Tube gear...Finally

[Frank Z]

I finally found some tube gear to play with! I picked up this amp from a guy that was selling it on ebay. The reserve was not met so I made a fair offer and ended up with a pretty decent amp. Here's a link to the original listing.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3053785500&category=39783&rd=1

I also won this preamp. It should get here in a couple of days.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=3057879648&category=14974&rd=1

I've got the amp connected to my wifes SDA-2b's, and everything seems to be working quite nicely. I' really like the warm sound.

Comments?

[gatemplin]

Congrats, looks great. I have never heard a tube amp before but am thinking about getting a used one like you did. I heard they are very clean and smooth sounding. Give a review when you get the preamp.

Graham

[RuSsMaN]

Looks like some cool gear Frank. I've had my eye on that preamp also - look forward to hearing your thoughts on it.

[madmax]

Frank,
Try playing something with a lot of sounds on top of each other, you know, something that has too much going on at the same time and just sounds messed up normally. If this amp is like some of mine you will hear all the sounds individually rather than an overall mush that you get from a SS amp. Congrats!!!
madmax

[Frank Z]

Max,
Any and all advice is welcome. Got any suggestions for tunes to try out?

[polkatese]

looks great, Frank! congrats...are these going to power LSi9 or the SDA? I would very much interested to hear how they perform with LSi, if you are going to pair 'em.

[Frank Z]

Right now it's all about tubes and SDA's, but I'm going to hook up the Lsi9's as well for a mini shoot out.

[madmax]

Frank,
The song that caught my attention was Cheryl Crow "the na na song" on the "tuesday night music club" CD. I had heard this song time after time and really knew what it sounded like. The first time I played it on tubes I heard many sounds separately, not the mush between words that I thought the song was. The rest of the CD is great as well. The only thing is that you would have to know the song through SS first, get used to it and then listen through the tubes. I'm sure you will find like sounds in your other CD's you are familiar with.
madmax

edit: the reason I say you will have to hear it through ss first is that once you really know what a song sounds like through tubes you will hear the same thing through ss. The mind and ears is a curious thing...

[RuSsMaN]

Thanks Chuck - I had not pulled that one out yet. I'm going to head to the cave now, and check it out on my tube pre and tube cd player.

Cheers,
Rooster

[madmax]

Being in Rooster mode may turn it back to mush :D

[organ]

Congrats Frank! Welcome to the wonderful world of tube audio.:cool:

Your tube amp will sound much better when the tube pre arrives. Adding a tube pre can give a bigger improvement than adding a tube amp with ss pre.

Please let me know how they sound with your LSi9. Both our amps use a quad of EL-34 Push-pull. I think it sounds amazing with the LSi.

What tubes are you using? If you really enjoy the tube sound, try Svetlana EL-34. They have the warmest and most romantic sound.

Maurice

[Tour2ma]

very simple, clean look, but for some strange reason I look at that pre and think, "Flintstones' mobile"...

will look forward to your review...

[madmax]

Originally posted by Tour2ma
very simple, clean look, but for some strange reason I look at that pre and think, "Flintstones' mobile"...



I see it too. :)
madmax

[RuSsMaN]

So it has a roll-bar, big deal. ;)

[Tour2ma]

maybe it's the key fob remote...

[madmax]

Actually I think it is those rear fenders.
madmax

[madmax]

I read the whole ad this time. The remote actually goes with the preamp! I thought it was there to show size.
madmax

[Frank Z]

Sorry I haven't kept track of the petty jealousy over my new remote!;)

Looking forward to getting my new Barney Rubble preamp....

I wonder if I can mount some off-road lights on the rollbar?!?!:D

[Tour2ma]

yabba-dabba-dooooooooooo

[Frank Z]

WWWAAAAAAAAAA!

[RuSsMaN]

Don't you mean 'yabba-dabba-tuuuuuube'?

[Wardsweb]

I like thinking outside the box. Trick little pre. I ended up building a custom one off version of the Bottlehead Foreplay for one of my systems.

[RuSsMaN]

Dual mono I take it? Looking at the 'connected' volume controls.

Cheers,
Russ

[Wardsweb]

You are correct sir. Very simple layout.

[Frank Z]

Well I’ve been listening to my new gear with mixed results. Keep in mind that I’ve never owned tube equipment before and was a bit unsure of what to expect. I was a little nervous about buying a DIY amp off ebay, but the sale went smoothly.

The amp is rated at 40x2, and really does sound good. I’ve listen to a wide variety of music on both the SDA-2b’s and on the Lsi-9’s. One of the things that became apparent right away is that 40watts is not enough juice, at least for me. Although the amp provided nice warm sound, it wasn’t able to drive the speakers at high volumes. Distortion was painfully obvious every time I cranked up the volume. 40 watts is 40 watts, no matter how you look at it. One of the things I learned from the guy that built it (via Email) was that I did not need a pre-amp to use the amp, it has a level control built in. It also is switchable from pentode to triode mode. The pentode mode is not as pleasant to listen to as triode. The only real problem that I encountered was some static from the speakers a few minutes after the amp was turned on. It lasted for 30-45 seconds and stopped after the tubes warmed up.

The sound is sweet, even though the low end does suffer. That’s not to say that the low end disappeared, but the loss of punch in the low range was distinct enough for me to notice. To my ears the SDA’s performed better overall, even though they are a larger speaker. I believe that having the passive radiator made a big difference. The one area that the Lsi’s did sound a lot better was at reproducing piano music, credit the Vifa tweeters. On the SDA’s pianos sounded kind of fuzzy, the detail just wasn’t as good as the 9’s. Mid’s where about the same with as light edge going to the SDA’s. Rock music did not sound as good (on either speaker) as jazz/blues/classical did. I was particularly impressed with the Lsi/tube combo when listening to Mozart –The 5 Violin Concertos by Itzhak Perlman (Deutsche Grammophon Cat #455-535-2). Perlman’s Stradivarius violin sounded absolutely incredible!

The Dared Pre-amp is small, but it performs well. The only thing that I don’t care for is the small amount of noise from the servo that rotates the volume knob. It’s not a real big deal, just something that I could do without. After listening to the tube amp mated to the Dared pre-amp for a couple of days I dragged out my spare Pioneer Elite M-10x 2 channel amp and went through a lot of the same music. At 75w x 2 @8ohms and 100w @ 4ohms it’s not he most powerful thing on the planet, but it did serve as a point of reference between tube and solid state. The sound was still excellent, but the mid range was not quite as warm. The low end was back, and higher volume levels were available without distortion when needed.

I used a Sony DVP-C660 5 disc changer as the source. Most of the CD’s were standard redbook titles, although I did play through a few stereo tracks from a couple of Hybrid SACD’s

Bottom line, the tube amp and pre-amp performed better than I expected as far as sound quality is concerned. I have to admit that I was expecting a bit more as far as volume is concerned. I’m sure that a more efficient speaker would be a good match for the amp, but I’m happy with my Polk speakers and am really not interested in sampling more speakers right now. So I think I’m going to hang on to the pre-amp and use it with my PE amp for the time being. The amp is going to be sold, either here or on ebay. I’m not giving up on tubes, but I’m going to research some more and perhaps invest in an amp that is rated at 100watts x 2 or more.

[F1nut]

Frank,

Nice review.

I've become a believer in the tube pre/SS amp camp. Just seems to be the best of both worlds.

[pjdami]

Frank,

Nice review and some good observations. I did get to audition some tube gear myself this past week. My dealer told me that in general, every tube watt amplification is equal to 2 - 3 watts of solid state amplification. So your 40 watt tube amp should equate to 80 - 120 watts of solid state. Most likely marginal for peek LSi performance which is more like 175 - 200 watts (in my opinion of course).

I listened to some JM Lab Electras (standmounts) and some Spendor S8s on a Rogue audio tube amp rated at 60 watts / channel in a carpeted sound room 15 X 25 ft with a 12 foot drop ceiling and the system never went to distortion .. pretty loud in fact. The source was a Cal Audio Lab CL-15 cdp. Easily 85 - 90 db from the listening position if I wanted it (loud enough for me!). The Spendors are 90 db efficient though and 8 ohms so that may have been a big factor.

I may be looking into some tube gear to experiment myself on the two channel rig. Of course the Rogue is high on my list but I have also been reading about the Jolida 202b modified tube amp available from Underwood Hi fi.

Paul

[madmax]

Frank,
I used the tube amps on the lsi15's and agree with you totally on the power. When hooked to the SDA-SRS 1.2's the sound level is more than enough but with the '15's it sucks. Maybe the 2B's are not efficient enough? Just keep in mind that a pair of 1.2's really don't take up much more space than the 2B's. Just taller. Don't react too quickly is all I'm saying. Once you get the right speakers with the tubes you will wonder why you ever listened to anything else. Maybe rather than selling the amp it is time to invest in a pair of large SDA's? You wouldn't be sorry. Just an opinion.
madmax

[Frank Z]

Paul,
Thanks F1 and Paul.

I'm leaning toward some Conrad Johnson gear, or perhaps this....

http://www.innersound.net/itubeover.html

Waiting to hear from them on dealers and MSRP.

[Frank Z]

Max,
I'm in agreement about getting some larger speakers, but the space just isn't there for 'em.


BTW, For anyone that is interested, I did put the amp up for sale in the Flea market. Polk-heads will always get first crack!

[pjdami]

I guess I have a question now about tube amps. If one watt of tube amp is equal to two to three watts of solid state (at 8 ohms), then how does this change when you use a 4 ohm speaker like a LSi? What my dealer told me pertains to 8 ohm speakers I'm sure because the speakers I was listening to were both 8 ohms. I'm thinking it should be the same as the solid state rules right?? roughly 75 - 100 % more power or is this a limitation of tube amps?? Seems like 40 tube watts should be a lot if one follows these rules for a 4 ohm speaker unless it is just equally a function of the speaker efficiency.

P.

[HBombToo]

Originally posted by pjdami
The source was a Cal Audio Lab CL-15 cdp. Easily 85 - 90 db from the listening position if I wanted it (loud enough for me!).
Paul

Paul you say was... did you dump your Cal?

I have the CL-20 and will never part with it. If the CL-15 is andything like my CL-20, the analog out stage is like 2 Vrms regardless and is such an accurate and smooth player it could make the worst amps sound good. Just an outstanding cd transport/player plus in my case DVD.

I see where Frank is going and I do believe power is what he needs.

HBomb

[madmax]

Tubes can seem more powerful than they are under certain circumstances. With efficient speakers they really bloom. They have mostly even order harmonics which are pleasurable as compared to odd order harmonics (like SS amps have) which do not harmonize with the other sounds. (sometimes called intermodulation distortion). A very small amout of IMD tells you the amp is up too far whereas harmonic distortion (which tube amps have) detract little from the performance. If the speaker is not efficient enough you never get to a reasonable listening level. Some speakers like the LSi series needs serious hp to get a reasonable listening level. Others are very loud before you reach a distorted level.

In some ways it is like tuning an engine to a car. If you get everything tuned it is fast. If not it is slow. (horse power is only part of the equation). If for example the rear end gearing is too high for a low torque high hp engine the car will be slow.

It seems that Franks 2B's are not efficient enough to use with tubes.

Whatever the case it takes a lot of experience to match power amps to speakers. If you have enough raw power you can use anything but if you are using low power and hungry speakers then you won't get a reasonable listening level. (So it doesn't matter how good it sounds)
madmax

[pjdami]

Paul you say was... did you dump your Cal?

Hbomb,

I don't own the Cal Audio cdp; it was setup at my local dealer. It sure is a sweet sounding cd player though. In fact the entire experience was exhilarating.

Madmax,

Thanks for the explanation.

Frank,

That's one killer looking tube amp. Wait till Organ reads this thread!

P.

[Frank Z]

Thanks for all the feed back folks.

Hopefully I can sell it quickly and try something a bit more powerful.

[organ]

Great review, Frank! You picked up some really nice gear there. I agree that with the LSi, the tube set up lacks deep bass. Even though it's less bass than my ss gear, it's enough for me. I don't even use my sub most of the time. But the mids and highs is the best I've heard. Just wondering, does your amp have impedance taps on the speaker outputs? When I switched from the 4 to 8ohms output for my LSi, the sound really improved due to more current flow.

Try to listen to the tube amp again for a few weeks before selling it. I just switched back to my NAD gear for fun and even though I get more bass, it's not the same quality as tubes. You may notice this too if you listen to the tubes longer and switch back to ss. With a tube amp, the bass has more texture, warmth, better decay and it has character. If you decide to sell it, I'm sure you can get a very good deal because your unit is pretty much brand new. btw, those Svets in your amp are great tubes.

Maurice

[organ]

madmax,
That's a very good explanation. I also heard that tubes tend to compress the sound when pushed too hard and SS clip which is audible.

Have you heard any of the Klipsch Reference line with a full tube set up? I'm getting a pair of RF-15 very soon. I noticed that the "tube magic" increases with higher efficiency speakers.

Maurice

[Frank Z]

Since we're talking tubes.....

http://www.hometheatertalk.com/ubb/Forum8/HTML/000899.html

Looks like a good deal.

[madmax]

Originally posted by organ
madmax,
That's a very good explanation. I also heard that tubes tend to compress the sound when pushed too hard and SS clip which is audible.

Have you heard any of the Klipsch Reference line with a full tube set up? I'm getting a pair of RF-15 very soon. I noticed that the "tube magic" increases with higher efficiency speakers.

Maurice

No, Sorry,
I have only heard the larger SDA's, the LSi9's and 15's. I would like to try some incredibly efficient speakers.
madmax

[Frank Z]

Well folks I've cancelled the sale here and on ebay until I get a few things resolved.

I got an email from someone that purchased an amp that was made by the same guy and basically he did not get what he paid for. His amp was listed as being able to put out 10watts per channel but he ran into the same problem that I was having, not a lot of volume. He had his amp tested and was surprised to find out the output was .6 watts per channel!!!

I cannot in good conscience sell this amp to anyone until I know that it is functioning properly and as advertised. I have sent an email to the folks that listed the amp originally on ebay asking for a refund, but I think I'm pretty much up the creek without a paddle on this deal. A very expensive lesson for me, but thats my fault for buying a non-name brand amp.

I'm going to look into having this amp checked out to determine the actual output.

I'll keep you folks posted.

[dorokusai]

Frank - Sorry to hear of your misfortune, you are a stand up individual indeed. You should talk to some of the guys over at Audio Karma, they may have some insight as to how to fix, or what to do.

[bikezappa]

Frank

Make your own measurements.

E= voltage or volts
I=current or amperes
R=resistance or ohms
W= power or watts

OHMS LAW is

E=IR or

I=E/R

Power is

W=IE or volts times amperes

get rid of the I by substituting I=E/R in the powerequation

or

W=E times E/R

Measure the peak volts across your speaker while listening to loud music. Assume the resistance of the speaker to be 4 ohms.

Lets say you measure 5 volts and have 4 ohm speakers, the power or watts would be W=5volts times 5volts/ 4ohms=6.25watts.

Have a blast.

[Frank Z]

Thanks guy!

Do unto others as you would have done to you. A simple philosophy, but it works for me.;)

Bike,
I'm very familiar with ohm's law, but I do appriciate your jumping on board to help me out, thank you. The reason that I'm considering taking the amp to a shop and have it tested is so that I can have written proof from an independant 3rd party.

[bikezappa]

Just curious about how watts are measured in Hi Fi.

If you have a volt meter anyone can do the measurement and calculate the watts to the speaker based on the listed resistance of the speaker. This is an average power measurement because the reisitance or impedance changes as a function of frequency. You can see from the equation:

W=ExE/R

that the lower the resistance the more power, with every thing else the same.

After breakfast I am going to see what power I have to SDA SRS with an Adcom power amp.

Keep you posted.

[bikezappa]

Well I'm confused. I measured the voltage to my SDA speakers at different volume levels. I used an old reliable analog Triplet VOM to measure the volts. At the loadest I could stand I get maybe 10 volts to the speakers from my 300 watt Adcoms power amp. My calculation for output power to the speakers is

W= 10Vx10V/4ohms=25 watts.

I know that instantanious voltage could be higher and may not be measured with the VOM. I would need an oscilloscope to get true instantanious voltage measurement. I suppose that I could drive the speakers with a sign wave continuosly.

Now I know that a 100 watt light bulb draws 1 ampere, so the bulb does infact consume about 100 watts of electricity because W=EI=120Vx1amp=about 120 watts.

I guess there are HI Fi watts, tube watts and SS watts and electric watts. Watt's up? Can anyone explain this difference.

Frank how did you measure the power from your tube amp??

[Tour2ma]

Frank,
Bummer. Here's hoping for a positive resolution...

bz,

Several factors are involved. First the impedance speakers site is a nominal impedance, as in "your results will vary". Impedance varies with frequency fed, driver temp's, and other factors. So you need to measure more than just voltage simultaneously.

You are on the mark with the need for an oscilliscope, but a signal generator is also necessary. I want to say that 1000 Hz is standard, but may be off here. I have also seen pink noise tests.

Last there are continuous output tests and instantaneous tests (tone burst). In either you are looking for peak clipping. Instantaneous power rating can be anywhere from a couple percent higher to double the continuuous power...

Here's a reference I found:

Today, the primary standards are dictated by the Federal Trade Commission (FTC). Many manufacturers also use standards developed by Industry associations—such as the Electronics Industry Association (EIA). Some manufacturers use other methods.

Safety agencies (particularly those in the European Union, and Underwriters Laboratories here in the US) have developed standards for measuring average continuous power of an amplifier. These are used in turn to measure maximum AC line power consumption and to confirm maximum temperatures. Safety groups have determined that typical worst-case power for an amplifier amplifying an audio signal occurs at one-eighth of the non-clipped output power (measured with a 1 kHz tone).

The amp is then “cooked” with a bandwidth-limited (20-20 kHz) pink noise signal whose power is equal to 1/8 of the tone full power. Measurements are then made for temperature and AC line power consumption. Thus 1/8 of the maximum tone power before clipping represents realistic worst-case continuous power levels for an audio amplifier.

[bikezappa]

Well your suggestion to use pink noise as a source was a good one. No more peak voltages to read. I put on my test CD that has a track with pink noise. I got up to 12volts. I couldn't go any higher before my ears broke started to bleed.

Watts = 12X12/4=36watts

I don't understand the 1/8 factor in the definition of continious power output. Why not use 1/16 or 1/32. Where does the 1/8 come from?

I could measure the power to the power amp by measuring the current drawn and multiply by 120 to get power (Watts)consumed by the power amp. But that is not music power because I could just have 10 light bulbs in the power amp and that doesn't mean I have a 1000 watt amp. Or does it.

Frank's thread about his tube amp asks the awuful question-how much electric power does the amp deliver to the speakers? How do you measure it?

Hope I'm not messing with Frank's thread.
How does a sevice tech measure power output of an amp?

[Tour2ma]

1/8 th comes from safety concerns for the overheating of amps...

Here's a link to a recent FTC ruling... pertinent stuff starts around page 21. Summation is on pages 33 and 34. Oh yeah, notice of "The Paperwork Reduction Act" is on page 32... :D

Oh, and power consumed by lightbulbs typically used in amps is negligible... or at least it should be...

[madmax]

I've never done it but this is my understanding. With a freq generator set at 1000 hz, a 4 or 8 ohm power resistor on the output and a scope measuring across the power resistor you turn the freq generator level up until you see the sine wave start to clip. Note the voltage of the signal on the scope. At that same voltage insert a current meter in series with the power resistor and note the current.

Peak power = IxV
RMS power = IxVx 0.707

I would think that you could use voltage only as was demonstrated previously but you would still have to multiply the solution by 0.707 to get RMS power. (unless the voltage measurement is in RMS).

madmax

[bikezappa]

Didn't see the site you refered to in the past post.

Thanks for information.

The impedance of any circuit is a function of only three things:

resistance
capacitance
inductance

The resistance doesn't change with frequincy.

The capacitive, Rc=C/frequency , and inductive, Rl=Lfrequency, resistance changes with frequency.

In fact, these are the only three components to ANY circuit ever designed or made...

[Frank Z]

Bike,
Don't sweat hi-jacking this thread! I think it's great that others are jumping in to help out in any way they can. I'm grateful to tour and all others that post and offer a hand. Keep going guy's your helping Bike, myself, and everyone else that takes the time to read this sob story of mine!:)

BTW,
I haven't had time to take any measurements yet, I took the family out to hunt down a Christmas tree! We bagged a beauty! 3,987,208 point buck pine tree......Doc will be jealous!:D

[bikezappa]

My Triplet VOM measures RMS voltage and an oscillascope will measure peak to peak voltage. You 100% correct.

What I don't understand is the meaning of power amp ratings such as:

100 watts per channel continious at 8 ohms.

If W=ExE/R
then
E=sqaure root of (WR)= square root of (100voltsx8ohms)=28volts.

This means that a 100 watt amp can supply 28 volts to an 8 ohm speaker.

This 1/8 bull shit factor may be advertisement gimmick.

A watt is a watt is a watt. Right?

Do you realise how fucking loud just 10 volts into your speaker is? Measure the voltage on your speaker connections. I bet you can't get past 10 volts.

[Tour2ma]

bz,

Sorry 'bout forgetting to post the link. Here it is...
http://www.ftc.gov/os/2000/12/amplifierrulefrn.pdf

The above issue of the rule was brought about by the advent of multi-channel (>2 ch) amps for HT.

The 1/8th is not an advertiser choice, it's in the rule.

[bikezappa]

Well Tour I read that 1/8 power story and it doesn't tell me the proceedure for measuring power output for an amplifier. The 1/8 rule as you said is about preconditioning, not sure what that is exactly

How does one verify 300 watts/channel output in an amplifier?

Is a Watt, a Watt. Is a Watt=Votage times Current?

This is not rocket science but simple math.

This seems like a basic question for any one who spends big bucks for electronic equipment.

[Frank Z]

I took the amp to an electronics repair shop this afternoon to have it checked out and get a written report of the findings. The gentleman that I spoke to said that he's going to check the output at both 4 and 8 ohms with a 1khz signal (Peak and RMS). He said that he'd also check it for the distortion that heard during warm-up and at the "higher" volumes, which is not very high. He also said that he'd check it out up to 10khz to see how it performs.

I got back from the shop and I had an email message from the guy that built the amp. I had sent him a message regarding the problems that I was having about 10-14 days ago and of course I heard nuttin'! I sent him another message when I listed the amp on ebay telling him it was for sale and I wasn't happy with it all. Now all of a sudden he's all fired up about wanting to help, but no mention of a refund. I'll what to reply until I can send him a copy of the test results.

If it gets ugly and he refuses to take the amp back I'll email every single person that bids on ebay auctions. Yes I am spiteful S.O.B. thank you very much!

Who knows, maybe it will turn out to be a simple fix and I'll be embarassed for getting so bent out of shape, But at this point I really don't think that will be the case.

[dorokusai]

Frank - Let things work themselves out....if it gets ugly, like you said....get spiteful :D

[madmax]

Good luck Frank! I've had friends who follow people around forever to spoil future auctions. It's a lot of fun but it doesn't buy you anything. Better to get the amp to proper specs and then sell it. One thing I noticed is that it is a no-feedback design. Even though the tubes are rated at 40 watts or whatever an amp design of this type is lesser in wattage than one with standard feedback. The reason people do this is to get a more pure output even though it is decreased. Of course the speakers must be super efficient. Not taking up for him because it may be defective, just throwing out a little info. If you want to try a Jolida 50 watt amp, known good, I'll be happy to ship you one to try (at your shipping cost). You are welcome to try and buy or ship back. Hoosiers amp would be a good choice as well. It should perform at an equal rate as the Jolida and you can be assured that he is a good seller as well. Just throwing mine in the mix. (I have 3 of them).
madmax

[Frank Z]

Max,
Thanks for info and the amp offer! Russ is sending his ASL amp out to me this week so I'll give it listen first.

*EDIT*
I bought my Lsi9's from Russ. Smooth transaction, a true pleasure to do business with.