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#67536 - 02/16/08 10:25 PM Tubes rule yet the High gain can be tough Please read.
Lizard King Offline
Desperado

Registered: 08/30/06
Posts: 425
Loc: NY
Hello to all in Outlaw land.

I know this is the 990 forum and not the 1070. I figure people here are more into high SQ.

Back in the 90's I was an audiophile and I kept my old system boxed up. I wanted to start out fresh so I bought the vaunted Outlaw 1070.

I placed high end speakers for mains, a high end DVD player that I had modified and I great sub and decent center and rears.

The 1070 is a an A/V receiver yet it is IMHO an audiophiles entry is home theater.

Wheter you use the 1070 or the 970/990 preamps, I feel you should use a mid to high end CDP that has good DACS and analong sections.

The Denon 3930CI is that yet I stil wanted a really high end player to start the chain.

I was not happy with the SQ when I hooked up the Denon DVD player to any of the normal inputs. I use the analog ICs and what I heard at first was not to my likeing.

Former tech man Steve told me about the DVD Multi channel input in bypass mode with full analong Bass MGMT (8oHz). For you 990 owners, you do NOT get Analog Bass MGMT, sorry.

That really made a huge difference. I did pick up a nice used Amp to increase my power and it works nice.

Finally I came to the point where I said, why not try some of my old system and build an HT that can also play high SQ music.

For a while now I have used an audio switch box and I shuttle between the 1070 and the HT preamp and my old Audiible Illusions modified tube preamp with two Mullard tubes.

This is a great sounding preamp yet it can be very annoying. No reamote control, no balance control and the two mono pots do not match each other.

The super high gain is a mismatch for my amp which has a input impedance of 21k Ohms. The preamp has an gain a 58db at 1khz. Talk about a hard time!

For all of you you may not know, the early front end tape decks and record players had a voltage output of 1 - 1.5 volts. Then came CD players that put out 2 volts and some outboard Dacs are higher than that. This can cause a mismatch to overload the amp where you can barely use the volume pot.

Should any of you haved this problem, I now know a way around it!

A company called Harrison Labs makes inline Signal Attenuators that go on you ICS between you Player and preamp or your preamp and amp. The values are 3, 6 and 12db. You can get these at a discount price from Parts Express web site.

I run a 35 ft Accell Digital Coax cable from my sound card's SPDIF (M-audio Revolution 7.1) to the 1070. That worked nicely, the 1070 locked into the signal and never dropped it!

The biggest change I liked about using my tube preamp is the 3d soundstaging. My Alons speakers can really image and they are known to perform that way with tubes. Of course my super high end modified player helps in that way too. So I decided to run the PC cable into the tube preamp yet I needed to use an outboard DAC. I looked around for budget DACs yet It seemed to me that over a long run, most of them would not work. I dug out my old Monarchy M22A (1992-93) to see if that early advanced clock circuit works and it did just that!

Next came time to use the 12DB signal attenators. It took one whole day for me to realize the sonic benefits. I can now listen to a decent number of CDs that are not over recorded and at 9:00 (position) the classical and jazzz music sound great. I tried some rock Cds and they sound forward and too loud so I am going to use another 6 or 12 db of attenuation since my case is extreme.

On the second day after the change using the signal attenuators, I noticed that classical music from mp PC (lossless) really threw up a deep soundsatge and replayed the hall well. I can't use my single sub (with e singal from the PC) and I am using the low level input as opposed to the high level inputs.

My HSU sub is very similar to the Outlaw subs yet I have two RCA inputs.

Do you who use the subs use the low level (RCA IC)
inputs or the high level (speaker cable inputs)?

I am thinking about getting a 2nd sub and using the extra set of main outputs on the tube preamp to feed the subs and use the built in crossover on the subs . I will probably also need to use signal attenuators to tome down the ouput to the sub. I can then run a single RCA from the 1070 to one sub and when I get the next generation 990, I am hopeful to run two cables from that preamp to the other set of inputs on each sub and switch between the built in crossovers on the sub for music, listen and the 1070/new 990 for HT crossovers for HT while I turn off the crossovers on the subs.

Again, I must ask if you use the ICS or prefer using speaker cables to feed the powereed subs?

I hope this post heplps others?

Liz out
_________________________
Outlaw 1070, Anthem MCA5 II amp.
Sony Ps3
Alon 2 Mk2 Loudspeakers
HSU VTF-2 Mk2 sub x2
VAC PA100/100 Tube Amp
ARC SP16-L tube Preamp
Audio Note Dac 2.1 "B" signature
Furutech E-TP80,
Ascend HTM-200, 340C
Sony KDS-55A2020

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#67537 - 02/17/08 03:09 PM Re: Tubes rule yet the High gain can be tough Please read.
Altec Offline
Desperado

Registered: 01/06/08
Posts: 334
You can also place simple 1% MF resistors in series with the "hot" ends (the input side of the pots) of the volume control pots to cut down the gain. A value the same as the pot will decrease gain by 6dB, a value 4 times the value of the pot will decrease gain by 12dB, and a value 10 times the value of the pot will decrease gain by 20dB. It's a far less expensive, and more reliable modification than using in-line attenuators. Of course you can also simply lessen the gain of the preamp by modifying the resistor values around the tube, but that's way more complicated.

As far as implementing subs, I would run the output of the preamp into the line input of the subs (through the crossover in the sub), and the filtered line output of the sub into the power amps for the main speakers. With two subs, this gives stereo subwoofers.

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#67538 - 02/19/08 05:14 AM Re: Tubes rule yet the High gain can be tough Please read.
Lizard King Offline
Desperado

Registered: 08/30/06
Posts: 425
Loc: NY
Altec,

My buddy wired the mone pots (Alps Black Beauty 50K) in a Shunt with 20K resistors yet the outpot increased. I am waiting for him to wires them back as my skills are not like his. I am using the Aux input which is less loud then the tape input. When I have him fix the pots, I will use the tape input since it is more transparent.

I am going to add either 6db or 12db attenuaters and I may want to change the value of the volem pots.

Any other ideas?
_________________________
Outlaw 1070, Anthem MCA5 II amp.
Sony Ps3
Alon 2 Mk2 Loudspeakers
HSU VTF-2 Mk2 sub x2
VAC PA100/100 Tube Amp
ARC SP16-L tube Preamp
Audio Note Dac 2.1 "B" signature
Furutech E-TP80,
Ascend HTM-200, 340C
Sony KDS-55A2020

Top
#67539 - 02/19/08 03:18 PM Re: Tubes rule yet the High gain can be tough Please read.
Altec Offline
Desperado

Registered: 01/06/08
Posts: 334
You don't need another pot - you only need to form a voltage divider with the pot that's already there. If your preamp has 50dB of gain, then you would would probably need to cut it down by 20dB. If your original pot is 20k, then 200k ohm resistors would do that very well, and not add noise or raise the output impedance of your line as external voltage dividers (attenuators) have to do.

It's impossible for a potentiometer to increase gain if it's wired correctly. Potentiometers operate by attenuation only.

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#67540 - 02/23/08 12:31 AM Re: Tubes rule yet the High gain can be tough Please read.
Lizard King Offline
Desperado

Registered: 08/30/06
Posts: 425
Loc: NY
Altec,

The Alps 50K mono Pots are now wired back to Nornal. I placed my Old Tube Sox over the two Mullard 7DJ8 tubes in the line stage and now I get DEPTH!
_________________________
Outlaw 1070, Anthem MCA5 II amp.
Sony Ps3
Alon 2 Mk2 Loudspeakers
HSU VTF-2 Mk2 sub x2
VAC PA100/100 Tube Amp
ARC SP16-L tube Preamp
Audio Note Dac 2.1 "B" signature
Furutech E-TP80,
Ascend HTM-200, 340C
Sony KDS-55A2020

Top
#67541 - 02/23/08 12:41 AM Re: Tubes rule yet the High gain can be tough Please read.
Altec Offline
Desperado

Registered: 01/06/08
Posts: 334
Quote:
Originally posted by Lizard King:
Altec,

The Alps 50K mono Pots are now wired back to Nornal. I placed my Old Tube Sox over the two Mullard 7DJ8 tubes in the line stage and now I get DEPTH!
To cut the gain down by 20dB, a 500K ohm resistor (for 50K pots) would need to be placed in line with the input side on each of the pots - did you do that mod?

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#67542 - 02/25/08 04:07 AM Re: Tubes rule yet the High gain can be tough Please read.
Lizard King Offline
Desperado

Registered: 08/30/06
Posts: 425
Loc: NY
Nope
_________________________
Outlaw 1070, Anthem MCA5 II amp.
Sony Ps3
Alon 2 Mk2 Loudspeakers
HSU VTF-2 Mk2 sub x2
VAC PA100/100 Tube Amp
ARC SP16-L tube Preamp
Audio Note Dac 2.1 "B" signature
Furutech E-TP80,
Ascend HTM-200, 340C
Sony KDS-55A2020

Top

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