Wondering if Upcoming DIY design will work with Tubes? Cheap DIY Kits?

[demon2091tb]

I would rather do a stereo. for a smaller footprint. But if i can do a pair of mono's but do them in a single chasis and still have fairly small footprint with a decent amount of power that would be ideal i'd think.

Can anyone help me find some well done schematics for a design, with a parts list mabey, and a very good explination of the parts and there workings.

I don't know enough about them to choose individual parts, and know theywill work together.

 

[Eli Duttman]

I would rather do a stereo. for a smaller footprint. But if i can do a pair of mono's but do them in a single chasis and still have fairly small footprint with a decent amount of power that would be ideal i'd think.

Can anyone help me find some well done schematics for a design, with a parts list mabey, and a very good explination of the parts and there workings.

I don't know enough about them to choose individual parts, and know theywill work together.

Dude,

Check this thread out. 7591 Project

It's a scratch build, but the crew here will definitely hold your hand. The 7591 project has a LOT of what you're looking for. Power O/P will be approx. 30 WPC. It's a stereoblock. It's an "integrated" amp and no preamp is needed.

 

[Alastair E]

Dude,

Check this thread out. 7591 Project

It's a scratch build, but the crew here will definitely hold your hand. The 7591 project has a LOT of what you're looking for. Power O/P will be approx. 30 WPC. It's a stereoblock. It's an "integrated" amp and no preamp is needed.

A great design, BUT perhaps a little complicated and possibly the Out-put Tx would be expensive, having that extra couple of windings...............

We all have our favourite tubes, I personally have no experience with the 7591 tube, but have heard that they are becoming expensive/rare to find for good NOS varieties.

A good chioce I would have thought for a more experienced builder would be the 6L6/KT66 series or maybe the EL34, which is my personal hate, but has a great reputation

The idea was a cheap but good sounding amp, with easily available parts, for someone just getting into tube construction--The 6C33, can be got for around a fiver each from Fleabay, and the o/p Tx is only 45 dollars --The same company also supply a choke and mains tx for the same application--I reckon this would be an inexpensive option to get into tubes, without sacrificing too much on sound quality, and fairly easily upgradable with better quality iron when the time comes, the layout could be made either Integrated or Mono-block, according to the wishes of the builder--I made a 3 channel integrated 6C33C for use with home theatre front channels--But thats just being silly!......

There are a lot of simpler (Maybe not as comprehensive) designs out there for a SET that has 20W output and is cheap to make, with the 6C33......

(Another thing in favour of the 6C33, is its a very impressive looking valve, and built like a brick-outhouse too, and very difficult to kill, in a SET/P-P........)

Any amp can be made in an integrated/monoblock/style so really the choice of parts, the cost and availability as well as the choice of amplifier type, ie, SET/P-P, etc.. are the main factors here....

 

[demon2091tb]

whats the difference in a SET and P-P, its it like mono and stereo, or completely different.

I've been looking for schematics and found some 300B desgins by Andrea Ciuffoli that look ok, but i really know nothing about them and price is a huge issue. I'd ideally like b/w 15-20w @4ohms, but i find that all amps seem to be rated for 8ohms, and don't state weither its 4ohm stable or not.

I find that the Andrea Ciuffoli designs uses there DAC's for conversion, is this really needed....?

Just really looking for a sexy, 20w @4ohm or so stereo tube amp, that stays cool, has a long life, and again looks sexy......I will not have something that looks like ish, where everyone will see it. It must be aesthetically pleasing in all aspects, and put out more than enough power for my needs.

BUT price is the biggest issue of all.

BTW is there a schematic, board diagram, and such out there that i could look at to follow along with and to know what those huge things are sitting on the back of most tube amps i see....there boxes as it looks. Would those be some of the transformers, or completely different?

 

[Alastair E]

whats the difference in a SET and P-P, its it like mono and stereo, or completely different.

SET = Single Ended triode, Meaning, one valve for the output of one channel, Mono. To make stereo, Two similar channels with one 'SET' is needed.

P-P,= Push-Pull, Generally, Two or more (Usually multiples of two) tubes working together for higher power/efficiency for the output of one channel, so for a twin tube P-P, four output tubes, two for each channel for stereo needed.

Mono = One channel of amplification driving one speaker set-up. This can be either a SET or a P-P

Stereo = Two channels driving two speaker set-up (A stereo Amplifier may share the power-supply components in an integrated amp, but usually has separate PSU components in a Mono-Block This again can be either SET or P-P....

I've been looking for schematics and found some 300B desgins by Andrea Ciuffoli that look ok, but i really know nothing about them and price is a huge issue. I'd ideally like b/w 15-20w @4ohms, but i find that all amps seem to be rated for 8 ohms, and don't state weither its 4ohm stable or not.

The 300B is one of those tubes that for some reason has a huge following and the prices of NOS and some chinese 300B's are really not in line with their performance IMO--Upwards of 500 dollars for a 300B by WE!--A LOT of these DHT's are the same, as to costs and availability Other similar ones are the PX4, PX25 etc.--Very old valves,

( To give you an idea of the costs some guys will go to, I recently sold 6 of these DHT's tubes on Fleabay,--The profit from which, I was able to buy a BMW, --Second-hand, BUT still!!--Totally INSANE)

Untill you are confident in your abilities, due to the silly money these valves command I would leave them well alone!

I find that the Andrea Ciuffoli designs uses there DAC's for conversion, is this really needed....?

DAC's are usually found in CD players, and similar Digital equipment, (DAC = Digital To Analogue Converter) and apart form integrated Home-Theatre Amps with built-in Decoders, are not generally found in any Tube amplifiers.............

Just really looking for a sexy, 20w @4ohm or so stereo tube amp, that stays cool, has a long life, and again looks sexy......I will not have something that looks like ish, where everyone will see it. It must be aesthetically pleasing in all aspects, and put out more than enough power for my needs.

Its entirely up to you how your amp ends up looking, how much work/costs you are prepaired to put into it as to the end result.
Check outr the picture-threads at this forum for other members ideas and amps--May give you a few clues how to go.

The choice of Output Transformer will determine the output Impedance, whether 4 or 6/8 or (rarely these days, 16 Ohm)
Most suppliers make a transformer with dual impedances of 4 and 8 ohm.

What Speakers to you plan to drive, that are 4 ohm??--Most good speakers are 6 or 8 ohm.........

No tube device runs cold. Amplifiers, as they are dealing with a lot of power, do get HOT! This is one of the drawbacks with valve-circuitry, is the inefficiency of it--A heater within the valve is needed, which wastes up to 30W (In the case of 6C33) in heat, Add to that, the current passing through the valve and the voltage accross it add up to its Dissipation, Also wasted in heat--If you must have a cool running amp--Tube Power-Amps may not be for you, although a Pre-Amp will stay reasonably cool-ish, and use your existing tranny/sand amp for driving the speaker.........

BUT price is the biggest issue of all.

Stay away from the 'Audio-Exotica' market and Hi-Fi Magazines, They often charge a premium price for parts and valves--Ive seen addies for a .1uF 600 Volt cap, at 50 dollars each in these places, where a standard excellent quality part is around a dollar, and I seriously doubt that the expensive cap sounds 50 dollars better.........

Shop around and be prepaired to compromise in some items, Know what you want and research the design you settle on as to the parts it uses and the availability/costs etc.

BTW is there a schematic, board diagram, and such out there that i could look at to follow along with and to know what those huge things are sitting on the back of most tube amps i see....there boxes as it looks. Would those be some of the transformers, or completely different?

There are many schematics on this Forum for SET and P-P with various power outputs and different types of output tubes-- have a search.........

Those 'Boxes, you see on commercial made tube-amps usually contain the mains and output transformers, as well as chokes and capacitors are often hidden under similar boxes.--For that sort of look, 19" Rack-cases and other cases could be used and modified, or you could copy a design from scratch out of copper/wood/steel etc--Its really personal choice

 

[kevinkr]

I still think that a variation of the ST-70 is a good place to start, decent chassis, lots of driver board upgrade options for later. UL connection in the outputs gets you 35W, triode connection will get you about 17W per channel. Very load tolerant, simple and relatively bullet proof.

Kevin

 

[demon2091tb]

Thanks for the run through Alistair, i'm not talking on running it cold, but i do know that excess heat can lead to failure, so a prolonged life is really wanted, or moderate heat.

The ST-70 seems the right way to go, as 17w per channel seems good.

The speakers i'm planning on running are some DIY that a made a few years ago, going to be upgrading sometime in the next year with a high effeciency 2 or 3way, and my reicever puts out best power at 4ohms, so i would like to use them interchangable if at all possible. That is the tube amp, and reciever, so 4ohms would be ideal.

Would a triode connection be 3 tubes per side?

Went looking for some kits using the ST-70 and i found this.
http://www.quadesl.com/schematics.shtml Scroll about a 1/5 of the way down and there is a ST-70 kit, boards + parts, not including tubes. Would that be the thing to buy to start out, or is that not what i'm looking for....a model that does 17 or so per ch.?

Also they have a replacement cap board, would i need that...Or am i on a tangent?

Just looking for a rather inexpensive place to start and really get the effect i'm looking for as a beginner who's never even heard a tube amp.

 

[demon2091tb]

Also forgot to ask what else i would need to make that design come alive.

Tranformers, Tubes, a chassis, and what else really? Which would be the better for the money, using the EF86's, or 6AU6's? What do the smaller tubes listed above do that the larger tubes don't do, the larger being the 7199's, and is this considered a P-P being a pair of tubes per ch, and how much power could i expect for output?

I really like the design of that, as it looks from his design pictures i would like mine to turn out that way as well. Looks very nice. Just not sure of the sonic signature, or really if it would work on a wall outlet ~120V.

I do like the thought of building a vintage design, but upgraded with technology as well. Would this be a extreemly difficult project for a extreme noob like me

All the input i can get on this would be perfect, to help sway me.

BTW any idea's on how much total i would be paying to get everything together, iron, tubes, board+parts is 89 i think i saw somewhere.

 

[Alastair E]

A Kit to start..........

Thanks for the run through Alistair, i'm not talking on running it cold, but i do know that excess heat can lead to failure, so a prolonged life is really wanted, or moderate heat.

The ST-70 seems the right way to go, as 17w per channel seems good.

The speakers i'm planning on running are some DIY that a made a few years ago, going to be upgrading sometime in the next year with a high effeciency 2 or 3way, and my reicever puts out best power at 4ohms, so i would like to use them interchangable if at all possible. That is the tube amp, and reciever, so 4ohms would be ideal.

Would a triode connection be 3 tubes per side?

Went looking for some kits using the ST-70 and i found this.
http://www.quadesl.com/schematics.shtml Scroll about a 1/5 of the way down and there is a ST-70 kit, boards + parts, not including tubes. Would that be the thing to buy to start out, or is that not what i'm looking for....a model that does 17 or so per ch.?

Also they have a replacement cap board, would i need that...Or am i on a tangent?

Just looking for a rather inexpensive place to start and really get the effect i'm looking for as a beginner who's never even heard a tube amp.

Also forgot to ask what else i would need to make that design come alive.

Tranformers, Tubes, a chassis, and what else really? Which would be the better for the money, using the EF86's, or 6AU6's? What do the smaller tubes listed above do that the larger tubes don't do, the larger being the 7199's, and is this considered a P-P being a pair of tubes per ch, and how much power could i expect for output?

I really like the design of that, as it looks from his design pictures i would like mine to turn out that way as well. Looks very nice. Just not sure of the sonic signature, or really if it would work on a wall outlet ~120V.

I do like the thought of building a vintage design, but upgraded with technology as well. Would this be a extreemly difficult project for a extreme noob like me

All the input i can get on this would be perfect, to help sway me.

BTW any idea's on how much total i would be paying to get everything together, iron, tubes, board+parts is 89 i think i saw somewhere.

I think a 'kit' of all the parts like this is an excellent way to start. At least then, its only the tubes and maybe the iron (Transformers) you need to worry about.

The ST-70 is a great design, gives good sound by all accounts, and will be reliable, with fairly easy to obtain tubes at a reasonable cost.
I think you could to a lot worse than one of these, as there is so much on the 'web for these designs as well as many members here have great experience of them, as well as lots of upgrades and modifications available designed just for that amp.

I personally have never seen one, but they do have an excellent reputation, and a huge following, so they must be doing something right!............

When you order your Transformers, Make sure that you get ones for your mains supply voltage of 120V then you have no problems with supply.--A lot of transformers have 'dual-primaries' anyway so could be wired either 120/240V input.
Similarly, if you want to run your 4 ohm speakers, Get Out-put transformers for your ST-70 that have the 4 Ohm tapping

'Triode Connection' Means, a Pentode/Tetrode Tube wired up to work as a triode, usually the 'screen' connection is wired to the cathode or anode in some cases, and appears 'invisible' during operation of the tube, so the tube acts like a triode in sound and power level. This can be done with small signal tubes as well as the power-bottles......

All the smaller tubes in the ST-70, are the pre-amplifier/phase-splitter tubes, that raise the drive voltage up to a point to drive the out-put pair (Tubes are 'Voltage' devices, and although they have a huge input impedance in comparison to sand, they need high voltages of drive, Say, 180V peak-peak for driving the 6C33C to full out-put..........)

Not sure of the costs of the Kit, --All according how much you end up spending for the iron and the tubes. That company on Ebay that does transformers for the 6C33, may do suitable types for the ST-70, so you may pick up a bargain there for the complete set of output/choke/mains Transformers if ordered all together--I have not dealt with them, but Ive heard fairly good reports on their quality and sound.....

I wouldnt invest huge amounts of money on the 'expensive' brand type tubes--The Russian/Chinese types are great and cheap especially if you are 'prototyping' and just need to confirm a design works, (In some cases, Ive found that the Russian Cheapies sound better than some NOS,----New, Old, Stock.......) before investing in so-called quality NOS tubes.........

Let us know what you decide to do...........