I'm planning a Seas CA18RNX + LPG 26nafm DIY combination very soon, and i wanted to eventually build a stereo tube amp, as it looks from www.Diytube.com, but i wanted to make sure that these speakers would actually work well with them.
I'm not sure what the overall sens of the combo will be yet, as my passives havn't been designed, but the LPG's are 92db, and Seas are 88db. But i am looking for a cheap DIY tube kit that would power these adaquately for pure SQ. I don't listen at that loud of volumes, but when i do occasionally watch a movie i do bump the volume up more.
Any DIY tube kits out there, for say $150, that would give me say 50-100w @4ohms?
I'm pretty new to thinking about building my own amps, granted tubes shouldn't be my first choice, i've never even heard a tube amp before, but people rave about them, so i wanted to hear one, as well as build one. Possible to find what i'm looking for for the price i'm aiming, or even less, or would solid state be better for my pocket? Would really like to try some Tubes....But not sure if my speaker choices would work well.
I'm not sure what the overall sens of the combo will be yet, as my passives havn't been designed, but the LPG's are 92db, and Seas are 88db. But i am looking for a cheap DIY tube kit that would power these adaquately for pure SQ. I don't listen at that loud of volumes, but when i do occasionally watch a movie i do bump the volume up more.
Any DIY tube kits out there, for say $150, that would give me say 50-100w @4ohms?
I'm pretty new to thinking about building my own amps, granted tubes shouldn't be my first choice, i've never even heard a tube amp before, but people rave about them, so i wanted to hear one, as well as build one. Possible to find what i'm looking for for the price i'm aiming, or even less, or would solid state be better for my pocket? Would really like to try some Tubes....But not sure if my speaker choices would work well.
50 WPC takes a pair of KT88s. The O/P trafos needed cost MORE than $150. Significant power O/P from tubes combined with a low price is simply out of the question.
There are kits available using 11MS8 tubes that deliver about 8 WPC at the $150 price level.
Tube amps mate poorly with speakers that have significant dips in their impedance curve. I'm concerned that your design will have the dips.
A practical way to get some of THE sound is to pair a nice tubed preamp with a quality SS power amp. A preamp is a GOOD 1st project. With careful shopping, you should be able to do something pretty good for < $200.
There are kits available using 11MS8 tubes that deliver about 8 WPC at the $150 price level.
Tube amps mate poorly with speakers that have significant dips in their impedance curve. I'm concerned that your design will have the dips.
A practical way to get some of THE sound is to pair a nice tubed preamp with a quality SS power amp. A preamp is a GOOD 1st project. With careful shopping, you should be able to do something pretty good for < $200.
I was plannin on no using baffle step on the midbass, but rather just level matching them, and using any EQing that needed to be done through the passive, as i'm currently talking with madisound on the passive design.
Was looking at around .7cf~38hz, f3 looks like 51hz with a steep roll off below there. My aim is for a Hifi SQ setup.....hopefully this size and tuning will do what i'd like. Bassbox 6 recommends .6cf ~ 39hz, f3 is 53hz.
Would that change the overall sensativity any for the better?
Would i even need baffle step comp for the best sound?
I'm planning on 8.5-9"wide cabinets.
Was looking at around .7cf~38hz, f3 looks like 51hz with a steep roll off below there. My aim is for a Hifi SQ setup.....hopefully this size and tuning will do what i'd like. Bassbox 6 recommends .6cf ~ 39hz, f3 is 53hz.
Would that change the overall sensativity any for the better?
Would i even need baffle step comp for the best sound?
I'm planning on 8.5-9"wide cabinets.
It depends on your room and placement, but you probably won't be happy with less than 3dB baffle step compensation. Whether you do this in the crossover or externally through some kind of equalizer, the effect on the speaker's sensitivity is the same.
Your low end tuning won't have any effect on the baffle step. It's a separate issue. The need for baffle step compensation starts at about 500Hz.
I don't want to discourage you from building a tube amp; you might be satisfied with just 30 watts per channel. But with a budget of $150, you can't even buy the iron for a 30 watt tube amp for that price. You could always build the K501 8 watt kit that has been mentioned. It's a nice sound, and it won't sound awful with your speakers, but it also won't go loud or have a great level of control over speakers that are as inefficient as yours. On the other hand, with that budget, you can build a nice tube preamp.
Your low end tuning won't have any effect on the baffle step. It's a separate issue. The need for baffle step compensation starts at about 500Hz.
I don't want to discourage you from building a tube amp; you might be satisfied with just 30 watts per channel. But with a budget of $150, you can't even buy the iron for a 30 watt tube amp for that price. You could always build the K501 8 watt kit that has been mentioned. It's a nice sound, and it won't sound awful with your speakers, but it also won't go loud or have a great level of control over speakers that are as inefficient as yours. On the other hand, with that budget, you can build a nice tube preamp.
I don't really want to have too much midbass, but just right, and i guess thats the hard thing to find out, how much is right. The baffle step if used will be implemented into the passive. I am waiting for madisound to re-email me on this issue, because i'm not really sure how much would be needed to have the best response possible, i'm sure they might be able to let me know.
My room isint really that big, lets say 13x20 at the most.....soundstage is across the 13' wall, tv sits in the center, bookshelfs currently sit about 1' from each side wall. Stage is quite wide. I don't really know how much midbass i want though, i mean i'd like it to just sound very full, pretty equalized without any peaks or troughs, and just have a very high level of detail, and reproduce everything i throw at it with ease, dynamics, and fullness.
My room isint really that big, lets say 13x20 at the most.....soundstage is across the 13' wall, tv sits in the center, bookshelfs currently sit about 1' from each side wall. Stage is quite wide. I don't really know how much midbass i want though, i mean i'd like it to just sound very full, pretty equalized without any peaks or troughs, and just have a very high level of detail, and reproduce everything i throw at it with ease, dynamics, and fullness.
You should be thinking about picking up a Dynaco ST-70 and upgrading it. A ST-70 should be available for less than 100.00. The remaining 50.00 you can put into upgrades. Upgrading an amp is much simpler for someone with little experiance. Doing an upgrade is excellent place to start your DIY journey. There are many upgrade kits available for the ST-70. The ST-70 won't be 50w but it will get you a nice 35w. If your speaker impedence swinge isn't to low then you should be in good shape.
I second Andy's notion that an ST-70 would be a good starting point.
In my neck of the woods (boston) good working ST-70's start at about $250 and go up from there, but occasionally they do show up in yard sales ridiculously cheap - I found one for $75 a couple of years back. (It wasn't working.) Many upgrades are available for these amplifiers.
See my website for some ideas if you are of a more diy bent: www.kta-hifi.net, schematics and a lot of information is there about modifying this amplifier.
Kevin
In my neck of the woods (boston) good working ST-70's start at about $250 and go up from there, but occasionally they do show up in yard sales ridiculously cheap - I found one for $75 a couple of years back. (It wasn't working.) Many upgrades are available for these amplifiers.
See my website for some ideas if you are of a more diy bent: www.kta-hifi.net, schematics and a lot of information is there about modifying this amplifier.
Kevin
How about an OTL?
With something like 6C33C's (Cheap off fleabay) and something like Andria Cuiffoi schematic, its fairly easy to stay away from the expensive iron of the O/P Tx, which can be very overpriced for some types, BUT maybe the PSU needs a bit more attention and expense, especially as in the case of a Circlotron.............
I personally dont have the sort of money to spend on iron so I either end up winding my own or doing without as in the case of an OTL............
With something like 6C33C's (Cheap off fleabay) and something like Andria Cuiffoi schematic, its fairly easy to stay away from the expensive iron of the O/P Tx, which can be very overpriced for some types, BUT maybe the PSU needs a bit more attention and expense, especially as in the case of a Circlotron.............
I personally dont have the sort of money to spend on iron so I either end up winding my own or doing without as in the case of an OTL............
I would harldly recommend a 6C33 based otl (or any otl) to a newbie..
There are lots of problems getting these to run reliably in the real world and with his speakers he would probably need a quartet of them per channel to get 50W or so. I designed and built a pair about 10 yrs ago and the cost of the power transformers alone was over $400, total expenditure over $2K and I was not that happy with the end result - admittedly I was targetting rather more power. (>100W per channel) An otl project I think is the perview of the rather more experienced DIY'er and I don't recommend it to anyone on a tight budget, you are just trading one set of constraints for another, and for a much tougher job of engineering.
Kevin
There are lots of problems getting these to run reliably in the real world and with his speakers he would probably need a quartet of them per channel to get 50W or so. I designed and built a pair about 10 yrs ago and the cost of the power transformers alone was over $400, total expenditure over $2K and I was not that happy with the end result - admittedly I was targetting rather more power. (>100W per channel) An otl project I think is the perview of the rather more experienced DIY'er and I don't recommend it to anyone on a tight budget, you are just trading one set of constraints for another, and for a much tougher job of engineering.Kevin
What i would be idealy looking for is a moderatly powerful, but simple tube amp, that i could do everything needed to get it to work correctly, and take my time in building and have the end result be something i can look back at and be excited about the result enough to be ready for another.
I do know that these can get expensive, but thats where i find that DIY is really the route to go, as well as a learning experience. I don't know that much about amps in general but i figured tubes were the audiophiles place to start learning. And i figure a pair of monoblocks would probobly do me fairly good, much simpler probobly than a stereo tube amp.
As far as power i'm generally looking for something that just puts out enough power to get say a max 85db sens. network to decent volumes, but SQ is more of the concern for me, and the lack of the feedback or hum that some of you refer to. But i would really like the tube sound.
I'm not sure what a preamp actually does, but it sounds like it ads any colorations, distortions needed for a tube sound, and how i would tie it into a SS amp to get the power needed. Not sure if i should dive into the SS or chip amp word before i go into the tube amps, but tubes just seem more of the audiophile platform than the others.
Why are tube amps so expensive when they are technologically less superior than chip amps or even SS amps.....?
I do know that these can get expensive, but thats where i find that DIY is really the route to go, as well as a learning experience. I don't know that much about amps in general but i figured tubes were the audiophiles place to start learning. And i figure a pair of monoblocks would probobly do me fairly good, much simpler probobly than a stereo tube amp.
As far as power i'm generally looking for something that just puts out enough power to get say a max 85db sens. network to decent volumes, but SQ is more of the concern for me, and the lack of the feedback or hum that some of you refer to. But i would really like the tube sound.
I'm not sure what a preamp actually does, but it sounds like it ads any colorations, distortions needed for a tube sound, and how i would tie it into a SS amp to get the power needed. Not sure if i should dive into the SS or chip amp word before i go into the tube amps, but tubes just seem more of the audiophile platform than the others.
Why are tube amps so expensive when they are technologically less superior than chip amps or even SS amps.....?
Its not technoligical superiority or inferiority that makes tube amps expensive, its plain old manufacturing cost (with a dash of bleed the yuppies thrown in). The parts are heavy, complicated, and niche to boot. Just raw materials would add up compared to SS except the class A aluminum levithons.
Its alot easier to find cheap power iron than output iron, the key is to avoid buying audio parts. Whereas output iron is almost by definition, audio parts. Output iron seems to be the area acquisition efforts / money are best focused on.
Its alot easier to find cheap power iron than output iron, the key is to avoid buying audio parts. Whereas output iron is almost by definition, audio parts. Output iron seems to be the area acquisition efforts / money are best focused on.
demon2091tb said:
A preamp controls volume, permits input selection, and optionally provides some voltage gain. Like any gain stage, tube or solid state, some distortion is introduced. You don't have to do anything to "tie it into a SS amp"... just plug the output of the preamp into the input of the SS amp.
It's perfectly reasonable to dive into tube amps as a first project, but because your budget is very limited, a preamp makes more sense. It requires a smaller power supply and doesn't require output iron, basically saving about 50% on parts costs. If you really want to build a tube power amp, the K501 kit is within your budget, but that's only 8 watts, not a great match for your speakers.
kevinkr said:I would harldly recommend a 6C33 based otl (or any otl) to a newbie..
Kevin
Ahh, My mistake, I didnt realise that the question was from a newbie to tubes.
How about a nice SET, again with the cheap 6C33, There are out-put iron on Fleabay, which by all accounts are pretty good, Very reasonable price too,--If I recall, 49 dollars each or so, direct from China, The same company also does transformers for other popular O/P valves and Mains transformers too--Search for 'Output Transformers 6C33C'.......
It would be limited on power to around 15-25W or so, but a good starting point for someone to get familiar with tube circuitry and a good performance too.
About the costs however, My current OTL project has cost less than 50 pounds stirling, all thats needed are some MOSFETs for drivers and some resistors, of various values--I may even have most of them somewhere.... The expensive parts I obtained REALLY cheap from Maplin, who were clearing out their old-stock of Toroidal 650VA transformers--Had a great pair of these for only 12 quid! The Caps of 3,300uF, 200V (RIFA, make) I got at a Ham-fest a few years ago for a tenner, There were 20 of them, Brand-new unused--Knew they would come in handy--Lovely screw top terminals on them!
The heater transformer, I picked up this week again from Maplin for less than a fiver, 250VA, 4x12V Toroid and 4 x 6C33C-B cost me 25 quid including shipping, from Fleabay--They are good quality ones, and pretty stable, which Ive run for many hours in my SET 6C33 amps.
Add to that a handfull of pre-amp tubes like 6SL7 and 6SN7 out of the general stock-parts box, and there you have it!
The HT and other supplies Transformer is Ex Tektronix 'Scope I scrapped a while ago--The 'scope cost me nothing had a faulty PSU but the Transformer is great, as well as many tube-sockets and other great quality parts--Perfect for bread-boarding and tweeking before the final construction!.
The moral here--If you see a 'special offer' in your local electronics outlet and can afford it--Grab it--Tomorrow itll be gone! Ham-fests are pretty good too for a lot of the more expensive parts like transformers and high value caps too, as well as tubes of all types.
It is feasable to get around 50W from a pair of 6C33C-B tubes in Circlotron but you wouldnt be able to run that sort of power for too long before something popped and for reliability I would limit to 30W output, while idling at around 35W Pa as a maximum--This is my current project--Ill let you know how it gets on.....
Running a quad of 6C33 in Circlotron will give 100W, but again you wouldnt really be able to run that sort of power for long--BUT you wouldnt really need to run that sort of power continuously anyway, and 60W would be more appropriate for longevity.
The capability of 100W makes a difference even at much lower power levels, just to cover those transients.
20-25w sounds golden to me really....not so little that i'd need a 95db net sens to get to moderate listening volumes, but also have some headroom and such.
I'm planning on saving up for a nice setup to build in the future, thinking mabey a high sens. 3way or 2way so this could be a perfect time to start trying out a few things, and have a nice tube amp to run them off of at a later date.
I don't exactly know anything about what a 6C33 is, any good cites to start reading up and learning about tube amps and such.
Not really sure where to start looking for actual designs though, as i'm not really sure from looking at the design weither its a monoblock, or stereo or whatnot. As i am a noob at this, a very straight forward design would be great, and for simplicity a stereo amp or a set of mono amps would be nice.
I've honestly never heard a tube amp though, which is why i want to build one so bad, and owning a diy tube amp would be awesome.
I'm sure most of you know by now from reading i don't know that much, but very intrested in getting into this.....VERY.
I'm planning on saving up for a nice setup to build in the future, thinking mabey a high sens. 3way or 2way so this could be a perfect time to start trying out a few things, and have a nice tube amp to run them off of at a later date.
I don't exactly know anything about what a 6C33 is, any good cites to start reading up and learning about tube amps and such.
Not really sure where to start looking for actual designs though, as i'm not really sure from looking at the design weither its a monoblock, or stereo or whatnot. As i am a noob at this, a very straight forward design would be great, and for simplicity a stereo amp or a set of mono amps would be nice.
I've honestly never heard a tube amp though, which is why i want to build one so bad, and owning a diy tube amp would be awesome.
I'm sure most of you know by now from reading i don't know that much, but very intrested in getting into this.....VERY.
6c33c-b
Try a search here on 6C33C-B, You will find lots of threads on OTL's but quite a few on SET.
The 6C33C-B, was a series pass regulator Triode valve designed in Russa for military service in the likes of the MIG 29 fighter aircraft. It has a very low plate impedance and high perveayence making it good for OTL service as well as a straight-forward SET or P-P with a fairly high output, 20 odd watts in SET or with two, up to 80W in Transformer coupled conventional P-P.
There is a thread somewhere here, I started ages ago, titled,
'Anyone wound an O/P Tx for a 6C33C-B SET--Lots of good info here and the other posts.
Give Google a try for tube data and background--Lots of tube-amp makers supplying 6C33 based amps in SET and in P-P with lots of info if you read between the lines of the sales blurb.
One thing against the 6C33C-B, It has a very hungry heater, and if the Plate dissipation is much above 50W the base sockets can become unreliable with time, if you use the cheaper chinese sockets anyway, as these valves run HOT!
--Best find some Russian sockets, Antony Welsh on Ebay have them , but they are a bit more expensive than the cheapie chinese ones, but worth it...
Try a search here on 6C33C-B, You will find lots of threads on OTL's but quite a few on SET.
The 6C33C-B, was a series pass regulator Triode valve designed in Russa for military service in the likes of the MIG 29 fighter aircraft. It has a very low plate impedance and high perveayence making it good for OTL service as well as a straight-forward SET or P-P with a fairly high output, 20 odd watts in SET or with two, up to 80W in Transformer coupled conventional P-P.
There is a thread somewhere here, I started ages ago, titled,
'Anyone wound an O/P Tx for a 6C33C-B SET--Lots of good info here and the other posts.
Give Google a try for tube data and background--Lots of tube-amp makers supplying 6C33 based amps in SET and in P-P with lots of info if you read between the lines of the sales blurb.
One thing against the 6C33C-B, It has a very hungry heater, and if the Plate dissipation is much above 50W the base sockets can become unreliable with time, if you use the cheaper chinese sockets anyway, as these valves run HOT!
--Best find some Russian sockets, Antony Welsh on Ebay have them , but they are a bit more expensive than the cheapie chinese ones, but worth it...
So my best bet for the cheapest noob setup, would be a 6C33C-B but with russian sockets.
Is this considered mono or actually stereo, and what would the output end up being?
Is there any schematics laying around for one of these designs that a noob like me, VERY big noob, could easily enough decipher and know what was happeneing. As well as possibly a slightly indepth explination of what i would need to get so that it would work correctly?
I'm not sure of the whole splickidy lingidy, but i take it SET is Single ended triode? P-P is push pull?
I'm not completly up to date on the whole inner workings of a tube amp, but what is this heater transformer.
Also i've heard a few references to people getting a nock on the door from the gov't, from what sucking too much power...or what...How can i avoid this, and i like in the US so power is at 120V wall socket. Anyway to optimize this to run from a wall jack...?
Thanks for the help?
Is this considered mono or actually stereo, and what would the output end up being?
Is there any schematics laying around for one of these designs that a noob like me, VERY big noob, could easily enough decipher and know what was happeneing. As well as possibly a slightly indepth explination of what i would need to get so that it would work correctly?
I'm not sure of the whole splickidy lingidy, but i take it SET is Single ended triode? P-P is push pull?
I'm not completly up to date on the whole inner workings of a tube amp, but what is this heater transformer.
Also i've heard a few references to people getting a nock on the door from the gov't, from what sucking too much power...or what...How can i avoid this, and i like in the US so power is at 120V wall socket. Anyway to optimize this to run from a wall jack...?
Thanks for the help?
Yes
In order for a vacuum tube to work, an filament is heated in order to furnish electrons for the tube to work. This requirement is one of the basic reasons that tube electronics are heaver, less reliable, more power hungry, lower power, and more expensive than solid state.
Transformers need to be chosen to match the local power. If you are in the US, you should have lots of choices.
Depending on the design, its going to be either a stereo amp or a pair of Mono amps.
Good Luck
Doug
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