Amplifier question, well, actually two questions...

starkiller

1. Decided to swap in an Adcom 545II amp for the refurbed Voice of Music tube amp as the computer room has just been way too frickin' hot. While the dynamics and soundstage improved it seems the low bass was not as good. Might this be because of the Adcom being extended in the high reaches and I don't notice the bass as much?


2. Decided to try another SS amp I have to see if I got the same result or not. Its a Denon POA-1003 dual mono. Does anyone have hands-on knowledge of these? I had not hooked it up till yesterday and on startup I get some transient "pop's through the speakers. Now I can use the button on the front to turn on and off the speakers but didn't know if that was so good for the button and whether the "pops" are an indictor of something else going on or imminent doom and destruction. I could always just leave it on also I guess.


Thoughts?

tonyb

The cheaper Chinese tube gear is usually a tad bass deficient. You won't get the same slam as with a higher current SS amp but you will get a sweeter mid range and highs. Some make that trade off, some don't, but the best option is a tubed pre and SS amp for the best of both worlds.

That said, if you like the Denon, keep it.....maybe do a refresh on it, but pops at start up or shut down sometimes are normal, sometimes not, depends on design and build quality. More times than not though, it's a sign of old caps needing to be replaced. So if you like that old Denon, you may want to invest a little into it.

heiney9

Depending on the tubes and the tube circuit it could be emphasizing the bass, whereas the Adcom might be a bit more neutral. It's very hard to compare used pieces as you never know (because they are used and older) if they are playing to their full potential or not.

As far as the popping, something is dirty or possibly on the way out, especially if they have an inexpensive start-up circuit like many Denon's do.

H9

starkiller

tonyb....the VOM is good old American tube gear so not sure why you thought it was Chinese.

H9..I would thought the Denon, being a true dual mono design would not have an inexpensive start-up circuit but you know more then I do that's for sure. The protection light is working fine also...

Both of ya -:)---the Denon also has less down under, just like the Adcom. Too me this is just so strange. Would tube rolling in my tube pre possibly help or does it seem its a tube vs ss reality?

mhardy6647

tonyb wrote: »

The cheaper Chinese tube gear is usually a tad bass deficient. You won't get the same slam as with a higher current SS amp but you will get a sweeter mid range and highs. Some make that trade off, some don't, but the best option is a tubed pre and SS amp for the best of both worlds.

That said, if you like the Denon, keep it.....maybe do a refresh on it, but pops at start up or shut down sometimes are normal, sometimes not, depends on design and build quality. More times than not though, it's a sign of old caps needing to be replaced. So if you like that old Denon, you may want to invest a little into it.

Not sure why you invoked "cheaper Chinese tube gear" in the context of this thread Voice of Music (VM) hardware was made in Michigan. I suspect he's conflating 'warm' bass with 'deep' bass... but I dunno.

I've never been too crazy about Adcom amplifiers (or preamps for that matter)... but the VM amplifiers were pretty generic examples from their time. Not bad, but not exceptional, either.

http://www.thevoiceofmusic.com/

I reckon the OP's reference is to the little EL84 pp stereo integrated that VM made.

heiney9

Like I said, tubes and/or the circuit they use has a huge influence. You could try rolling signal tubes, in some designs there is a huge difference, some not so much. RCA blackplates tend to overemphasize bass, for example, in some gear.

H9

starkiller

mhardy6647--

actually my post refers to this one ...

tonyb

My bad, I had Music Angel on the brain, lol Time to change the caps in my head huh.

Regardless, most vintage tube gear wasn't exactly dynamic either in the lower regions. Tube rolling as H9 suggests may bring along some improvements, but I gather your looking for a bigger one for that lower bass.

Tube rolling can get costly too, with no guarantee's of success. Maybe try a warmer sounding more dynamic SS amp. Halo or McCormack come to mind and I think you may find the bass you've been missing.

starkiller

Ah, Music Angel...:)

dunno, the VOM was plenty hefty in the bass and the two SS amps are lacking...only left for me to try is a pair of Marantz MA6100 mono blocs or try the VOM again and listen a little more carefully to the high mids/highs....

heiney9

That Adcom 545 is 25-30 years old. If the caps haven't been replaced that could make a huge difference. Again, this goes back to my comment about older used gear most likely not performing like when they were new (or newer).

Tube power amp sections take on the voice of their transformers too. Could be those vintage tranny's flavor the sound and emphasize the bass too. Lots of reasons for the differences you are hearing.

H9

heiney9

starkiller wrote: »

Ah, Music Angel...:)

dunno, the VOM was plenty hefty in the bass and the two SS amps are lacking...only left for me to try is a pair of Marantz MA6100 mono blocs or try the VOM again and listen a little more carefully to the high mids/highs....

How old are these SS amps? Have they ever been properly serviced? A stock 25-30 year old Adcom is going to be lacking at it's age, same goes for any other 20-30 year old amp.

You can't expect gear long in the tooth to perform to a standard of when they were new.

H9

starkiller

Have no idea on the servicing but doubt if anything has been done to them. Might as well try the Marantz's also just to see.... Thanks for all your thoughts...

heiney9

Just food for thought is all. Sometimes we forget how old some of this stuff is.

H9

starkiller

Well, then I think about how old I am and it all falls into place Like I mentioned though, just seems strange that two decent SS amps, while being very dynamic and all just don't have the bass like the tube amp does...will see what happens with the Marantz's tomorrow and then possibly trying out the VOM as the weather is suppose to cool down some...,

mhardy6647

heiney9 wrote: »

Just food for thought is all. Sometimes we forget how old some of this stuff is.

H9

heh -- I don't have much trouble keeping that in mind, somehow.

This ol' guy, e.g., is roughly the same vintage as me (late 1950s)

P1020749 by Mark Hardy, on Flickr

We're in similar cosmetic condition, but the EICO's in considerably better working order than I am

starkiller

So tried the Marantz MonoBlocs...better imaging and dynamics then the Adcom but still deficient in the bass. Crap! Put the VOM back in the mix and voila'! Bass is back in spades but dynamics/detail/high end are very much lessened....sigh...

lightman1

Bi-amp. VOM to the highs and monos to the lows. Taaa-Daaaa!!!!!

mhardy6647

lightman1 wrote: »

Bi-amp. VOM to the highs and monos to the lows. Taaa-Daaaa!!!!!

I like your thinking -- On a good track, but bass-ackwards based on the OP's estimation of the amplifiers.

So tried the Marantz MonoBlocs...better imaging and dynamics then the Adcom but still deficient in the bass. Crap! Put the VOM back in the mix and voila'! Bass is back in spades but dynamics/detail/high end are very much lessened....sigh...

I am not sure what it is that the OP likes about the bass from the VM amplifier, but it may well cost him dynamics (depending on the loudspeakers); that amp's push-pull EL84 I think, so you're talkin' 12 to 14 wpc -- and he's not happy with the HF extension (which is probably a factor of the... modest... output transformers on the VM).

I'll guarantee you that the HF linearity and extension is limited, maybe even severely limited by the small OPTs on that VM amp. It probably rolls off below 50 Hz, and/or HD is probably very high in the bass. Might be pleasant but not likely accurate.

I am thinking that the best use for the VM amp is in the midrange -- so maybe triamping... or... biamping with the VM on the bottom (bear with me a moment), pretty much anything with good HF linearity on the top -- and a subwoofer to lighten the load on the VM somewhat.
How's that sound?

starkiller

Interesting points but what i was poorly trying to say was that when i went from a ss amp to the VOM in the lst place i really liked the sound, did not like the loss in power, but i did like the sound.

So, in an attempt to cover as many bases as i can, i am going to replace the tubes in the preamp and see whats what....

mhardy6647

Replacing the preamp tubes will (may) change the sound, but not the power.

A better thing to do -- in my ever un-humble opinion -- is to find loudspeakers that are better paired with the little VM amplifier. There are loudspeakers (mighty fine ones) that are pretty darned happy with 12 wpc full-range... although an ampilfier like that one isn't really, quite "full-range" by modern standards.

BTW, they were always known as "VM", note their logo.



Nice array of VM logos from http://www.thevoiceofmusic.com

starkiller

going to replace the tubes in the preamp, not the amp, in case one of them is going bad and if nothing else reseating those pins...

mhardy6647

Yes I understood that -- one going bad is certainly possible. Reseating (heck, cleaning) pins isn't a bad idea, either.

starkiller

oh ok, just thought i wasnt clear as usual that did not do anything either...12ax7 and 0d3 replaced on tube pre and 6922s replaced on the DAC....

mhardy6647

well -- there are better vacuum tube amplifiers, you know... and there are better soiled state amplifiers, too. Remember, "better" fundamentally means "better suited to one's application [source and loudspeakers]" in this context.

The VM amp is a pretty modest component (essentially a console hifi amp aimed at the furniture store/appliance store massmarket segment ca. 1960). Good bits and pieces, but a simple circuit design with, frankly, cheap OPTs. The OPTs in that amplifier are indubitably limiting the extension of flat response at both ends of the frequency spectrum. The power output may be limiting dynamics (depending on your choice of loudspeakers).

So, to my mind, none of your "complaints" (observations) about the performance deficits of the VM amplifier is a surprise... except the one about "imaging". That said, this is a push-pull amplifier and I'm sure it uses some NFB to extend frequency response and hold down THD... I would further suspect that the NFB is fairly crudely implemented (given both the age and very modest provenance of the amplifier), so that might be causing a fair amount of smearing relative to a better-implemented PP design. This is purely speculation on my part, though -- that particular amplifier I have not heard in the flesh.

The other puzzling thing is your preference for the bass from the VM. Again, given the OPTs, I suspect the LF is rolled off but also "soft" in a way that you may just prefer.

All in all, my moderately educated guess is that the amplifier & loudspeakers just aren't a very good match for each other. There are two ways to "fix" that -- although neither may be particularly inexpensive

tonyb

What speakers are you driving with this amp anyway ? Mark's assessment is a good one imho.

starkiller

geez, thought sure i did post the speakers being used....sigh....so, Totem Dreamcatchers, Silverline Minuets and ERA D5s.

Again, its not necessarily that i prefer the VM bass as much as...

1. wondering why it goes away with the ss amps

2. why i liked the sound of the VM so much when i inserted into the system, bass nice yes but no dynamics.


3. I wanted to try a ss amp as my room was too dang hot with the tube amp and preamp and dac and tube phono pre and was going to reinsert the tube amp when it cooled down...now i am not so sure.

as an addendum i took the Amherst A2000 out of the garage system with the same results as the other SS amps so guess i need to rethink some things