Audio Asylum Thread Printer

baileyler

I have tried to post this over on Audiogon as well, but you never know if the moderators will allow the post so I am repeating it here.

This is a very long story about Aural Thrills amplifiers. This is only about the amplifiers and not his cables. I actually have two pairs of his cables and (other than a very minor quality issue) they seem just fine.

Anyway, I purchased his prototype 300B PP monoblocks off of Ebay and, to ruin the end of the story, those monoblocks were sent back. The issue is not having to send the monoblocks back, but why they were sent back and the path it took to get there.

The seller (Tom Kenny) did in fact advertise the monoblocks as prototypes, indicting the only issue was that the �bottom did not fit well�. He had listed one photo of one of his production units, and one photo of one of the monoblocks with its bottom off.

The expectation from that description is that maybe they did not look so great, but that they should be complete, fully functional and without reliability issues. Certainly they should not be a science project.

After the listing started, he indicated that he had modified the units to add a 6SN7 gain stage, and changed some capacitors. He also indicated in a phone call that he had changed the original 6DJ8 input to a 12AU7. He said that the amps were very quiet. I was OK with that.

He also indicated in a phone call (prior to purchase) that they were set up for 8 ohms output, but that there were 4 and 16 ohm taps off the output transformers. Did not turn out that way.

The amps were supposed to come with a little tool to check bias but, of course, he �forgot� to pack it. They were not hard to make, so I did that myself (a little time and expense).

Although I had informed him prior to the end of the auction I needed to pay via Paypal (to use the Bill Me Later option), he called after the auction and asked if I could pay via money order. I offered to pay a small piece via the �personal transfer� option, but he ultimately withdrew his request.

The amp was supposed to come with all tubes but, during that conversation, he indicated he needed the money for another project, so I offered to help him out by letting him keep all the tubes except the 300Bs (I needed those), and I also ended up purchasing two pairs of his cables with the money I was going to send via the �personal transfer� payment (and I paid via that option). Turns out I was way too nice.

He told me that, when I received the amps, I should inspect underneath for any damage. When I got the amps I opened up the bottoms and, to my surprise, not only were they NOT identical, they were NOT the same as pictured (taking into account the 6SN7 mod).

I also found a small piece of loose red wire floating around in one of the amps. It did not appear to have come loose from anything, so it was probably just a remnant left behind (sloppy).

I am not an expert (or even a rank amateur) at circuits, and it turns out I missed a bad solder joint. I did ultimately find that (explained below).

I asked about the differences between the two amps, and he indicated that he had swapped out some values in the capacitors in the bias section, and that it would have no effect on sound. He �dared� me to hear a sound difference between the two amps.

I also asked about a transformer and some other caps shown in the Ebay photo, and he said they were wrong values for the mod and changed (they were not changed, they were simply removed).

I was still OK about all that, but starting to wonder about what else was going on.

I ran the amps for a while, and they actually sounded good, but there was a significant hum coming from underneath (in addition to a very slight hum in the speakers). Turns out that the input chokes were humming, and were right up against the bottom covers making the problem even worse. I asked if this was normal and what to do about it, and got no answer. I ended up putting felt spacers between the frame and bottom cover which helped but did not completely get rid of the issue.

I then decided to check the 300B tubes (cheap Chinese, should have done that first, of course the Ebay photo shows better quality 300Bs), and found one had an intermittent short.

At that point I decided to check a few other simple things.

Specifically, I checked the filament voltage on the 12AU7 and 6SN7 inputs and found that they were 7.3V (on a stable 122V input). Hmmm....

While initially doing this check, one of the amps starting having a bad feedback issue, so I turned it off, looked under the hood, found the bad solder joint and put a little solder on it.

I asked him about the filament voltage issue and what I should due to fix it, and the response I got back was that I was complaining about the amps, that �[m]y ego can no longer take you�, and do not send any more emails.

He went on to say that he was �an ear person, not an engineer type,� and accused me of modifying the amps by fixing a solder joint and adding the felt spacers.

After another round of emails, he admitted he could not remember what output transformers he put on the units (from above), and that he had not described all the variances in the amps. I wonder what else he did not remember or describe about the units.

My point to him was that I was not informed up front, and that there should have been no surprises.

After all that I was still interested in keeping the amps because the sound was interesting. All I wanted was a little help to make sure that the amps were running properly. He said he would send the schematic, but would not answer any more questions.

I was still going to try to figure it out on my own (or with a little help if I could find it), so I requested that whatever he sent as schematics needed to be clear (so I could read it) and to include some other information so that I could determine if the amps were operating to a design spec. What he originally sent were two low resolution photos of the schematic, and none of the text could be read. I said that was unacceptable, and he replied that he would put originals in the mail but that he was very busy and don�t bother him anymore.

He did ultimately say I could return the amps for a refund, but only the amount paid via Ebay. Since he had asked $200 to originally ship the amps, I had paid for that directly via my FedEx account (in addition to a $25 packing fee he requested). Turns out that actual shipping was about $75. Of course, I also paid for return shipping.

He now has the amps back, but getting a full refund of the amount sent to him required a Paypal claim. Unfortunately, even with the refund, this transaction has ended up costing me about $200.

There is more but you get the picture. I will be happy to forward the email string to anyone who wants it.

Bottom line is that while his concept is interesting, he design is flawed and his implementation is sloppy. His customer service is nonexistent (if not downright offensive).

If you have bought an amp from Aural Thrills, I would definitely check a few basic things (like filament voltage) to make sure that it is operating properly.

If you are contemplating purchasing an amp from Aural Thrills, you would be better off putting your money elsewhere (there are plenty of friendly and competent amp builders out there).

If you still insist on purchasing an amp from Aural Thrills, make sure you have a clear understanding of exactly what you purchasing, including a right to return it.

Shady Lane

Aural Thrills Amplifier Issue

Post a Message!