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I have not posted for quite a while as I've been busy on other things, and enjoying lots of music when I've had time to. Lucky!Anyway, I have a nice self built 300B SET (called Valentine); driven by a 6SL7/E83F mu stage with its own PSU; fixed bias; AC heated 300Bs. I have recently changed from TJ 300Bs to recent WE's and wow, what an upgrade that is!
OPTs are Lundahl LL1620s and they can't be bad as this amp is the most musical I've ever heard. However, a friend (and Asylum member) whose opinions I respect a lot suggests that a change of OPT will give far better tonality and better sound generally.
So I'm tempted to try something else. I'm into accoustic music; classical, folk, some rock with a special liking for female vocals.
I've done lots of research here, diyaudio and google which brought up lots of oriental sites. My short list so far is:
Hashimoto H-20-3.5U
Hashimoto H-30-3.5S
Tamura F7002
Tango FC-30-3.5S (very similar to older XE-60-3.5S)
Cost is not a major issue if I get a 'result'. As I'm in the UK I looked at the Audionote site but prices seemed excessive to me.I tend to rule out the Tamura F5 series as it seems to lack some bass; while I'm not a bass freak, I like that of the WE300Bs and Lundahl OPTs and don't want to lose this.
Any comments or recommendations welcomed.
Any help to choose from within my short list is specially valuable.
Thanks in advance.
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Hi,
you could also use the Lundahl LL1664 80mA or 100mA.
This one is not expensive. I like it a lot!Kind Regards
Barossi
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Well, if cost isn't a big concern... may I suggest parafeed using MQ iron? I tried this for the first time on a 45 amp, used some Robin Hoods that included some nickle, and I forgot the choke part number, but it was MQ. The sound is fantastic. This is a synergy thing, of course, and it all has to work together, but I'm impressed that the bass is much more articulate and overall music more satisfying than any 300B I've made using air gapped TFRs (I've used OPT from Audio Note, Bartolucci, James, ElectraPrint).
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Hi Steve,
Very good suggestion - but not as a mod for this amp as it's tightly packed in.
It's on the list for my next amp though. I wonder if Hashimoto iron would work well ... perhaps by the time of my next build we might know!
My next full DIY build will be another phono stage as I've done two decent ones but not quite hit the target. It's a challenge! Anyway, a simple OPT upgrade of the power amp will suit me pretty well for the moment.
Regards, Mike
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Pick a good manufactor Electra-Print, Magnaquest, Tamura, Hashimoto
Silk, James, any of them. But have the secondsaries wound in Silver.
Silver prices are much higher than they were 4 and 5 years ago when
I had mine made. But I would do it again, sacrficing some other
project. If you ever heard the sound of silver OPT's, it will
definitly make you think about it.
have fun
Willie
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Hi,Given that you are in the UK, the obvious suggestions (listed in order of delivery time)
Sowter
SJS
AE
Tribute
Is what I am using, excellent sound with superb bench measurement.
Picking good OPT is like looking for good coffee, everyone has his own favourite. Be careful with amorphous, silver and other exotic material, all have their own character.
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Hi,
Reports of direct comparisons suggest that Sowter are not up to the standard of sound quality of the best Japanese. I use their PSU tx's and chokes though.
SJS is a thought - this amp uses his power TX's and they are fine. But I think he's now based in the US?
I'll have another look into AE, but I believe Tribute take about a year!
Thanks for good ideas.
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The Hashimoto would be an excellent choice I would think.
Elecktra Print is pretty fair game to from a sonic standpoint.
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Try the Kimmel Choke coupled MUstage with a O-Netics or a Tribute interstage transformer.Their will be no coupling caps in the signal path.
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BenHow do you use a choke coupled mu stage
with an interstage without a coupling cap?
If you search Welborne forum for "twystd" it will tell you all about it including some Reviews of the Mod.
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Good thoughts, but I'll save that for my next project.
The main point about that will be better 2 pi PSUs and that won't fit on the existing chassis.
Once I design a new chassis I'll consider ITs or grid chokes etc etc ...
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To keep the bass, you'll want to be sure that the inductance and maximum DC current rating of a replacement transformer are not compromised. These numbers are often hard to find, especially if you insist on them being measured in the same way so that a comparison is valid ... :^)According to the data sheet, the LL1620 has quite a high inductance.
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particulary pertaining to the importance of having a high primary
inductance and current handling ability. If you want your SET amp to
sound "BIG", then you actually need a pretty BIG piece of iron to
accomplish this. Size does indeed matter here --even at 6-10 watts
output.Good luck,-
MikeSince you like the sound of the Lundahl LL1620,
why not try the LL1620AM (amorphous core).
Same musicality but more detail.DanL
I strongly recommend two things .1) Add Magnequest to your short list. They make an extremely reasonably priced SE Output Transformer (TFA-204) that was originally designed specifically for the WE 300B when run at 8 Watts out or less - and they have other SE Output Transformers rated for higher power. Though my opinion is biased in that I love their stuff they are certainly at least as good as the other big names.
2)
You say the amp is the most musical you've heard and I take that to mean you're enjoying the sound with the Lundahls. Well, this is pure opinion and waxing philosophical but IMHO . . .
Isn't it a mistake to change something while you still really like the sound of what you have? - It could well be that a future you will value a different amp more - but enjoyment doesn't come cheap (Look how much everybody is spending to try and get it!!`,;^)and it's good to appreciate what you like while you can. Especially as this amp is your own creation you have an interest in hearing deep into the sound, getting to know the sound intimately.
Of course, nothing is perfect and eventually the things that you want to change will surface in your own mind before they do in anyone else's.
There are so many uneasy, 'concerned' guys who spend all their time modding (or thinking about it) because they once made the choice to ignore what they liked and now have to wander the land of everybody else's recommendations trying to find it again.
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Hi Ian, I really like your post!Re the uneasy, concerned guys wandering trying to find what they like; I was perhaps a bit like that (not as bad as most of my friends). But the situation changed totally once I changed over to valves. :-)
I still change things, but I tend to have a backout plan (easily reversible changes). DIY helps enormously with this. And of course in this case I can always swap back to Lundahls, but somehow I doubt if I will need to. Anyway, that's how I address your highly valid point of why change when I really like the sound of what I have.
And .... other people's recommendations on several Asylums have proved exceptionally reliable; more so than dealer or magazine advice (in the distant past, before I discovered these Asylums, valves, DIY ...).
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