BasX PT1 with a tube amp?

[cyto]

I have a 3wpc tube amp, self built, that I need a preamp for and am thinking of the PT1.

Has anyone paired it with a tube amp?

and

How good is the phono preamp?

[DavidR]

What speakers will you be driving with just 3 wpc?

I find that I get more mileage with a tube Pre/Phono into a SS amp than a tube amp.

The PT1 should work. I have no knowledge of the phono board in the PT1. Perhaps do a SEARCH on the PT1. The introduction thread should have that answer. You can also look thru the various forums on the site's front page. It should be in Equipment and Reviews.

[cyto]

Nov 21, 2021 20:43:42 GMT -5 DavidR said:

What speakers will you be driving with just 3 wpc?

I find that I get more mileage with a tube Pre/Phono into a SS amp than a tube amp.

The PT1 should work. I have no knowledge of the phono board in the PT1. Perhaps do a SEARCH on the PT1. The introduction thread should have that answer. You can also look thru the various forums on the site's front page. It should be in Equipment and Reviews.

My speakers are Klipsch La Scalas, I built the amp a few months ago and have been using it, just want a proper preamp. I modified an old Sanyo Plus 55 receiver and put pre-outs on it but want to use that elsewhere. I did quite a bit of searching and really couldn't find much about the phono pre. I am looking at the Emotiva PT1 or an Adcom from the GFP series.

Actually I prefer the sound of a solid state pre and tube amplification.

[Boomzilla]

Hi cyto!

First, congratulations on successfully building your power amplifier! Not that many can actually do that, but YOU did - I salute you.

Second, from the mention of your need for a phono stage, I'm assuming you need the following:

Phono equalization with phono preamp
Other analog inputs for other source(s)
A line stage section capable of driving the power amp

Yes, you get all those things with the Emotiva PT-1 preamp (and more). AND the PT-1 is an awesome sounding preamp (in fact, it's one of the biggest bargains on the market at its price). What does the phono stage sound like? You got me, I don't do vinyl (sorry).

But since you took the time and effort for the power amp, might I suggest to you that you at least consider "separates" for your front end, too.

There are some snazzy phono preamps on the market that are becoming quite reasonable in price.
You can get a "headphone amp" that could be used as a line stage, but you don't really need one - phono preamp + remote control passive attenuator + power amp/speakers - done.
Input switching can be done with a really inexpensive passive switch box (or you could build your own)
Volume control is available as a passive attenuator that could feed your amp directly (and with the high input impedance you probably have on the amp, the combo would work fine).

If it were me, I'd just go with the awesome sounding PT-1 (I have one and just LOVE it). But, as I've said, I have NO idea how the phono stage sounds. I did discover that I prefer the sound of my Emotiva Big Ego+ DAC over the built-in DAC of the PT-1, though. It may be that my Big Ego+ was already warmed up & burned in while the PT-1 was cold and new? I'll need to go back and check that some day.

But for the $$$, you just can't go wrong with the PT-1. That's my story, and I'm sticking to it.

Happy shopping & Happy Thanksgiving - Glenn

Postscriptum - Yes, the Klipsch La Scalas and tube power amplification (ANY wattage) are a match absolutely made in Heaven! If that combination doesn't bring tears to your eyes, you don't really like music. Also, as an aside, I'm currently reviewing a $9,000 power amplifier and a pair of $7,000 speakers using the Emotiva PT-1 as the preamp. And the weak link in the audio chain ISN'T the preamp!

[cyto]

Nov 21, 2021 21:53:48 GMT -5 Boomzilla said:

Hi cyto !

First, congratulations on successfully building your power amplifier! Not that many can actually do that, but YOU did - I salute you.

Second, from the mention of your need for a phono stage, I'm assuming you need the following:

Phono equalization with phono preamp
Other analog inputs for other source(s)
A line stage section capable of driving the power amp

Yes, you get all those things with the Emotiva PT-1 preamp (and more). AND the PT-1 is an awesome sounding preamp (in fact, it's one of the biggest bargains on the market at its price). What does the phono stage sound like? You got me, I don't do vinyl (sorry).

But since you took the time and effort for the power amp, might I suggest to you that you at least consider "separates" for your front end, too.

There are some snazzy phono preamps on the market that are becoming quite reasonable in price.
You can get a "headphone amp" that could be used as a line stage.
Input switching can be done with a really inexpensive passive switch box (or you could build your own)
Volume control is available as a passive attenuator that could feed your amp directly (and with the high input impedance you probably have on the amp, the combo would work fine).

If it were me, I'd just go with the awesome sounding PT-1 (I have one and just LOVE it). But, as I've said, I have NO idea how the phono stage sounds. I did discover that I prefer the sound of my Emotiva Big Ego+ DAC over the built-in DAC of the PT-1, though. It may be that my Big Ego+ was already warmed up & burned in while the PT-1 was cold and new? I'll need to go back and check that some day.

But for the $$$, you just can't go wrong with the PT-1. That's my story, and I'm sticking to it.

Happy shopping & Happy Thanksgiving - Glenn

Thanks, I went to electronics school in the 70s and was a licensed tech for a while. Got out and just use what I learned to build and modify. 
 This is a build video of the amp, I made it from a schematic. youtu.be/Lgj0mC7HYU4

[cyto]

I just ordered a PT1, looking forward to it!

[Boomzilla]

Congrats, cyto - I'm betting you'll really love it. I think it's definitely the best preamp Emotiva has ever made, and it trounces most of the others I've heard too, regardless of price. Leave it on - keep it warmed up. Otherwise it takes 20 minutes each time you turn it on to stabilize and sound its best. Let me know what you think - and feel free to disagree with me - I really and truly want to know if the PT1 is as good as I think it is.

Boomzilla

[leonski]

Since it appears you would PREFER to go SS for the pre? Just look at the USED listings on Audiogon or USAudioMart. Find a 300$ or so (aprox....) Parasound P3.
It'll have a decent phono stage.
The upmarket but still out of produciton P5 will also solve your prolbem AND add bass management and semi-useful tone controls.


www.tubes4hifi.com/pre11.htm

A Tube pre with an SS phono stage MIGHT also work for you, too........

VTA seems to do good work and have stable designs.


I JUST looked at the amp build video.    Very nice, indeed.    You may consider it a hybrid, since transistors DO appear in the signal path.....?

Beautiful scope shots.     Clean and an HONEST 3 watts.      

[DavidR]

Nov 25, 2021 23:56:10 GMT -5 leonski said:

Since it appears you would PREFER to go SS for the pre? Just look at the USED listings on Audiogon or USAudioMart. Find a 300$ or so (aprox....) Parasound P3.
It'll have a decent phono stage.
The upmarket but still out of produciton P5 will also solve your prolbem AND add bass management and semi-useful tone controls.


www.tubes4hifi.com/pre11.htm

A Tube pre with an SS phono stage MIGHT also work for you, too........

VTA seems to do good work and have stable designs.


I JUST looked at the amp build video.    Very nice, indeed.    You may consider it a hybrid, since transistors DO appear in the signal path.....?

Beautiful scope shots.     Clean and an HONEST 3 watts.      

I have a VTA SP12 + PH14. The tube phono is awesome. Roy is the pits to work with thou.

< right now the attachment feature will not load photos. I will try later >

Attachments:

[leonski]

One OTHER minor point which should be at least mentioned.
Phono comes in 2 major flavors. Moving Magnet and Moving Coil. All seem to be measured in MILLIVOLTS....a very low number.
Some phono preamps have adjustible gain so you can match to another source.

nadelectronics.com/product/pp-2e-phono-preamplifier/

Link to the NAD take on phono pre. LESS than 200$ Check out the specs for basic idea......

[cyto]

Nov 25, 2021 23:56:10 GMT -5 leonski said:

Since it appears you would PREFER to go SS for the pre? Just look at the USED listings on Audiogon or USAudioMart. Find a 300$ or so (aprox....) Parasound P3.
It'll have a decent phono stage.
The upmarket but still out of produciton P5 will also solve your prolbem AND add bass management and semi-useful tone controls.


www.tubes4hifi.com/pre11.htm

A Tube pre with an SS phono stage MIGHT also work for you, too........

VTA seems to do good work and have stable designs.


I JUST looked at the amp build video.    Very nice, indeed.    You may consider it a hybrid, since transistors DO appear in the signal path.....?

Beautiful scope shots.     Clean and an HONEST 3 watts.      

Thanks, yes there are TIP50s on the cathodes so I guess one could consider it a "hybrid".
I use a Hana SL that has been re-tipped by Andy Kim with a microline stylus and use Cinemag CM-1254 step up transformers to bump it up.
I have a tube phono stage I built several years ago and still use when I want to, it has two 6SL7 gain stages and a 6SN7 cathode follower output, it is Jim Hagerman's Cornet Octal design.

[leonski]

I understood EVERYTHING up to 'CATHODE" than went blank.

JUst kidding. I've been educating myself about tubes for the last 2 or so months and am making slow progress.
I worked semiconductor / IC manufacture for decates past, so am not a complete goof about schematics...but close.

Your 3 watt amps?    MIGHT make my Panels make an Annoying Noise, but I doubt actual music.    They are of EPIC
low sensitivity.

The reason I've been going thru tubes / tech is that I'm interesting in building a PAIR of the VTA M-125 amps....which
SHOULD have more than enough grunt to make my panels work well.   Especially considering my normal use....

[Boomzilla]

Tube pre + SS power or SS pre + tube power? IMHO, (and profoundly obviously) it depends on the speakers.

Speakers I’ve found to like tube power:

Big horns
Magnepans
Electrostatics

The majority of box speakers, for some reason like high-wattage (and often high-current) SS amps. Using a tube pre + SS power is a MUCH less expensive option than vice versa.

OTOH, my 12-W Heathkit tube power amps kick the boo-tays of most everything, so who knows?

Boom

[KeithL]

There's nothing especially mysterious about it.

While nowadays there are a few high-power tube amps they were not common at all until recently (and they still tend to be very expensive).

Tube amps also have a VERY low damping factor (the DF on tube amps ranges from 4 to about 8; as compared to 500+ on a typical solid state amp).

This means that the tube amplifier has very little ability to control the motion of a woofer electrically.

It is damping factor that enables an amp to "apply braking force" and prevent a driver from continuing to bounce back and forth and produce sound after the signal stops.

(The effect is the same as the way "electromagnetic braking" works.)

In the old days most speakers were relatively efficient (in order to be able to work with the low-power amplifiers available at the time).

But, since they were designed to work with amplifiers with a very low DF, they had their own mechanical damping.

The speaker didn't expect or need for the amplifier to be able to apply mechanical braking force to the driver.

HOWEVER, when solid state amplifiers came along, it became relatively simple to build amplifiers with plenty of power, and a VERY HIGH damping factor.

(A high damping factor is essentially a "side effect" of how most solid state amplifiers work... and not something that must specifically be designed for.)

Since most modern amps have plenty of power speakers designed to work with newer amps can trade off efficiency for other benefits...

Modern speakers also tend to heavier cones and more powerful "motor mechanisms".

This enables them to move further, and make lower bass, with less distortion, for a given box size.

However speakers designed this way RELY on the amplifier to provide electrical damping to control the cone motion (mostly on the woofer).

Since a high damping factor is normal for modern amplifiers this also works out well for both.

If you drive a vintage speaker, using a modern amplifier, it may well end up being OVER-damped (since the speaker has its own mechanical damping AND the amplifier has a high DF).

This result may be less bass than you expect (because the speaker is not designed to be "tightly controlled").

And, if you drive a modern speaker with a vintage tube amp, or even a modern tube amp, it may end up being UNDER-damped, as well as not being able to play very loudly.

The result there is usually "sloppy" or "boomy" bass... or uneven bass (because the woofer is NOT being controlled tightly by the amplifier as it expects).

(The speaker cone continues to wave around after the signal stops because the amplifier is unable to apply "braking force" to control it as it expects.)

Speakers like the Klipsch LaScala (even the modern versions) are DESIGNED to be used with low-powered tube amps.

Horns are also sort of a special case because their horn loading makes them less sensitive to amplifier damping than ordinary cone speakers in general.

Likewise, electrostatic speakers, which have very little mass, and an entirely different drive method, are not particularly sensitive to damping.

Incidentally, if you WANT to reduce the damping factor of a solid state amplifier, to make it sound more like a tube amp (in terms of damping), it is trivial to do so...

Simply put a 1 Ohm resistor in series with each speaker... and you will have a damping factor similar to the DF of most tube amps.

(If you put a 1 Ohm resistor in series with a 4 Ohm speaker then you have reduced the amplifier's "apparent DF" to around 4.)

(If you put a 1 Ohm resistor in series with a 8 Ohm speaker then you have reduced the amplifier's "apparent DF" to around 8.)

(Be sure to use a nice fat 5 or 10 watt resistor - the resistor will be burning between 1/4 and 1/8 as much power as is going to the speaker.)

You can also experiment with lower values to achieve a result somewhere in-between.

As for preamps and power amps...

Both tube preamps and power amps introduce coloration.

A tube PREAMP will mostly introduce some second harmonic distortion and perhaps a little noise.

A tube POWER AMP amp will also do this, but in addition will add distortion from the output transformers, and have a lower damping factor than a solid state amp.

Therefore, if you want a little bit of "tube sound", but without the transformer distortion, and without the lower damping factor, then pair a tube preamp with a solid state amp.

(In case you hadn't realized... damping factor ONLY describes an interaction between the power amp and the speaker... preamps do not have a "damping factor".)

May 30, 2022 23:44:19 GMT -5 Boomzilla said:

Tube pre + SS power or SS pre + tube power? IMHO, (and profoundly obviously) it depends on the speakers.

Speakers I’ve found to like tube power:

Big horns
Magnepans
Electrostatics

The majority of box speakers, for some reason like high-wattage (and often high-current) SS amps. Using a tube pre + SS power is a MUCH less expensive option than vice versa.

OTOH, my 12-W Heathkit tube power amps kick the boo-tays of most everything, so who knows?

Boom

[Boomzilla]

I’ve never tried using a series resistor to reduce damping factor, but next time I have La Scalas in the house, I might try it. That would certainly be cheaper than using a tube power amp…