Need opinions

[daz]

I have to builds right now. One is a el34x2 with marshall stype trannys and the other a 18 watt with heyboers converted to 6V6. Both have identical high gain preamps and both are cathode biased with switchable NFB.

the main difference between them besides the output tubes, trannys and different PI values is the EL34 amp has a 20H choke hooked up as in a marshall 50 while the 6V6 has a resistor. The EL34 amp sounds better in several ways and i think this is due to the choke because if i replace the choke with a resistor the amp sounds and feels a lot more like the 6V6 amp.

So logic tells me that putting a choke in the 6V6 amp will make it much closer to sounding like the big amp. But before i go spending money on the choke, can anyone tell me why it won't make the amp sound much more like my big amp? remember....the big amp sounds close to the small one when i put a R in place of the choke. So it seems that doing the reverse should result in the small one sounding more like the big amp. What doth thou think?

[tubeswell]

Originally Posted by daz

... So logic tells me that putting a choke in the 6V6 amp will make it much closer to sounding like the big amp... What doth thou think?

Sort of all other things being equal, the choke will provide better filtering and will allow higher screen and pre-amp plate voltages throughout, giving you a higher B+ (which translates to a 'higher' load-line) for each stage, giving you more scope for a slightly cleaner, more-defined sound at a wider range of frequencies methinks.

I should also add that when you raise the screen voltage, you will be able to get more output out of the output stage.

[txstrat]

Would it be a problem for you to put the choke in the small amp?
I mean you've tried it the other way round and if you go and try you would exactly know what the small amp will sound like with a choke.

Just a thought

[daz]

Well, no. It wouldn't be a problem if i had one. But the purpose of the thread was to get opinions as to whether it would likely make the smaller amp sound like the larger one. I suppose i could clip the one amp's choke into the other, but they are at two separate locations. It's just easier to ask.

[Steve Conner]

Originally Posted by daz

suppose i could clip the one amp's choke into the other, but they are at two separate locations. It's just easier to ask.

No it's not. It's like asking us to eat two different pizza toppings for you and tell you which you'll prefer.

I personally like the CLC filter and use it wherever possible. But that's just because I think it's more elegant. It gets rid of hum better, and wastes less power, than a CRC.

[daz]

i wasn't asking which i would like better, i was asking whether with all the similarities between the two whether you think the tone difference was likely due to the choke vs a resistor, since that is the main difference between the 2 amps aside from the output tubes. Like i said, the el34 amp sounds a lot more like the 6v6 amp when i put a R in place of the choke. so i wanted opinions as to whether the opposite would likely happen, IE: the 6v6 amp would sound a lot more like the el 34 amp with a choke in place of the R. The preamps are the same too as i said. anyways, i was able to get my hands on a fender twin choke and i tried that but heard and felt no discernible difference. Yet with the el34 amp i hear, and even moreso FEEL a huge difference between choke adn a R. But then the fender choke i used was likely only a few henries while the huge choke in my el34 amp is a 20H. so i'm still unsure. But it may well be the big difference i hear between a choke and a R in my el34 amp is because the choke is so huge. In fact i'd wager. I guess i'm going to have to try the 20H in the small amp if i'm ever going to be sure. But at this point i'm beginning to thing it's the large size of the choke thats causing the better tone in that amp. With a resistor it's really obvious that it doesn't sound/feel as good.

[Bruce / Mission Amps]

EL34s draw WAY WAY more screen current the a little 6V6s so the variation in voltage drops across a 90 ohm choke and a power resistor should be measurable if their DC resistances are wide.
With respect to a choke vs resistor, I wouldn't be surprised to hear a difference in the two setups, especially with the EL34s... but not quite as much with the 6V6s using the resistor vs the choke since the variable current through the choke and resistor wouldn't be as extreme in that amp.
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added
Also, the EL34s are true pentode tubes and the 6V6s are beam forming tubes so they sound and react differently with respect to screen current, drive levels, load lines, ... etc.
I think EL34s amps ALL sound better with a healthy choke vs a resistor.
6L6 amps sound better to me with a choke too... 6V6s amps seem to be a little more forgiving with respect to a choke node or resistor node... but a choke is superior in most all applications.

[daz]

I think EL34s amps ALL sound better with a healthy choke vs a resistor.

I think EL34s amps ALL sound better with a healthy choke vs a resistor.

You're dead on on both counts. I tried it today and while the choke vs resistor in the el34 amp is quite huge, in the 6v6 amp i heard nothing. At least i couldn't tell, so if there was it was subtle.

[daz]

One of those quotes was supposed to say...

6V6s amps seem to be a little more forgiving with respect to a choke node or resistor node

But apparently you cannot edit your post after a certain amount of time of i'd have done that.