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Whats the difference RH84 or Mullard 3-3?

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M Gregg

M Gregg

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Joined 2010
Thanks for the reply,

I'm hoping someone will give a sort of listening (practical) review. Ie which sounded better to them and why, or someone with experience of RH84.
Has anyone built RH84 with valves like ECL86 ECL82?

I know quite a few people have built these amps.:)

NB please keep it to practical advice, discussion context.
I like this amp because..
Or what would you build and why...:D
not heated debate.<<<:whazzat: Thanks for your help :)

I must admit I signed on today hoping for "This works great or that is not so good". A lass not much to be read.. :D

Regards
M. Gregg
 
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M Gregg

M Gregg

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Joined 2010
DF96 said:
Alas, not many lasses on here, but one of them may have heard these two amps and can comment.
Click to expand...

To be sure,

But they ain't a commenting either..:D

Twas a dark night, and in the distance in a dark cave the sound of sweet music drifted across the misty river.

Oi matey be that a Mullard 3-3 what I hear, Naww tis the Rh84 that was found at the bottom of a salty chest returned from Davey Jones locker.

Aye it has a hiss like the sound of a shell to me ear. :D:confused:

Ahh that would be shot noise from a rusty pistol me thinks..

Regards
M. Gregg
 
P

prelius

Member
Joined 2010
I've built quite a few of RH84 amps over the years. And several Mullard 3-3 amp. Both amps are quite diffrernt in terms of schematics, tubes, and of course, they sound different too.

M3-3 is a classic, tried and true... Some hate tone controls and rip the out, some build the amp as it is. Personally, I think both ways are good, and the decision is ultimately (IMO), depends on the projected use... If used with iPod, I leave the vol and tone controls in, and just add an iPod connector and a charge circuitry... Not having vol and tone controls makes sense if the amp is used as a straight power amp.

RH84 amp uses different tubes and it's topology is different. Two distinct features that set it apart from M3-3 are:Local feedback, ala Schade; unorthodox configuration of the driver tube. The latter one sparked quite a few heated discussions on this forum. If you like pentode sound and careful not to overload the amp with the input signal, RH84 sounds quite good.

I've used ECL82 and ECL86 in RH84, and it sounds great with them, provided the values of the components changed to reflect the differences in tubes. I do not particularly like the amps based on these tubes, because I can't change the driver tube. I prefer RH84 topology, mainly because it is more flexible, and allows for significant tweaking and improvement. There are quite a few mods of RH84 published here and on other forums, which address the issues of the original design, particularly the driver configuration. I built an amp based on RH84 that could use either EL84/6BQ5 or Russian 6P1P tubes (Russian 9-pin equivalents of 6V6) by merely changing the tubes and toggling a switch! Worked very well...

Cheers, Paul
 
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M Gregg

M Gregg

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Joined 2010
prelius said:
I prefer RH84 topology, mainly because it is more flexible, and allows for significant tweaking and improvement.

Cheers, Paul
Click to expand...

Thanks for the information. Can you expand on the sound of these amps.
I know its a bit audiophile, any difference in sound stage (width height), clarity, bass, treble. (Talking 3-3 without tone controls in the comparison).
You prefer the RH84 due to tweaking, is this also a preference in the "Type" of sound?
Do you have a preference on input tube pentode/triode? (from a sound point of view)

Regards
M. Gregg
 
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M Gregg

M Gregg

Disabled Account
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I'm wondering, (I tend to do this a lot:D)

If we are putting EL84 + another tube in the circuit.

What's stopping us fitting ECL?? and only use the pentode section+ another tube like EF86 and have a switch to use the internal triode?:confused:
Two amps for the price of one? same number of bottles.

Regards
M. Gregg
 
Shoog

Shoog

Member
Joined 2002
M Gregg said:
I'm wondering, (I tend to do this a lot:D)

If we are putting EL84 + another tube in the circuit.

What's stopping us fitting ECL?? and only use the pentode section+ another tube like EF86 and have a switch to use the internal triode?:confused:
Two amps for the price of one? same number of bottles.

Regards
M. Gregg
Click to expand...

Using the triode is suboptimal, but we will leave that aside.
the real issue that cannot be overcome with the triodes in ECL types is that they are very low current (1mA generally) which is just not enough to adequately drive the feedback network in a Schade amp, you need to be thinking of at least 5mA in the driver.
Its best to use the ECL's in a different circuit.

Shoog
 
Shoog

Shoog

Member
Joined 2002
M Gregg said:
That makes sense,

OK so the ECL's better in something different.

Ok so do you have any thoughts of the RH84 Vs the mullard 3-3?
I accept the gain is a bit high in the 3-3.

Regards
M. Gregg
Click to expand...

I don't want to relight an old controversy, and I haven't heard a 3-3 so I cannot comment.
However when a schade amp is done properly you can expect very tight bass which I predict will be better than the 3-3. However - I would only consider using a pentode driver and would use the cheap 6AU6.

Shoog
 
M Gregg

M Gregg

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Why only the 6AU6?
Not EF86? or other.
Any thoughts on DC heating?

Do you have a link to schematic?

I'm thinking about making both ie 3-3/rh84 on a couple of identical plates and give them a try. (I can swap them over) same OP tx PSU.
Time permitting..

Regards
M. Gregg
 
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Shoog

Shoog

Member
Joined 2002
M Gregg said:
Why only the 6AU6?
Not EF86? or other.
Any thoughts on DC heating?

Do you have a link to schematic?

Regards
M. Gregg
Click to expand...

The EF86 is likely to be more expensive than the 6AU6.
DC heaters would be a waste.
The Mullard 3-3 is likely to have massively to much gain for modern applications so is unlikely to be a runner without modification.

All my amps for a long time have been PP so i haven't got a schematic.

Shoog
 
P

prelius

Member
Joined 2010
M Gregg said:
Thanks for the information. Can you expand on the sound of these amps.
I know its a bit audiophile, any difference in sound stage (width height), clarity, bass, treble. (Talking 3-3 without tone controls in the comparison).
You prefer the RH84 due to tweaking, is this also a preference in the "Type" of sound?
Do you have a preference on input tube pentode/triode? (from a sound point of view)

Regards
M. Gregg
Click to expand...

I can't answer your question in a meaningful/objective way, as there are so many variables that affect soundstage, clarity, bass, treble etc. The OPTs used, speakers, room dressing, etc will influence all of the above. IMO, both RH84 and M3-3 can sound good, but you need to hear them.

Yes, I prefer RH84 both in terms of flexibility of schematics and actual sound of the amp, (I like "tubey" coloring).

I prefer triode in RH84 as a driver, or a triode-strapped pentode. Currently, my favorite drive tubes for RH84 are: 6N6P, running at 7mA-9mA, or 6J9P, triode strapped, running at 12mA.

Cheers, Paul.
 
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