Tube Amp Doctor - 6550A-STR Premium - Power Tubes
Thank you for visiting The Audio Tailor.
We’re Stuart, Gabby, Liam and Vaughan. It’s a pleasure to have you here!
The first question we get from customers usually starts with, “What’s the difference between...”
When you’re shopping for new speakers, a turntable, or even thinking of putting together that home theatre of your teenage dreams - you’ll likely be faced with stacks of comparisons.
Why would I buy the Bluesound Pulse 2i when the Flex 2i is half the price?
Is Tube Amp Doctor the best?
Should I wait for a sale? Or get this now? What will I be missing out on when the new model comes out next year?
Endless questions. Lots of FOMO. Loads of hmm-ing and ha-ing.
And there SHOULD be.
Because you don’t go to a Hi-Fi store and drop $2000, $3000, or $15000 on something you're not 100%, positively, secure-in-your heart sure of.
It’s a lot of hard-earned money on the line.
Imagine doing hours of your own research. Reading up the suppliers’ websites, taking notes from Hi Fi blogs, categorizing the differing opinions as you trawl r/audiophile. You know what you’re getting. You’ve narrowed the online stores down to the final five. You’ve checked and re-checked that you’re getting the best deal. You’re sure you’re not getting ripped off by shipping.
You hit the “Checkout” button. Momentary relief!
Until your speakers haven’t arrived by the estimated delivery date and you have yet to hear a peep about its progress.
Until your new turntable arrives with a crack in the dust cover.
Until your long-awaited amp set-up fails to deliver the kind of sound you had in mind. Now you’re not even sure if you got the right one anymore, or how to troubleshoot it.
What could possibly be worse?
What about: No after-sales service. No phone number to call. And no one responding to your tickets.
Not to mention the hundreds of man hours you’ve already lost on reading layman opinions from the likes of Graham H. from Melbourne and Sarah D. from Perth; dutifully scrolling through pages and pages of reviews. Torturing yourself by looking for all the ones with less than 3 stars... when you could have been sitting back and diving into a whole new world of immersive sound and deliciously satisfying body vibrations.
Would it make sense to go to audio specialists that know brands, specs, and installation like the back of their hands?
Should you spend less time on weighing up pros and cons and more time enjoying good music?
Want to get the absolute best home theatre for your budget and surroundings without the weight of 100++ brand offerings bogging you down?
We like to think so!
And that’s why we’re here. Two things to know about us:
Thing 1: We were voted Australia’s 2021 Hi Fi Retailer of the Year (Yay! And THANK YOU!)
Thing 2: This is purely because we are sound specialists and audioheads - NOT salesmen.
We got into this business because we genuinely love audio and because we realized there was a lot of faceless dropshipping in the HiFi industry - and not enough expertise out there. People who keep coming back to us do so because they’re getting attention to detail and individualized solutions that they can’t find elsewhere.
Our clients don’t need to worry about budget, brand name, or size.
All they need to worry about, is talking to us.
Because, when you come to us, you’re in for a conversation.
We want to know the picture in your head.
That final portrait of you back from the flea market with Pearl Jam’s Ten, eager to place it gently upon a turntable you haven’t quite decided on yet.
A summer barbeque in your garden with the boys. Having a yarn around a beer-filled cooler while appreciating the crisp, clear, quality of sound streaming through the open doors of your listening space.
The kids having mates over - quiet for once - immersed in a good movie, lights out, in the comfort of the home theatre that is your pride and joy. “I wish we had one of these at our place!”
Once we know precisely what your ultimate scenario looks like, we’ll want to know what you’re working with.
What kind of budget have you set aside?
What’s the existing set-up look like?
How big is the listening room you have in mind?
How much ambient light is coming in?
Are you running drywall or wood panelling? Carpet or hardwood?
What about room resonance and reflection?
No idea what we’re going on about? No worries. We intend to talk you through all that. Our aim is that you get the absolute best sound system for your home, at a price point you’re happy with, and an aesthetic you can’t help but want to show off.
To get to this end goal, an unhealthy interest in all things audio simply isn’t enough. That’s why we spend countless hours behind the scenes sourcing products from only the most reliable brands and trustworthy suppliers - regardless of their branding and marketing.
We don’t rely on them to tell us what’s good about their equipment. We’ve developed our own proactive testing process to judge what’s what. So you get hands-on knowledge every single time. Coupled with our tight networks and stable supply chain meticulously refined over the years, we strive to ensure that the experience you get at The Audio Tailor is personal, seamless, and painless.
Personal, because it’s uniquely you in musicality, design, and taste. Your options are hand picked by us from amongst some of the world’s biggest, best, and most dependable brands.
Seamless, because we’re only small. You get one of us. Not one of dozens of salesmen milling about the place, working for commission and pushing the most expensive products.
Painless, because we don’t recommend anything until we’re clear about your needs. We follow up with you to make sure everything’s arrived in one piece. For us, the transaction isn’t over until your equipment is safely installed and fully satisfying.
Some of the big things we feel are missing in the HiFi world are:
- The need for expertise before, during, and after the sale
- A vast wealth of comparative knowledge, and
- A commitment to end-to-end service.
At The Audio Tailor, we hope we’ve made it clear that service doesn’t shut off when a problem pops up. It’s an opportunity to tighten the ship we run, bolster our 5-star reputation, and most importantly - make someone’s day.
Hi! We see you’ve actually made it to the end of this page. Love it!
We’d like to end this by giving a shout out to all the enthusiasts and audiophiles we’ve been fortunate enough to work with over the years. It has been a privilege to share our desire, passion, and journey for the purest sound and finest entertainment solutions for your homes and businesses.
Thank you to all our customers - past, present, and future - for helping us chase after something above the ordinary.
To make your audio dreams come true - call, email, or hop on down to our Brisbane store.
We’re looking forward to meeting you!
Smooth, Liquid Bass, Natural Sounding Tone
The TADtm 6550A-STR is a glass envelop ban power pentode having a plate dissipation rating of 42 Watts with convection cooling. It is intended for the use in high power audio frequency amplification in either pentode, ultra-linear or triode connection and can be used in single or push-pull/parallel applications. The 6550A-STR has an indirectly-heated oxide cathode, which ay be DC operated for the absolute best hum/noise performance.
Its plate is made from a stronger and purer laminated material that improves heat transfer and has superior performance under high power conditions which are often seen with guitar amplifiers and especially in bass amps. Close manufacturing specification tolerances and improved processing provide enhanced reliability and superior sonic performance. The 6550A-STR gives electrical and audio performance very similar to that of the legendary original GE 6550A and is hence very suited for High End applications also.
Since Sept. 2010, the TAD 6550A-STR has been manufactured with a stronger and exceptionally pure anode material combination. In conjunction with the extended TAD burn-in and formating process, the 6550A-STR reaches an outstanding consistency and stability and outperformes even the 6550C -C-.
This makes the 6550A-STR withstand even the most critical application like e.g. the Ampeg SVT. (Fits only without the tube retainer!)
The TAD 6550A-STR is a true remake of the vintage GE 6550A with a heavy, straight glass envelope, polished metal base and the authentic triple getter construction. A balanced tube, known for its incredible bottom end and rich mids. Smooth, liquid bass, natural sounding tone and a wide open character make this tube extremely popular for bass guitar amps and High End Hi-Fi applications. The ratings of the TAD 6550C-STR meet or exceed those of the classic 6550A tubes. It performs superbly in any application asking for 6550.
Q: When does a power tube become a Premium Selected power tube?
A: All power tubes labeled Premium Selected have passed the following tests:
- Plate Current (PC) and Amplification (TC)
- Low Noise Test
- Microphonic Test
- Sonic Tests
- Shock Tests
- Listening Tests
- Shorts and Leakage Tests
Premium RT-Matching of Power Tubes - Our Premium Matching is an exact matching of power tubes with identical Plate Current (PC) and Transconductance (TC).
TAD Premium Selected tubes are guaranteed for a period of 6 months (according to terms of warranties) for the quality criteria mentioned above.
- Voltage (AC or DC) - 5.8V(min), 6.3V(nom.), 6.8V(max)
- Current - ca 1.6A
cathode-to-heater potential, max - +200V
Direct interelectrode capacitances, max*** -
- Grid no.1 to cathode and grid no.3, and grid no.2 - base sleeve and heater <15pF
- Plate to Cathode and grid no.3, grid no.2 - Base sleeve and heater <10pF / grid no.1 <0.85pF
- Operating position - Vertical only
- Base - JEDEC #8ET, octal, 8-pin
- Dimensions - 116mm (height),103mm (seated height), 45mm (diameter)
- Cooling - Convection
- Approximate net weight - 75g
AF Power Amplifier
- DC plate voltage - 680V
- Grid no.2 DC (screen) voltage - 440V
- Grid no.1 (control) voltage - -300V
- DC Cathode current - 190mA
- Grid no.2 DC (screen) dissipation - 6W
- Bulb Temperature (surface hottest point) - 250 degrees celcius
AF Power Amplifier, Class A1 (single tube)
- Plate Voltage - 400V
- Grid 2 screen voltage - 225V
- Grid 1 control voltage* - -16.5V
- Peak AF Grid 1 control voltage - 14V
- Zero signal plate current - 87mA
- Maximum signal plate current - 105mA
- Zero signal grid 2 screen current (avg) - 9mA
- Transconductance (nominal) - ca 11,000 mS
- Load resistance - 3000 Ohms
- Output power at 5% distortion - 10W