Peter,

The standby switches on this amp are not really needed with this circuit in that they aren't going to prolong tube life like they would in an amplifier that was drawing more mils and running higher plate voltages.   But since I had all the chassis cut for them, they are there.   Your plan to use them as you described is no problem though.  There is a nice pop that occurs when you bring the amp on using these switches, however at 6 watts it's not enough power to blow up a speaker.  At one point along the way I wired these switches so that they did not create a pop on startup and sent an amp off to Europe that came back because it didn't sound good.  To my surprise the problem was traced to the modifications to the standby circuit, so they were removed.

As for using a preamp, the SE34I.2 is originally designed for 6N1P, 6DJ8 or 6922 input tubes.  There is one for each channel.  Using these tubes, the amp can not be clipped even when turned all the way up provided you have a standard 2 volt source.  Because of this it responds VERY favorably to a good tube preamp with some gain.  It allows the amp to play louder and increases the dynamics and presence.

Having said all that, we recently discovered an incredible sounding Russian tube called the 6N2P that has over twice the gain of it's brother, the 6N1P.  These tubes are not always noise free, but they sound so good in this amplifier that we are shipping the amps with them.  Using these 6N2P tubes you have accomplished the same thing as adding a good preamp to the SE34I.2 using 6N1P's.   As good as an SE34I.2 sounds with the 6N1P tubes by itself, a good preamp always had a way of taking the amp to a new level.  Using the 6N2P we are getting the same net resulting sound so it's a win win situation.

You should experiment with both types during your trial and use the amp both with and without a preamp.  If you preamp has a lot of gain, you'll want to be sure to use the original 6N1P tubes or equivalents otherwise the amp will sound too hot.

A 24 chip 1543...  that should sound rather damn good with this amp!

-Steve

Peter,

I have a feeling you are going to be VERY HAPPY with this amp.  I have a pair of Steve's E34L Monoblock amps, newly reconfigured by Steve, and love the sound!

Please do write about them Peter!  Keep us posted.  Thanks.

the se34 has landed. hooked it up and it is going. i know it needs to settle in for a while -- how long? can anyone tell me? am trying to follow steve's recommended method -- few hours on, then off and on again.
anyway am going to use the standard complement of tubes for all of this. ruby 5u4g/=c=el34s/6n2ps.  
first impressions: with the tone switch in forward position (not tried flicking it back yet)
great.  very musical. clarity abounds. bass with hdts definitely go deeper than with the se84/csp combo i have been using. perhaps there is more of a match with the dddac 1543 d/a convertor i am using. the family resemblance with the se84 is all there but with a fuller tone.  
another happy decware customer!
i will report in as the amp progresses in its burning in.
on sound, would i choose it over the se84? not too sure yet as my se84 drove different speakers. but the se34 definitely mates better with the hdts!
but for my purposes, since i need more inputs and wanting to simplify things on my audio rack, the se34 is perfect .
thanks steve for another great product! let the music play!
cheers
peter

On and off for 5 or so hours at a time for a few days. Then longer periods of on time if you like but not necessary and not recommended if unattended. Leaving it on all day to play music if your home is good and on weekends too. You'll find that with daily playing it will get super sweet at about 4 to 6 months, but you'll be most of the way through the break in process in a week or two.

Glad to hear things are going well with your new amplifier!  One thing you can do to increase the top end twinkle a bit is to run 6922 or 6DJ8 tubes in the amp.  If you are using the 6N2P tubes shipped with the amp and change to either of the other tubes, you will notice a large reduction in gain.  Where you were at 1/2 volume with the 6N2P, you will be at nearly full volume with a 6922 or 6DJ8.  In this case you may want to try a good preamp with it.  Point being, you can tailor the sound a lot.  During the burn in period the lower gain tubes are generally less aggressive.

Steve


BTW, another thing that you can do to increase the top end a bit is to tilt your HDT back 5 or so degrees with something slid under the front edge of the cabinets.  This often improves several things in fact.

well its about two weeks and the amp has settled down. the scratchy 6n2ps are still a bit irksome but things improved once i put a second set in -- definitely much quieter.
i have seen some 6n2ps on e-bay -- there's one with a different suffix -- 6n2p er and the seller says this is extra durable over the 6n2p evs -- anyone tried the fromer?
okay, follwed steve's advice to tilt the speakers back -- yes that works as he says and improved things from sounstaging and overall balance of the sound -- great tip.
this morning, i decided to put the csp in the chain -- i use a gz30, a 7083 and two 6n1ps. -- compared to the se34 alone -- massive improvement -- sound flowed out of the hdts with an organic liquidity and i could hear a lot more going on. certainly the sound was not aggressive even though the 6n2ps were in the se34. the sound was clear but not harsh to the ears. this is the first time i have heard the hdts singing so well. with my dddac putting out just 1.6v, maybe this was what the se34 needed to bloom. bear in mind that because of where my stereo is, i am not able to move the speakers around for best placement. they are plonked down and sit where they are. perhaps now i will have to fiddle the csp's volume control to find how that best balances with the se34's volume control. at the moment, i find 1 o' clock on the csp volume is about right with the se34's as the master. i am very happy that the sound is so good -- best i have heard in a long, long time. so much so, i am not going to try 6922s or 6n1ps in the se34.
cheers all and thanks steve and decware.

hey lon
you will like the ev version of the 6n2p. the two sets i got from decware when i ordered the se34 were really bad with the intermittent crackling -- even after lengthy use. the hissing and crackling was a turn-off. however, i ordered the 6n2p evs off e-bay and they sound great. no more crackle, hiss or pops.
the se34 is sounding great, my recent acquisition of a CAL delta transport to partner my dddac has been another good step.
i also did get some cryoed mullards for rectifiers and cryoed el 34s but think the difference against stock tubes does not justify the extra cost.
happy listening

Well, have the new tubes in place.

I'm getting a hum through one channel that I did not have before but it's not loud enough to be really bothersome.

They seem to have a mellower sound to them and that's always welcome!