design and manufacturing philosophy.

I initially pulled the post but then made it public again, my feeling being that users deserve to be informed about what is inside the gear they buy. I’m not scared by fanboys or the manufacturer, actually, I’m not paid by or afraid of anyone. I’m a completely independent repairer and writer. I provide information that helps people make informed decisions. Equipment like this Redgum RGi120 amplifier exists in the public domain and is therefore subject to public scrutiny.

Readers can make up their own minds about what I found. I have no agenda, other than to debunk bullsh#t and to examine the engineering behind audio equipment. I have nothing against Redgum, or any other manufacturer for that matter. I just love well-engineered equipment, without silly and superfluous garnishment.

I’ll also make the point that it takes courage to step out from the crowd and write an article like this, knowing that there might be retaliation or retribution. That’s why you don’t see many articles like this. Do you think the manufacturer is going to send any work my way, even though I may be the best qualified to do it?

My Second Redgum

I hadn’t (at this point in 2014) worked on other Redgum gear before except for a sub-woofer amp. I have however worked on a great deal of hi-fi and laboratory gear over the years. I’d heard rumours that Redgum gear was overpriced and used low-grade parts. I was able to find out for myself when a customer brought in a Redgum RGi120 amplifier for service.

One of the twin volume controls (more on that later) had come loose and the speaker connectors were also loose. Popping the lid, I was surprised by what I found. The Redgum RGi120 chassis contained two small amplifier boards populated by very cheap components, attached to a fan-cooled heatsink. Sundry other low-quality power supply input and chassis parts completed the build.

Fan cooling enables smaller heatsinks to be used than would otherwise be possible with convection cooling. This is usually done to save money, small heatsinks and fans are cheaper to manufacture and than large heatsinks. The Krell KSA-150 for example operates in class-A and generates an enormous amount of heat, but there is no fan to be found. Krell went down the path of massive heatsinking, which is costly, but quiet and very reliable.

Altronics for example sells ‘PA’ style amps like this, with seemingly high power outputs (into an unspecified load, at an unspecified power bandwidth), for a low cost. These products are cheap partly because they use small fan-cooled heatsinks and cheap Chinese parts. Most of this gear is also made in China.

Cheap Parts

The capacitors in this Redgum RGi120 are low-spec Lelon and Samwha brand parts. These are not what one would expect to find in products that cost close to $3,000 AUD (in 2010!). The main filter capacitors are Lelon brand and similar in quality to the other small caps.

I strongly dislike Lelon capacitors and other cheap Chinese caps like them. In my opinion, they do not belong in an amplifier like this, and yes they really DO make a difference sonically and in terms of reliability. There are lots of cheap ‘green caps’, which are a metalised polyester capacitor. Film types by ERO/Wima/Siemens have better characteristics, but of course, cost more.

The transformer is a cheap Chinese toroid. It looks to be around 300VA max, which really is marginal for the power spec of the amp and again a way to save money. The output transistors are Exicon MOSFETs. Exicon is a brand known to be associated with fakes of other higher-spec transistors in the past – you can read about this here. I’ve had some success using real ie old Exicons, but there is a lot of variance with these devices.

For those who mistakenly think that parts don’t matter, I can only say that science and ears say they do. I know how premium parts make a real difference in reliability and performance. Capacitors and semiconductors vary enormously between nominally similar parts. Spending a few cents more per part will potentially decrease a manufacturer’s margin, but will potentially add increased service life and improved technical performance to a product.

Peddlers of the ‘cheapest is good enough’ approach are either unaware of the merits of using better parts or are hiding something. The merits of using better parts are easy to justify, plus we have two very refined instruments called ears and they prove that when we use quality parts, performance always improves.

The owner of Redgum operates (or did) with this cheap parts philosophy and to a point, I agree – a good design, using cheap parts will still sound good. But the same design using really good parts will sound even better, so there’s that.

Questionable Value

To be clear – I am not saying that there is anything fake or counterfeit in this Redgum RGi120. In my opinion, a manufacturer like Redgum would never knowingly use fake parts. What I am saying is that for your $AUD2,650 I believe you deserve a better build and bill of materials.

Yes, this amp is made in Australia, which is great! My concern is that this amplifier be made with high-reliability, high-quality parts. Everything about this amp would be better with better parts, especially low ESR, high ripple current, high temperature Panasonic/Elna/Nichicon/Nippon Chemi Con/Rubycon capacitors.

The boards are quite simple and nicely laid out and are of reasonable quality at this price, all good points. Assembly adhesives are used to hold parts to one another and this is good practice in places. Trimpots are locked with sealant to prevent movement, but the mechanical construction of the chassis and the wiring is crude.

Poor Design

Trying to maintain channel balance is hard (almost impossible) when you have to adjust two volume controls independently. Seriously, who ever thought that using two separate volume controls was a good idea? I have seen rubber bands placed around these dual volume controls in an attempt to get them to move in sync with one another! This is simply a stupid design choice.

On the Redgum website, they talk about how having two volume controls is “better for sound” (Really? Now you care about sound but parts don’t matter??) because the number of contacts in the signal path is reduced by using dual mono pots.

Nonsense! The number of contacts in the signal path is exactly the same whether using one stereo pot or two mono pots. Each channel has exactly the same number of contacts, same signal path etc! It’s this pseudo-scientific nonsense that reduces brand credibility and that commenters defending the brand fall for.

This is a bad design choice, guaranteed to generate channel imbalance. It’s no surprise that almost all other manufacturers use one volume control, with a balance control that can be used to correct minor channel imbalances as needed. Perhaps we should ask Accuphase, Mark Levinson or Nelson Pass why they choose not to use dual-mono volume controls?!

As for the amp having a ‘key’ to turn it on, the less said about that the better. A good way to guard against theft I guess. Just don’t lose the key, or leave it in the ‘ignition’! 🤣

A Better Way

If in doubt, ask yourself this: why is it that HP/Agilent, Marconi, and Tektronix test and measurement instruments, the gold standard in engineering excellence, always contain premium parts?

This gear is used by the military, NASA, NSA, CIA, FBI, Lockheed-Martin, Boeing etc. They buy the best and purchase equipment that can deliver the specified performance for decades sometimes. Parts matter and if manufacturers want the best performance, they choose the best parts.

As for the loose volume knob I spoke about earlier, these volume shafts with knobs attached are held to the potentiometer shaft by a small piece of engine cooling or fuel hose, the same hose you might find in your local auto parts store. These have been hand-cut to length and then glued to the potentiometer shafts.

Let’s just say that I was shocked when I first looked inside this thing. Sure, it works and I am a fan of simple solutions, but there are more elegant and robust solutions to this problem. The volume knob had just been pulled out of the rubber hose because the glue had failed. The shafts didn’t even line up with the potentiometer mountings.

Perhaps that explains the cooling hose and the flexibility this allows because normally, angles like this would be dealt with by small universal joints, like the ones found in this Yamaha CA-2010 for example:

Because of how the shafts are angled, relative to the case, the knobs are also not square to the front panel, nor can they ever be. Perhaps Redgum has improved things since this amplifier was made – I sincerely hope so.

Food for Thought

My goal here wasn’t to harm or upset anyone, it was to raise awareness. There aren’t many unbiased and truly independent writers able to write pieces like this, and I really appreciate the support from those who understand that.

For those who think I might be out to get Redgum, ask yourself which is more likely to be true:

• That a respected, independent repairer who’s been contributing positively to the hi-fi community for over a decade would one day wake up and decide to attack an Australian hi-fi manufacturer for no reason? Or,
• That this repairer simply found an expensive product that isn’t very well made and wanted people to know about it despite the personal risk in doing so, knowing the mainstream hi-fi press won’t ever mention it?

As always, thanks for reading. You’ll see there are some robust discussions in the comments, so check that out and feel free to leave a comment of your own. Just remember to be respectful!