[SK138]

Earl...that's bad news (for me)!! Now I have to consider purchasing it before the Head-Fi speciall sale is over. May my wife forgive me...but I will beg for mercy AFTER I get it

Quote:

Originally Posted by sacd lover /img/forum/go_quote.gif I spent the last 30 minutes or so listening to modded grado sr-80's using the 5998's plus a tall bottle 7n7. This combo works very well. I swear I even hear some soundstage with the 80's. This amp will undoubtedly drive grados more than fine.

 

[tom hankins]

Earl, have you talked to Mikhail about adding binding posts so this amp can also be used as an integrated amp? This would be killer if it could drive speakers and headphones. I'm thinking balanced for my bedroom system, for use with both speakers and headphones.

 

[sacd lover]

Quote:

Originally Posted by tom hankins /img/forum/go_quote.gif Earl, have you talked to Mikhail about adding binding posts so this amp can also be used as an integrated amp? This would be killer if it could drive speakers and headphones. I'm thinking balanced for my bedroom system, for use with both speakers and headphones.

Actually yes .... but there is a problem. If he optimizes the amp as a 2.5 watt OTL speaker amp the headphone sound quality suffers. If he "detunes" the amp slightly for the best headphone sound quality then the amp wil not work nearly as well for speakers.

A nice push/pull, class A, transformer coupled amp from SP would be a treat too. I wonder if anyone has approached him about doing one of those.

Where is the very evil smiley when you need one?

If you are going balanced .... two 6080's per side would have some definite mojo!

 

[jamato8]

Quote:

Originally Posted by sacd lover /img/forum/go_quote.gif Actually yes .... but there is a problem. If he optimizes the amp as a 2.5 watt OTL speaker amp the headphone sound quality suffers. If he "detunes" the amp slightly for the best headphone sound quality then the amp wil not work nearly as well for speakers. A nice push/pull, class A, transformer coupled amp from SP would be a treat too. I wonder if anyone has approached him about doing one of those. Where is the very evil smiley when you need one? If you are going balanced .... two 6080's per side would have some definite mojo!

I am waiting for you to get some 7242 tubes. Up the heater current a little and off you go. I would say it is a fairly stout tube. 7.5A current draw for the filament and killer plates and rods.

 

[gfgfmoses]

Congrats!!!!

possible to have any idea of the sound for pairing with K1000 and other AKG cans?

enjoy

)

 

[boomana]

Quote:

Originally Posted by gfgfmoses /img/forum/go_quote.gif Congrats!!!! possible to have any idea of the sound for pairing with K1000 and other AKG cans? enjoy )

I heard the Extreme (stock) at the FL meet with the K1000 and a modded Denon 2900. It is the reason I bought this amp immediately. It drives them with a fullness I was not expecting. My other cans: K340 and Senns 650/580 do beautifully as well. Granted, it was meet conditions, but I'm not alone in thinking this. Looks like we're going to have another S. FL meet, maybe on Jan. 6th. I should have had my amp for a least a week by then and others will have a chance to post their impressions as well (don't think there will be any 701s or other AKGs present though).

 

[shigzeo]

damn, that is quite the set of sinful picks. i have the dosh to get one now, but what a waste when im moving and cannot carry something like that in my suitscase nor even stand in my new room... but at 60w per valve, this thing would negate need of furnace. that thing dissapates more heat than my laptop, than my parents computer, tell me what your electricity bill is like and i'll think more on this.

 

[Bob_McBob]

Since when is 60W a lot?

 

[markmaxx]

Quote:

Originally Posted by Rob N /img/forum/go_quote.gif Have you got the 2c51 adaptors yet? I'm interested to hear how the 2c51/5670's sound in any SP amp.

I have had my 2c51 tube in the gain position for 1 hour or so [size=xx-large]Huge[/size]soundstage with the K340 from Headphile. By the way it is a small, very small tube.

 

[909]

Quote:

Originally Posted by SK138 /img/forum/go_quote.gif Earl...that's bad news (for me)!! Now I have to consider purchasing it before the Head-Fi speciall sale is over. May my wife forgive me...but I will beg for mercy AFTER I get it

Tell her it was on sale. She might be more understanding about not missing out on that special price...

 

[gfgfmoses]

Quote:

Originally Posted by boomana /img/forum/go_quote.gif I heard the Extreme (stock) at the FL meet with the K1000 and a modded Denon 2900. It is the reason I bought this amp immediately. It drives them with a fullness I was not expecting. My other cans: K340 and Senns 650/580 do beautifully as well. Granted, it was meet conditions, but I'm not alone in thinking this. Looks like we're going to have another S. FL meet, maybe on Jan. 6th. I should have had my amp for a least a week by then and others will have a chance to post their impressions as well (don't think there will be any 701s or other AKGs present though).

thanks for the info

BTW, would u mind to tell me what tubes combo used then?

 

[adhoc]

I've always wondered - how do you all swap tubes willy nilly without having to modify the amplifier to accommodate the new tube's completely different curves?

It's something that has always confounded me - it's the main reason why I dropped down to 'stock' 6AS7s from 5998/421As in my HD-25. Just because the plugs fit and music comes out doesn't mean that everything is a-OK!

Not trying to troll here, but just expressing something that's been bothering me for some time... YMMV.

 

[PFKMan23]

Quote:

Originally Posted by adhoc /img/forum/go_quote.gif I've always wondered - how do you all swap tubes willy nilly without having to modify the amplifier to accommodate the new tube's completely different curves? It's something that has always confounded me - it's the main reason why I dropped down to 'stock' 6AS7s from 5998/421As in my HD-25. Just because the plugs fit and music comes out doesn't mean that everything is a-OK! Not trying to troll here, but just expressing something that's been bothering me for some time... YMMV.

What do you mean exactly? The pin out is the same and the heater current and voltage are appropriate for the amp. So long as you are keeping the limits of the resitors and trasformer in mind you should be fine. Of course something like a 6528 with the same pin out as the 5998 isn't necessarily ok, because it draws 5 amps of heater current per tube which when totaled would exceed the transformer. As long as you're not taxing the transforemr too hard you should be fine. Although, that being said you need to make sure things work ok in the long run or are practical as an amp optimized for something like a 12au7 won't necessarily be ok with the 12ax7 given the difference in gain. That's especially something you need to keep in mind with tubes that draw more heater current than the stock tube types. Of course you need to research the tubes first...

That being said in some cases some modifications (like upping the voltage and bias is necessary or advisable because it makes the tube more linear or simply because it sounds better. Of course in other cases making different circuits also comes into play.

 

[jamato8]

Some tubes tolerate this well and some are just plain wrong. I agree with you, on many tubes I have never figured this out since I take measurement and make sure the tube is within operating points. A 12AU7 swaps for a 12AX7, right? :^)

 

[sacd lover]

Quote:

Originally Posted by adhoc /img/forum/go_quote.gif I've always wondered - how do you all swap tubes willy nilly without having to modify the amplifier to accommodate the new tube's completely different curves? It's something that has always confounded me - it's the main reason why I dropped down to 'stock' 6AS7s from 5998/421As in my HD-25. Just because the plugs fit and music comes out doesn't mean that everything is a-OK! Not trying to troll here, but just expressing something that's been bothering me for some time... YMMV.

Most of the "new tubes" used in the amps require an adapter. Most of the adapters have compensation networks included to change specific parameters of the tubes opertaion .... so the tube operates as required in the circuit. The 5687 adapter, for instance, has a network that prevents oscillation as well as providing circuit compensation. As you know, some tubes are electrically identical and only need the adapter to provide the correct base and pin out; example 6sn7> 7n7. But understand, many tubes will not work at all or some will only work in certain amps under certain conditions; examples provided below.

Singlepower also recommends you dont try to use a SP adapter in another manufacturer's amp without consulting BOTH the said manufacturer and SP to determine compatability.

Now .... some tubes just wont work period because they have to much gain and / or to little current drive; example 12ax7.

Some tubes wont work because they draw to much current and will fry the amps resistors even though the amps tube sockets have the correct pin out and the amps transformer can handle the heater current draw; example 6as7 output tubes in the Supra's.

Some tubes work only in combination with certain other tubes; example the 6su7gty/ 6080 in the Extreme.

Now lets be more specific with some examples. Lets look at the 6414>6bl7gta combo @ 300 volts in the first new chassis MPX3's. This combination works very well in this amp. The 6bl7gta tube, however, sounds awful using the typical lower gain 6sn7gt running at the same 300 volts in this vintage MPX3; because the tube is underdriven. This 6414>6bl7gta combo works extremely well in the SLAM SE @ 300 volts and even better at 375+ volts .... with the standard SE bias. Up the bias on a SLAM SE like mine that has a manual bias control using this 6414>6bl7gta combo @ 375 volts .... and you will overdrive the output tubes.

Therefore and understandably, if you arent following the tube substitution threads closely and receiving information regarding tube compatibility from the manufacturer .... about your specfic and often custom amp .... these tube subs may appear "willy nilly" .... but they are not.