[ACMP investiupgradifications] All things PREAMP

[mitsos]

kind of sounded like someone was whispering in his ear

not sure what that means???
about saving the rest of the thread, scrapbook (firefox extension) works pretty well.

Well, I don't know about you guys with 1081s, I have a 1084, and the only real problem now is the humming from the PSU trafo (I think).  Last week, with extensive help from member Harpo, I did a 4 rail PSU for a 312 board I'm working on and, as I sat there staring at my almost working 1084s, it dawned on me that they too use a 4-rail PSU. So I redid the layout and added some series resistance before the +/-12V rails so that the regs may run a bit cooler and am waiting for some blank boards so I can test/etch it. This PSU would allow one to use a more commonly available 2x24VAC toroid instead of a custom one.

If anyone is interested in reading the original thread and or has use for a home-etch file for a 4 rail PSU this is the thread:
http://www.groupdiy.com/index.php?topic=36462.0

(I know this doesn't help people who have already prepaid for trafos; I don't have a solution for that).  And I don't think this would help people with 1081s because Alex already tried a JLM PSU with a different toroid and that did not help. But I hope at least it will solve my problem and if so, that of other 1084/73 owners.

Anyway, if this ends up working OK, we could even do a small board run to get decent looking boards in there, although I'm not sure it matters.

 

[Paul G]

Just wondering who is still waiting for parts from Steve Hogan.

I paid $100 deposit on a mod kit.  I was supposed to be in on the first run of tranfo's.  I have two brothers who sent Steve 73's for modding and a deposit as well. 

BTW electrochronic, thanks for staying on this.  I was just getting ready to send him another email myself.

Paul ;D

 

[Rockit88]

Read my post of Sept 30 to hear my sad story.

Mr Hogan has my ACMP73 and my $100 deposit.  I've sent a few emails and I posted here to see of I could smoke him out.  I wonder just how much money he has taken from people without producing anything.  I think it is called swindling.....

I tell ya, these preamps are cursed.  As soon as I feel like spending more energy I will try to get my money and pre back.

 

[okgb]

I don't think it's a matter of
" they fell for it once with Chance , bet they can
get suckered again "  [ i'm still pissed at Chance and the big scam
thanks for all the help on that Chance BIH ]
He did seem to say people were telling him
not to get involved ?  but i bet he now feels he's undervalued his time
and is working on the better paying things  [ you do have to stay in business
to be a business ]

Of course there is an expectation and if people have paid upfront they deserve
at the very least honest information , regardless of  the deal he thinks
you're getting

Can we turn this into a separate thread ?

 

[redddog]

No one is that busy.


Send an email to the people who gave you money. It would take all of 2 minutes.

 

[ddt]

Mmm, guys.. how about showing some respect for the guy who must have spent hours and hours typing up stuff he found out about the preamps, and basically giving it away for free??

I'm pretty sure that his motivation to help forum members and share his knowledge again, given the comments above, will now be pretty much zero.

Attitudes like this have driven a number of very valuable contributors away, and if this continues all that'll be left of this forum will be a few people answering questions like "how do I hook up the power transformer on my GSSL?", before they too decide it's not worth their time.

Now, my personal experience with Steve has been nothing but great, and I'm sure he'll sort everything out in the end, but I don't think a hostile approach is the way forward.

Thanks,

Dan

 

[redddog]

You guys are right. I have edited my previous post. This kind of thing just gets me going.

 

[Rockit88]

Where's the respect, you ask?  Respect is a two way street.

I've asked for a simple update a number of times and have always gotten what appears to be his stock reply..."Next week I'll post something...I'm really busy...blah, blah"

Then nothing...silence.

If I take a piece of gear into my local guy to be repaired, or a shirt to the dry cleaners, they give me a done date.  if there is a problem they contact me and we figure out how to proceeed.  That is how commerce is done.  Even on a casual level, as I thoufght this was, that is how it works.  One has a reasonable expectation that they work will be done in a timely manner and the other has a resonalable expectation to get paid in a timely fashion. 

I figured we had a handshake deal.  I trusted Mr Hogan on his WORD and his good name.  He has shown me and others who made the same handshake deal not an ounce of respect.  I work hard for my money.  When I want to give it away I choose my causes.

Sure he is a wealth of information and has offered much insight into the repair of these things.  But in the end, it seems he has already checked out of here and taken our cash with him.  The best con jobs are pulled off by smooth characters.

Good gawd.

 

[tommypiper]

Well, I trusted Steve too, but I was very careful not to send him any money or pres.  His posts were too manic, too enthused, too over-the-top.  Something didn't seem right.  He spent hours on the posts.  Yet now can't spend two minutes for a quick update to people who have sent him money?  Not acceptable.

Even if he had honorable intentions and is an honest person (I'm not making judgements on those points), his complete disappearance without explanation or update for such a long time for those who have given him money is NOT ACCEPTABLE.  Period.

Other long-time forum members also departed without sending things they owed and appeared to be lying and making phony excuses... whether these people intended to do this, or simply got trapped into the stresses of life and an embarrassing situation on the forum, we don't know.  So we can't judge the person.

But we can judge the actions.  And the actions are not acceptable.

I'm hopeful he will return with a good story and make amends immediately.  He's lost serious credibility in the meantime.

 

[okgb]

Can we turn this into a separate thread though
we still want to fix out chineve pres [ No thanks Chance ]
where the problems started

 

[alexc]

My Chineve 1081s are still going strong and quiet!

9months of frequent and lengthy use, in a hot climate - no blowups, brownouts or whitewashes.

Completely stock except for Carnhill inductors+OEP shields, Zmix transistor fix and gain switch pop mod (80usd in parts each)

 

[tommypiper]

My Chineve 1081s are still going strong and quiet!

9months of frequent and lengthy use, in a hot climate - no blowups, brownouts or whitewashes.

Completely stock except for Carnhill inductors+OEP shields, Zmix transistor fix and gain switch pop mod (80usd in parts each)

Great news, Alex!  Can you elaborate?

 

[alexc]

Sure.

Basically, after noting the well documented TnC 1081 EQ broadband noise and applying the Zmix transistor replacement fix, I found that there was still a lot of mains harmonic noise with EQ engaged. I isolated this to the mid-low inductor by using basic fault finding techniques.

I then replaced that inductor with a Carnhill part. That noise was then greatly reduced. Then I added an OEP mu-metal shield on that inductor. Significantly reduced noise again.

Repeated for the mid-hi inductor, even though it contributed only a minor amount of mid-freq noise.

Result was a unit with a noise floor around 23-28 dBu lower than stock. I can't hear any noise anymore.

Did the resistor mod to the gain switch to remove the 'pop' setting.

Along the way, I tested alternative mains transformers (25aud chinese toroid), alternative PSU (JLM) both internally and externally (3ft away).
I found toroid and PSU changes made no improvements at all. (Slightly worse, in fact).

I noted that toroid rotation was good for a couple of dBu, case lid on was good for a couple of dBu.
I noted that proximity to other powered on units worsened noise floor by a couple of dBu.

I also experimented with PSU cap changes, grounding changes and all of that. No improvement at all.

All of this was tested in a rack with surrounding powered up units as well as on the bench, using a DAW spectral analyser and a Motu 2408MkII set for +4dB balanced connections, line input unity gain conditions with max EQ boost settings. Mic input was similar in noise floor.

So I ended up with stock with Carnhills+OEP, Zmix transistor fix and gain switch pop fix.

Now I get easily and consistently around -80dBu at real world gain settings and boost applied on the EQs (worse when all EQs are on, full boost).
Some noise remains with mains harmonics noise at around -90dBu for worst individual components. For really high gain use, there is also some hiss, which I feel is expected for a unit of this cost. I believe that performance varies significantly from unit to unit and location to location.

And that was good enough for me, being about the same as I get with my other diy builds.
Cost was 350aud for the unit with shipping to Aust. and around 80usd in parts to fix. (4x transistors, 2x inductors, 2x shields each unit)

There are obviously a lot of other very, very, very detailed fixes which I did not feel were very well substantiated and definately not economically viable for me. I saw no reason at all why they would translate to a better sound in the real world. (I am an EE with a lot of mixed signal medical device QA experience)

And so, I use a pair all the time for DI guitars (active and passive), and tube condensor mic (no ribbons), into a diy 1176 or diy la2a then to my Yamaha digital mixer + Motu and Cubase.  They are my 'go to' lounge room studio units.  ;D

Since then, I bought some HotBaby's toroid shielding strips which I will test over Xmas.
Bottom line, is that I believe trying to get these to a higher spec with even more expenditure is not worth it.

Now, I am focussing on my Tommy 1081 builds and, I expect, a pair of Bluzzi's upcoming 1084 EQs (GREAT work guys!)
They will all use external PSU, Carnhill inductors and transformers.

So I'm happy.

But I really feel for others whose saga seems to have grown new legs and is running further down the long and winding road of chance.

 

[mitsos]

the long and winding road of chance.

ROFL!! what a perfect closing!  ;D

I was going to ask "where is chance nowadays?" and popped over to PSW and lo and behold: here is an interesting post by Oliver Archut:

Hello All,
the first unit is evaluated and a fixing plan has been worked out. Still working on logistics, table set up, as well getting an intern here and trained.

in response to:

chris carter wrote on Sun, 15 November 2009 10:09

Oliver Archut wrote on Thu, 01 October 2009 07:00

Hello Guys,

I am currently evaluation the situation to fix up broken units in a set up where an intern doing the work.
Upgrade? As soon the repair situation is figured out I will take a look. But for right now AES prep as well as getting CS-1s out the door.

Best regards,

Hi Oliver,

What's the latest on the preamp fixes?

So I guess this means they are living up to the warranty situation?

 

[diyfanatic]

I feel for you guyz!!!

money's gone and  you can't even fix it yourself since...he's got the pre too.
I can't understand this kind of behavior!!!

so after used my 1081 for more than a month...work pretty well...
transistor fix + shielded inductors and power trafo. I'm pretty happy.

the only issue is that I have 2 board n°4 so twice the medium band...no high.

but for the price it's ok.

Jr.

 

[crazydoc]

I would like to compile a list of people who were tricked
into sending deposits or gear and have received nothing in return.

I've sent him an ACMP81, value $225 ($175 purchase price plus $50 shipping to me and then to Steve Hogan), about $5 in replacement transistors I sent with the pre, and $125 in cash, for a total of $355, not to mention mounting frustration and disappointment.

If this is a swindle, it's a pretty miserly low stakes one and not worth losing his reputation over. My guess is that notwithstanding the new transformer and other psu mods, he was unable to rid the unit of the eq inductor resonant hum. So despite having worked on these, and having spent all our cash, he can't return them because they are not fixed, and he's not going to be able to fix them - much more damaging to his rep.

 

[crazydoc]

I gave Steve a Dozen chances to make amends and I have the phone call statements to prove it.

Thanks for doing this. I have a string of about 20 emails and replies showing the same, if needed.

I would be happy to have my 81 back, in whatever condition (it was the "guinea pig" for the mods), and two of the new transformers to cover the one he destroyed and the cash I paid him.

Steve - if you are following this, you should really come on and explain the truth about your position.

ACMP bad karma strikes again. I hope Oliver Archut doesn't have the same results.  ;D

 

[tommypiper]

ACMP bad karma strikes again. I hope Oliver Archut doesn't have the same results.  ;D

How is Oliver involved in this? 

 

[crazydoc]

ACMP bad karma strikes again. I hope Oliver Archut doesn't have the same results.  ;D

How is Oliver involved in this? 

See post #926 above, or head over to PSW Whatever Works.

 

[stringofpoloponies]

i have 2   81-units and 200$ into  a deposit. i live on the east coast and too far away but count me in on the list if nothing happens by end of january. that is my time frame to see something done by steve. i talked to him on the phone in september and got the same story about another big project and i can understand bills need to be paid so maybe give a little more time. this is getting strange but not hopeless yet i think.