Valve amplifiers

[SPS]

I thought so Ali..

is funny how trouser flapping bass and watts seem to go together for many, its not my experence. even with open baffles

[Ali Tait]

Aye, it's a different kind of bass methinks. If you like it and get used to it, nothing else will do.

[jaym481]

Something that has not been mentioned so far is the Damping Factor of amplifier and speaker. In fact it's hardly ever mentioned anywhere, considering it's importance, so could someone provide us with an explanation?

Because it's not as important as some think, I guess. I wish I could provide the quotes, but a few big names in hi-fi design and engineering have commented on how low damping factor is in their priorities.

On topic: using my smartphone spl app, and not taking any weighting into account, I read peaks of 39dB and average of 29dB over a minute or so listening to soft jazz, mono, with a 40 wpc PP valve amp driving Tannoy Cheviots (about 92db sensitivity, I think). I often wish I could put the spurs to it, but certainly not at this time of night in a flat, and with two small kids sleeping down the hall. Measurement at the listening position.

[SPS]

Something that has not been mentioned so far is the Damping Factor of amplifier and speaker. In fact it's hardly ever mentioned anywhere, considering it's importance, so could someone provide us with an explanation?

I do my best be it in simple terms
damping factor is a calculation between the impedance of the output stage of the amplifier and the speaker impedance.

so an amplifier with a low output impedance will give a better damping factor with higher impedance speaker.
that is why in the 50's 16 ohm speakers where the norm when quality was important with valve amps of the time,
back in the 30's many speakers where wound with very high impedance coils that dramaticly increased the damping factor and removed the need of output transformers, at the expense of fragility, as very few lasted long at all...but I have read that the sound quality could be very good.

todays SS amps can have a much lower output impedance, which can be considered important to control generally less powerfull drivers used in the modern speaker

there is also speaker self damping.. generally a speaker with a less powerful motor has less self damping, it relys on a stronger energy field from the amplifier to control the cone, and the speaker with the higher powered motor needs less help to control the cone.. in some cases much less

it is really nowhere as simple as that.. but it may help your understanding

[nightyy]

Wow, thank you all, that was a whole lot to learn!

But getting back to real life decisions:
Does it harm to use higher power tube amps with high sensivity speakers? What are the negative effects of using a 2x12W or 2x40W tube amp instead of a 2x3W? Are the high power layouts prone to sound quality deficiencies?

[lewis]

I do my best be it in simple terms
damping factor is a calculation between the impedance of the output stage of the amplifier and the speaker impedance.

so an amplifier with a low output impedance will give a better damping factor with higher impedance speaker.
that is why in the 50's 16 ohm speakers where the norm when quality was important with valve amps of the time,
back in the 30's many speakers where wound with very high impedance coils that dramaticly increased the damping factor and removed the need of output transformers, at the expense of fragility, as very few lasted long at all...but I have read that the sound quality could be very good.

todays SS amps can have a much lower output impedance, which can be considered important to control generally less powerfull drivers used in the modern speaker

there is also speaker self damping.. generally a speaker with a less powerful motor has less self damping, it relys on a stronger energy field from the amplifier to control the cone, and the speaker with the higher powered motor needs less help to control the cone.. in some cases much less

it is really nowhere as simple as that.. but it may help your understanding

Thanks for your reply Steve, time for a bit of research!

[SPS]

Wow, thank you all, that was a whole lot to learn!

But getting back to real life decisions:
Does it harm to use higher power tube amps with high sensivity speakers? What are the negative effects of using a 2x12W or 2x40W tube amp instead of a 2x3W? Are the high power layouts prone to sound quality deficiencies?

i've borrowed this quote

“To raise the performance of a single triode amplifier above the crowd it is necessary to optimize the design and parts quality used in its realisation. It is not enough simply to use triodes.” Kondo

the best low power amplifiers are expensive and can rarely be bought from the hifi shop...
the hifi shop/ internet will point you in the direction of the masses.. larger output amplifiers..
as most people do not understand what real 100+ db speakers can do matched with a high quality amplifier.. and if you knew, you would not be asking us daft questions.. best of luck...
steve

[Ali Tait]

Wow, thank you all, that was a whole lot to learn!

But getting back to real life decisions:
Does it harm to use higher power tube amps with high sensivity speakers? What are the negative effects of using a 2x12W or 2x40W tube amp instead of a 2x3W? Are the high power layouts prone to sound quality deficiencies?

No harm but possibly may not be not ideal IMHO. For instance, I used to drive my statics with an Audioromy 813 SE which was about 35 w/ch if memory serves. Sounded very good on the statics, but less so on other cone speakers for some reason.

I don't think higher power automatically means inferior sound, it's all about the quality of the components and the transformers. Good ones are expensive.

Steve is right in saying that some of the very old triodes can sound very special, but unless you are in his fortunate position of having a large collection of such things, it could get extemely expensive making such an amp nowadays as NOS '20's and '30's triodes are seriously pricey items these days.

[nightyy]

i've borrowed this quote

the best low power amplifiers are expensive and can rarely be bought from the hifi shop...
the hifi shop/ internet will point you in the direction of the masses.. larger output amplifiers..
as most people do not understand what real 100+ db speakers can do matched with a high quality amplifier.. and if you knew, you would not be asking us daft questions.. best of luck...
steve

That's right: you can only tell the difference if you
a) own "real" 100db+ speakers -> money
b) you own high quality tube amp -> really a lot of money
c) have already had experience with a lot of other expensive gear from the low db, high wattage camp -> even more money

So I guess it's save to say that most people simply cannot understand because of limited budget

No harm but possibly may not be not ideal IMHO. For instance, I used to drive my statics with an Audioromy 813 SE which was about 35 w/ch if memory serves. Sounded very good on the statics, but less so on other cone speakers for some reason.

I don't think higher power automatically means inferior sound, it's all about the quality of the components and the transformers. Good ones are expensive.

For collecting experience higher power tube amps give the chance to try them with different speaker sets. For example I own three sets of speakers, I can test one amp with all three sets, maybe one combination is just the perfect fit. If I go at the task with a 2x3W amp I cannot really use my 90db speakers with them, and future speakers will have to forfill a minimum of x db at the least.

I have just acquired a used Melody SP3 with upgraded tubes for 435€ incl. shipment, and am keeping an eye open for a used 2A3 or 2A3/300B amp:
http://www.ebay.de/itm/150829050914?...ht_1664wt_1142

[SPS]

So I guess it's save to say that most people simply cannot understand because of limited budget

sort of... the thing is there are good, and not quite as good, in everything, there are not to many places where one can hear qualitiy HE &quality SE triodes

so for many its taking a chance, as a DIYer, it different you start off with cheaper and build up, my first valve amp was el84 based, the 4 watts convinced me valves was better, but not in every way,
it took some time and experimenting to acheve the sound i now get, and i've spent alot of money on the way. the funny thing is when others listen to my kit some really like the sound, but not every one gets it,


buying any amp i would lean towards one that uses older valves that can be bought at reasonable prices, the 2a3/45 is an example,
I have a pair of 1940's 300a ..there is a marked difference in sound quality between them and all of the new production, but the cost and rarity are prohibative for most.
where as say globe px25 and px4 (they sound close to 300a/b) are more affordable and available, the amplifiers are not, and so mainly limited to diyers...