Banned
Joined 2002
Banned
Joined 2002
RH34 schematic
Due to "popular demand" -- Yugo... I am posting a print-screen of the schematic and most important simulation results for the RH34 amp -- the RH amp for EL34/6CA7.
The schamatics posted is for "high power" purposes and to my opinion it represents the "last careful" step i attaining high power with this design. Actually, by lowering the B+ (the only mod. needed) you will loose some power, but gain reliability
I suppose some 400V B+ is OK.
The RH34 which is in regular use was built for a B+ of approx. 350V and leaves nothing to regret on 86dB/W/m speakers... I suppose it would do great on higher efficiency speakers!
Regards,
Aleksandar
Due to "popular demand" -- Yugo... I am posting a print-screen of the schematic and most important simulation results for the RH34 amp -- the RH amp for EL34/6CA7.
The schamatics posted is for "high power" purposes and to my opinion it represents the "last careful" step i attaining high power with this design. Actually, by lowering the B+ (the only mod. needed) you will loose some power, but gain reliability
I suppose some 400V B+ is OK.The RH34 which is in regular use was built for a B+ of approx. 350V and leaves nothing to regret on 86dB/W/m speakers... I suppose it would do great on higher efficiency speakers!
Regards,
Aleksandar
Attachments
RH84 in development
Andrewbee,
Generally speaking, I think that the PS as appears on my web site is the lowest version in terms of uF -- your PS will give more ripple and has less Joules in reserve... but for a first approach, I think that it will do.
Problems with one channel? Either you have miswired one output transformer, or you are experiencing some problem in the input connection... miswiring one output channel can cause that problem: try what happens when you disconnect the input cinch of the channel that works -- if by turning up the volume you can hear some sound on the not-working channel, and even something on the normally-working channel, than rewire the primary of the faulty channel... Maybe. You'll correct that by yourself, I'm sure.
The sound? Well, at least some "frist impressions". Yes, it is going to be similar to that every time (except for the faulty channel). The amp is "bassy" in a positive way, as it performs much better in the bass department as compared to "usual" SE amps, especially those built around the same output tube: the bass is good indeed, deep and with good control (for the power). When the amp starts working as it should (if it is about a miswired OT, than it means that neither channel is working correctly right now), you will get some reward from it!
Planet10 -- is it so difficult for your friend to replace a couple of resisotrs and a tube... and get it going in RH mode? Is it possible that people are eager to do endless variations on the same theme, without trying anything different?!
Regards to all,
Aleksandar
Andrewbee,
Generally speaking, I think that the PS as appears on my web site is the lowest version in terms of uF -- your PS will give more ripple and has less Joules in reserve... but for a first approach, I think that it will do.
Problems with one channel? Either you have miswired one output transformer, or you are experiencing some problem in the input connection... miswiring one output channel can cause that problem: try what happens when you disconnect the input cinch of the channel that works -- if by turning up the volume you can hear some sound on the not-working channel, and even something on the normally-working channel, than rewire the primary of the faulty channel... Maybe. You'll correct that by yourself, I'm sure.
The sound? Well, at least some "frist impressions". Yes, it is going to be similar to that every time (except for the faulty channel). The amp is "bassy" in a positive way, as it performs much better in the bass department as compared to "usual" SE amps, especially those built around the same output tube: the bass is good indeed, deep and with good control (for the power). When the amp starts working as it should (if it is about a miswired OT, than it means that neither channel is working correctly right now), you will get some reward from it!
Planet10 -- is it so difficult for your friend to replace a couple of resisotrs and a tube... and get it going in RH mode? Is it possible that people are eager to do endless variations on the same theme, without trying anything different?!
Regards to all,
Aleksandar
RH6550
Allow me just one more digression... I've been busy the last couple of days building the RH6550.
The amp is in a "10W class" and the schematic is of a slightly different kind as compared to the RH amps. I call it RH2G - second generation. Of course, it is under development, but a breadboard is already making itself heard, and how strongly!
For those who asked, although I think it is explained in the only text on my site... RH stands for "racing horse". For those who speak Serbian (and Croatian) "I mi konja za trku imamo". I think it is actually non-translatable.
Allow me just one more digression... I've been busy the last couple of days building the RH6550.
The amp is in a "10W class" and the schematic is of a slightly different kind as compared to the RH amps. I call it RH2G - second generation. Of course, it is under development, but a breadboard is already making itself heard, and how strongly!
For those who asked, although I think it is explained in the only text on my site... RH stands for "racing horse". For those who speak Serbian (and Croatian) "I mi konja za trku imamo". I think it is actually non-translatable.
Attachments
Re: RH84 in development
He has his own agenda... i'm getting one of the working mules from this project so i'll get a chance to try out the RH.
dave
Alex Kitic said:Planet10 -- is it so difficult for your friend to replace a couple of resisotrs and a tube... and get it going in RH mode? Is it possible that people are eager to do endless variations on the same theme, without trying anything different?!
He has his own agenda... i'm getting one of the working mules from this project so i'll get a chance to try out the RH.
dave
planet10 said:
It just happened one day --> Zen Clone > Bogus Zen > Bogie > Mulligan ....
Because they are clones they often get souped up pretty quick. My buddies has gone from as close as he could get to the schematic(except for a hybrid bridge)... then PS improvements (including choke), most recently, splitting the EL84s Rk and upping of the driver tube bias (both of which he reports made big improvements)... now on his bench is a pair of parafeed monoblocks (with 5 pieces of iron each)
dave
IIRC Dave, the inspiration for "Mulligan" came from the days when my son* was golfing a lot,; in that world the term means (loosely translated from the profane) "I think I'd like to try that one over again"
*amazing how I can start to credit him for some perspectives.
As to the ongoing revisions to the mono-blocks: once I get my hands on a pair of EF86 to try (NOT a direct swap out!) they just might remain that way for a few days. Of course if I ever tear them down for painting, all bets are off.
The schematic I sent you last night was rather hastily sketched out from memory - I'll probably revise it tonight. The only uncertain value is the inductance of the OPT/parallel feed choke.
As for the Decware Zen amp(s) - there are several minor variations on the basic circuitry, all of which are close to as "simple as possible" that rolling of any of the tubes makes a huge difference.
I've yet to hear an example that wasn't emotionally involving in a way that my Jolida PP EL34 or previous Linn integrated couldn't approach. Notwithstanding the "polite discussion" regarding the merits of ANY specific design, isn't that what it's all about?
Even though I'd already seen the light of "the thermionic truth", it was primarily the sound of this amp that got me really juiced about DIY electronics. For that I will forever be thanking Mr Deckert.
The first love...
NO PUN INTENDED...
"Polite discussion" notwithstanding... and no pun intended...
Do you know the simple general truth about never forgetting your first love? They say it is particularly true of girls and the first boy they... er... sleep with.
Is this the case? The Zen was there first?
Happy New Year to everyone, in advance... in case I do not post tomorrow!
Aleksandar
NO PUN INTENDED...
"Polite discussion" notwithstanding... and no pun intended...
Do you know the simple general truth about never forgetting your first love? They say it is particularly true of girls and the first boy they... er... sleep with.
Is this the case? The Zen was there first?
Happy New Year to everyone, in advance... in case I do not post tomorrow!
Aleksandar
RH84 (well kind of mostly) lives !
Well folks,
both channels now work, I forgot to wire the Left input socket to the 12ax7 grid
which helps when you want to get a signal through the amp
I also added a 330Uf to the final cap since Aleksander felt the ripple would be high as is.
Anyway it is playing and even at this very early stage I think it sounds quite nice.
I have a low voltage SE EL34 UL amp that I built many months ago that I was underwhelmed with and am now going to change it over to RH mode but am waiting to see the second generation version with the 6550 as I have KT88's to put in and a few extra watts may help with these Swans, otherwise it will be the RH807 but with higher power and using 6l6GC's or KT66's,
In the mean time I think I will connect my Jeriko horns up with this amp and listen, I just need to get them out of storage (they are buried in my "office" at home as I was planning to keep the Swans in position for a while).
I was trying to get some 6094's about two months ago to do a SE amp but it did not work out so maybe I will try some 6AQ5's and also the 5V6 with this one, very punchy amp ! This may end up in my office at work.
Thanks Aleksander.
Andrew
Well folks,
both channels now work, I forgot to wire the Left input socket to the 12ax7 grid
which helps when you want to get a signal through the amp
I also added a 330Uf to the final cap since Aleksander felt the ripple would be high as is.
Anyway it is playing and even at this very early stage I think it sounds quite nice.
I have a low voltage SE EL34 UL amp that I built many months ago that I was underwhelmed with and am now going to change it over to RH mode but am waiting to see the second generation version with the 6550 as I have KT88's to put in and a few extra watts may help with these Swans, otherwise it will be the RH807 but with higher power and using 6l6GC's or KT66's,
In the mean time I think I will connect my Jeriko horns up with this amp and listen, I just need to get them out of storage (they are buried in my "office" at home as I was planning to keep the Swans in position for a while).
I was trying to get some 6094's about two months ago to do a SE amp but it did not work out so maybe I will try some 6AQ5's and also the 5V6 with this one, very punchy amp ! This may end up in my office at work.
Thanks Aleksander.
Andrew
Re: RH6550
Interesting. What kind of modifications have you made?
Hmm... this plate to grid type feedback topology is interesting. We'll probably have to start a new thread soon with more variations on the theme (I have a few ideas myself which I'm going to try...)
Happy New Year to all! (Only 8.5 hours of 2004 left for me)
Alex Kitic said:
Interesting.
What kind of modifications have you made?Hmm... this plate to grid type feedback topology is interesting. We'll probably have to start a new thread soon with more variations on the theme (I have a few ideas myself which I'm going to try...)
Happy New Year to all! (Only 8.5 hours of 2004 left for me)
First Love?
Well actually Alex, the design in question was not the first tube amp I've heard, nor did it awaken me from over ten years of deep sleep. (Linn Intek integrated amp to be precise)
The "first" was actually an AudioNote P1SE loaned for a quick audition by a very accomodating local dealer. Since my budget (or should I say ego) didn't allow me to spend that kind of money on those few a number of watts, I ended up with a Jolida 302 (EL34PP /approx 35wpc?)
In the past 3 years or so since then, I've had opportunity to attend a couple of "tube geekfest" audio shows, as well as listen to a fair number of both commercial and DIY/ kit tube amps. Among them the Zen Select and Bottlehead Paramour (2A3 parafeed) stood out as representing both very emotionally satisifying performance, and considering that the designers (Steve Deckert and the Bottlehead team) need to make some sort of living through their enterprise, excellent value for the money.
I have no particular axe to grind, nor the technical expertise or experience to criticise any designs finding their way into the public parlance. I chose the Zen design as a starting point for numerous reasons, not the least of which is that a buddy of mine is in a position to provide most of the required parts for very reasonable considerations, and as it turns out EL84 based single-ended chassis happened to be quite common in his collection.
Secondly, it's a very simple circuit, and success with the initial build and subsequent modifications has given the confidence to tackle more advanced projects.
I may have just as easily found your design first, and may probably build it as well, afterall a guy needs a hobby ( I don't fish or do the macho outdoor thing ) , and can never have too many amps.
Well actually Alex, the design in question was not the first tube amp I've heard, nor did it awaken me from over ten years of deep sleep. (Linn Intek integrated amp to be precise)
The "first" was actually an AudioNote P1SE loaned for a quick audition by a very accomodating local dealer. Since my budget (or should I say ego) didn't allow me to spend that kind of money on those few a number of watts, I ended up with a Jolida 302 (EL34PP /approx 35wpc?)
In the past 3 years or so since then, I've had opportunity to attend a couple of "tube geekfest" audio shows, as well as listen to a fair number of both commercial and DIY/ kit tube amps. Among them the Zen Select and Bottlehead Paramour (2A3 parafeed) stood out as representing both very emotionally satisifying performance, and considering that the designers (Steve Deckert and the Bottlehead team) need to make some sort of living through their enterprise, excellent value for the money.
I have no particular axe to grind, nor the technical expertise or experience to criticise any designs finding their way into the public parlance. I chose the Zen design as a starting point for numerous reasons, not the least of which is that a buddy of mine is in a position to provide most of the required parts for very reasonable considerations, and as it turns out EL84 based single-ended chassis happened to be quite common in his collection.
Secondly, it's a very simple circuit, and success with the initial build and subsequent modifications has given the confidence to tackle more advanced projects.
I may have just as easily found your design first, and may probably build it as well, afterall a guy needs a hobby ( I don't fish or do the macho outdoor thing ) , and can never have too many amps.
change a few resistors?
Alex, I hope my last post didn't sound petulant - that was not my intention.
I missed your post number 87 - by now I gather you've seen Planet 10's post of the current schematic. I'd have 2 concerns over trying your circuit configuration;
1) due to the restrictions of the power transformer, I've got only 286V B+ after the filter chokes and caps in the power supply - would that be close enough for your design?
2) I've implemented a parallel feed configuration on the output tube, would that be a problem?
While I'm at it, I should mention that the next scheduled revision is to change the input tube to an EF86 (once again courtesy of my "mystery" benefactor) Since I've got another 3 day weekend, I'll probably implement that before your reply.
cheers y'all
Alex, I hope my last post didn't sound petulant - that was not my intention.
I missed your post number 87 - by now I gather you've seen Planet 10's post of the current schematic. I'd have 2 concerns over trying your circuit configuration;
1) due to the restrictions of the power transformer, I've got only 286V B+ after the filter chokes and caps in the power supply - would that be close enough for your design?
2) I've implemented a parallel feed configuration on the output tube, would that be a problem?
While I'm at it, I should mention that the next scheduled revision is to change the input tube to an EF86 (once again courtesy of my "mystery" benefactor) Since I've got another 3 day weekend, I'll probably implement that before your reply.
cheers y'all
Re: Re: Re: RH6550
Yep, I know it has. I placed a link somewhere in the thread.
Page 332 of RDH4 (Radiotron Designer's Handbook 4th Edition, Fritz Langford-Smith) has a bit on this type of topology as well. As an aside, copyright has passed on RDH4 and it is now available online!
I've attached one of the diagrams from that chapter. A few minor differences and we'll end up with the RH series of amps.
Brett said:
Yep, I know it has. I placed a link somewhere in the thread.
Page 332 of RDH4 (Radiotron Designer's Handbook 4th Edition, Fritz Langford-Smith) has a bit on this type of topology as well. As an aside, copyright has passed on RDH4 and it is now available online!
I've attached one of the diagrams from that chapter. A few minor differences and we'll end up with the RH series of amps.
Attachments
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