Some of his early transformers were good stuff. Then he shipped poorly constructed junk. After that he took money and delivered only excuses. I consider myself lucky that I actually got something in return for my money (which was the Ebay starting price) all 3 times. In each case, I had to go through the email - phone call - excuse cycle to get my transformers. After the third pair he had my account locked out by Ebay because " I complained too much."
There were long threads here and on other forums about this guy and his "business practices". The usual avenues for lodging a complaint were all saturated.
The technique that I have resorted to twice seems to work. Look up the offenders web hosting service. This can usually be found by doing a "who is" search on Network Solutions. Then send a polite email to the web site hosting company asking them how to file a fraud complaint, implying legal action. Send a CC to the offender. I got my transformers the next week!
There were long threads here and on other forums about this guy and his "business practices". The usual avenues for lodging a complaint were all saturated.
The technique that I have resorted to twice seems to work. Look up the offenders web hosting service. This can usually be found by doing a "who is" search on Network Solutions. Then send a polite email to the web site hosting company asking them how to file a fraud complaint, implying legal action. Send a CC to the offender. I got my transformers the next week!
hi tubelab.com,
10K SE OPT little problem was Turn ratio for prmary & secondary was too high.
It will very easy to cause HF roll off easy & HF atmosphere was not good.
I use Kondo Ongaku to compare my Nano Amorphous core 10K SE & also use Tango X-10S already.
I feel nano had better HF & detail, vocal was smooth then original Hi-B core. the most important was distoration was quite low or said most linear of this OPT.
I also test with ultra Hi-B core & found this core was good in bass( compare to permalloy & nano amorphous ) But dynamic was little bit weak than Low loss Z11/M6 core. But its bass was more detail, texture was better.
I will test my 10K SE for U to reference.
I only use Audio precision to test for my nano 3.5K only.
I will test them later & post result in here.
many thanks
BTW,
I forgot to say my friend diy your 845SE circuit very good sound.
I will send my 10K nano OPT to him & operate in your corcuit to test for performance later.
Photo was my 3.5K nano testing result!
thx
thomas
10K SE OPT little problem was Turn ratio for prmary & secondary was too high.
It will very easy to cause HF roll off easy & HF atmosphere was not good.
I use Kondo Ongaku to compare my Nano Amorphous core 10K SE & also use Tango X-10S already.
I feel nano had better HF & detail, vocal was smooth then original Hi-B core. the most important was distoration was quite low or said most linear of this OPT.
I also test with ultra Hi-B core & found this core was good in bass( compare to permalloy & nano amorphous ) But dynamic was little bit weak than Low loss Z11/M6 core. But its bass was more detail, texture was better.
I will test my 10K SE for U to reference.
I only use Audio precision to test for my nano 3.5K only.
I will test them later & post result in here.
many thanks
BTW,
I forgot to say my friend diy your 845SE circuit very good sound.
I will send my 10K nano OPT to him & operate in your corcuit to test for performance later.
Photo was my 3.5K nano testing result!
thx
thomas
An externally hosted image should be here but it was not working when we last tested it.
No they were made by a con artist in Pennsylvania, USA. They cost me $150 USD for the pair including shipping. I am afraid that Audio Note products are far beyond my budget.
I have the Audio Note (UK) power transformer that was specified in the original Sound Practices article. I will probably put it on Ebay to raise some cash. I have come to the realization that I have far more projects than I can possibly complete.
I make one of two trips per year to my mother - in - laws house in northern WV. The closest airport is Pittsburgh. Several of my friends asked me to "visit" him a few years ago. It was probably wise that I didn't.
I was informed that before he was involved with transformers, he did the same thing with electrostatic loudspeakers. Only it is not clear if anyone ever received anything other than some poorly copied "plans".
I was informed that before he was involved with transformers, he did the same thing with electrostatic loudspeakers. Only it is not clear if anyone ever received anything other than some poorly copied "plans".
tubelab.com said:
Hi George,
There was that lame model along with a set of badly drawn plans of the electrostatic wonder woofer he hawked in AA or was it GA? (Cant' remember.) One of my friends got hooked by that scam, and looking at the plans there wasn't really enough information there to determine whether it would have actually worked, but it seemed unlikely without a lot of additional detail work/experimentation. Needless to say he did not build it. Later still there was that prohibitively expensive reprint of an old transformer design manual, and finally the bad transformers themselves.
Handmade would be more appropriate for another thread - they're a dead issue, anyway. I've been looking around and think that I'll probably use GM-70s instead of the 211 for the amplifier. I'm wondering if they would be compatible with something like the One Electron transformer with 6400 ohms primary impedance?
Yes we have discussed the con artist far too much already, but note his name was HandWOUND electronics. HandMADE is a different company that is still in business.
I have no experience with the GM-70, but there is a discussion group at Yahoo devoted to that (and similar) tube:
http://groups.yahoo.com/group/GM70/
If I remember correctly, you have to ask for membership, which takes a few days. From their main page:
" This group is for enthusiasts of audio tube amplifiers/preamplifiers of a variety which are usually large, extravagant, and totally excessive, oftentimes employing tubes such as the GM70, GM100, 45, 112A, or the 845, hence the nickname "boatanchors". We consider membership to start at amps which could anchor, oh say a 15 foot sailboat, on a moderately calm day."
I can find no mention of a 6400 ohm One Electron OPT on their web site. Their OPT's are rated at 15 watts which is on the small side for a 211 or GM - 70.
I have no experience with the GM-70, but there is a discussion group at Yahoo devoted to that (and similar) tube:
http://groups.yahoo.com/group/GM70/
If I remember correctly, you have to ask for membership, which takes a few days. From their main page:
" This group is for enthusiasts of audio tube amplifiers/preamplifiers of a variety which are usually large, extravagant, and totally excessive, oftentimes employing tubes such as the GM70, GM100, 45, 112A, or the 845, hence the nickname "boatanchors". We consider membership to start at amps which could anchor, oh say a 15 foot sailboat, on a moderately calm day."
I can find no mention of a 6400 ohm One Electron OPT on their web site. Their OPT's are rated at 15 watts which is on the small side for a 211 or GM - 70.
Handmade, Handwound - whatever (I stand corrected, though). I'm sick of hearing about the guy (Lucas), and I've never even dealt with him.
I thought it was One Electron that had the 6400k iron, but I was mistaken. I've looked at a lot of transformer sites over the past couple of days...When I find the ones I was thinking of again, I'll post a link. The amp I'm considering probably won't qualify for exalted boat anchor status, as the switching power supply will take out a lot of the weight. However, the output iron should keep it from being blown across the table by a stray breeze.
Here is the concept - at work, we have a piece of test gear built into one of those sloped-front Bud cabinets. I was imagining one of these with tubes on top, a pair of antique round meters on the sloped front for monitoring bias current, with a glass jewel pilot lamp in the old style (smooth, not faceted). The case will be painted with red crackle finish. I was inspired by a picture of the wacky space ship control console in the old Flash Gordon movies (Buster Crabbe, I think). Any way, it's the Flash with the cape and silver bathing cap. The 211s would look more true to the concept, but the GM70s will probably sound better.
This concept of marrying switchers to tube amps started for me with the "Shrine" amp from earlier this year (up and running and still being tweaked - see the thread). That was a hybrid vacuum tube/JFET amp with 1625 outputs in a 6" cube. The switcher and tiny Edcor 5k transformer made that small size possible.
I thought it was One Electron that had the 6400k iron, but I was mistaken. I've looked at a lot of transformer sites over the past couple of days...When I find the ones I was thinking of again, I'll post a link. The amp I'm considering probably won't qualify for exalted boat anchor status, as the switching power supply will take out a lot of the weight. However, the output iron should keep it from being blown across the table by a stray breeze.
Here is the concept - at work, we have a piece of test gear built into one of those sloped-front Bud cabinets. I was imagining one of these with tubes on top, a pair of antique round meters on the sloped front for monitoring bias current, with a glass jewel pilot lamp in the old style (smooth, not faceted). The case will be painted with red crackle finish. I was inspired by a picture of the wacky space ship control console in the old Flash Gordon movies (Buster Crabbe, I think). Any way, it's the Flash with the cape and silver bathing cap. The 211s would look more true to the concept, but the GM70s will probably sound better.
This concept of marrying switchers to tube amps started for me with the "Shrine" amp from earlier this year (up and running and still being tweaked - see the thread). That was a hybrid vacuum tube/JFET amp with 1625 outputs in a 6" cube. The switcher and tiny Edcor 5k transformer made that small size possible.
I have been following that thread, and have my own tube amp with SMPS technology inside. It seems that yours is already working, while I am still in the "sometimes it works, sometimes it blows up" stage.
I am using a conventional linear supply (for now) followed by a pair (one for each channel) of agile buck converters to keep the output tubes operating with a constant DC voltage across them. I will eventually make this work. I just haven't had time to experiment.
It's my contention that there are only a few switcher topologies really suited for work with tubes. What you want is something that is gentle to the HV rectifiers and doesn't try to jerk them out of conduction (lots of RF racket, not too nice to the diodes, either). You also want a supply that doesn't bathe the outside world and your amplifier in RF crud. The RCC flyback I used on the Shrine is pretty gentle to the output rectifiers, as the primary switch cannot turn on until the transformer has completely reset, so that the current in the output rectifiers is zero. As evidenced by the EMI scan, it's fairly quiet, but I'd like a supply that is much quieter. My next pass wil use a ZVS (zero voltage switching) flyback. Making one is reasonably simple, as there are at least 3 vendors (On, TI, ST) with ZVS controllers. Using ZVS, one can shape the dV/dt of the primary switching waveform and really bring down the noise. I will use one of these to power a 1.5-2W SE amp usiing the 6LR8 in triode mode and 125CSE output iron. The next will probably power a 6550 SE amp with the Transcendar 3k large-size iron.
For higher power such as with the GM-70, I'm considering using a ZVS half-bridge which has low dV/dt and dotes on capacitive loads like voltage multipliers. The are alot of there in production now, as they have been adopted by practically all of the LCD TV manufacturers.
For higher power such as with the GM-70, I'm considering using a ZVS half-bridge which has low dV/dt and dotes on capacitive loads like voltage multipliers. The are alot of there in production now, as they have been adopted by practically all of the LCD TV manufacturers.
Im still looking for the transformers I thought I saw... The closest so far are 6K Electra-Prints at $250 each - ouch. I made the plunge and bought 2 pairs of the GM70s. The curves are interesting. If I don't mind dipping into A2 operation, I could get 25+ W with 800-900V on the plate and the 6k transformers. This was assuming about 80W plate dissipation. I don't know if I want to get too frisky with these tubes, as they are specified for 1000 hrs life.
Yeah, there's always Hammond, though if I'm going to all the trouble to build this monster, I might want better iron. As a data point, do you think the Electra-Prints sound $150 better (seeing as you have a pair)? I don't care too much about cosmetics, as the transformers will be tucked inside the box. Only the tubes get to come out and play... Im thinking of using 6GF7s to drive the GM-70s.
I may just wind my own monster iron for this project. I've been scouting around for appropriately sized 6 mil lams, but they are hard to find. I struck out completely at Ram Sales - they only have 14 mil lams. Tempel has some but in sizes too small to be of use for this project. At present I'm going to soak apart some chokes I have that incorporate the right thickness lams in the EI121 size, which happens to be the size used by the One Electron transformer (1600 ohm) I just scored on Ebay. I can do some experiments with interleaving with this iron before I wind the final product, which will probably use an EI150 or EI175 lam size, though I may try a double wide stack of the EI121s if I can get enough wire on them. I'm designing for 15kG at 200 mA peak current, 6500 ohms primary impedance. This will get me around 30W RMS at 800-900V on the plate, assuming I let the amp dip slightly into A2 mode. This is not as much output power as some boast for this tube, but enough for me.
There's a guy on eBay (HK/China) who sells an interesting assortment of C Cores which might be suitable for such a project. I have a friend who wound his own output transformers (10K) for 845's - the end result after three tries was excellent. Winding interconnection order may need to be tweaked for best overall HF flatness.
Bandersnatch - I took a look at Thomas and Skinner - I had no idea they sold to individuals. I'l l maybe ask this time.
Kevinkr - I saw those C-cores on Ebay. I'd feel a little bit better about them if the seller listed the core parameters. Again, I guess I'll just ask. BTW, there's a two part article series by Norman Crowhurst (RIP) regarding transformer construction that offers a lot of insight as to optimum interleaving.
Kevinkr - I saw those C-cores on Ebay. I'd feel a little bit better about them if the seller listed the core parameters. Again, I guess I'll just ask. BTW, there's a two part article series by Norman Crowhurst (RIP) regarding transformer construction that offers a lot of insight as to optimum interleaving.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.