[Fitz]

Quote:

Originally Posted by Bosk So you haven't noticed too much difference when rolling the back tube Fitz? 6080's/6AS7's are a heck of a lot cheaper than 6SN7's that's for sure. I see no reason not to go ahead and buy some of the better NOS variants out there, but if they won't make much difference maybe I should just buy some cheapie used vintage 6080's instead?

I'd bought 3 different 6AS7s, but never really noticed any major differences between them.

 

[Fitz]

I forgot to mention: I've also gone and replaced the heater wires with some 16 gauge stranded copper I had laying around, with the two wires twisted tightly together. The Tung-Sol is dead silent now. I also dont hear much difference anymore for my original mod, besides the increase in gain when it's on. I need to go back and hot-glue some of the things that have been knocked loose during all the times I've gone poking around, but it looks like I have the amp nice and happy now.

Additional modding is now a low priority.

 

[swt61]

Quote:

Originally Posted by Fitz I forgot to mention: I've also gone and replaced the heater wires with some 16 gauge stranded copper I had laying around, with the two wires twisted tightly together. The Tung-Sol is dead silent now. I also dont hear much difference anymore for my original mod, besides the increase in gain when it's on. I need to go back and hot-glue some of the things that have been knocked loose during all the times I've gone poking around, but it looks like I have the amp nice and happy now. Additional modding is now a low priority.

Now if I could only talk you into going to the Dallas meet next Saturday! With soldering iron in hand!

Quote:

Originally Posted by Bosk So you haven't noticed too much difference when rolling the back tube Fitz? 6080's/6AS7's are a heck of a lot cheaper than 6SN7's that's for sure. I see no reason not to go ahead and buy some of the better NOS variants out there, but if they won't make much difference maybe I should just buy some cheapie used vintage 6080's instead?

I bought a new Sovtek 6AS7G to check this theory out. It looks pretty, but I don't believe it's very highly regarded.

 

[swt61]

I've been burning the Darkvoice and new tubes in. Just got home after spending the day out. Put on my headphones and no humm. The low level humm that the Kenrad black glass 6SN7gt/vt231 was exhibiting is completely gone. It was a NOS tube, is this normal for a tube to burn in and stop humming? It wasn't very bothersome anyway, but I could hear it between tracks and in very low level passages. I definately notice a smoother more dynamic sound overall from yesterday when I plugged in the new tubes. In the 10 months or so since I found Head-Fi, this is the fourth amp that I've bought to pair with my K340's. I tried a Rega Ear first, then a Dynalo, onto a PPA and now the Darkvoice. They all had qualities that I liked, but ultimately were not quite the right match for my babies. I now feel that the amp search is over. I know that's a strong statement on this forum, but I really think I've found the right mate for the 340's. Now I can concentrate on other additions to my collection. I'm indebted to all the Darkvoice owners for their help and impressions that led me to this great amp. And a big shout out to echo1 for all of his legwork in finding a supplier!

 

[echo1]

Sorry about the schematic everyone. Its what I recieved from the dealer. Thanks Fritz as I will call the repairman on wed. 5th and let him know the schematic isnt right on.
I took my Darkvoice into a repaireman that is in Chico, Calif. and he advertises that he is a vintage tube amp specialist. I took in 4 tubes that do not hum and 4 that do.He says he will let me know after the fourth and only charges a 20 dollar diagnosis fee. I am going to try to get him to sketch out what he does and if i can I will post it.

Well I have about 6 tubes that dont hum but now have about 8 that do. So I am really hoping he does it.

One thing I notice is that if the tube hums, and I shut the amp off, It keeps playing the music for about 10 sec. and the hum goes away and sounds great before fading away.This behaviour is in all my tubes that exhibit hum.
Well I will post anything new that I find out. Echo1

 

[Azure]

Anymore high quality pictures of the amp in the dark?

I'm still not sure if I should bother with saving up for the Darkvoice though, especially since I already have quite a warm amp (M3) already coming. Sure, people say no solid state can come close to the sound of tubes, but I remember reading a post about how a user was surprised at the sound of tubes because of how small the difference in SQ was compared to SS. I don't think that was with a particularly warm SS either, so the difference would be even smaller for me.

 

[echo1]

YES I have some tubes that the hum goes away after listening to them.
I notice if the tube hum is low the hum usually goes away after listening to them awhile. My ken-rad v-231,sylvania 6sn7gt,cbs/jan 5692,all used ,had a small amount of hum that disapeared after a few hours.
Now I dont get worried if the hum is low level and put them on half volume for awhile and it seems to do the trick.
But what I do notice is that if the hum is loud it will not go away. Those are the tubes that I took in to the repairman today. They are 2 national union, 1 grey glass and 1 black glass, A RCA 6sn7gtb, and a hytron 6sn7gt with a military Jan disignation on it.
I wish I had a Fritz for a neighbor. My neighbors could tell you how to take apart a international harvester, but that wont help me here. Bye all

 

[echo1]

Oh,no the dreaded double post.

 

[swt61]

Thanks echo1. I wasn't sure if it was a normal thing or not. I figured it probably was though. I did order a GE 6SN7GTA to try out, but as this amp is primarily for my K340's I think the Kenrad will be my main tube.

 

[Teerawit]

Quote:

Originally Posted by Azure I'm still not sure if I should bother with saving up for the Darkvoice though, especially since I already have quite a warm amp (M3) already coming.

Why don't you ask Fitz. He has both the M3 and the Darkvoice.

 

[swt61]

Quote:

Originally Posted by Azure Anymore high quality pictures of the amp in the dark? I'm still not sure if I should bother with saving up for the Darkvoice though, especially since I already have quite a warm amp (M3) already coming. Sure, people say no solid state can come close to the sound of tubes, but I remember reading a post about how a user was surprised at the sound of tubes because of how small the difference in SQ was compared to SS. I don't think that was with a particularly warm SS either, so the difference would be even smaller for me.

Azure you're 17, you're supposed to want everything.

 

[echo1]

I miss my amp like real bad. I am withdrawing. Echo1

 

[echo1]

Day 1:
anxiety
figity
Tried to substitute the movie "The hill has eyes"
Now I fill creepy and figity.
Want my amp of choice.
Echo1

 

[Fitz]

Gyahh.. I just had to be watching an awful movie instead of keeping up on this thread.

About noisy tubes playing cleanly for a few seconds after power off. This is because once you've flipped the switch, you disconnect the transformer and completely eliminate the 60Hz hum from the entire circuit, but the power supply capacitors still have more than enough power stored to keep the sound going until the tubes cool off. The heaters are powered directly off the transformer, so once the power is off they immediately begin to cool off.

Like echo1, I've also noticed that NOS tubes or ones that have been sitting for a long time will often have a small amount of hum until they've been burned in a couple hours. Even the stock tubes did the same thing when I first got mine. Loud humming is the result of a bad tube, or just a tube that doesn't play nice with the circuit. The Electro-Harmonix 6SN7 is a good example of this; I've tried two different ones and let both burn in a few dozen hours with no reduction in hum at all. The Tung-Sol RP I'm using now originally had a moderate amount of hum that only went down a small amount after some burn-in, but has disappeared completely now after all the mods. I wish I still had one of the EH tubes in my possession to see if any of these mods would have an effect on it as well.

I already have a schematic sketched out on paper with all the component values (except for the pre-out caps on the newer Darkvoices), I just need to draw it up on the computer. I think the other schematic is another amp the Darkvoice is originally based on, since the general topology is mostly the same, and the differences lie mainly in the component values.

I'm starting to think I may have to make a parts order sometime just to continue playing around with changes to the Darkvoice, even though I've got mine working just fine. I've got a few ideas kicking around for whenever I want to play with the insides of mine... Add preamp outputs like on the newer Darkvoices, change/upgrade the various components (volume control, output caps, etc), replace some wiring with stranded wire so it can be moved around more easily for modding, add additional tone controls besides my first mod, and probably a lot more ideas as I keep looking at the internals. I think in only a matter of weeks there will be more replacement parts than original parts.

Unlike some source/amp mods, this is more out of sheer fun and curiosity than seeking SQ improvements.

 

[DennyL]

I am in the UK and I have just received my DarkVoice 336. I ordered it on 5th June, I was emailed on 23rd telling me it had been shipped (no tracking number) and to expect it in 3 - 4 days, and it was delivered in London on 28th. The shipper was 'Sinotrans Express'. It was marked as 'Sample of Amplifier' of value USD300, marked as 'No Commercial Value'. What all this amounts to I don't know. I have not as yet paid any VAT or any other charges other than the USD280 that I initially sent by Western Union. I have heard that some courriers don't ask for VAT on the doorstep, but subsequently send an invoice, so I shall see.

It arrived in a nailed-up wooden crate, and it took me a good half-hour to open it carefully. I'm pleased I had a stout screwdriver to prize gaps open and some pincers, as there are a lot on nails!

The crate contains 1) the DarkVoice, 2) the two valves (tubes), 3) the instructions in Chinese, 4) the power connector with a plug not usable in the UK, but I have plenty of suitable mains leads that fit the IEC socket on the back of the DarkVoice.

When I ordered the DarkVoice I specified that it be suitable for UK mains voltage of 240V. but it is marked as 220V. There are debates in other hi-fi forums about the wisdom of using Chinese 220v equipment on 240v UK mains power, as the components could be over-run by the higher voltage, shortening their lives. I am aware that generally power, and maybe ageing rate, is proportional to the square of the voltage. I have an un-calibrated voltage meter connected to my mains at the moment and it is displaying 234v.

I'm new to headphone listening, but not to high-quality sound reproduction, I have AKG K501s and several other cheaper Sennheisers (PX100 and CX300), and I got a Rockhopper Pimeta about two months ago, which I think is quite good driving the 501s. So as you see this site is beginning to drain my wallet. There are no problems with the DarkVoice as it seems to work fine, but obviously it much too soon for me to comment on its sound quality, which seems very good so far. I can hear no hum or noise with the 501s.