can I eliminate my preamp??

0 Members and 2 Guests are viewing this topic. Read 10721 times.

Steve Eddy

  • Full Member
  • Posts: 877
    • http://www.q-audio.com
Re: can I eliminate my preamp??
« Reply #20 on: 28 Dec 2006, 08:58 pm »
Any Steve in a storm I always say  :lol:

Ha! Good one!

Quote
Thanks for the CineMag link!  Somebody (you or mgalusha?) posted about them some time back and I lost the name/link.

No problem!

Quote
I still recall the selfless post you made at decware with diy instructions for turning wooden IC barrels like the ones you use with your Tao line   :thumb:

I did WHAT!?

*sigh* Well that's it. I think it's finally time to add giving up crack to my list of New Years resolutions.

se


Steve Eddy

  • Full Member
  • Posts: 877
    • http://www.q-audio.com
Re: can I eliminate my preamp??
« Reply #21 on: 28 Dec 2006, 10:19 pm »
These are the specs on my amp and my previous pre -amp set up:

Pre-amp : Adcom GFP-345
Output impedance    100 ohms    (normal and LAB)
Output level            2.0 V          (normal and LAB)
Input impedance(high)    22,000 ohms
Input sensitivity(high)     210 mV

Power- amp : ATI 1202
120WRMS into 8ohms with 28db gain
Input sensitivity       1.3 Volts
Input impedance      28k ohms (nominal)
Gain                      24 db (voltage gain)
Slew rate               50 V/microsecond
Damping factor        greater than 400 from 10Hz to 100kHz
DC Output offset      less than +/- 5mV

Mmmm. That's a bit odd. The amp is spec'ed at having 24dB of gain, but its rated output power is for 28dB of gain.

Anyway, I assume that you're wanting to get rid of the Adcom preamp and use something else between the SB and your amp?

Quote
Wayne does remove the analog section of the SB 3, doing this reverses the polarity of the output. I'm not sure if the output is capacitively coupled, but I believe it is.

Ok. Reason I ask is because if you use output transformers to get your additional voltage gain, you have to be careful of cap coupled outputs. That's because the primary inductance of the output transformers is typically significantly lower than for input transformers and unless you're using a healthy amount of capacitance for the output coupling, you can end up with a bit of peaking at low frequencies due to the resonant circuit formed by the coupling cap and the primary inductance.

Quote
What I'd like is to step up the voltage output and have an extra output to send a line level signal to my active subwoofer. I emailed Wayne, he's got something in the works that should take care of that, but it'll be down the road a bit.

Gotcha. You may want to think of combining a step-up transformer with an active buffer. With the input of your amp in parallel with the input of your active sub, the load impedance will be lower and perhaps not as well suitable for using step-up transformers (which will increase the output impedance of the SB by the square of the turns ratio).

Quote
The SB is the cat's meow, and the coolest thing since sliced bread . I'll never look back. Having your entire CD collection on your hard drive, being able to scroll through, make playlists, random accessability, internet radio, all from the comfort of being being behind your laptop, or by remote control, with great sound, and a minimalist set up, is a radical concept.

Yes. If you music is pretty much all in digital form to begin with, that seems to be the way to go.

Quote
No jitter, no unreadable CD's, no searching, hunting for CD's. No need for CD storage, never having to deal with another broken jewel case alone, makes it worth it for me.

Yeah, I hate those jewel cases too. I tossed all my jewel cases and made some simple jackets out of brown kraft file folders (didn't care for the white jackets that everyone seems to sell) along with some Tyvek sleeves. It's almost like having LPs again, only smaller. :)

se




Daygloworange

  • Industry Participant
  • Posts: 2113
  • www.customconcepts.ca
Re: can I eliminate my preamp??
« Reply #22 on: 28 Dec 2006, 11:04 pm »
Quote
Gotcha. You may want to think of combining a step-up transformer with an active buffer. With the input of your amp in parallel with the input of your active sub, the load impedance will be lower and perhaps not as well suitable for using step-up transformers (which will increase the output impedance of the SB by the square of the turns ratio).

That's what Wayne has in the works. A 1:2 step up transformer with a tube buffer stage. He says he should have something in about 6 months or so.


Quote
Yeah, I hate those jewel cases too.

Sorry, I've got the market cornered on hating those freakin' things!  :cuss:

Quote
Dayglo,

I am using a Sonic Euphoria PLC (autoformer design) with my Bolder SB2 analog out.  It provides as much as +10db gain (stock is +4db) using the autoformer as well as optional remote, 2 sets of outputs, tape out, and 4 inputs.  My BEL amps require 2v when bridged for full output, so this really does the trick without getting in the way of the sound at all.  There are several on a'gon for $800 or so, possibly without the remote, but it can be added on.  The only downside to using the version with gain is you can't turn the volume all the way off, but who cares since the SB does that for you.

Tom

Ok, I'll check that out.

Steve Eddy. Any thoughts on this unit as a possible solution for me ?

Cheers


TomS

Re: can I eliminate my preamp??
« Reply #23 on: 28 Dec 2006, 11:10 pm »
...should have added the url for reference www.soniceuphoria.com

Daygloworange

  • Industry Participant
  • Posts: 2113
  • www.customconcepts.ca
Re: can I eliminate my preamp??
« Reply #24 on: 28 Dec 2006, 11:18 pm »
Thanks.  :thumb:

Cheers

Steve Eddy

  • Full Member
  • Posts: 877
    • http://www.q-audio.com
Re: can I eliminate my preamp??
« Reply #25 on: 29 Dec 2006, 02:31 am »
That's what Wayne has in the works. A 1:2 step up transformer with a tube buffer stage. He says he should have something in about 6 months or so.

Ah, ok.

Quote
Sorry, I've got the market cornered on hating those freakin' things!  :cuss:

Ok, you can have it.  :thumb:

Quote
Steve Eddy. Any thoughts on this unit as a possible solution for me ?

Well, it's certainly a possible solution. Provided of course that it gives you enough gain.

Are you able to get sufficient loudness when you're using the Bryston preamp? I know you plan to get rid of it, but just trying to get an idea how much gain you'll need to get where you want to be.

se


Daygloworange

  • Industry Participant
  • Posts: 2113
  • www.customconcepts.ca
Re: can I eliminate my preamp??
« Reply #26 on: 29 Dec 2006, 02:52 am »
Quote
Are you able to get sufficient loudness when you're using the Bryston preamp? I know you plan to get rid of it, but just trying to get an idea how much gain you'll need to get where you want to be.

I'm assuming you mean my Adcom pre. Haven't tried running the SB thru it. I guess I could. I just know it's not what anyone considers a high quality pre, so when I got the SB 3, I just ran it straight to the amp.

Don't get me wrong, straight in to the amp, it still goes quite a bit louder than I would listen to on average. But sometimes, I feel like really cranking it. That's when it falls a little short. And I can't run a line out to my sub from the SB either, hence the search for a high quality alternative to my Adcom.

Quote
Well, it's certainly a possible solution. Provided of course that it gives you enough gain.

I read the specs on the Sonic Euphoria PLC, but it doesn't mention anything about the input or output voltages or impedances. I don't gather anything about it stepping up the gain. TomS says he's running it with a Bolder modded SB2 and he's boosting the signal with it. I think he explains he's getting a 10db increase, while having an additional set of outputs, and 4 sets of inputs. If this is true, this could be all I'm looking for.

 I'm not too keen on the tube buffer stage that Wayne is suggesting. I know for a lot of guys, this is desirable. I just don't want to get into the whole tube rolling thing if I can avoid it. It's not for me.

Cheers


TomS

Re: can I eliminate my preamp??
« Reply #27 on: 29 Dec 2006, 03:05 am »
I think of the SE as a "stop gap" until I see what Wayne is putting together.  The manufacturer of this unit sets it "standard" to +3.8db, but can set it for anything in increments of 2db from 0 to 10.  Mine is currently standard gain going into the 2v inputs of my BEL amps.  I just leave the SE turned all the way up, then adjust from 60-100 on the SB2 remote.  With that setting it cranks pretty hard in my setup with the Merlin VSM-MX's, easily 95-100db peaks if you want.  If memory serves me, but +6db gain of 1.1v would yield 2.2v, right? (20*log10 Vout/Vin).  I think the in and out impedance and response curve was measured by Jon A in Stereophile at one time.  I'd have to google a bit to find it but it's there somewhere.  From my experience, this one is much less sensitive than most transformer and resistor type passives to these types of issues (cables too).  I'm using either Gregg's Reality Cables or Cardas Golden Reference at 2meters to the amps with no apparent problems to my ears at least.

edited: corrected gain calculation, should be 6db
« Last Edit: 29 Dec 2006, 01:20 pm by TomS »

Daygloworange

  • Industry Participant
  • Posts: 2113
  • www.customconcepts.ca
Re: can I eliminate my preamp??
« Reply #28 on: 29 Dec 2006, 03:15 am »
Hmmm. Maybe I'll drop them a line and see if that's the case. If they can step up the output a bit, as you're speculating, to 2.2volts, that should be more than enough for me I think.

6moons, and a few others did reviews on the SE PLC, and had really good things to say about it.

I'll see what they have to say.

Cheers

TomS

Re: can I eliminate my preamp??
« Reply #29 on: 29 Dec 2006, 03:23 am »
Here is the link to Jon Atkinson's measurements in Stereophile.  The ultrasonic hf rise/peak he mentions isn't an issue in my setup which is SB2 only right now.

http://www.stereophile.com/solidpreamps/106sonic/index4.html

Steve Eddy

  • Full Member
  • Posts: 877
    • http://www.q-audio.com
Re: can I eliminate my preamp??
« Reply #30 on: 29 Dec 2006, 03:54 am »
I'm assuming you mean my Adcom pre. Haven't tried running the SB thru it. I guess I could. I just know it's not what anyone considers a high quality pre, so when I got the SB 3, I just ran it straight to the amp.

Yes, I mean your Adcom pre. It would be useful to know if you're able to get sufficient output using it. It's got about 20dB of gain so it bloody well better, but would still be good to know just to be sure.

Also, don't worry too much about what others consider "high quality." You're listening to please yourself, not others. While it may not be everyone's cup of tea, it just may be yours. So don't sell it or yourelf too short.

Quote
Don't get me wrong, straight in to the amp, it still goes quite a bit louder than I would listen to on average. But sometimes, I feel like really cranking it. That's when it falls a little short. And I can't run a line out to my sub from the SB either, hence the search for a high quality alternative to my Adcom.

Understood. Though I don't know that you can't run a line out to your sub from the SB. Does the sub have stereo inputs or is it mono? If it's stereo, there shouldn't be any problem. The input impedance of your Adcom amp is 28k. If the input impedance of your sub is as high or higher, the SB should have no problem driving that parallel combination, which would be about 14k. All you'd need to do is use some Y adaptors.

Quote
I'm not too keen on the tube buffer stage that Wayne is suggesting. I know for a lot of guys, this is desirable. I just don't want to get into the whole tube rolling thing if I can avoid it. It's not for me.

It's easy to avoid the whole tube rolling thing. Just don't do it. :green:

Seriously, there's no reason to avoid tubes just because others have OCD.

se


Daygloworange

  • Industry Participant
  • Posts: 2113
  • www.customconcepts.ca
Re: can I eliminate my preamp??
« Reply #31 on: 29 Dec 2006, 04:26 am »
Quote
Yes, I mean your Adcom pre. It would be useful to know if you're able to get sufficient output using it. It's got about 20dB of gain so it bloody well better, but would still be good to know just to be sure.

Also, don't worry too much about what others consider "high quality." You're listening to please yourself, not others. While it may not be everyone's cup of tea, it just may be yours. So don't sell it or yourelf too short.

This might be a little premature for me right now. I just got the SB hooked up the other day. My CD collection is going to be ripped to an external hard drive by my computer tech guy. ( He's also gotten a SB 3 after checking mine out, so he went out and got the latest, greatest , fastest CD drive that rips an entire CD to the hard drive even before you put it in the drive.  :lol:)

I'll try running it into the Adcom. I bought it used from a really great dealer here in Toronto. Audio Oasis. He's on the web. I auditioned it against a Parasound, and a few tube pre's as well as some hybrids. I found it to sound the most neutral of them all, and a little punchier. It has 2 sets of outputs, so that was great for running the sub. And yes my sub amp has stereo line level inputs, as well as the high level( or whatever they're called) inputs as well.

Quote
It's easy to avoid the whole tube rolling thing. Just don't do it.

Seriously, there's no reason to avoid tubes just because others have OCD.

It's just a philosophy thing with me. I want to find a minimalist way to do my set-up (circuit wise) that synergizes well and be done with it. That way I can avoid any OCD tendencies that might strike during full moon cycles.  :lol:

Just a carry over from pro audio, the less in the signal path, the better. But as I'm learning, you've got to be aware of impedance mismatches and so forth, hence, asking a lot of questions and advice from people who know more about that than I do.

Cheers


NewBuyer

  • Full Member
  • Posts: 612
can I eliminate my preamp??
« Reply #32 on: 29 Dec 2006, 04:27 am »
...I tried it without a pre-amp (just a passive volume control just for shits and giggles) with my cd player and it played plenty loud enough. And it sounded okay, I suppose. But with a tuner; and especially with a tape deck; I couldn't get any 'drive' and/or sufficient fullness at moderate volumes to be satisfying. The sound was thinner, indicating that the output stage(s) in my tape deck and tuner are not capable of enough voltage...and more likely, current....to drive my amplifier properly. At loud levels the sound was better, but didn't sound 'right'. Still no 'body'...

Hi WEEZ, I'm wondering please, was your passive volume control a resistive type, and was it connected directly to the amp inputs (as Scott Endler suggests)?

Daygloworange, and especially Steve Eddy,
What do you think of the idea, of using the chain SB3 -> Burson Buffer -> Endler Attenuators -> Amp.
It seems this would give the desired voltage/current/gain boost from the SB3, and easily drive the signal through the amp - in fact you could use several Y-adapters with the Burson unit with no performance drop.
Your thoughts please?

« Last Edit: 29 Dec 2006, 04:40 am by NewBuyer »

TomS

Re: can I eliminate my preamp??
« Reply #33 on: 29 Dec 2006, 04:44 am »
Does the Burson provide gain?

Gordy

Re: can I eliminate my preamp??
« Reply #34 on: 29 Dec 2006, 04:52 am »
Does the Burson provide gain?

Here's the Burson spec. list...

    Output Noise Level :  0.015MV(nil input)

    Maximum Output Voltage :12VRMS

    Maximum Input Voltage: 6VRMS

    SN:118DB

    Frequency Response :0-220KHZ(-3DB)

    Gain: 6db

Steve Eddy

  • Full Member
  • Posts: 877
    • http://www.q-audio.com
Re: can I eliminate my preamp??
« Reply #35 on: 29 Dec 2006, 05:00 am »
This might be a little premature for me right now. I just got the SB hooked up the other day. My CD collection is going to be ripped to an external hard drive by my computer tech guy. ( He's also gotten a SB 3 after checking mine out, so he went out and got the latest, greatest , fastest CD drive that rips an entire CD to the hard drive even before you put it in the drive.  :lol:)

Hehehe. Sweet!

Quote
I'll try running it into the Adcom. I bought it used from a really great dealer here in Toronto. Audio Oasis. He's on the web.

Yeah, I'm familiar with him. He carries Peter Daniel's Audio Zone line. He may be a great dealer, but I've never quite forgiven him for sticking those donkey dick power cords into Peter's gorgeous little amplifiers.



Quote
I auditioned it against a Parasound, and a few tube pre's as well as some hybrids. I found it to sound the most neutral of them all, and a little punchier. It has 2 sets of outputs, so that was great for running the sub.

Great! Now I don't want to hear you dissin' your little Adcom anymore.  :green:

Quote
And yes my sub amp has stereo line level inputs, as well as the high level( or whatever they're called) inputs as well.

Ah, good. Then just get a pair of Y adaptors and give it a try. I don't think there should be any problem.

Quote
It's just a philosophy thing with me. I want to find a minimalist way to do my set-up (circuit wise) that synergizes well and be done with it. That way I can avoid any OCD tendencies that might strike during full moon cycles.  :lol:

Hehehe. Understood.

Quote
Just a carry over from pro audio, the less in the signal path, the better. But as I'm learning, you've got to be aware of impedance mismatches and so forth, hence, asking a lot of questions and advice from people who know more about that than I do.

And that's the beauty of forums such as this and others. They bring together such a diverse group of people, all of whom can learn from others.

se

NewBuyer

  • Full Member
  • Posts: 612
can I eliminate my preamp??
« Reply #36 on: 29 Dec 2006, 05:06 am »
...He may be a great dealer, but I've never quite forgiven him for sticking those donkey dick power cords into Peter's gorgeous little amplifiers...

Steve Eddy, you are hilarious! I almost fell off my chair laughing about your comment and picture.  :rotflmao:
I've never seen donkey dicks, and now you are making me even more glad about that! :D


Daygloworange

  • Industry Participant
  • Posts: 2113
  • www.customconcepts.ca
Re: can I eliminate my preamp??
« Reply #37 on: 29 Dec 2006, 05:27 am »
Quote
Yeah, I'm familiar with him. He carries Peter Daniel's Audio Zone line. He may be a great dealer, but I've never quite forgiven him for sticking those donkey dick power cords into Peter's gorgeous little amplifiers.

George is a really cool guy. He let me bring my speakers and amp to audition the pre amps. How many guys will let you do that?

Quote
Daygloworange, and especially Steve Eddy,
What do you think of the idea, of using the chain SB3 -> Burson Buffer -> Endler Attenuators -> Amp.
It seems this would give the desired voltage/current/gain boost from the SB3, and easily drive the signal through the amp - in fact you could use several Y-adapters with the Burson unit with no performance drop.
Your thoughts please?

Sorry, I missed your suggestion about the Burson. I've heard about it before. I was just reading about it. Sounds interesting. This stuff is way over my head though. It talks about maintaining the same voltage, but lowering the impedance.

See, I just learned something new. Ok, now I'm curious as well. Steve Eddy. what are your thoughts on applying this Burson thing to better drive an amps input? ( considering the modded SB's output of 1.1 volts, not sure of the impedance though)

Or what about that TVC thing I keep seeing posts about on AC? Man, there's like 64 pages on that thread!

And yes, I'm starting to feel neurotic about all of this, I've reached that slippery slope thing, and I guess I've fallen off.  :duh:

Guilty as charged.

Cheers
« Last Edit: 29 Dec 2006, 05:37 am by Daygloworange »

Steve Eddy

  • Full Member
  • Posts: 877
    • http://www.q-audio.com
Re: can I eliminate my preamp??
« Reply #38 on: 29 Dec 2006, 05:36 am »
Daygloworange, and especially Steve Eddy,
What do you think of the idea, of using the chain SB3 -> Burson Buffer -> Endler Attenuators -> Amp.
It seems this would give the desired voltage/current/gain boost from the SB3, and easily drive the signal through the amp - in fact you could use several Y-adapters with the Burson unit with no performance drop.
Your thoughts please?

That'd be fine, though unless you're intending to put Burson Buffer right at the output of the SB3 and the Endler Attenuators right at the input of the amp, I'd recommend putting the Endler Attenuators right at the input of the Burson Buffer.

se


Daygloworange

  • Industry Participant
  • Posts: 2113
  • www.customconcepts.ca
Re: can I eliminate my preamp??
« Reply #39 on: 29 Dec 2006, 05:41 am »
What exactly would the net effect of the Burson be? Would it up the voltage to the amp input?

I know you've posted on the TVC thread before. What the deal with that pre-amp? Anything of special interest in this SB set up?

Cheers