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Whats the difference RH84 or Mullard 3-3?

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prelius

Member
Joined 2010
TheGimp said:
What transformers did you use?
Click to expand...

For RH84, I've used relatively inexpensive OPTs:

Edcor GXSE10-5K-8 and GXSE15-5K-8. The latter sounds better on LF end, as it is a tad bigger...

James JS 6113HS: It sounded different from Edcor; in the end I decided to use James in the amp for my office. Still out on the fence if it was worth the price difference (~$100US). But this amp is the one that has HP output and can work with 6P1P tubes, so in this particular case, I guess, James OPTs came out on top.

Cheers, Paul.
 
rdf

rdf

Member
Joined 2004
Sorry M. Gregg, I must have notification off and didn't see your questions in my old Mullard thread. This post covers what I ultimately didn't like about it. The design trades low numerical distortion for a really nasty harmonic distribution. That measurement is at 1 watt. My recollection is of a 'relentless' sonic character at odds with traditionally expected tube sound. Some might call it life but for me an MC240 is much warmer.
 
A

Andrewbee

Member
Joined 2002
Never tried the 3-3 but if memory serves that is the Mullard, EL84 with a voltage starved EF86 as driver ?

The RH84 I have built I think 3 iterations. The last using Lundahl 1663 (I think it was) 4800 Ohm primary with a single 5 or six Ohm secondary and I think 35H of inductance. I thought it good enough to purchase the Lundahls.

The EL84 is a favorite of mine, having used it PP, series SE and Shunt Feed SE (about 4 different Shunt feed variations). Of course these have all been different amps and I can without hesitation say the RH84 was my favorite going from memory. Also did a RH6L6 /807.

Am trying soon (famous last words) his RH300B. I have never heard a 300B I liked so ....

On paper and in reality perhaps a pentode driver is the way to go with the Schade feedback scheme, never tried it. Persons here have been less than flattering about the RH84 design but have not stated whether or not they have actually heard it. We all have our likes / dislikes / prejudices, thats what makes the world the interesting place it is.

I just wish we could agree to disagree and leave it there.

I would not bother with a 3-3 and have not heard it, my prejudice.

Build them both and try, both are simple and cheap.

If you want a Pentode only Schade type Alex is thinking of you.

Standby, from his description I call it Beauty and the Beast (somewhat tongue in cheek);).

I got off track and and long winded but I hope something here helps.

Andrew
 
M Gregg

M Gregg

Disabled Account
Joined 2010
Andrewbee said:
I thought I should indicate where the new RH84 version can be found. Here it is
RH Amplifiers: RH84 PPE – "Parallel Pentode Edition"

It is now using a Pentode driver with a parallel output stage. 6AU6 driver or EF86. Maybe sub an EL84 for the EF86 with the necessary socket changes for an all EL84 amp?
Andrew
Click to expand...

Well,

I am collecting parts to try the EF86 driver RH84 with a single EL84.
I don't know if I will use the 7805 (yet to be decided)<<SS:confused:
Just want to hear it.

Regards
M. Gregg
 
T

tnvijay

Member
Joined 2015
prelius said:
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
Click to expand...

Can you please give component values for ecl 82 and ecl 86 for RH84 topology? I am new to tube technology. I wish to hear a RH84, but these are the only tubes that I have
 
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