Glassware 12vac Aikido vs SRPP Line stage

[Hederiform]

In laymans terms, what is the difference between Glass ware 12vac Aikido vs SRPP Line stage pre-amps? Which is better?

[1Michael]

The word better is subjective. Perhaps you should provide more information, assuming your not a bot.

[JonMarsh]

In laymans terms, what is the difference between Glass ware 12vac Aikido vs SRPP Line stage pre-amps? Which is better?

What is YOUR criteria for better? Just curious, really. I could put them on my Audio Precision APx555 and tell you how they measure, but that wouldn't take into account user interface, compatibility with the rest of your system, and your own personal preferences, which may not be strictly neutral- and they don't have to be. The question in my mind, is what is better for you? And we don't know your criteria. Other than you like vacuum tube gear... having used a fair amount of that way back when, I can relate (70's) but I'll compare, for example, the bench performance of the Schitt Audio Freja with 6SN7 vacuum tubes or pure passive mode, versus the gen 2 version with their current mode differential amplifiers, with pure passive, active unity gain, and active with gain, and my APx tells me the passive mode is much cleaner than one of my favorite vacuum tubes from way back (the 6SN7), and the version with current mode amplifiers is very clean and much more flexible in usage, given the gain and load driving capabilities.

One point to bring up, apparent from a quick read through on their site, the 12VAC Aikido is designed to work from a 12VAC source, such as a "wall wart", though I might personally be inclined to build something specific using standard small power transformers... because Wall Warts aren't usually line isolated and have no EMI isolation.

This is the product page for the Aikido, which is relatively free of any pesky specs or performance graphs.

http://glass-ware.store.turbify.net/aikido12vac.html

This is the product page for the SRPP 12VAC, PCB cost is the same.

http://glass-ware.store.turbify.net/12vacsrpp.html

Here's their descriptive copy:

Stereo SRPP Amplifiers

This board holds two SRPP line amplifiers. The SRPP circuit provides low distortion and the distinctive tube sound. The SRPP delivers roughly a gain equal to half the triode's amplification factor (mu). As the PCB is so small, it can be fitted into existing solid-state audio equipment, such as CD players, which are large empty. The SRPP can then be used to superimpose lush tube sound on otherwise cold-sounding gear.

Now, based on my experience playing in bands to work my way through high school and college, on keyboards and guitar, and my experience helping build small recording studios in Boulder CO, and building custom high performance phono preamps, this sounds like a device intended to add a specific coloration or sound, most likely 2nd harmonic distortion. This unfortunately generally impacts IMD in negative ways, as can be seen from spectral analysis.

This reminds me of items like the recently released HRM (Hot Rubber Monkey, from J. Rocket Audio Design) pedal, which is, as the Guitar World review goes, "a beautifully voiced Dumble-style drive pedal of the sort that encourages you to keep playing". Dumble amplifiers are a very limited production (no longer produced, as the Howard is deceased) with very nice clean tonality as well as superior sonics when you push them... so this pedal might be inserted into the signal chain of an otherwise "cold" amplifier to help recreate a specific kind of sound. Many of the top artists you hear have Dumble amplifiers, and they are very prized, even used commanding six figure prices. There are companies also attempting to recreate that sound at a more affordable (relatively speaking- $4K for a small amp head is pricey for many working musicians) and there is good reason for it. For example, one of my favorite guitarists, Eric Johnson, uses Dumble amplifiers in live and studio work.


A well executed system doesn't sound "cold", it sounds "transparent". But individual components may have design choices that weigh against that kind of transparency- this is why there is a market for Schnerzinger mods to some high end solid state preamps, which I have heard. As well as their excellent cables. Again, the comparison to the versions of the Schitt Audio Freja preamp seem pretty relevant.

https://www.schnerzinger.com/english/

I have personally heard some of Scherzinger modified gear and cables with a close friend that used to live in Germany (back in Singapore now) and I can attest to the results.

Regarding Glassware's web site, the prices are reasonable for bare PCB's, but IMO there's nothing "heavy duty" about 2 oz copper boards; I used to design pro audio gear and 3oz was normal for us with 0.093 PCBs. In the 70's. I did search a bit for technical performance data, but not extensively- didn't come across any.

But, you know, that doesn't mean building these wouldn't be fun.

In case my comments seem snarky (and perhaps they are snarky) in my past life I have been Engineering director for a small but reasonably successful pro audio company that was sold to Taco/EV, and have 35 years experience in product definition and applications engineering for an international semiconductor company, so I do have some experience and expectations.

OTOH, we're all into DIY Audio for the fun, and if these projects spark joy for you, then get them both and compare!

[JonMarsh]

I'm going to toss in one more idea for consideration, that may be a viable path to what you are searching for sonically... you could even use this in conjunction with one of these line preamp modules, though I would suggest trying it out alone.


Sigfreid Linkwitz was investigating some system voicing issues before his passing, based on the psychosacoustics of how hearing works for stereo recordings, and came up with some specific recommendations.



I built some simple balanced modules to go between preamplifier and power amplifier to test this out, and shared this with a number of HTG members.

This is a PDF I put together on this topic..


System Voicing Update.pdf




This is one of the follow up threads on this topic...

https://www.htguide.com/forum/missio...-investigation


the actual implementation for amplifiers with typical input impedance around 100K is quite simple...





I recommend considering this approach for any system designed and measuring flat in room. It can also be quite useful for rooms that are reflective acoustically and with speakers with very wide dispersion in such rooms (like the Isiris!)

The owner of my original Wavecor Ardent build has this in his system, and is quite happy with the effect.