** Class D amplifier upgrade for your favourite boomer**

[Superduper]

Norm, I think that link you posted is for a D-class amp. At least that's what I think I read when I opened it up?

It was for this product:
https://www.parts-express.com/sure-electronics-aa-ab33182-4x100w-at-4-ohm-class-d-digital-audio-amplifier-board-sta508-(t--320-335

If you read the description, you’ll see it is advertised as perfect class-T architecture.

Anyhow you can go to the partsexpress website and view all of their t-amp offerings. Each product has links to product specs & manual. View them all but I don’t think you will find one that will mention requirement for non-common grounded input sources.

As for class D vs class T, google if you want to know the difference but in a nutshell, class T is really just class D so you can say all class T is class D but not all class D is class T. Some folks don’t even consider T an actual classification of for amplifiers.

 

[hopey]

Just use two of them or wasn't there a line isolation transformer you can use?

 

[trippy1313]

Norm, I think that link you posted is for a D-class amp. At least that's what I think I read when I opened it up?

It was for this product:
https://www.parts-express.com/sure-electronics-aa-ab33182-4x100w-at-4-ohm-class-d-digital-audio-amplifier-board-sta508-(t--320-335

If you read the description, you’ll see it is advertised as perfect class-T architecture.

Anyhow you can go to the partsexpress website and view all of their t-amp offerings. Each product has links to product specs & manual. View them all but I don’t think you will find one that will mention requirement for non-common grounded input sources.

As for class D vs class T, google if you want to know the difference but in a nutshell, class T is really just class D so you can say all class T is class D but not all class D is class T. Some folks don’t even consider T an actual classification of for amplifiers.

Okay yeah that page definitely shows it. That makes sense why the other page doesn't say T class if T-class is still actually D-class. Thanks. I'm still ignorant on the subject of amp chips. But I'm learning!!!

 

[floyd]

In my opinion a class t is a compact class d.
One thing is for sure neither one will sound as good as a class a or b or a/b.
They just use less power that's the only advantage to class d or class t amps.

 

[jimmyjimmy19702010]

The main difference between T amp Class D units and normal Class D amps is the switch rate. Many say T amps sound superior (I’m one of them)

Rest assured though, quality Hifi AB amps will sound better so for mains power applications, I’d choose AB.

However, feed a class D amp 10 D cells and be prepared to be blown away by the massive increase in power and clarity over what you’re used to. Much better battery life is also offered so you can see why class D amps are so popular with manufacturers.

If a modern ‘vintage boombox’ was ever offered and you had a choice of either a replica AB Boombox amp or a class D amp, it’s extremely unlikely you would choose AB after a listening demo.

 

[floyd]

I agree Because the class d will deliver more power therefore more clean sound.

 

[jimmyjimmy19702010]

I agree Because the class d will deliver more power therefore more clean sound.

But to be fair, we are being a little unfair to the oldies as they are 40 years old and assumidly aren’t runnng entirely to their original spec. When the occasion calls for max cranking, I usually grab one of my DIY builds instead of risking damage to my classics.

I really want a Chris right now! Talk about the best of both worlds - the power AND the look. Perfect.

 

[floyd]

I've learned over the years about when building a high-end car audio systems that is not all about power it's about balancing the system and matching the components to work together

 

[jimmyjimmy19702010]

I've learned over the years about when building a high-end car audio systems that is not all about power it's about balancing the system and matching the components to work together

True. You’ve got to get everything else right before being able to fully enjoy the benefits offered by an amp with superior output, frequency range and THD levels. For a given RMS output, it’s handy the class D amps use around 1/7th the power draw too. (Obviously not an issue with car audio applications).

 

[floyd]

In car audio class d Amps are almost used exclusively for subwoofers because of the efficiency . now in the sq category its a whole different story , class a a/b rules.
But really at the end of the day the tube amps ****ing steal the show.

There's a place about 30 minutes from me that makes some of the best car audio tube amps in the world.

 

[floyd]

I set up my 2 old skool kicker 8 inch sub's in ideal boxes and they smoke the **** out of 2 15's in mediocre boxes so that goes to show utilizing what you have makes a huge difference.

I was able to remove 2 15 inch sub's from the system because those tiny kickers are dialed in like a motherfuker.

 

[jimmyjimmy19702010]

I set up my 2 old skool kicker 8 inch sub's in ideal boxes and they smoke the shiat out of 2 15's in mediocre boxes so that goes to show utilizing what you have makes a huge difference.I was able to remove 2 15 inch sub's from the system because those tiny kickers are dialed in like a motherfuker.

Sounds like you absolutely nailed the setup of those 8s.
Love all this construction talk Floyd.

Kick arse performance on a budget - making dreams come true.

You know those ABS plastic project boxes you see around the place? Water/air tight, durable etc. They would be perfect housings for a portable unit but the plain sided ones available are just to damn small for the job:

310 mm wide is about as big as they go. The larger ones have hinged doors etc which is no good.

If we could source a manufacturer that would be interested in pumping out some M90 sized, thick walled ABS cabinets, we’d be well on our way to making something cool looking that would also although for proper tuning etc. Maybe some cool exterior classic details + some chrome trims etc. If the internal walls were part of the cabinet, we wouldn’t need an internal frame. We could also incorporate a proper fold down handle setup too.

Any ideas?

 

[floyd]

I think that 1/4 inch birch plywood with marine resin is the lightest strongest option.

 

[jimmyjimmy19702010]

I think that 1/4 inch birch plywood with marine resin is the lightest strongest option.

I was thinking something in ABS plastic to keep the ‘no wood’ guys happy. A glossy black or silver cabinet could be cool - black plastic handle with chrome metal ends like an Hitachi TRK-8080 would be easy to implement.

Real steel chromed or polished alloy driver and tweeter trims with fine mesh low sheen black metal grills. Some slits cut half depth into the rear case to simulate cooling vents + front mounted bass, treble, balance, volume and loudness controls. A pair of horizontal led VU meters with green/red LEDs and a battery indicator could complete the front panel details.

I don’t think it would cost much to simply upsize an existing cabinet design to a large, one piece vintage boombox sized cabinet to allow easy bass reflex cabinet tuning. Should be light weight too.