Biamp Issues

Kingrex

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I attempted to biamp my speakers again. The last time I tried i had a bad ground loop. This time I decided to take it slower. I first hooked up the Dartzeel. Only the mid/high drivers play. So far so good. This time i take it slow with the SET 845. I only hook up 1. This time the high/low run, and the woofers on 1 speaker run. At this point I decided to adjust the built in volume knob on the SET. This not only alters the SET, it also alters the Dartzeel. Dial the SET to 0 and the Dartzeel is muted through both channels too. Not just 1 channel . It seems to be a big loop. Not sure why this would happen. Is this normal?

My preamp is a First Sound. It is an active unit with a stepped volume. It is true duel mono. 2 power supply, 2 ground plain. There are 2 output RCA on the back of each channel. The RCA are internally wires together. I have a channel of each amp connected to one each of the rca. Effectively the amps inputs are tied together.

I assume this is why I got a big ground roar last time. If I connect the second amp, there would be 2 amps driving both channels of the dartzeel, and possible trying to drive each other.

Is this normal. Amps with their inputs effectively tied together will try to drive each others gain. Or loop their systems together.

Do I have to use an active crossover to do this.

Or is this another weird manifestation of issues pertaing to these amps.
 

Solypsa

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Do you have a pic of the crossover schematic you can post?
 
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ddk

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I attempted to biamp my speakers again. The last time I tried i had a bad ground loop. This time I decided to take it slower. I first hooked up the Dartzeel. Only the mid/high drivers play. So far so good. This time i take it slow with the SET 845. I only hook up 1. This time the high/low run, and the woofers on 1 speaker run. At this point I decided to adjust the built in volume knob on the SET. This not only alters the SET, it also alters the Dartzeel. Dial the SET to 0 and the Dartzeel is muted through both channels too. Not just 1 channel . It seems to be a big loop. Not sure why this would happen. Is this normal?
It’s not normal, only thing I can think of is the speaker’s crossover aren’t designed for bi-amping.
My preamp is a First Sound. It is an active unit with a stepped volume. It is true duel mono. 2 power supply, 2 ground plain. There are 2 output RCA on the back of each channel. The RCA are internally wires together. I have a channel of each amp connected to one each of the rca. Effectively the amps inputs are tied together.
They can affect each other but not in the manner you’re thinking of.
I assume this is why I got a big ground roar last time. If I connect the second amp, there would be 2 amps driving both channels of the dartzeel, and possible trying to drive each other.
No but their grounds are tied together as well as the grounds of everything else in the chain.
Is this normal. Amps with their inputs effectively tied together will try to drive each others gain. Or loop their systems together.
Their grounds are connected by the ic
Do I have to use an active crossover to do this.

Or is this another weird manifestation of issues pertaing to these amps.
First, is your speaker designed for bi-amping? If it allows for bi-amping an active crossover is definitely a must when using such diverse amps together, but IME you’re wasting your time mating these amps.

david
 

Kingrex

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The ceissover to my speaker is designed to Biamp. It has a couple jumper you remove. It has 2 sets of speaker cable terminals. Yes the jumper are out.

Owe yea. I have fought theae originally Black Shadow amps ever since I got them from Phil. They have an internal ground issue. I have never been able to run them without lifting the ground. I was told a while back they have "leaks" somewhere.
Somehow voltage is leaking to ground. The tech wanted thousands more to find it. Having what I feel is wasted money in the order of $10k or so already on these, I said no.
 

Kingrex

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I don't have a crossover schematic.
 

ddk

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The ceissover to my speaker is designed to Biamp. It has a couple jumper you remove. It has 2 sets of speaker cable terminals. Yes the jumper are out.

Owe yea. I have fought theae originally Black Shadow amps ever since I got them from Phil. They have an internal ground issue. I have never been able to run them without lifting the ground. I was told a while back they have "leaks" somewhere.
Somehow voltage is leaking to ground. The tech wanted thousands more to find it. Having what I feel is wasted money in the order of $10k or so already on these, I said no.
I don’t know anything about your amps but having to ground lift some electronics isn't unique to them.

david
 

Kingrex

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David, can you think of a test or process to sort this out. I was thinking, next step might be to replace either amp with some other. I have an 811 amp and a KT88 I can try.
 

Alrainbow

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Rex mixing amps is problematic for a few reasons I can think of and I’m sure many I can’t.
one is gain if not the same amp it’s bound to be off making the drivers be Imbalanced and since it’s gain a pot on the cross over don’t fix this.
next is imp curve to amp
again a gain issue made worse by the amps able to deal with it.
many speaker makers don’t want a biamp used.
the man who makes ur speakers is smart man e-mail him for advise
next is the input of amps now being connected to the other input of the other amp again not an easy fix
does your pre amp have dual outputs ? isolated to each output ?
i did this a few times and unless it’s built on not the design it’s a big process to make work well.
what kind of issues are you having ?
aside of my above comments
have you tried two per channel iso blocks
cheap ones by iso max ? use these at pre amp outputs secondary to each amp
now electrically isolated
they have dip sws to change the type of isolation needed
but they keep the gain the same.
now know this the output imp to amp input imp matters
and the cable lenth. Call tgere tech support to get best shot of the type / model needed

they solve issues and don’t add much either
 
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ddk

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David, can you think of a test or process to sort this out. I was thinking, next step might be to replace either amp with some other. I have an 811 amp and a KT88 I can try.
I have no direct experience with your speakers, SETs, preamp or sources to know what's going on, your speaker manufacturer might know what's going on. Try the other amps and see what happens, don't worry about ground lifting as long one component is grounded.

david
 

Kingrex

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Thanks Al. I don't believe there is any chance the amps will actually sound "good" together. I have multiple sets of amps sitting around and wanted to try it. Hear it for myself. Nothing like first hand experience.

I understand what your saying about a pair of stereo iso transformers. My preamp duel output are not at all isolated.
They are in essence 1. So isolating them may help.

When I got the coaxial 10" driver update for my PAP trio 15 horn, it came with the crossover. It appears the design is all the woofer components on 1 half of the board with a jumper to a second side that powers the coax driver. I started out using a single speaker cable to feed it. A friend said, why not pull the jumper and put 2 sets of cables to the crossover. I thought this interesting as the provided jumper is a very small clip that slides over a pair of pins maybe 18 awg. Pulling the pin and using 2 sets of cables significantly changes the impedance of the speaker amp relationship. The 2 sets of drivers are no longer series, they are parallel. I'm not sure how the amp sees the whole load. Its still 4 drivers per speaker. I thought, because of this design, it might be interesting to biamp it and hear how the amps responds to a again, significantly altered load.

When I went to 2 sets of speaker cables, I immediately heard a jump in dynamics and a sense of ease in the music. A greater sense of fullness. I have heard some people like 1 speaker cable. Who knows how we arive at our preferences.

I'm still trapped out of town with Covid. I'm going to fly home Saturday. I have been away from home far to long. When I get back I'm buried with commitment for a couple weeks. In short I am not trying any new biamp experiment any time soon. But I will circle back around to it.
 

Mike Lavigne

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if you have a Home Theater multi-channel receiver or multi-channel amplifier you can use 4 of those channels to test the speaker's bi-amping capabilities. if that works then you have an amp problem. you might need a (actually 2 of them) cheap splitter to feed it the stereo signal. or the processor might be able to do it.
 

Kingrex

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I am swirling around this idea of biamping again as opposed to, do I upgrade the amp??? I am kind of wondering where you get the most bang for the buck.

My speakers are made to biamp. There are 2 jumper on the crossover across terminals that separate the woofers from the mid/high driver.
I currently have the jumpers out and I have 2 sets of cables from the same amp to each speaker.

I was thinking of getting another Dartzeel NHB108 model 1 and Biamping by having one amp run the woofers and the second amp run the mid/high. Jonathan Tin said why not vertical. So one amp runs one speaker. Now the amps run the woofers with one channel and the mid/high with the other.

Anyhow, the question is not how to go about biamping. The question is, do you get a higher level of performance by upgrading the amp to a model 2. Or do you biamp and reduce the power required of the amp to run the speakers.
 

ddk

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I am swirling around this idea of biamping again as opposed to, do I upgrade the amp??? I am kind of wondering where you get the most bang for the buck.

My speakers are made to biamp. There are 2 jumper on the crossover across terminals that separate the woofers from the mid/high driver.
I currently have the jumpers out and I have 2 sets of cables from the same amp to each speaker.

I was thinking of getting another Dartzeel NHB108 model 1 and Biamping by having one amp run the woofers and the second amp run the mid/high. Jonathan Tin said why not vertical. So one amp runs one speaker. Now the amps run the woofers with one channel and the mid/high with the other.

Anyhow, the question is not how to go about biamping. The question is, do you get a higher level of performance by upgrading the amp to a model 2. Or do you biamp and reduce the power required of the amp to run the speakers.
It all depends on what you're after Rex, I doubt very much that your Dart amp is struggling with your speakers so what is you're looking for? You already have some experience that there's more to bi-amping than what you were told. There are rules for this and if you're not satisfied with what you're hearing now you can octa-amp with the same and nothing will change!

david
 

Kingrex

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It all depends on what you're after Rex, I doubt very much that your Dart amp is struggling with your speakers so what is you're looking for? You already have some experience that there's more to bi-amping than what you were told. There are rules for this and if you're not satisfied with what you're hearing now you can octa-amp with the same and nothing will change!

david
I kind of though about this. My speakers are suppose to like a lot of power. They may be 96 db, but that is not the whole story. They are large 15" paper drivers and it take a solid grip to stop and start them on a dime. I am told some at PAP like a Pass mono 250 amp to drive them. I was hoping with biamp, I might get tighter bass.

To answer the question, what do I really want. I want a tad more bite. A little more life. A little better bass driver control that I believe will create a more realistic musical sound. I think the Dart is a tad soft and that its not as natural and real as it could be. Its lacks that last level of a breath of life.

In some sense, I am up and down on the desire to listen to tubes or SS. My Dartzeel is obviously more linear with less distortion than my Black Shadow 845. I could not do some of the testing I do with wire and bus bars if I did not have the Dartzeel. The Black Shadow is too non linear in its frequency response and heard distortions. But, I still like the sound of the Black Shadow at times. It can give a stringed instrument a life. Maybe its a distortion anomaly. And after maybe a few weeks, I reach what you may call a saturation point and want the Dartzeel back in. And when I put the Dartzeel back into play, its a bit of an ahhhhhh. You hear its more correct. But being more correct does not mean its 100% right. Maybe is has to do with the amp being a 2012. (Serial #.012A). It has the SCNP upgrade. But its older. Caps could be tired. The circuits is definitely outdated. A lot has changed in 10 years. Maybe I just like tubes and their distortion signature. But then again, I burn out on the sound of the current 845 amp I have an want to get back to a clean, neutral and accurate sound.
 

ddk

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I kind of though about this. My speakers are suppose to like a lot of power. They may be 96 db, but that is not the whole story. They are large 15" paper drivers and it take a solid grip to stop and start them on a dime. I am told some at PAP like a Pass mono 250 amp to drive them. I was hoping with biamp, I might get tighter bass.

To answer the question, what do I really want. I want a tad more bite. A little more life. A little better bass driver control that I believe will create a more realistic musical sound. I think the Dart is a tad soft and that its not as natural and real as it could be. Its lacks that last level of a breath of life.

In some sense, I am up and down on the desire to listen to tubes or SS. My Dartzeel is obviously more linear with less distortion than my Black Shadow 845. I could not do some of the testing I do with wire and bus bars if I did not have the Dartzeel. The Black Shadow is too non linear in its frequency response and heard distortions. But, I still like the sound of the Black Shadow at times. It can give a stringed instrument a life. Maybe its a distortion anomaly. And after maybe a few weeks, I reach what you may call a saturation point and want the Dartzeel back in. And when I put the Dartzeel back into play, its a bit of an ahhhhhh. You hear its more correct. But being more correct does not mean its 100% right. Maybe is has to do with the amp being a 2012. (Serial #.012A). It has the SCNP upgrade. But its older. Caps could be tired. The circuits is definitely outdated. A lot has changed in 10 years. Maybe I just like tubes and their distortion signature. But then again, I burn out on the sound of the current 845 amp I have an want to get back to a clean, neutral and accurate sound.
Maybe you should look at a different approach! There are some of us here who have opted out of the mainstream audiophile sound for natural sound and realism, travel a bit and find out more before blowing more money chasing your tail, you're not going to find what you're looking for in any of the above mentioned scenarios.

david
 

Kingrex

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What are you suggesting?
 

ddk

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What are you suggesting?
What you heard that led you here might have been impressive to you at the time but you now know it’s not for you. I’m saying rethink it all if you’re looking for natural sound.

david
 
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microstrip

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(...) To answer the question, what do I really want. I want a tad more bite. A little more life. A little better bass driver control that I believe will create a more realistic musical sound. I think the Dart is a tad soft and that its not as natural and real as it could be. Its lacks that last level of a breath of life. (...)

Bi-amping will not give you any of these if you have such feeling about your system. Anyway, do you know what is the impedance curve of your speakers?

Just my opinion, but I have owned and listened a lot to to the NH108. Great amplifier in the proper system, but I never liked it with tube preamplifiers of simple topology. My suggestion - try listening to it with a Dartzeel NH18 - if it is not the sound you are wanting move away from it.

Disclaimer - I have no idea of what your speakers sound and you have not listed the music you listen, take these comments just as a forum opinion! ;)
 

Kingrex

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I hear you both Micro and DDK. Bi amp won't change the general character of the amp voice. I did hear the very latest 468 at Michael's. I gather Herve have done some additional modification to the circuit. The amp definitely goes where I want. But its way above me. Everyone says the 108 older model such as I have is sweet and warm. That it is. And it has a tube like character. What it does not have is bite. Yes I do have a tube preamp. I would have to purchase a used 18NS. Not sure I want to go all Dartzeel.

Its all so very close. But I guess that is what all audiophile say. I could very easily say I am done. But my nature is more one to keep on experimenting and striving to achieve more. I fear what would happen if I feel down a horn hole. My wife would leave me when good enough was never enough and a wall of the house became a horn itself.
 

Kingrex

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I was reading Harley's review of the Altaira. I was sort of shocked he used words such as Offensive Sizzle in vocals and Too Hot or Metallic Sheen. I think I am complaining about far less in my system , or maybe the opposite end of the spectrum, and I'm being told to toss my amps and speakers.

Of course, I'm pretty sure David would say the same to Robert.

My real point is, when do any of us sit back and say, thats it. It's perfect as it is. Or is there always some something under your skin. I unfortunately believe there is always something. I wish I knew better how to address the finest detaile instead of hearing toss it all and start over. That doesn't help me or the audiophile. It would only buy Christmas presents for the dealer.

I'm going to try some ground box some day. I sort of wonder if DSP might also provide a degree of needed shaping. Owe boy, did I say that.
 

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