Best output TXs for the money help

Darren · Post by **Darren** » Tue Jul 31, 2007 11:19 am

I'd plummet for the James, more versatility and future experiments.

I also wouldn't fuss so much over the exact loading. I use 2.5K on my PX4's and the ideally should be 3.5K.
You'd never notice in my experience.

Others would quite naturally disagree of course, just giving out my own thoughts on the matter. Take for example my 6EM7 SE amp, I have no idea what the loading is on them, nor do I care as they sound great. But I can almost guarantee they are way off the spec sheets.

andrew Ivimey · Post by **andrew Ivimey** » Tue Jul 31, 2007 12:01 pm

HA Ha, how far is 'way off' Darren. When I went way off with 6EM7 I actually got them to sound very unpleasant; loud but ... yuk!!!

I too think James are the better bet. They are neat, attractive and much more versatile. The equivalent Hammonds and chunky black things.

Post by **Nick** » Tue Jul 31, 2007 12:08 pm

Having a quick look at the triode curves, looks like ra is about 1K1, so 3k would be ok, as normal, higher impedance will lead to a flatter load line, so lower distortion in theory.

I say in theory, as the lower distorition will come with lower output, so you may end up turning it up and ending up with more distortion than a lower load would have predicted.

Darren · Post by **Darren** » Tue Jul 31, 2007 12:12 pm

Well the transformers for the 6EM7 came out of an ECL86 amp.

So whatever an ECL86 valves needs I guess.

colin.hepburn · Post by **colin.hepburn** » Mon Aug 06, 2007 6:17 pm

Hi all

With output TX 2.5k or would 3k be a better choice TX in mind are
Hammond 1627 se2500ohms 30Watts 120mA 20 Hz. to 20 KHz 20 Henry's or sowter
SE05 the Sowter Spec 2500 ohms, 15 Watts at 30 Hz, 90 mA, 15 Hz to 70 kHz, 15 Henry's
See 2A3 schematic
Can you pleas advice on this
Thanks

Post by **Nick** » Mon Aug 06, 2007 7:58 pm

Well, personally, I wouldn't worry about the 3k/2k5 difference, but the Hammond seems to be designed for a much larger current than a 2a3 would pass. Its entirly a guess, but that would make me think its got more copper in there than is actually required for a 2a3, and that would make me wonder about how optimal it would be.

Is this amp intended to be a experiment, or are you building it as a "best you can make" keeper?

I must admit, I got a bit lost how the choice fell to the Hammond or Sowter.

Actually, looking at the Sowter and Bluebell site, the Sowter is gapped for 120ma and the Hammond for 170ma. There isn't much between them on price.

colin.hepburn · Post by **colin.hepburn** » Mon Aug 06, 2007 8:15 pm

Hi Nick

Yes it will be my main amp a keeper this is why I'm being picky about choosing a TX as I cant afford to make a mistake but want the best I can get for about £260/280 a pair

Post by **Nick** » Mon Aug 06, 2007 8:50 pm

Ok, having said before what I would consider (no I am not on a commission

), another choice would be a Lundahl LL1623 60 or 90ma, thats also in the same price area.

Will · Post by **Will** » Mon Aug 06, 2007 8:50 pm

I would change the 5842 to anode 160v 20-22ma and -2v grid, this will give a 6k anode resistor or keep what you have and up the the current to 13-14ma and add a anode choke, this is T's Lady Day driver.
You will need at least 50 ohms on all 4 grid pins with ferrit beads and ferrits on the heater pins.
James outputs would pay for the anode chokes

Paul Barker · Post by **Paul Barker** » Mon Aug 06, 2007 9:10 pm

colin.hepburn wrote:Hi Nick

Yes it will be my main amp a keeper this is why I'm being picky about choosing a TX as I cant afford to make a mistake but want the best I can get for about £260/280 a pair

You will make loads of mistakes I guarantee it.. unless I am really different to you and the rest of the world.

Post by **Nick** » Mon Aug 06, 2007 9:48 pm

Yes, Paul is thinking the same as me I am afraid. Unless just happen to strike it lucky, and by accident get the perfect amp for you first time (which to be honest, won't happen), or you never listen to any other amp again. Finding your perfect amp, will at first be a itterative process. And not every iteration will get you closer.

I think that why the other folk here are not falling over themself to succest the best TX for the money. I think all that people can say, is what they orefer from what they have tried.

I know thats maybe not the answer you want, but it is the truth as I see it

.

Having said that, if you want to pick a 2a3 as the outout valve (and you could do a lot worst) that removes a lot of the variables, and does narrow down what TX's you could consider (ignoring para feed I guess).

colin.hepburn · Post by **colin.hepburn** » Mon Aug 06, 2007 10:28 pm

Hi All
Yes nick I had forgotten the lLundahl LL1623 HO more decisions added to list of possibly

Well Paul mistakes I can pretty must warrant but hopeful not with the output TXs can’t afford to do that
Will, I like you idea of anode choke which one would you recommend or if its not to must to ask would you consider re drawing the schematic on post 25

with choke or other changes you think worth it as a later upgrade path It would be very helpfully

Thanks
Colin

colin.hepburn · Post by **colin.hepburn** » Tue Aug 07, 2007 4:52 am

Nick wrote:Yes, Paul is thinking the same as me I am afraid. Unless just happen to strike it lucky, and by accident get the perfect amp for you first time (which to be honest, won't happen), or you never listen to any other amp again. Finding your perfect amp, will at first be a itterative process. And not every iteration will get you closer.

I think that why the other folk here are not falling over themself to succest the best TX for the money. I think all that people can say, is what they orefer from what they have tried.

I know thats maybe not the answer you want, but it is the truth as I see it .

Having said that, if you want to pick a 2a3 as the outout valve (and you could do a lot worst) that removes a lot of the variables, and does narrow down what TX's you could consider (ignoring para feed I guess).

Hi Nick
Yes I follow all you points and respect what your are saying my thinking is 2A3 would be good place to start I know I will want to try other drive affordable valves in and around a TX of 2.5/3k so I can see why the James would be the way to go here I am aware TX choose is a black art my school of thought is the more iron the better i.e. more henrys I fully understand other members don’t want too comet to one particular TX It just seems that the Hammond’s or Sowter are the must poplar unless you want to pay silly money

Paul Barker · Post by **Paul Barker** » Tue Aug 07, 2007 6:59 am

colin.hepburn wrote: my school of thought is the more iron the better i.e. more henrys

Yes if you are obsessed with bass and have the room speakers and other components like tuntable, plinth arm cartridge phono stage to make doodle squat difference. Most likely reality is your speakers won't do justice to bass, but the other elements are also essential.

Core material is more important than amount of it. You can get very good sounds using less material of a higher quality than more material of a lesser quality.

I prefer simple transformer design on high quality core to fancy design aimed at maximising bandwidth on crude core.

I haven't heard the transformers you are asking about.

I have found that you just have to buy some, and then some more and so on.

Buy cheap, buy twice.

Come down to earth, you can't make the perfect amp on your budget, so be happy with a slightly good one and you will be happy sooner, then move on to other areas of your life instead of neglecting them like we have done.

simon · Post by **simon** » Tue Aug 07, 2007 8:50 am

I haven't added an opinion so far because my experience is rather limited - I have Hammond 1627SE and AE c cores, both 2.5k. Nick keeps recommending AE and in my very limited experience with good reason. To me the c cores sound better than the 1627s, they're smaller and more neatly packaged, and they're cheaper than the latest Hammonds. The only drawback is you have to be patient - the waiting list is about 6 months.

Perhaps another option is to get some 3.5k amorphous from AE? They'll cost about £400 plus shipping but you could use them for 2A3, 300B, 45 etc. Perhaps not an optimal solution but you'd have a really good pair of opts you could use with different amps over the years? Part of me now wonders why I didn't order some 3.5k silver amorphous instead of the c cores and have done with it.

audio-talk

Best output TXs for the money help

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