• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

DIY Holton amplifier builds underpowered and distorted

noiseangel

Active Member
Joined
Sep 24, 2020
Messages
296
Likes
463
Location
Perth, Western Australia
If you are considering building your own Holton amplifiers then best you read the saga of these 2 poor souls. Enough said.

https://www.stereo.net.au/forums/to...-for-stereo-hpa-nxv800l-r4-amplifier/page/11/

https://www.stereo.net.au/forums/topic/120101-holton-diy-kit-for-stereo-hpa-nxv800l-r4-amplifier/

https://www.stereo.net.au/forums/to...power-amp-build/?tab=comments#comment-4554832

Buyer beware. Also note that one of the builds was tested, the results are posted for all to see.

Build a PURIFI, Hypex instead. At least they are backed up with credible testing results, right here of course.
 
Last edited:

lemnoc

Member
Joined
Jun 9, 2020
Messages
70
Likes
97
So reading those links one thing has become evident in that the said vendor claims that the design is mature and he has sold 1000’s of them. Then on the other hand in another thread, test results have been provided by a third party that shows that this amplifier is way under powered. Unless these modules are faulty one could easily conclude that the said vendor has been engaging in deceptive marketing on a grand scale and has relied on the ignorance of his customers not to question the validity of the specifications.

cheers
 
OP
N

noiseangel

Active Member
Joined
Sep 24, 2020
Messages
296
Likes
463
Location
Perth, Western Australia
John Doe
50+ Post Club
John Doe
Full Member
153
122 posts
Location: WA
Country: Australia
Donor
Report post
Posted 10 minutes ago
3 hours ago, Marc said:
We are in unusual times and circumstances, so processes are probably not what they normally would be. I would hate to see Anthony's reputation destroyed on here over one unusual case

John Doe said
By this. I assume you mean one documented case? Are we to believe that this is the first amp that has required replacing. I see no issue in members voicing their dismay at the way this is being handled.


The above comment by John Doe was deleted by the dictator that runs the forum. Dissent will not be tolerated.

You have been warned if decide to build one of these amps.

Obviously the modules are not fit for purpose as the above comment by lemnoc shows, they don't meet the specs provided on the website and some government body that protects consumer rights in Australia should get involved here (ACCC). Nothing short of a disgrace and the deleting of customer problems is in itself a problem when a commercial website that accepts money from advertisers (Although they call them sponsors) masquerades as a public uncensored forum. An immediate conflict of interest.
 

John Doe

Member
Joined
Oct 22, 2020
Messages
5
Likes
13
Hi all,

I have to agree, I didn't think that my post was really that bad! As well as the post being deleted I was banned for 2 days for "Abusive, language or disruptive behaviour". Go figure.

As for Holton amps, I do have first hand experience with them. Not the DIY models in the threads. I am not an electrical/electronics guy, so would not have the skills to know what I was doing. With that in mind, I bought a $AUD10k amplifier off Anthony. I wanted the case in black rather than silver, which Holton amps told me was not an issue. Payment was required up front, which in hindsight should have been a red flag, but I was happy to support a local business. Lead time I was told would be 6 weeks.

Fast forward 3 1/2 months and my amp arrived, no explanation as to why it was late. To be honest I was not really bothered as I had been working overseas. Recall your excitement of pulling a new bit of gear out of the box. Imagine if you pulled a 10k amplifier out and it wasn't square? Well that is what I was faced with. The heat sinks on either side where different lengths, not a lot but certainly noticeable. Hmmm, appears there is some quality control issues. Suffice to say I was not impressed. If I had known how this was going to play out, it would have been prudent of me to pack it up there and then.

Regardless, I just wanted to plug it in and have a listen, I would contact Anthony about that issue later. Hooked it all up, turned it on, arghh, only one channel works. Swapped speakers, yep it's the amplifier. An internal fuse on the circuit board had blown, spoke to Anthony, he advised to change it from a fast blow to a slow blow. I was a little uneasy, There are some big capacitors in there. As I said, I am not an electrical/electronic guy but I know enough to be very wary of capacitors. Anthony said I would be fine. Luckily I listened to my internal voice and took it to a local electronics guy. (Holton amps are on the opposite coast 5000 km away from me). The local tech went to pull the fuse and the capacitors discharged. He told me the fuse would not solve the issue, as it was upstream/downstream of the fuse. (Can't remember which, sorry). Spoke to Holton amps and was told to send it back and it would get repaired and the heatsink issue would get sorted. When I enquired why the amp would have been sent with such an obvious flaw (squareness), I was told that it was an issue with the heat sink supplier and he was going to build me a new amp anyway but he sent this one because he didn't want me to be without an amplifier. If that was the plan why would Holton not inform the me, before the amp arrived? The cynical side of me tends to think it was sent to me to see if they could get away with it.

Packed the Holton amplifier up with the original packaging and the courier, which to his credit, Anthony organised and payed for, arrived and picked it up. The amp was repaired and returned to me, plugged it in, listened for about 30 minutes and then went to bed.

Imagine my surprise in the morning, when I had a full day available to finally listen to my new amplifier and it would not turn on. The main fuse in the back of the amplifier was ok. A little trouble shooting over the phone with Anthony resulted in the Holton amplifier needing to be returned and repaired.

I informed Holton amps that I had lost faith in their product and would prefer a refund. Anthony agreed, but told me he could not refund my money until I had returned the amplifier and he checked that I had not damaged it. Fair enough. Apparently when I packed it the first time it was repaired I had not done a good job and the amplifier was very "nearly" damaged. Err I packed it with the original packaging. Never mind, in 10 days when I get my refund I can go amplifier shopping and get my system up and running again. I packed the amplifier up at a local HiFi store and documented the packing with photos. The local store even assisted me with extra bubble wrap just to be sure. Courier picked the amplifier up and I just waited.

Tracking on the amplifier showed that it had arrived at Holton, and I still waited. Left it about a week still nothing. Contacted Holton amps and Anthony said yes the amp had arrived and it was fine, but I couldn't just expect a refund straight away. Small business etc etc. He would organise the refund by the end of the month, waited till the end of the month and you guessed it. Had a few more exchanges, a few more deadlines and then I had enough. Holton amps had stopped replying. So there I was, no money, no amp. So much for supporting a local Aussie business!

To cut a very long story short, I did get my money back, only after CBOS, the consumer affairs department concerned, contacted Holton on my behalf and threatened him with legal action. Even then he missed a deadline that they issued him. I was basically on the verge of having to take him to court to recover my money. I was out $AUD 10k for 11 months with an amplifier that ran for 30 minutes.

Imagine if I tried to post my Holton experience on Stereonet.
 
OP
N

noiseangel

Active Member
Joined
Sep 24, 2020
Messages
296
Likes
463
Location
Perth, Western Australia
Sorry to hear about all the drama John.

I nearly bought 8 amps from him to run my 4 way active. Imagine the crap I would have been in.

I would love Amir to get a hold of one and test it.
 
  • Like
Reactions: wje

John Doe

Member
Joined
Oct 22, 2020
Messages
5
Likes
13
All good. Proud owner of a Luxman that has never missed a beat!

Just recounting my experience so that members can be aware of some of the pitfalls . I would imagine it is more difficult to get issues like discussed in the Stereonet threads resolved if you lived overseas as many members here do.
 
  • Like
Reactions: wje

Tranquility Bass

Member
Audio Company
Forum Donor
Joined
Oct 22, 2020
Messages
96
Likes
143
Location
Australia
Hello

I am the one who tested the diy Holton amp in one of the the above links. I wasn’t paid to do it and I did not pay anyone to build Holton’s stuff as Holton’s sidekick has accused me of doing in a quite recent and threatening phone call to someone else. A ridiculous and fanciful conspiracy theory. One thing that became very clear early on was that this amp build was way under powered but not faulty in anyway. You only needed a scope and signal generator to verify this. When I got my dScope III audio analyzer later on I was able to do more accurate power measurements so I could compare it to measurements done by Hypex.

I have had only nightmare dealings with Holton and his sidekick in the past when I sold one of them one of my original preamps/crossovers. Nothing but trouble with them right from the outset and in the end they became very aggressive and un-cooperative whilst trying to destroy my reputation and ripoff my IP. It turns out the common mode noise issue was a storm in a teacup and the fool did not understand the ramifications of sitting 2ft in front of 125dB 1w/m disco speakers in a shipping container was never going to work for practical reasons unless you used a 5 watt SET amp. Along with a power amp with poor common mode rejection ratio it was always going to be noisy. But that is a story for another day.

As for the conspiracy that I am somehow involved in paying people to build Holton’s amps for the purpose of ruining his reputation, well he is doing a pretty good job himself without me. Any time there is an issue he has a tendency to blame everyone else except his own workmanship and there is this chestnut they use of having sold 10,000 modules so it must work and you must be doing something wrong - yes I am the 1 in 10,000 who has actually sat down and tested the amp in a real world situation and not on the bench with a regulated power supply. Quite welcome to come on here to defend himself instead of sitting in a dark corner like a monks butt plug like he did on diyaudio whilst he let his mate chew me out for months on end. Since ASR is more about real world measurements instead of audiophoolery lets have a look at the power measurements for the Holton NXL800 which has a power name plate rating of 500/800 into 8/4 ohms respectively and still advertised as such.

Test into 4 ohm dummy load - one channel driven. Should be at least 800 watts !!

dScope-HPA800-1KHz-1%-THD-4ohms.png


Test into 8 ohm dummy load - one channel driven. Should be at least 500 watts !!

dScope-HPA800-1KHz-1%-THD-8ohms.png
 
Last edited:

Harmonie

Major Contributor
Forum Donor
Joined
May 30, 2020
Messages
1,927
Likes
2,085
Location
France
Sorry to hear about all the drama John.

I nearly bought 8 amps from him to run my 4 way active. Imagine the crap I would have been in.

I would love Amir to get a hold of one and test it.


At such a stage it's not the amp that needs to be tested ....
 

AudioJester

Addicted to Fun and Learning
Forum Donor
Joined
Jan 7, 2020
Messages
938
Likes
1,246
Stereonet is famous for protecting its adverisers/vendors. Its a one man business and run that way. Not defending it, but its pretty much stated as you sign up what the rules are. Dont like the way its run, well then its not the place for you. The guy is just protecting his business interests. You can argue the morals/merits of that, but it is what it is and doesnt pretend otherwise.

The worst is when threads are edited to make the dissenter look bad and the vendor righteous.
 
OP
N

noiseangel

Active Member
Joined
Sep 24, 2020
Messages
296
Likes
463
Location
Perth, Western Australia
I think its more famous for screwing them over.
 

March Audio

Master Contributor
Audio Company
Joined
Mar 1, 2016
Messages
6,378
Likes
9,319
Location
Albany Western Australia
Stereonet is famous for protecting its adverisers/vendors. Its a one man business and run that way. Not defending it, but its pretty much stated as you sign up what the rules are. Dont like the way its run, well then its not the place for you. The guy is just protecting his business interests. You can argue the morals/merits of that, but it is what it is and doesnt pretend otherwise.

The worst is when threads are edited to make the dissenter look bad and the vendor righteous.

It is indeed. However I dont think its clear to all users that the sites is edited and censored to that end. I was banned once for a period of time for just asking Marc why he closed a thread :) It was about a certain Ethernet cleaner. He also censors objective conversation. Completely benign threads get shut if they go in the "wrong" direction. Its not in his business interest to have real knowledge out there.
He has also been extremely rude in communication so I wont spend any time or money there.

The forum is not an open forum it is an extension of the business advertising objectives. Thats fine but don't expect the unbiased commentary and content you see here.
 
Last edited:
OP
N

noiseangel

Active Member
Joined
Sep 24, 2020
Messages
296
Likes
463
Location
Perth, Western Australia
Reading through stereonets reviews and looking at the advertising that goes on over there, (yes I'm a member but he will never find me I only go there to spy on them :)) they seem firmly in the pocket of Harmon International. I hope the current paying sponsors that don't sell Harmon think they are getting real value for money.
 

Tranquility Bass

Member
Audio Company
Forum Donor
Joined
Oct 22, 2020
Messages
96
Likes
143
Location
Australia
It is indeed. However I dont think its clear to all users that the sites is edited and censored to that end. I was banned once for a period of time for just asking Marc why he closed a thread :) It was about a certain Ethernet cleaner. He also censors objective conversation. Completely benign threads get shut if they go in the "wrong" direction. Its not in his business interest to have real knowledge out there.
He has also been extremely rude in communication so I wont spend any time or money there.

The forum is not an open forum it is an extension of the business advertising objectives. Thats fine but don't expect the unbiased commentary and content you see here.

Yes I got a legal threat from him just last night to change something on my own website he didn't like :(

And btw you need to remove that link to your website in your signature. That is strictly forbidden according to stereonets T&C's. Oh I forgot we are on ASR :D LOL
 
OP
N

noiseangel

Active Member
Joined
Sep 24, 2020
Messages
296
Likes
463
Location
Perth, Western Australia
Anyway Back to the original point of this thread, what can be done for the unfortunate souls to get their amps up to the advertised spec?
 

March Audio

Master Contributor
Audio Company
Joined
Mar 1, 2016
Messages
6,378
Likes
9,319
Location
Albany Western Australia
Yes I got a legal threat from him just last night to change something on my own website he didn't like :(

And btw you need to remove that link to your website in your signature. That is strictly forbidden according to stereonets T&C's. Oh I forgot we are on ASR :D LOL
So long as you have not posted anything defamatory and its demonstrably true just ignore the threats.
 

Tranquility Bass

Member
Audio Company
Forum Donor
Joined
Oct 22, 2020
Messages
96
Likes
143
Location
Australia
So long as you have not posted anything defamatory and its demonstrably true just ignore the threats.

I didn't think I did but then he is not a lawyer either. And as a small business owner I have a right to defend myself against unfair trade practices and anti-competitive behaviour !

cheers
 

Tranquility Bass

Member
Audio Company
Forum Donor
Joined
Oct 22, 2020
Messages
96
Likes
143
Location
Australia
Anyway Back to the original point of this thread, what can be done for the unfortunate souls to get their amps up to the advertised spec?

Not much ! The transformer and rail voltages are too low to generate sufficient power. You need at least a stable +/-97V DC to get the required output to allow for the voltage drops in the FET's, rectifier diodes, mains variation etc Problem is the capacitors are only rated at 100V and the FET's are rated at 200V meaning that you could not reliably operate this amp at anything above +/-100V ! And even at +/-97V the power supply would have to be tightly regulated so an unregulated peak rectifier type power supply is out of the question.

As it is there is only +/-85VDC on the main rails with no load. Also the driver stage regulated supply is struggling to supply +/-91V and should really be +/-107V if the rails were running at +/-97VDC !!

So I don't think the owner is ever going to get the 800 watts he thought he was paying for !

cheers
 
OP
N

noiseangel

Active Member
Joined
Sep 24, 2020
Messages
296
Likes
463
Location
Perth, Western Australia
So it's current state is basically what they are stuck with.
 

Tranquility Bass

Member
Audio Company
Forum Donor
Joined
Oct 22, 2020
Messages
96
Likes
143
Location
Australia
So it's current state is basically what they are stuck with.

Even if you increased the transformer voltage to get the right rail voltage the design is so close to the maximum ratings of the caps and FETS that it would only take a 10% increase in the mains voltage to make this design unreliable. To be quite honest this amp module should really be advertised as a 500/300W into 4/8 ohms respectively. In fact none of his commercial amplifiers offer anything above 500w in 4 ohms so I do not know why he keeps advertising these modules at the inflated power figures.

Has anyone else tested these modules ?

cheers
 
Top Bottom