Plitron 3035SE toroid OPT
Hi Awedio,
After listening to the 3035SE OPT for few years, I still like it a lot for it's wide bandwidth extension from both low to high. It's very airy and open sound.
The important thing is - it's price is rather reasonable for such quality. I would say it's really worth for such investment.
Johnny
awedio said:
Hi Awedio,
After listening to the 3035SE OPT for few years, I still like it a lot for it's wide bandwidth extension from both low to high. It's very airy and open sound.
The important thing is - it's price is rather reasonable for such quality. I would say it's really worth for such investment.
Johnny
tubelab.com said:
I needed a 10K primary for my SET EL34 project, which severly limited off the shelf options. I'm in no way a designer, so I just doubled (maybe a little more) the ratings of the 125ESE and ordered a pair to be wound at Heyboer. I am thoroughly impressed with the sound, obvious build quality, and most of all service. They didn't fool around. I had them at my door in two weeks with an invoice for 60bux! Had them do a 300mA 10Hy choke for the same amp. Same great service and price, 40 bux. I know they work with people on quantity buys too. May be worth a try, Jay
I have looked around the web, and this forum, and have found that others have had the same experiences with the 1628SE. The problem is supposed to be related to the way that the secondary is wired to get 8 ohms. I tried the 16 ohm connection and they do work better.
I have not decided whether to find a use for them, or to try to return them (shipping was $25).
I have not decided whether to find a use for them, or to try to return them (shipping was $25).
It's surprising the 1628SE was still available, the SEA version has been on Hammond's site for quite a while. My pair will end up as a bench transformers for testing circuits. Though flawed it's still a rugged unit with UL taps and should work well.
I've had great experiences with Plitron and Lundahl.
The power supply transformers in all of my amps are Hammond - best value for power supplies - no doubt about it.
The Plitron output transformers are excellent.
Why hasn't anybody mentioned Plitron or Lundahl yet?
The power supply transformers in all of my amps are Hammond - best value for power supplies - no doubt about it.
The Plitron output transformers are excellent.
Why hasn't anybody mentioned Plitron or Lundahl yet?
Wondering anyone tested the Hammond 1628SEA yet? I really anxious to know if the SEA version fixes the problem with the SE.
Johnny
Johnny
Kashmire said:
I believe people try to get the OPT with Hammond's price but with Lundahl/Plitron's quality.
Johnny
That was what I wanted to test, but I received a pair that are two years old. I haven't decided what to do with them yet. I could try to return them, but shipping is $25 each way. I am still experimenting with them to find a circuit that will make them happy.
I have been experimenting with them for a few days and I have discovered that the severe ripple (6 db) in the 10 to 20KHz region is much better with all of the secondaries in series (16 ohm) and this is how I have them connected currently. This presents the tube with a non - optimum 2500 ohm load. After listening to them over the weekend I am thinking, maybe I will just add two more tubes, and use them this way.
I have used Allied Electronics, "Allied's Own tube Transformers" for the power transformers in most of my amplifiers. They are made by Hammond, except that they are rated for less VA than the equivalent sized Hammond transformer (cooler running) and they are cheaper! The only one that I have ever seen fail got wet during a hurricane, and still lived for several months.
My 300Beast uses a Plitron power toroid. It was from their general transformer line (not tube) and therefore reasonably priced (2 X 175 volt secondaries). Their output transformers (and Lundahl's) are beyond my budget.
I have the $75 Edcors on order, I will test as soon as they arrive.
tubelab.com said:
Have you tested continuity between windings yet? The Hammond schematic implies two individual secondaries yet mine had continuity between every pair of leads. I'm wondering if a little OPT surgery is in order. The schematic isn't handy but I recall one winding labelled 0-4-8 and a second completely separate. Possible feedback winding?
Yes, I have. There are two distinct secondaries with no continuity between them. They are supposed to interconnected in different manners to yield different inpedance ratios. I have seen a similar arrangement used on some Electra-Print transformers (4 seperate secondaries). The problem arises when two secondaries do not generate exactly the same signal and they are wired in parallel.
On a different note there were two boxes from Edcor left on my doorstep (in the rain) by UPS. The outer boxes were wet, but the transformers were dry. The first observation is that they are about the same color as the pimped out Cadillac that sits in a yard in my neighborhood. Bright metallic blue! They are about the same size as the Hammonds, but not as heavy.
The Hammonds are back in their boxes, and the Edcors are connected into the test amp. The sound is far better than the Hammonds, but not quite perfect. The high end sizzle is not quite as good as the $18 Edcors. These are louder than the Hammonds. I played a lot of music through them, and I liked what I heard.
I ran a quick frequency response test at 10 watts. the lower 3 db point was 21 HZ and the upper was 24.7 KHz.
I plan to test all of my transformers with this amp. I will have a report on my web site when it is done.
tubelab.com said:
Time for me to reconfirm my measurements then. I was sure my samples diplayed continuity. The result was so strange I didn't trust the DVM measured impedance correctly and double-checked by applying a DC voltage to leads one at a time. Different production runs (or metering under the influence?)
Hammond switched to a continuous tapped secondary with the introduction of the SEA models. I have received e-mail (and I think there was a post on this forum) about transformers that were mis - labeled. At least one user of my PC boards received Hammond transformers that had a single tapped secondary even though the box was labled with the dual secondary hookup. This was about 2 years ago before the SEA models were introduced.
Do you have 4 secondary leads or 5. That seems to be the easiest way to figure out which transformers you have.
Do you have 4 secondary leads or 5. That seems to be the easiest way to figure out which transformers you have.
Hi tubelab. The secondaries have five leads and the HF response the patented 1628SE 'de-esser' curve. If I have time this weekend I'll remove and re-test them this weekend.
Well, I am going to find out. The supplier that I got the 1628SE's from has agreed to let me return them, and order 1628SEA's. They do not have the SEA's in stock. They said that the "special order" would take 3 to 4 weeks. This experiment will cost me about $50 in shipping, so I will thouroughly test and document the 1628SE's before returning them.
It will be about a month, but I will have frequency response, distortion and efficiency curves for both transformers (and a few others) on my web site.
Since people are all here I am going to ask a question. I plan to use the 30W rated 1627SEA in my 8W SE 100mA EL34 amp. Is there a particular problem by using big OPT in small amps? On the other hand, is there benefit by doing that?
Tempered congratulations. Looking forward to your findings, you'll be the first. Interesting about it being a special order. Partsconnexion doesn't yet list any of the SEA models!
I am using the 1628SE(A) (and others) in a similar amp. I am running EL-34's, 6L6GC's or 6550's at 420 volts and 60 Ma. This is why I am using a 5K transformer. I get similar power levels. I have tried transformers from tiny to huge. I plan to sell these amplifiers in the future, so I have been testing a lot of transformers.
The advantages of using a big (25 to 30 watt) transformer are far better bass, no saturation issues with strong bass notes, plenty of headroom.
The disadvantages of a big transformer are lower transformer efficiency, and often poorer high frequency response.
I have decided that I will use the $18 Edcor unit in budget amplifiers. I haven't yet decided on a "10 watt" transformer (One Electron, Transcendar) or a "25 or 30 watt" transformer (big Edcor or Hammond 1628) for the high end amplifer.
There is some measureable (and audible) saturation distortion with strong bass at full power with the 10 watt transformer, but it is usually not obvious. The big Edcor SE transformer will take any music (dance, techno, etc) that I can throw at it at full power, but it is 2 db down at 20 KHz. The 1628SE has awesome bass (the best of all transformers tested) but did not have that SE sparkle that most of the other transformers have. I will test the 1628SEA when it arrives.
The decision as to which transformer to use in an amplifier that you will make several of has a few more constraints than a "one off" amplifier. The biggest one is availability. Cost is another. Shipping is also important, The Hammonds or Edcors will add 10 pounds to the weight of every amplifier.
I got mine from a different distributor. I guess that there must be a lot of old transformers sitting on shelves.
I spent much of yesterday testing, and listening to transformers. Two sets in particular, the big Edcors, and the 1628SE's. I noticed during listening tests that one of the Hammond transformers sounded significantly different than the other. Upon further testing, I discovered that one tested far better than the other. The two transformers LOOKED different. They were both made on 11-17-2004, however it appears that one was dipped in varnish, and the other drowned. The leads are all black for the first 6 inches. That one is the good one!
I was about to dismiss the other as a defective transformer when I decided to check it with an ohmmeter (because of the comments made by RDF). Well the secondaries look normal, but the primary does NOT. After a little head scratching, I came to the realization that the blue and the blue - yellow wires are SWITCHED! I have been testing these transformers in UL mode, and this would really confuse the poor tube, so I swapped the wires and tried again.
OK, these things sound pretty good. It is immediately obvious that the bass is far better than my speakers are. I can see 1/2 inch cone movement, but very little sound comes out. I have only seen this before with a SS amp. The SE "sparkle" (noticible on piano transients and cymbals) is not as good as the $18 Edcors, but it is similar to the big Edcors.
OK, test time. I re-ran the freqiency response tests. The 1628SE's now look reasonable, there is a gentle rolloff starting at 10KHz, with the 3db point at about 19 KHz. No 13KHz notch, or funny ripple. Both transformers now test and sound the same. The HF response can be improved about 1 db with about 3 db of cathode feedback.
Further testing is underway. See the next post.
The picture is the frequency response of the 1628SE in UL mode without any feedback. It is being driven with a 6L6. I am using a cheap 6L6 because I can pound these hard without fear of them blowing up, and If it does blow up, it cost $4. I am running it slightly above maximum ratings, for the most available power.
I was about to dismiss the other as a defective transformer when I decided to check it with an ohmmeter (because of the comments made by RDF). Well the secondaries look normal, but the primary does NOT. After a little head scratching, I came to the realization that the blue and the blue - yellow wires are SWITCHED! I have been testing these transformers in UL mode, and this would really confuse the poor tube, so I swapped the wires and tried again.
OK, these things sound pretty good. It is immediately obvious that the bass is far better than my speakers are. I can see 1/2 inch cone movement, but very little sound comes out. I have only seen this before with a SS amp. The SE "sparkle" (noticible on piano transients and cymbals) is not as good as the $18 Edcors, but it is similar to the big Edcors.
OK, test time. I re-ran the freqiency response tests. The 1628SE's now look reasonable, there is a gentle rolloff starting at 10KHz, with the 3db point at about 19 KHz. No 13KHz notch, or funny ripple. Both transformers now test and sound the same. The HF response can be improved about 1 db with about 3 db of cathode feedback.
Further testing is underway. See the next post.
The picture is the frequency response of the 1628SE in UL mode without any feedback. It is being driven with a 6L6. I am using a cheap 6L6 because I can pound these hard without fear of them blowing up, and If it does blow up, it cost $4. I am running it slightly above maximum ratings, for the most available power.
Attachments
I have been looking for a way to quantify the ability of a transformer (and the entire amplifier) to handle big bass. I have run frequency response curves on all of the transformers, and they all look pretty good. It is evident from listening that the physically small ones saturate heavilly below 100 Hz. This does not show up on a frequency response test. I need a better test.
The SS boys use a test called power bandwidth. It is basically a distortion sweep made at full power. I tried this on several SE amps and the results look pretty bad. I still need a better test.
I am now doing distortion VS power curves. I do one set at 1KHz which reveal the capabilities of the basic amplifier, and also tell you about the losses in the transformer. (look at the power available at the knee in the curve). I started to do a second set of curves at 20 Hz but the ONLY transformer that worked here is the Hammond 1628SE. The big Edcor can't make it. I think that 3 sets of curves are needed 1KHz, 100Hz, and for big transformers 20Hz (or maybe 30 or 40 HZ). I am working on these tests now.
Now that I have figured out the mystery of the 1628SE's (at least the set that I have) I will keep them. The 1628SEA's are still on "special order" and I will report on them when they arrive. If they do have improved HF response as Hammond claims they may be the low cost (under $100 USD) winner. They are by far the heaviest. So far I can not disprove the "bass is sold by the pound" theory.
Included is the frequency response plot for the big Edcor transformers. The test conditions are the same as the Hammonds. The HF response and efficiency is slightly better than the Hammonds, but the low end is not as good.
The SS boys use a test called power bandwidth. It is basically a distortion sweep made at full power. I tried this on several SE amps and the results look pretty bad. I still need a better test.
I am now doing distortion VS power curves. I do one set at 1KHz which reveal the capabilities of the basic amplifier, and also tell you about the losses in the transformer. (look at the power available at the knee in the curve). I started to do a second set of curves at 20 Hz but the ONLY transformer that worked here is the Hammond 1628SE. The big Edcor can't make it. I think that 3 sets of curves are needed 1KHz, 100Hz, and for big transformers 20Hz (or maybe 30 or 40 HZ). I am working on these tests now.
Now that I have figured out the mystery of the 1628SE's (at least the set that I have) I will keep them. The 1628SEA's are still on "special order" and I will report on them when they arrive. If they do have improved HF response as Hammond claims they may be the low cost (under $100 USD) winner. They are by far the heaviest. So far I can not disprove the "bass is sold by the pound" theory.
Included is the frequency response plot for the big Edcor transformers. The test conditions are the same as the Hammonds. The HF response and efficiency is slightly better than the Hammonds, but the low end is not as good.
