Proud new Tube Papa, My impressions.. (1 Viewer)

[Joel X]

If you had to complain about this amp what would it be? At this point it seems like a great amp but there is always some type of compromise...

At this point i'm weighing all my options for my upstairs computer system. I think i'll go with a revolution sound card though I intend on only using four channels and a sub. This brings me to why i'm posting here... How would those monoblocks due in a small office type environment? What is the mean time of failure with this type of amp? I would imagine tubes go bad but how long can someone expect before a problem?

I am very close to purchasing a receiver to do my bidding but like the idea of monoblocks since they are in essence all I need mated with an M-audio card and a Griffin powermate USB volume knob. A receiver is loaded up with superfluous switching and what not that I don't need though it would be sent with the s/pdif so I could use its DAC's.

Would you use this amp for your computer sounds?

 

[Brett DiMichele]

Joel,

I honestly can't put my finger on a specific complaint
simply because I went into this knowing and understanding
all of the drawbacks of tube amps and accepting that fully.

There are no issues with build quality or sound quality.
Tube life will be dependant on how much you switch the
units on and off (worst enemy of tubes). But generaly I
would say these tubes could last upwards of 5000 hours
without issues. Tubes can be as costly or as affordable
to replace as you choose them to be. For example you
could buy NOS (New Old Stock) tubes from the 30's 40's
and 50's from Telefunken,Gold Lion, RCA, Phillips,Mullard
Etc. Al. And spend hundreds of dollars. Or you could buy
all new Russian made ElectroHarmonix tubes for less than
$50.00

Would I use these in a computer system? No... But I am not
into computer audio so my opinion hardly counts. If you
want very good audio from your PC yeah these would definatly
sound awesome mated with a pair of reasonably high efficiency
bookshelf speakers.

But I would suggest keeping the amps away from the PC because
these are after all old school technology and they may
interfere with the PC (EMI) and remember tubes used in
an amp run hot, real hot.. Hot enough to burn you..

Another option would be to check out the new motherboard
from (don't quote me on this) A-Open? That has Tubes
built into the integrated sound. From what I understand
this MoBo was said to sound really good.. It could be an
option?

But then if you do another audio system you won't have a
nice pair of tube monoblocks sitting around to make use of.

 

[LanceJ]

Just a tube "FYI" :

Tubes are voltage-sensitive devices. I.e. theoretically, the HIGHER a speaker's impedance is, the MORE power they produce. That's why so many speakers from the tube era are 10-16 ohms. And the reason for the step-down transformer between the output tube & the speaker.

Transistors (solid-state) on the other hand are current-sensitive devices. The LOWER the impedance the MORE power they produce.

LJ

 

[Michael R Price]

Hi again Brett, thanks for the schematic, interesting stuff and definitely real simple/easy to build. (I've been away for a few days.) Good to see the break-in has helped.

I'll add to Lance's post by saying that a tube amp or any other amplifier limited by output current (such as most Class A designs) will exhibit power proportional to the load, until the power is limited by voltage. For example let's say you have an amp that can deliver up to 24 volts, or 3 amps above which it clips. That amp produces 36 watts into 16 ohms, 72 watts into 8 ohms, and 36 watts into 4 ohms.

Joel, I would say for a computer-based office system amps such as these may be overkill and getting a good value used integrated amp of $200-400 would be fine. But, AV-20s or any other monoblock (like the AV-8s perhaps) would still be a good mate to smaller speakers of 90+ db efficiency. The tubes are fine, don't worry about them burning out especially if you use them lightly.

 

[Brett DiMichele]

Lance,

Thanks for the info!

 

[Brett DiMichele]

Mike,

Real simple huh? Suuuuure easy for you to say..

I know enough about electronics to get me into trouble!

It is a simple design though. I think you'd be hard pressed
to find any tube amp that is complex (aside from S.S/Tube
Hybrids).

So since you seen the diagram what would you recommend
changing or upgrading? Just for curiosities sake.. I think
later on I may replace all of the capacitors and the one
inductor with a mills unit and I am changing the LED lights
from red to blue.

I am worried about changing the LED though. From what I can
see the LED looks like it's tied somehow into the tubes and
I don't know what the voltage is on the stock LED. The blue
LED's I have take up to 3.6V but they don't list the amperage.

 

[Michael R Price]

Brett,

Simple doesn't mean I understand how it works! I'm not familiar with tube circuits much at all. But, it looks like a good standard Class A amp and it's easy to build.

The first thought would be to replace the important capacitors (C4 and C5, maybe) with MKP or some exotic type. Also, you could put new electrolytics in the power supply and upgrade the rectifier to the diodes du jour (that's a funny term). And then there's tube rolling.

Don't worry about the LED much. I don't see it in the schematic, but it's probably just put across one of the power supplies with a resistor to limit its current. The voltage the LED drops is insignificant, and I don't think you'll overpower a blue LED unless the current one is really bright.

 

[Brett DiMichele]

Mike,

Thanks for the info! Have you any experiance with Jensen
Copper Foil with Silver Lead Out Caps? How about Rikken and
Wima? What would be good sources to purchase those caps
from?

 

[Mark R O]

Joel,
While on walkabout at the last CES show, I discovered a small (6"x10"x8"??) pair of speakers that were individually powered by a pair of tubes sticking up from the top rear of the units. They employed a single 3" driver per cabinet. They were exceptionally well crafted and obviously a serious attempt at desk top hi-fi. They were not a speaker you'd immeadiately replace your 5 digit price tag mains with, but were none the less amazing. To make sure I wasn't letting their considerable "cool factor" sway me, I fetched a couple of buddies that are speaker designers/suits with "hall of fame" accomplishments to have a look-see. Both were moved by the little hybrids enough to offer "they have promise!" (high praise from these propeller heads). Anyway, I will flip through the stacks in my office for the info sheet on them, and will copy to you if you are curious. By the way, they were built by a small, obscure manufactuer in mainland China, so they won't be in your local CircuitBestGuysOneMart.

 

[Brett DiMichele]

Mark,

Post that info for us all to see.. Heck I may be interested
in a new pair of PC speakers down the road!

That's neat stuff


Mike,

I changed the LED's over to blue... They look so much
better now than they did with the red lights.. I just love
the look of blue led's it was the holy grail of led-dom and
they finally figured it out! I made some nice spiked amp
stands for the monoblocks also this weekend and I sit the
amps on the stands which elevate them about 4" off the
carpet.. They look great down there and trust me when I say
it's much better than where I had them

Now all I need to do is get the new audio rack built and I
will actually have a nice place to have all of my components.

 

[Yogi]

I haven't let the tubes burn in like most people do but
already the sound is impressive. I notice more decay on
instruments than I did on my solid state amps, a well known
guitar piece sounds completely new to me as the strings can
still be heard vibrating longer than I ever could before..

Could that ringing be as a result of the lower damping factor of the tube amp compared to SS amp. Just curious. I have never had a tube amp in my system although I have listened to many outside and have just recently started playing with a tube pre in my system. Would love to hear about people's opinion on this.

 

[Brett DiMichele]

Yogi,

It sure could be.. Or it could even be microphonics (which
certainly wouldn't be out of the question considering where
I had my amps temporarily sitting) either way I love the
sound.. It is the sound I have been looking for.

My Onkyo M-282 2 Channel Power Amp is a real robust unit in
terms of build quality and has loads of extra capacitance
for hard dynamic loads plus it has a fairly high dampening
factor of 200. This unit is very "warm" sounding to my ears
(Don't chew my leg off Chu!) but it still can't compare to
the way the ASL Monoblocks sound. They put out a whole 90
watts less per channel than the Onkyo at 110Wpc but they
drive the mids and tweeters (all I am using the tubes for)
to the same levels and the midrange is so much better with
the tube amps that it blows my mind.

And these are in no way rolling off the high end either.
Joe Lau (designer) said that he has tested these clean up
into the mid 40Khz range (even though they only list them
into the high 20's).

I truly am amzazed at the sound per dollar ASL offers
compared to some of the "high end" companies. You are
paying for pretty construction and very low production
numbers in some of those companies. I have seen the guts
of Cary's products and while Cary uses better caps and
probably uses a better "grade" of internal wiring, the
ASL's are no less neatly designed and wired internaly.

Most of the ASL's wiring is P-P they do use a PCB for the
tube sockets and to hold the capacitors but even so they
are still well constructed and I would recommend them to
anyone looking for a true bargain and fantastic music
reproduction!

 

[Michael R Price]

Brett,

Nope, don't have any experience with exotic components. You could probably put in good standard polypropylene (MKP) and Panasonic FC-series electrolytic capacitors and notice a difference. (Also, you can put fancy diodes in the power supply and increase the value of the power supply capacitors. That probably makes more difference.) Beyond that are the exotic brands like Wima, Solen, Black Gate, etc... It depends how good the components are in the amps as they are, I guess. I don't have any idea just how much the quality of passive components influences the sound, but I would doubt it's really significant. (Haven't bothered changing the components in my amps, I just put in good standard quality ones the first time.)

 

[Brett DiMichele]

Mike,

Well the Transformers are good the stock tubes are very
decent other than that it's just resistors and capacitors
as there really isn't much more to it than that. The caps
in the critical audio circuits are already paper in oil
audio specific jobs from some company called "Illusion" I
don't think that's the same company as Illusion Audio. I
haven't checked the brand of the smaller caps. ASL says
the parts used in the Wave 20's are more "audiophile" than
those used in the 8's (whatever that means ehh...)

They sound absolutely fantastic as is, so any changes are
not high on my priority list at the moment..

I should have my new PreAmp in a few days I need to place
an order to PE for a couple more Neutrix XLR's and I think
I better get a 100' spool of Mic Cable and a 100' spool of
Carol Architectural 12AWG Speaker Wire while I am at it..
I am going to make some new speaker cables and I am going
to make my own balanced XLR Cables from the Pre to the
Tube Ultra-Q and to the amps.. Ohh I also need some more
of those neat brass spikes I bought from them (for my new
audio rack I am working on).

Now if I could only get my friends to get back in touch
with me about machining the center parts for my rack then
I can actually place the order for the rest of the junk to
built the rack and get it done! (it's gonna be a thing of
beauty I tell ya!).

 

[Joel X]

Alley oop