• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Any good flea-watt SET designs?

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Dear Tube Freaks;

I have never built an tube amp before, ever. I have basic electronics knowledge and understanding. No more, no less. I am looking for a easy-to-build, moderate cost, single ended triode that would be suitable for a first-time DIY-tube project.

  • Power is not an issue, a single watt is more than sufficient.
  • Lower end extension (say below 200Hz) is of less importance.
  • My preferred tubes would be the 45 or the 10Y, although I am open for suggestions.

Any experienced suggestions on a well documented project that could suit me?
 
We have decided to update the original circuit to incorporate the C4S active load on the driver stage. This will significantly decrease noise and hum levels and increase the linearity of the driver stage. The previous version of the kits averaged about 20-30mV RMS hum with Valve Art 2A3s. With the C4S installed the hum level is reduced by approximately a factor of ten, to about 2mV RMS. Subjectively the C4S will also improve the transient speed and image localization of the amps. The change is not subtle and we feel that our customers will find the improvement significant.

I believe the distortion comment is no longer true :)
 
Rocky,

The fly in the ointment is the fact that the PM's power trafo is strictly 120 VAC. Have Bottlehead confirm that 50 Hz. power is OK. You will have to acquire a step down autotransformer for the monoblock pair. Bottlehead carries "230" VAC power trafos, but they are fairly costly.

All SET amps have high THD numbers. That is nothing to fret about. The distortion of SET units is mostly 2nd order and a LITTLE 3rd order. Many people find it EUPHONIC.
 
Eli Duttman said:
The fly in the ointment is the fact that the PM's power trafo is strictly 120 VAC. Have Bottlehead confirm that 50 Hz. power is OK. You will have to acquire a step down autotransformer for the monoblock pair. Bottlehead carries "230" VAC power trafos, but they are fairly costly.

Thank you very much for this essential information. I had not noticed it yet.
 
From bottlehead's FAQ:

At this time we do not have universal power transformers in any of our kits. They are all built for 120VAC mains only, except for the Paraglow and Parabee kits which are also available in a 230V (actually 220V -240V) only version. You should be able to fairly readily access a stepdown transformer in your home country that will accomodate the Paramour amplifiers. A VA rating of 100 or higher will be adequate for a pair of Paramour monoblocks.

In other words the VAC Hz shouldn't be a problem?
 
It seems 50 Hz. power is not a problem for the PM power trafo. Ask Bottlehead to confirm that. It's only a question of how robust the trafo is. 50 Hz. service requires a little "beefier" construction than 60 Hz. only does.

Take a look at this URL (http://www.alliedelec.com/catalog/pf.asp?FN=616.pdf). It shows that a 100 VA step-down autotransformer costs about 40 USD. You should be able to source an equivalent item in the EU for about the same cost. Don't forget to allow for VAT.
 
Rocky,

Death and taxes will always be with us. April 15th, just past, is the most hated day of the year in the US. Income tax returns must be filed by April 15th. Regimes world wide would tax the air we breathe, if they thought the populace would not revolt. I know, I know, don't give the b*stards any ideas.

If you decide to order Paramours, search the Bottlehead Forum archives for info on the 45 tweak. You should find something. BTW, all sorts of help, from stock construction to MAJOR modifications, is available on the Bottlehead Forum.
 
Eli Duttman said:
If you decide to order Paramours, search the Bottlehead Forum archives for info on the 45 tweak. You should find something. BTW, all sorts of help, from stock construction to MAJOR modifications, is available on the Bottlehead Forum.

The 45 tweak will be first on my tweak list, unless I find negative results on the bottlehead forum. along side with some resistor and capacitor upgrades probably, I'll decide when i've inspected the kit contents. I also have some fine 24 gauge teflon insulated round solid silver wire laying around, and I guess this would be a nice opportunity for it to prove itself useful.. :)

Many thanks for your outstanding advices, they have been truly helpful! :)
 
planet10 said:
I have a buddy with the Paramours -- one of the 1st tweaks was a beefier pair of trafos... if i were you i'd buy the kit without trafos (and save on shipping at least) and buy some locally of the appropriate voltage.

Then I'll concider the kit without trafos nor 2A3 tubes.. I'll check what price i'll get it for.. Both for visuals and sound I fancy the "45 Premium Mesh Plate globe shape matched pair with 2.5V heater. Ceramic base, gold pins and strengthend plate structure." although it's $269 the pair at diyhifisupply.com.. But with some bucks off the kit retail, it might just fit my budget. :D

James D. said:
If your interested in low power SETs and the 45 family or 10Y the this site is a must VT52 . Lots of fascinating info...

Very interresting page. I'll make sure to have a good look before I make my final desicion :)
 
slowmotion said:
Hi Rocky

Have you tried Demostenes in Norway?

http://www.demostenes.no/2.0/nor.htm


cheers ;)

Eg venta meg virkeleg ikkje å finne ein slik nettressurs tilgjengeleg på norsk sidemål!! :D

BTW the WE555 driver I mentioned to you earlier... It got busted by some freak for top $$$.. Even in the condition it was in it went for over a 1000$ :crazy: Guess i'll have to live without compression below 500Hz :bawling: :crying: :worried: :no: :( :Ouch:

Well, back on topic... Great to find a trafo source here at home :) I've been requesting a quote on the Paramour kit without power trafos or 2A3s, I'm awaiting their desicion.. :rolleyes:
 
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