Building 400 wpc Tube Monoblocks....

madmax

Its way more fun (and safer) to build 1 watt amps and 100+ db efficient speakers.

Good luck and don't forget to turn on the AC this winter.

sm88

Outfitter03 wrote: »

In my reading I have been under the impression that watt ratings on Tube Amplifiers vs Solid State are not an apples to apples comparison, just as they are not a good apples to apples comparison from an AVR to high current solid state power amplifier. To illustrate I have read about pushing a set of speakers with a 80 watt tube amp with excellent results where a 200 watt solid state power amplifier would be required for same kind of response. In general is this true?

With that in mind what kind of speakers would need, or the listener hear a significant improvement with a 400 watt tube amp vs 180watt tube amp?

This amp sounds really cool, can't wait to see pictures as you put it together.

I might be wrong, but my understanding has generally been that tubes are extremely high current, which makes up for the lack of wattage.

But do also understand that in order to DOUBLE to volume of 30 watts you need to go up to 210 watts. Because it is not a linear scale, small differences in wattage aren't necessarily so noticeable. That said, I wouldn't even try to run my speakers with tubes, they are ~85 db or less, but high efficiency speakers really don't take much.

So specifically, more watts does not equate to an improvement; the kinds of speakers that are good with less powerful amps are high efficiency, it is a matter of volume and potential clipping. So a 400 watt tube amp has the option of running speakers such as mine, which are very low in efficiency

zingo

Yes tubes are a high voltage power source, but that does not make up for them being low current. All speakers prefer a high current power source because they are fairly inefficient, and electronically, tubes are not be the best match. Thankfully, electronically is not audibly...

madmax wrote: »

Its way more fun (and safer) to build 1 watt amps and 100+ db efficient speakers.

Good luck and don't forget to turn on the AC this winter.

I wouldn't say my SET 845 amp with 20wpc at 1Kv is any safer.

sm88

zingo wrote: »

Yes tubes are a high voltage power source, but that does not make up for them being low current. All speakers prefer a high current power source because they are fairly inefficient, and electronically, tubes are not be the best match. Thankfully, electronically is not audibly...



I wouldn't say my SET 845 amp with 20wpc at 1Kv is any safer.

Ah there we go, I mixed current and voltage up. I'd love to get my hands on a high powered tube amp but will have to settle for a tube pre instead

cristo

That's why you need an output transformer with a tube amp - to convert the high voltage, low current, high impedence output of the power tubes into a lower voltage, higher current, low impedence output that matches the speakers and drives them as efficiently as possible.

nooshinjohn

I appreciate the solid state/tube debate guys, but this thread is about the building of tube amps. All I ask is that comments made in the thread stay within the topic of DIY amps and building them.

I have no more news on these until I get the chassis back from the shop.

nooshinjohn

Finally some success on the granite front. The tube decks and front panel have been cut and I have some pictures I will try posting tonight. They went through 7 pieces of stone plus countless templates in both steel and aluminum to get them right. They are still being etched with the Carver name and being polished and bonded, but they still look freaking amazing!


Bob will be proud!

disneyjoe7

Can't wait for the pictures, sounds very nice.

bigaudiofanatic

I need a set of these for my ML's lol always wanted a tube amp.

cstmar01

pics or it didn't happen!

sounds like a fun project hope it goes well and nothing blows up!

nooshinjohn

Here are a few pictures of the work in progress:)...

nooshinjohn

....

zingo

Nice.

SolidSqual

Where are the tubes?

EndersShadow

SolidSqual wrote: »

Where are the tubes?

I think he's just showing us the completed housing, the rest is still in the works.

nooshinjohn

EndersShadow wrote: »

I think he's just showing us the completed housing, the rest is still in the works.

Correct. The next step is fitting the chassis with all the eye candy. I have a whole bunch of Cardas rhodium going on the rear panel, an EIC socket and ceramic tube sockets going in next. Then the wiring fun begins!:p

zingo

You are a man not scared of a challenge.

nooshinjohn

zingo wrote: »

You are a man not scared of a challenge.

I am actually pretty intimidated by this one, but I am having a ton of fun with it. I placed the order today for Cardas wire/posts/solder, and picked up a professional solder station from Weller. I have also cleared my workbench off for the first time in years. Now is when the fun begins!:eek::cool:

SolidSqual

John do you have Life Insurance and rubber gloves?

nooshinjohn

Some updated pictures... This is the first time the two amps have seen each other in more than a month. I think they missed each other!;)

thsmith

Wow ! Very nice

cnh

I wish you the best of luck John! Though I think Brock's comments above are relevant.

When I toured the Shenda (Jolida) plant outside of Shanghai, the amount of testing equipment, controlled burning of tubes, schematics, and 3 Certified Engineers (etc.) presented me with a far too formidable atmosphere to 'ever' consider what you're doing. And even with all that. One of the amps blew in a demo--and an engineer immediately took it back to the shop to inspect it (a new model)?

I have a few degrees behind my name but an M.E.E. isn't one of them.

cnh

nooshinjohn

I am just following the instructions of an already proven and working design. So far the biggest challenge has been getting the tube decks cut. Other than that, these are proving to be no more difficult than building an advanced level model kit. I have built a couple Pocher kits, and the level of difficulty is about the same.

As stated before, they will be inspected by Bob Carver to verify the build and be tested on his equipment before they are ready for use. Because of the detail and effort I am putting in to these, he will even make the needed repairs for me and provide verification of their performance. Any fears I have that would normally make me shy away from such an undertaking are gone because of Bob's support and guidance.

mewisemagic

are you gonna take them to him yourself? i would hate to have to ship those as heavy as they are

nooshinjohn

mewisemagic wrote: »

are you gonna take them to him yourself? i would hate to have to ship those as heavy as they are

I will be shipping them, heavily insured. I do have exceptional packing skills, and although nervous about doing so, I am not deeply concerned.

george daniel

so when does the wiring start? You gonna PP wire them? Just curious--george

nooshinjohn

They will be point-to-point and the wiring will start in another couple weeks or so. I want to finish the wood side panels first(cutting and fit at least) before I start wiring it up.

thsmith

John will the amps use SS for power retification or tubes ?

steveinaz

This is going to be very cool.

nooshinjohn

The front end is tubed, using two 12ax7's. I am going to be learning a bunch of terminology as these progress and I assume that power rectification is one of them.:eek::)