Making the move from P-P tube power to Class D/T power...

[chops]

Right now I'm using an old (1955 vintage) converted Baldwin Organ Co. push-pull tube amp running a pair of 5U4G rectifier tubes, a pair of 5751 driver tubes and a matched quad of coin-base Russian 6N3C-E output tubes (equivalent to 6L6GC). It is rated somewhere between 23-28 watts per channel into an 8 ohm load. This amp has some major balls!

This is a very good sounding, very robust amplifier that has no problems feeding power hungry speakers such as my trusty NHT 2.9's (87dB 1w/1m) or my more efficient DIY towers (guessing around 89-90dB 1w/1m). Loads of extremely deep, extremely tight bass, natural, full mids and smooth, extended highs.




I think I am wanting to switch over to a small and simple Class D/T amp because for one, the Baldwin amp is really my brother's and I'd like to give it back to him since I fixed it and got it back up and running (it was totally dead when he had it). The other reason I want to switch over is because I don't always have a chance to run my system for extended periods of time and don't want to have the tube amp on just for an hour or less. Plus there are plenty of days when I'm off that I will easily have the system running for more than 16 hours straight.

I'd rather have a Class D/T amp that I can power up and listen for a little while, then turn right back off. Plus I really like the idea of "building" my own amplifier.

I have heard that a lot of these digital amps start producing quite a bit of THD once they reach about half of their total output power. So for that reason, I want to get the highest power amp(s) I can within reason.

I've been seeing a lot of mention of the Sure kits from PE and others such as Connex, Hypex, Hifimediy and a few others.

One that has really caught my eye is the Hifimediy T3 amp set that consists of 2 x T3 amps and 2 “T3e” PSU boards. I'm very interested in this set as it is essentially a dual mono design which also requires two 48V Meanwell S-350-48 power supplies to power the stereo pair.

I think this amp set would be perfect for me as it doesn't have a built-in volume pot. I'm using an Accuphase C-200 preamp so the volume pots would be discarded anyway. I'm sure I can modify the amps some by replacing/upgrading the various caps in the signal chain as well as in the PSU boards. Maybe even use a toroid transformer PS instead of the Meanwell units? Possibly put a rather large bank of PS capacitors in it for great power reserves? I don't even know if anything like that would be needed with these amps.


Anyway, I'm posting this thread as I'm looking for help, suggestions, pointers in what to do and what to possibly go with. I just started looking at all the different amp kits/sets last night, so not too much research as of yet. I've got a good idea about what's out there and what to look for, but I know there's a lot I don't know yet either.

Anything you guys can offer will be greatly appreciated! Many thanks in advance!

[Speedysteve7]

I had (still have) a PP Class A KT88 amp. Draws 300+W all the time. Was using it on a variety of speakers. Always drove them all more to my satisfaction than fair few SS I've tried.
I got into the same situation as you. Wanted to have music on more, more on/off & what I would call background music of lower quality e.g. streaming, mp3s etc.

I found a T-amp would not run less efficient speakers.
The T-amp ran out of puff on other speakers (bass) and tinny treble perhaps because the bass was missing.

Having made uber efficient front loaded horns I found that 1 little T-amp would drive them to about 95% sound quality of the tube amp.
They are 110+dB/W apart from the tweeter is only around 105dB/W

Now I have 5 T-amps one for each way and this set up sounds good, total draw just 15W and as you say they are instant on / off. I think they sound better after about 5 mins of running.
Going dedicated amp per speaker pair I could ditch the L-pads and this made the whole sound preferable over just one really great tube amp.

So if you are using inefficient speakers you need higher power ones than the 20 and 25W ones I am using.

[chops]

The Hifimediy T3 amps I'm looking at are rated to 150w @ 8 ohms, which my speakers are. The DIY speakers I'll be using these amps on are roughly 89-90dB efficient. They should have more than enough drive from my speakers.

I just need to know more about these particular T3 amps. I want to use them as two individual mono amps, one powering each speaker for a true "dual mono" setup. This means two power supplies and two chassis'.

I want to find out what I can about the T3 amp "set" before I order, so I know what I can do to it further down the road as far as modding it goes. And if anyone has any say about the sound quality of these amps.

[stokessd]

I'm an electrostatis speaker fan, and I've built and refurbished a bunch of tube amplifiers. I was running a 35 watt stereo tube amp with my quads, but lately I've switched over to a set of Hypex UcD 180 modules and I'm very happy. The tube amp is very musical, but not without coloration (and it's very low distortion by tube amp standards). The Hypex amps are in a whole other league, I've got three different Tripath designs and a couple ICEPower boards as well to compare. All three of the class D amps are impressive, the tripath designs the least so.


Sheldon

[chops]

So I guess no one has any experience with these T3 amps?

[kristleifur]

They're being discussed in a few other threads, you'll find them quickly if you search

[Bernie7]

I have built both UCD400HG monos (with HxR and linear supplies) and the T3 monos with Meanwell smps.

I find myself preferring to use the T3. My speakers are Swan F2.2.

Yes, do some searching to find more reports on the sound of hifimediy modules.

[chops]

Originally Posted by kristleifur

They're being discussed in a few other threads, you'll find them quickly if you search

Originally Posted by Bernie7

I have built both UCD400HG monos (with HxR and linear supplies) and the T3 monos with Meanwell smps.

I find myself preferring to use the T3. My speakers are Swan F2.2.

Yes, do some searching to find more reports on the sound of hifimediy modules.

I have searched, and have found a few threads regarding various Hifimediy amps, but not the T3 mono amps or mods made to them. I'll try searching some more but doubt I'll find what I'm looking for.

Also, who's a good source for quality chassis' to install all of the electronics in?

[chops]

Hmm... Looks like I'm on my own with this one.

[dangus]

There's at least one article on a switching amp in AudioXpress this year.

I would give preference to an amp that includes a clipping indicator; otherwise you have no real idea what the headroom is like.

I've used basic Hammond chassis boxes and bolted a 19" rack panel to the front. For a fancier look, use a panel of exotic hardwood, etched glass or acrylic, engraved aluminum. Middle Atlantic Products made some homely but solid steel cases, (in the USA, last time I bought one).