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The DIY transformer box thread (for electrostatic phones) (coming up: review on JRM M99B trans) - Page 7

post #91 of 100
8/19/09 at 1:26pm
Thread Starter 
more realistic mids, wider stage. Bass is about the same as the SRD7. Less harshness.

the only problem is, the big LL's are $400~$500 a pair, while a SRD7 is less than $100. But if you already have a good SS speaker amp, the LL is the way to go.
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post #92 of 100
8/25/09 at 3:08pm
would nt the ll1630 be a better bargain at about half the price, especially with not top of the line headphones like the lambdas, as it might present the same characteritics as the 1627 but with perhaps a smaller soundstage? what you guys think? if the prognostics are good, i m tempted to give it a try
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post #93 of 100
8/28/09 at 3:38am
Trouble is that there are not as many pro biased transformer/energizer boxes out there for easy comparison. Apart from stax and illusion, I am no aware of any others.
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post #94 of 100
11/18/09 at 12:23am
Thread Starter 
the main advantage of using pre-amp output xformer (smaller than the speaker output xformers) is that they are a bit easier to drive. The DC resistance of 1630 is already 14 ohms, the overall impedance will be even higher, any amp should drive it ok. The same thing can not be said about the big LL1627 I am using, my modded Kenwood KA89 (100w x2) can drive it quite well, but with a low power amp the sound gets messy really fast at complex passages. I will guess it needs 50w per channel of good power to run well.

My little class-T experiment setup can drive the modded SRD7 box quite well (this is with direct wiring from the amp to the transformer), but the "lack of juice" is apparent when pusing the big LL's.

Spritzer got a bunch of smaller LL's laying around, maybe he can give us some helpful info in that area.
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post #95 of 100
11/18/09 at 4:53am
I haven't had much time to work on the Lundahls but I hope that changes soon.
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post #96 of 100
11/22/09 at 4:32pm
I have 1:20 CT'd E-P iron that I'm using with Spritzer's boards for two transformers. Also have a SRD-6 on the way that will be upgraded to a Spritzer board.

I need to order a second set of E-P iron for another application with either1:25 or 1:50 since the power available will only be 25W/ch.
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post #97 of 100
5/10/10 at 10:30am
Thread Starter 

updated the first post in the thread (JRM transformer reliability issue). 

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post #98 of 100
5/10/10 at 10:39am

It's a shame the transformers have failed but it appears to be a common problem with anything JRM related. 

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post #99 of 100
5/10/10 at 10:57am
Quote:
Originally Posted by AudioCats View Post

Bass is about the same as the SRD7. 

 


Too bad your transformer failed.  Still, it's disappointing that the bass was not improved over SRD7, since that's one area I would like to see improvement from my SRD7 MkII setup, esp with OII 

 

BTW.  Anyone try contacting Jack at Electraprint to get a quote on custom transformers?  Last time I tried that for another project, the quoted price was way less than I was expecting...

 

Anyhow, once the transformer and bias supply from Spritzer are finalized, I would personally love to see a group-buy/group-build type of thing happening 

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post #100 of 100
5/10/10 at 8:16pm
Thread Starter 

Jon,

that review was done with a Kenwood KA96, which somehow is too overpowering (that is my TV amp.... :o).

With my battery powered Gainclone, the bass of LL was quite a bit better than the SRD7. LL goes deeper and cleaner; (the SRD7 gives mostly mid bass). But that Gainclone, being battery powered and low voltage, doesn't have the juice to drive the 1627 to it's full potential.

 

I don't think we need some kind of custom electrostatic transformers. The large LL has highly sectionalized windings, and can be wired so the primary and seconday interweave. (well, kind of). 

 

Anyway, I will put the existing "good" JRM transformer aside, maybe use it to make a parafeed guitar amp later on.

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