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SET Amp recommendations?

Rockmeister said:
First and foremost, most of the valve effect you crave is found in the 'sound' of a pre amp stage, not a power amp. Or more correctly, power amps 'sound' less than pre amps do IME.
The simplest answer to your query is then to buy a sweet sounding valve pre amp stage(s) and use some very solid class A monoblock power amps to continue the warm but powerful line to the speakers.
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I currently have a Conrad Johnson PV10 part tubed pre amp directly coupled to my Kora EL84 60w valve power amp to the tweeters...maybe I'm already as far down the 'warm' route as I can go?

I have tried SS power amps such as very chunky Unison Research 150W monoblocks on previous Proac speakers using the CJ pre and absolutely hated them.
(I had most of the old Proac Response series but sadly the bass was too fat with rear ports but mids and highs were sooooo good, especially on the 2.5 - but the Proac D18 down firing bass port solves bass issue brilliantly)
 
Hi , have you thought about changing the crossover capacitor for a different make same uf rating , I had a clarity cap mr in for tweeter duties , but wanted
more sparkle so fitted a jantsen silver , placed in one speaker first , and you can hear the difference , happy now , capacitors make most difference at the
start of the audio chain , dac , but even at the other end in tweeter duties you can hear the difference , phil.
 
Sounds like you should borrowing - trying a dsp unit to see if there are any settings that will give you what you are looking for.

My end guess is that the speakers need changing
 
Bit late to this thread but...

Glad to see you're still using the Kora - I thought it had a glorious sound. But it was very EL84 - clear and with a bell-like, chiming quality.

I can't comment from a technical perspective on the bi-amp idea but it does sound rather complicated

I'd have thought you'd be better off looking for a similarly powered EL34 integrated which might offer you the extra warmth your after.

As an aside, Nelson Pass gives an interesting perspective on SET amps here:

http://www.firstwatt.com/pdf/prod_m2_man.pdf
 
That Nelson Pass design is bizarre. I rather fancy building that. There is another design of his that uses light bulbs as power resistors, that's an odd design too. All of them are extremely simple, other than the case you could build them in an evening without a PCB.
A SE power mosfet design generating 25 wpc is enough for most needs.
 
stevec67 said:
The Pass is nothing like a JLH, or were you replying to another post?
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I was replying to yours as they are similar in many ways and often compared to one another. (yes I'm very familiar with both so would prefer not to now go down a dead end of pedantry comparing and contrasting the designs!).

Unrelated, but I was also deadly serious about the idea of making a valve distortion adding box for those wanting such a sound! it was not a wind up! I see its been deleted during the pruning of the unnecessary ad hominem but fail to see why it was also deleted.... It would have uses for musicians and recording as well I reckon.
 
I bow to your superior knowledge, obviously. One of us builds these things for a living, the other runs food factories. I'll stick to what I know.

However the Pass circuit I'm talking about is the one that has 2 power FETs, a variformer in the middle and another pair of FETs making up the imput stage. How does that compare with the JLH that has Darlington pairs of bipolars and some other bipolars upstream? I can't see any similarities at all, have you got a different circuit altogether?
 
Arkless Electronics said:
I was replying to yours as they are similar in many ways and often compared to one another. (yes I'm very familiar with both so would prefer not to now go down a dead end of pedantry comparing and contrasting the designs!).

Unrelated, but I was also deadly serious about the idea of making a valve distortion adding box for those wanting such a sound! it was not a wind up! I see its been deleted during the pruning of the unnecessary ad hominem but fail to see why it was also deleted.... It would have uses for musicians and recording as well I reckon.
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And I was serious with my reply that you should. If you were successful, you would have to build a new factory to keep up with demand.
 
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stevec67 said:
I bow to your superior knowledge, obviously. One of us builds these things for a living, the other runs food factories. I'll stick to what I know.

However the Pass circuit I'm talking about is the one that has 2 power FETs, a variformer in the middle and another pair of FETs making up the imput stage. How does that compare with the JLH that has Darlington pairs of bipolars and some other bipolars upstream? I can't see any similarities at all, have you got a different circuit altogether?
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Sorry Steve but this is exactly the conversation I want to avoid lest it goes on for pages of probable disagreements over Son of Zen V Godzilla V JLH V the Elliott rehash V whatever else and which will no doubt attract tossers who reckon the brand of mains fuse or using silver wire to the power-on LED is the critical bit...
 
jamesd said:
And I was serious with my reply that you should. If you were successful, you would have to build a new factory to keep up with demand.
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The pilot run of Pass's F6 amp featured a pot controlling the harmonic distortion - all 2nd harmonic, all 3rd, or somewhere in between.
 
...but to get back to the OPs issue.

OceanObsession's suggestion regarding the crossover seems a sensible approach to me. There are people who specialise in that sort of modification and it is always reversible should one want to move the speakers on as original.
 
I use an 8w SET and wouldn't look elsewhere. I know the specs are shyte, but the sound is sublime.

But back to the OP question:

I think the hard part is the 1K pounds. You could take a little risk and import a used Japanese SET amp from yahoo Japan. Some makes such as Sun Audio or Sanei are essentially unheard of out of Japan (in general hifi circles) and are cheap. Buying and shipping out of Japan is mildly costly but not crazy expensive. I have used a bidding/shipping service called Jauce.com several times with good success.

Take a look at this current auction a 2A3 SET:

http://yahoo.aleado.com/lot?auctionID=g246848893

or this 2A3 Sun Audio one..

http://yahoo.aleado.com/lot?auctionID=274352630

More pricey, but a kin to Shindo, A Kanno Works 300B:

http://yahoo.aleado.com/lot?auctionID=c631409116

My gear has been bought used from all over the planet and shipped into Vancouver albeit with some mild hiccups. Tube preamp from Japan, Tube power amp from Italy, field coil speaker drivers from Japan, horns from Australia, Tuner from Germany etc...

I would buy a used Japanese amp long before Chinese unless Line Magnetics. The Japanese where into SET tube amps back in the 80's and there are lots available over there.

Also, the SET design is relatively simple for repair.

I have not tried to address the suitability of a low watt SET for your speakers.

Simon
 
Japan uses 100V mains electricity so unless they have a switchable transformer you well need a transformer to run them.
 
Years ago ( when l had more money than sense) l used a EAR/YOSHINO 859 13W SET into a pair of ProAc Response 2S and it sounded brilliant in the midrange/high frequencies however the pairing did not go loud and the bass was terrible, so got a pair of EAR 509 1OOW Monos and that was a great sound!
 
Simon said:
I use an 8w SET and wouldn't look elsewhere. I know the specs are shyte, but the sound is sublime.

But back to the OP question:

I think the hard part is the 1K pounds. You could take a little risk and import a used Japanese SET amp from yahoo Japan. Some makes such as Sun Audio or Sanei are essentially unheard of out of Japan (in general hifi circles) and are cheap. Buying and shipping out of Japan is mildly costly but not crazy expensive. I have used a bidding/shipping service called Jauce.com several times with good success.


Simon
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I recall visiting San-Ei in the late 80's, an amazing audio department store near Akihabara. Lots of very fine kit amps on sale to DIYers as well as very nice individual chassis, pots, switches, transformers from Tamura & Tango, boutique capacitors & resistors etc not to mention funky speaker drivers & horns. An incredible resource for hobbyists over there. There was & still is no real equivalent that I'm aware of in Europe. The legendary Maison de l'audiophile in Paris had a similar ethos but a much smaller range of products. Any San-Ei kit will be using very high quality parts and will usually have been assembled very well. The illustrated instructions they supplied were very comprehensive.
 
I love the obsessive wiring in some Japanese equipment. Look at this old Shindo 300B mono amp. It must have taken ages to do this so beautifully. When there was a pair, such as with this mono amp, they were identical. This attention to detail bodes well for overall outcome. Would you spend the time if the design was naff.

33uvayh.jpg


Simon
 
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