The Truth Pre Amp Review

[Blumlein 88]

If you want both accuracy and resolution, then you're looking at a ridiculous number of relays or a PGA. VCAs are OK, though their linearity leaves something to be desired most of the time.

Not necessarily true. True of most products. One can put together resistors for volume control similar to how ladder DACs used resistors. So you can have like 256 volume positions with just 8 switches. Excellent accuracy and resolution without a huge number of parts.

 

[JeffS7444]

You can sometimes do better with pots by slugging a linear taper. Linear taper pots tend to track better, so channel matching is theoretically better. That was standard practice at Neve back in the day.

That's what circuits by Douglas Self and Bruno Putzys use. I've come to really appreciate the work of designers who achieve excellent results economically.

 

[HammerSandwich]

Dude, are you drunk? There was nothing to read about that weird shit. There was nothing in the review about it and I never posted on my forum or mentioned it in public. I told it to show that, let me spell it out for you, .......even though the measurements were wrong because of
the improper testing method it got a positive review...... the implication is that sometimes things are not what they seem.

Do you have a problem with me asking to simply check the dc offset which should have been done before it was measured in the first place?
Ed

Make your own decisions, Ed, but I would not want to question others' sobriety unless my own post were impeccably clear. Jumping without segue or context from Stereophile's review of your speaker to ASR's Truth review, well... I apologize in advance if I misunderstood & the speaker does require DC adjustments.

Anyhow, the Stereophile review includes:

It's crucial to note that the Horn Shoppe Horn is designed to be used only in the corners of a room. That's what I did.

 

[Bob from Florida]

...I'm not entirely sure what the takeaway from that story was meant to be, but personally I got "thank god I wasn't born in the 60s".

I don't mean to offend you, and I'm sure you turned out fine, but I'm glad no one was allowed to backhand me when I was growing up.

The takeaway was "don't attack people personally even if what you say us true". As far as the backhanding goes it is the only time I remember my Dad striking me.

 

[Deleted member 26571]

If you want both accuracy and resolution, then you're looking at a ridiculous number of relays or a PGA. VCAs are OK, though their linearity leaves something to be desired most of the time.

I thought about building a relay stepped attenuator, but then I read about the problems people have with control signal timing and clicks and pops. I decided I didn't want to sign up for days of hacking on a microcontroller to get it to work right. I read that paper on multiplying DACS -- thanks. I know in principle it's a great solution, but there's always this nagging concern that more active circuitry in the signal path will compromise sound quality. Or that my sub-par implementation of a circuit using it won't get the best performance out of the part.

 

[Deleted member 26571]

The takeaway was "don't attack people personally even if what you say us true". As far as the backhanding goes it is the only time I remember my Dad striking me.

If someone tells a lie, and if that lie puts people at risk or causes harm, then one has a moral obligation to call it out forcefully. I'm not talking about anyone on this forum. It's just the principle of the thing.

 

[Bob from Florida]

If someone tells a lie, and if that lie puts people at risk or causes harm, then one has a moral obligation to call it out forcefully. I'm not talking about anyone on this forum. It's just the principle of the thing.

Not the same point at all. A harmful situation may require some action. Being unkind to another individual when it is unnecessary serves no useful purpose.

 

[Deleted member 26571]

Not the same point at all. A harmful situation may require some action. Being unkind to another individual when it is unnecessary serves no useful purpose.

True, and I hope I made it clear I was speaking of the case where real harm occurs. I probably shouldn't have called Ed "incompetent" but I was so appalled it triggered a kind of knee-jerk hostility.

Edit: Ed may not be "incompetent," but his preamp is incompetently built. Hopefully, the preamp's feelings will not be hurt by my saying that.

 

[H-713]

I thought about building a relay stepped attenuator, but then I read about the problems people have with control signal timing and clicks and pops. I decided I didn't want to sign up for days of hacking on a microcontroller to get it to work right. I read that paper on multiplying DACS -- thanks. I know in principle it's a great solution, but there's always this nagging concern that more active circuitry in the signal path will compromise sound quality. Or that my sub-par implementation of a circuit using it won't get the best performance out of the part.

The MDACs are pretty slick, and in my testing distortion was very low when used with a good op-amp like the OPA1656. You can also use something like the PGA2310, which is a simple, all-in-one-chip solution.

The problem to keep in mind (which also applies to stepped attenuators) is that if you don't switch at the zero-cross point, there will be a transient. In practice, this translates to a "ticking" sound as you turn the volume knob. I have not found a good solution to this problem with stepped attenuators (maybe someone else has). With the PGA, you can get around this by using a sufficiently high-resolution DAC (you can get 16-bit multiplying DACs, so you still get quite a few steps even after the log conversion). With lower resolution DACs, it's possible to get around this by transitioning between fixed dB settings gradually.

You can also implement a really, really slick mute function that gradually "fades in" when you unmute it. The old MC series amplifiers from MC2 did that (they use an MDAC based PGA for gain control), and it's quite handy to have.

 

[ed schilling]

op48no1...don't bother to read this, it's too long for your attention span, bless your heart.

Well, here is something to ridicule that I designed. I am sure Bruce has no clue as to what performance is. He's probably never heard a "real" subwoofer so he does not know how ****** it is (that was sarcasm). Well except he actually measured it and has one or 2.
Build 2 and get a Crown xls series amp. Run it bridged mono. FFRS in parallel. The xls series has a superb xover and you'll be dumbfounded at the ability to integrate the thing into your system.

I have one in a corner behind a cabinet and I have offered to give one to anyone that can honestly tell me where it is by listening. The listening spot is 6 fee away. Turning it off is shocking. I have never had to give one away.
It's my gift to the world.............DO NOT MODIFY THE DESIGN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
https://www.transcendentsound.com/bucket-sub.html
You are welcome.
Ed
ps...FFRS Mark 4:20 i " F***ing Fantastic Redneck Subwoofer Mark 4:20 Inspired". The Mark 4:20 can either be a Cheech and Chong reference or to the verse in the King James Bible ..........Mark 4:20. You decide which you like, they both work, don't they? See, the door is open to ridicule me more! I don't mind. Oh, and I did not ask Bruce to put it on his site nor did I ask him to measure it. I just told him he needed to make one. He did and that happened.

 

[H-713]

Well, I might just have to build your bucket subwoofer just so I can say that I've built a speaker "with a bucket of junk from my basement".

Normally I use 5-gallon buckets as "cat box waste receptacles".

 

[Jmudrick]

op48no1...don't bother to read this, it's too long for your attention span.

Well, here is something to ridicule that I designed. I am sure Bruce has no clue as to what performance is. He's probably never heard a "real" subwoofer so he does not know how ****** it is (that was sarcasm). Well except he actually measured it and has one or 2.
Build 2 and get a Crown xls series amp. Run it bridged mono. FFRS in parallel. The xls series has a superb xover and you'll be dumbfounded at the ability to integrate the thing into your system.

I have one in a corner behind a cabinet and I have offered to give one to anyone that can honestly tell me where it is by listening. The listening spot is 6 fee away. Turning it off is shocking. I have never had to give one away.
It's my gift to the world.............DO NOT MODIFY THE DESIGN!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
https://www.transcendentsound.com/bucket-sub.html
You are welcome.
Ed
ps...FFRS Mark 4:20 i " F***ing Fantastic Redneck Subwoofer Mark 4:20 Inspired". The Mark 4:20 can either be a Cheech and Chong reference or to the verse in the King James Bible ..........Mark 4:20. You decide which you like, they both work, don't they? See, the door is open to ridicule me more! I don't mind. Oh, and I did not ask Bruce to put it on his site nor did I ask him to measure it. I just told him he needed to make one. He did and that happened.

Been meaning to build one for years...even have the extra Crown amp sitting around

 

[H-713]

Been meaning to build one for years...even have the extra Crown amp sitting around

Maybe I shouldn't have given away that Macro-Tech 3600 I've been tripping over for years. Actually, scratch that, getting that 3600 out of my basement was the best thing I've done all week. Made a fantastic white-noise generator though.

 

[ed schilling]

H-713..... LOL, If you do you will be shocked. Get a Crown xls series ......it deserves it. It's the xover that is special and the massive power when bridged doesn't hurt either.
Ed

 

[H-713]

H-713..... LOL If you do you will be shocked. Get a Crown xls series ......it deserves it.
Ed

I don't have very many good things to say about XLS amps. At least the Macro-Techs were reliable. That's all I'm going to say. They'll survive things that no other amplifier will. The XLS series has been the polar opposite in my experience.

When I do get around to building a subwoofer (or a pair of subwoofers), I'll probably run them off one of my Crest amps or the BSS amp.

 

[Bob from Florida]

Been meaning to build one for years...even have the extra Crown amp sitting around

My son and I built one to use at his house with the monitor based audio system I helped him set up. It can make some pretty decent bass - well enough to make the monitor speakers sound full range. Also doubles as a conversation piece. What's that 5 gallon bucket doing in the corner?.....
If you zoom in the top of the bucket sub can be seen behind the Dayton sub amp on the rack.

 

[ed schilling]

Well, many pages ago it was suggested that no one that had heard real high end stuff would consider my pile of junk and the folks that own it probably have never heard really good stuff.

With that in mind I asked permission to reveal something I never have.

" Dick Olsher has one, he bought it a couple years ago. Yes, he paid for it. DO NOT contact him. If you think I am a liar, trust me, he will hear about it. I asked his permission to post this.`` The consensus seemed to indicate that anyone who had ever heard really high end would never buy one based on blah, blah, blah, well there you go, Arthur and with Dick's pemission I can say he has one too. Pretty sure they qualify as having heard "good stuff".​

So, there you go. He gave me his permission to post that paragraph.
Ed

 

[solderdude]

I gotta hand it to you Ed.

Ed dodges all technical questions/issues, only adresses attacks made on his person in a similar fashion and then uses this thread to promote his other 'products' which he does not sell but get's compensated for.
We can say a lot about Ed but this guy is a sharp tool...

 

[ed schilling]

Solderdude, I am not promoting anything. I do not get compensated in anyway for the FFRS Mark 4:2-i. It is a gift. As a matter of fact Bruce is mad at me and not talking to me at this time but he did not take the speaker down. He ain't that mad.
I did not come here to do anything except express my opinion about what was being said about me both personally and about what I build. Everything I have said is true. I have tried my best to explain everything I could and even amuse you guys with my true stories.

BTW, SD, your posts have been fair and I appreciate it. Make no mistake, I could do without this mess but hey I am a "honey badger" . Leave me alone and you are fine. Poke at me for no reason and maybe I poke back....harder.

I and my product which many enjoy have been ridiculed, made fun of and some have personally attacked me. No one that knows me thinks I'll put up with that.

I did not come here because of the "measurements" but rather because of all the nasty, snarky things said.

Oh, lest I forget. What moron would use a toaster that he knows could kill him if he acted like a moron? Well, not me. #2 is no danger to me or anyone else at all. It is on a shelf in the laundry room.. When I got it I tested it. Worked perfectly. Took it apart to inspect wires. Uh Oh.....put her back together and on the shelf. Will replace the wires one day. It will be a PITA. Had I not inspected her I would not have been aware of the issue since she worked perfectly. Good thing I know better than to touch any appliance and another that has an earth ground. I told that story only to illustrate that even a known, really dangerous situation requires a certain amount of stupidity to hurt you.
Ed
Sd.....I think you are a good guy....just so you know...the only thing I sell is The Truth...on many levels.

 

[solderdude]

Noted... about the toaster... and the reason for replying in general.

A technical question... is the balance control indeed used in the way I drew below ?