I am trying to figure out a good physical layout of a PP amp (it is the Ralph Powers´design but with ECC99 at the input like Stigla did some time ago).
Ever since trying to make a valve preamp work (and failing miserably concerning hum + noise levels) I have been feeling very humble about the actual building part of the DIY valve amp game. Or perhaps "nervous and disillusioned" covers my feelings better
However, I recently bought Morgan Jones new title "Building valve amps" and that made a lot of things clear and also brought my courage up a bit. It can´t be impossible, can it? Anyway, to cut the crap, I have two suggestions here for physical layout of those big things (transformers, valves and stabilizers) and would very much appreciate comments on these alternatives.
Alternative 1 is "everything on one chassis". Alternative 2 is separate chassis for signal and power supply. Both are for one channel only but I am open to suggestions for stereo layouts too.
Did I get the orientation of the transformers right? Or should I rotate some of them? (arrow is the axis of the core, thus windings are at right angles to the arrows)
The placement of the parts, are those OK or have I got things wrong? I am a bit worried about the power supply choke inducing hum in sensitive parts. And the OC3/VR105:s, if they belong on the power supply chassis/half or as I have put them, near the IT transformer?
Many questions, I know. The circuit I am going to try to build is this one. Any good hands-on or knowledgeable or encouraging tips are welcome!
/Mats
Ever since trying to make a valve preamp work (and failing miserably concerning hum + noise levels) I have been feeling very humble about the actual building part of the DIY valve amp game. Or perhaps "nervous and disillusioned" covers my feelings better
However, I recently bought Morgan Jones new title "Building valve amps" and that made a lot of things clear and also brought my courage up a bit. It can´t be impossible, can it? Anyway, to cut the crap, I have two suggestions here for physical layout of those big things (transformers, valves and stabilizers) and would very much appreciate comments on these alternatives.
Alternative 1 is "everything on one chassis". Alternative 2 is separate chassis for signal and power supply. Both are for one channel only but I am open to suggestions for stereo layouts too.
Did I get the orientation of the transformers right? Or should I rotate some of them? (arrow is the axis of the core, thus windings are at right angles to the arrows)
The placement of the parts, are those OK or have I got things wrong? I am a bit worried about the power supply choke inducing hum in sensitive parts. And the OC3/VR105:s, if they belong on the power supply chassis/half or as I have put them, near the IT transformer?
Many questions, I know. The circuit I am going to try to build is this one. Any good hands-on or knowledgeable or encouraging tips are welcome!
/Mats
Attachments
I can suggest a few things Zix. Firstly you want to keep the regulator tubes away from your signal tube. You also want to have the laminations of your choke perpendicular to the laminations of your power transformer. Try to put the output transformer on one end of the chassis and the power supply on the other. The regulator tubes are part of the power supply so keep them close to it. I hope that helps. You have certainly picked a difficult circuit for a first project. I hope it turns out well.
Thanks a lot, G!
Having another try at it, I came up with this suggestion. It is only approximate, like the first suggestions, in sizes or distances between parts, one or two chassis and so on.
OC3/VR105 is now moved to the power supply half and the orientation of the choke and other transformers is changed. Also, I moved the rectifiers in front of the choke, which would mean a little longer cable runs from the mains transformer to the rectifiers, but shorter runs from the capacitor bank (I thought to put them underneath) to output valves, and the OC3:s are still in the vicinity of the IT (since they are regulating HT for the input ECC99 I thought this might be good). Plus it looks a little better now...
What say you good people? Better or just different? Other tips?
Having another try at it, I came up with this suggestion. It is only approximate, like the first suggestions, in sizes or distances between parts, one or two chassis and so on.
OC3/VR105 is now moved to the power supply half and the orientation of the choke and other transformers is changed. Also, I moved the rectifiers in front of the choke, which would mean a little longer cable runs from the mains transformer to the rectifiers, but shorter runs from the capacitor bank (I thought to put them underneath) to output valves, and the OC3:s are still in the vicinity of the IT (since they are regulating HT for the input ECC99 I thought this might be good). Plus it looks a little better now...
What say you good people? Better or just different? Other tips?
Attachments
It's the interstage (driver) transformers that will be most susceptible to picking up hum. Locate these with even more caution than the output transformers.
Also it's desirable, but not essential that the choke laminations are perpedicular to the mains transformer and the signal transformers; - yes, it's possible, we live in a 3 dimentional world (AFAIK)
You might like to post a sketch of your layout before you start drilling. There may be slightly differing advice from various members, but it'll give you a "feel" for right and wrong, so you can make an informed decision.
Also it's desirable, but not essential that the choke laminations are perpedicular to the mains transformer and the signal transformers; - yes, it's possible, we live in a 3 dimentional world (AFAIK)
You might like to post a sketch of your layout before you start drilling. There may be slightly differing advice from various members, but it'll give you a "feel" for right and wrong, so you can make an informed decision.
Oh, good! Star grounding and hardwiring is what I had in mind, I will try not to make too big a mess out of it. Will probably be back here for more advice when that time comes
Thanks, dhaen! I will try rotating the choke and the IT:s and OPT:s in many planes with an oscilloscope attached to them before soldering. As long as they don´t need a supporting subchassis directed along the fourth dimension axis I am game... well, more or less. Again, I will probably be back here (hopefully not in tears) in a couple of weeks with the first layout questions.
Aha, star ground on both chassis! Errr... You mean both power supply and signal chassis, or both left and right channel chassis?
Sorry to hear about the lack of bass, bau. I have heard good things about the 6c45pi, but don´t have the designer capabilities needed to redesign Ralph Powers/Gary Dahls design, as Stigla could do - at least not yet. However, the ECC99 has good rep too, so I will follow Stiglas circuit.
I will of course let you, and anyone else that wants to, know how it sounds when, and if, I get it working.
PP6b4g Layout
http://www.audiocircle.com/circles/...ame=gallery&file=index&include=view_photo.php
Andrew
http://www.audiocircle.com/circles/...ame=gallery&file=index&include=view_photo.php
Andrew
I made a boo boo, that was the se version. Here is the pp version now 300b as monoblocks. I used the 5842 and also tried paralled 6n1p and parallel 6sn7. I prefered the 6n1p best. Bass is / was not a strong suite, I believe there maybe insufficient drive as is.
All iron was custom wound by Jack at Electraprint except the output which was from a Fisher x-202? It was a pp 7591.
http://www.audiocircle.com/circles/...ame=gallery&file=index&include=view_photo.php
All iron was custom wound by Jack at Electraprint except the output which was from a Fisher x-202? It was a pp 7591.
http://www.audiocircle.com/circles/...ame=gallery&file=index&include=view_photo.php
Ahh, great. Informative images. Thanks Andrew! Putting the choke underneath looks better, even though mine may be a bit too big for that. The Hammond choke I looked at is rather big.
Mains, interstage and output is Lundahl. I haven´t actually bought them yet but Lundahl and Hammond are the easy ones to get hold of here in Sweden so I used their size data when drawing.
There is quite a bit of parts collection still to do before I can get started, actually I have none of them but the 6B4G:s, but that will hopefully be all done by friday unless some of my parts vendors are still on vacation. It is hot over here right now and everyone just wants to go to the beach...
Mains, interstage and output is Lundahl. I haven´t actually bought them yet but Lundahl and Hammond are the easy ones to get hold of here in Sweden so I used their size data when drawing.
There is quite a bit of parts collection still to do before I can get started, actually I have none of them but the 6B4G:s, but that will hopefully be all done by friday unless some of my parts vendors are still on vacation. It is hot over here right now and everyone just wants to go to the beach...
Agh! Can´t find power transformers
I am sorry to report that I have not suceeded in getting the power transformer for this project. The Hammond transformer I was thinking of using was not as suitable as I thought it would be when looking more closely at the ratings for it, and neither are Lundahls power transformers so I am currently trying to find a european custom winder company.
Any of you european members know of such a company? I have found Bartolucci, but they don´t seem to answer. Perhaps the Italians are on vacation at this time of year? (hope they are still in existence)
Since I am a bit eager to get going on this one, your tips are appreciated.
I am sorry to report that I have not suceeded in getting the power transformer for this project. The Hammond transformer I was thinking of using was not as suitable as I thought it would be when looking more closely at the ratings for it, and neither are Lundahls power transformers so I am currently trying to find a european custom winder company.
Any of you european members know of such a company? I have found Bartolucci, but they don´t seem to answer. Perhaps the Italians are on vacation at this time of year? (hope they are still in existence)
Since I am a bit eager to get going on this one, your tips are appreciated.
Why not try
www.sowter.co.uk
They deliver worldwide, but check the price is OK with you first.
Not cheap, but certainly will last ...
www.sowter.co.uk
They deliver worldwide, but check the price is OK with you first.
Not cheap, but certainly will last ...
Hi,
The owner of the company, Mr. Wil Blauw will gladly make them to your specs if you give him enough to go on.
As I'm sure he already has made several PT and OPT for PP 2A3s and equivalents I'd thought I'd recommend them as a possible alternative.
Asking for a quote will at least allow for some comparison between sources.
Shipping across the Channel was never cheap in my heydays but that may have changed favourably over the past ten years or so....
Cheers,
The owner of the company, Mr. Wil Blauw will gladly make them to your specs if you give him enough to go on.
As I'm sure he already has made several PT and OPT for PP 2A3s and equivalents I'd thought I'd recommend them as a possible alternative.
Asking for a quote will at least allow for some comparison between sources.
Shipping across the Channel was never cheap in my heydays but that may have changed favourably over the past ten years or so....
Cheers,
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