Hello, I've been on and off again lurking here for a couple of years now. I thought I'd register finally to be able to visit from time to time. I know I won't be able to contribute much as my time and money doesn't allow for anything to get built in a reasonable time, but do enjoy an occasional vicarious build with the associated learning.
Thank you for all the shared insights and info.
Many Thanks Tomas.
First Post
#4
Welcome Tomas, i think most of us have time issues, but i think its the, inclination thats the issue for me,
What sort of stuff do you build ?
Cheers ..
What sort of stuff do you build ?
Cheers ..
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
#5
Hi Steve,
I'm trying to piece together an S/E amp right now, sort of collecting the pieces and info. Probably end up being a C3g in triode to IT to 45. Not much power but I've been putting together some higher efficiency speakers for a
while now. Line-up to date is Goodmans Axiom 150 +/-100Hz to 800Hz, unknown driver to +/- 4Khz, Emilar EK175 on a 1210 Horn from 4Khz to natural roll off and a Heil tweeter from +/- 7 Khz. This will be on open baffle sitting on top of an enclosed vented cerwin vega 12" <100Hz. Should be about a 98DB I figure, would like it to be higher but that would definitely be a wishlist sort of an idea.
Problem there of course is that I know zero about Xovers.
I've been getting the pieces of the power supply for the amplifier together
- motor run caps, chokes etc., a piece at a time, very slow process with the cost factor and distractions of life, but I'm hoping to have something that I'm reasonably content with for retirement. I would appreciate any suggestions or advice you may have on this for me.
Thanks Tom.
I'm trying to piece together an S/E amp right now, sort of collecting the pieces and info. Probably end up being a C3g in triode to IT to 45. Not much power but I've been putting together some higher efficiency speakers for a
while now. Line-up to date is Goodmans Axiom 150 +/-100Hz to 800Hz, unknown driver to +/- 4Khz, Emilar EK175 on a 1210 Horn from 4Khz to natural roll off and a Heil tweeter from +/- 7 Khz. This will be on open baffle sitting on top of an enclosed vented cerwin vega 12" <100Hz. Should be about a 98DB I figure, would like it to be higher but that would definitely be a wishlist sort of an idea.
Problem there of course is that I know zero about Xovers.
I've been getting the pieces of the power supply for the amplifier together
- motor run caps, chokes etc., a piece at a time, very slow process with the cost factor and distractions of life, but I'm hoping to have something that I'm reasonably content with for retirement. I would appreciate any suggestions or advice you may have on this for me.
Thanks Tom.
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simon
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#6
Sounds like an interesting and most worthy project Tom. It might be quite a challenge to integrate all the drivers and the bass cab, but the raw materials look promising. Steve probably has the best experience of this type of speaker as he's been playing with multiple drivers in OBs for a while and having heard some of his speakers in his home they're very good.
C3g IT 45 could be very good too. I breadboarded a Bugle (5751 SRPP 45) a few years ago which I really rather liked, and without a pre amp my Fostex 208 horns were pretty loud, surprisingly so. The room was quite small though. If you like music loud and have a big room the 45 might run out of steam a little. No doubt about it though the 45 is a magical valve.
It sounds like the Somme reenactment outside has finally stopped so it's time for bed. Happy New Year to all.
C3g IT 45 could be very good too. I breadboarded a Bugle (5751 SRPP 45) a few years ago which I really rather liked, and without a pre amp my Fostex 208 horns were pretty loud, surprisingly so. The room was quite small though. If you like music loud and have a big room the 45 might run out of steam a little. No doubt about it though the 45 is a magical valve.
It sounds like the Somme reenactment outside has finally stopped so it's time for bed. Happy New Year to all.
#7
Hi Simon, thankfully as far as S/E amps go, I have a small listening room and don't tend to listen at high volume. I suppose that in one way the time taken to choose parts and direction also allows for a change of direction as I am not absolute on the speaker choices that I have made so far. Good to hear that you found a 45 amp to be so appealing.
#8
Sounds to me tomas that you have the makings of a good system, and not too different to earlier versions of my set ups
An amp with good bass is a must for ob in my books, cross overs should be simple if you 1st order and treat each speaker separately
Where are you ?
An amp with good bass is a must for ob in my books, cross overs should be simple if you 1st order and treat each speaker separately
Where are you ?
The tube manual is quite like a telephone book. The number of it perfect. It is useful to make it possible to speak with a girl. But we can't see her beautiful face from the telephone number
#10
I suppose starting with a 1st order and moving to a higher order if need be would simplify it as much as possible for a start. I know I tried the Goodmans for a 2 way with a 1200Hz 2nd order and found I didn't care for it crossed over that high. I was wondering if a 1st order at 800 would be enough. Do you think that lowering the Xover point and staying 1st order is preferable to a higher Xpoint and sharper cutoff? Good to hear there's potential there for good bass even at 2 watts.
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simon
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#12
A 45 can definitely do bass 
.
Thinking back I once tried trioded C3g cap coupled to a 45. It was actually a 2A3 amp that I revised the OP for a 45. Neither amp has stood the test of time, maybe I didn't make a very good job of building it. But the Bugle was a big step forward I recall. The circuit and explanation are available on Gordon Rankin's website.
It's amazing what's out there is cyber space. Here are some words I wrote quite a long time ago at a location I can no longer get to now, for what they're worth.
http://www.atrj13.dsl.pipex.com/na-C3g2A3.htm
http://www.atrj13.dsl.pipex.com/na-Bugle.htm
I've mused a number of times since how I might drive a 45, and I suppose the only real difference might be another DHT, perhaps a 26. But that would need another stage and then it starts to get more complicated, and not necessarily better. Thomas Meyer has used a parallelled 6N7, which I have some to try one day. But perhaps a Bugle is good enough.
.Thinking back I once tried trioded C3g cap coupled to a 45. It was actually a 2A3 amp that I revised the OP for a 45. Neither amp has stood the test of time, maybe I didn't make a very good job of building it. But the Bugle was a big step forward I recall. The circuit and explanation are available on Gordon Rankin's website.
It's amazing what's out there is cyber space. Here are some words I wrote quite a long time ago at a location I can no longer get to now, for what they're worth.
http://www.atrj13.dsl.pipex.com/na-C3g2A3.htm
http://www.atrj13.dsl.pipex.com/na-Bugle.htm
I've mused a number of times since how I might drive a 45, and I suppose the only real difference might be another DHT, perhaps a 26. But that would need another stage and then it starts to get more complicated, and not necessarily better. Thomas Meyer has used a parallelled 6N7, which I have some to try one day. But perhaps a Bugle is good enough.
#13
That's what I'm wondering Simon, it's not that I want an end all be all amplifier and very much doubt whether it will be a one time build either. However I would like to start from a point that feels right to me, some of the remarks people have been making about actually using pentodes and DHPs to improve the upper end have me thinking that a good balance between odds and evens using DHPs and DHTs might be the way for me to go. I see that some people suggest that an IT can be used while others say it won't work. I have a pair of Hammond 126C's, being 10K, 105H, would this work for a pentode driver and what are your thoughts given the Bugle didn't stand the test of time for you? Thanks for your help, Tom
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simon
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#14
Well, I wouldn't say the Bugle didn't last the course as much as I needed to recycle the bits. And 2W isn't enough for me for a main amp.
The beauty of DIY is that you can try a few things and see what works for you, as it probably won't be the same as what works for others. Start with something simple say an indirectly heated trioded pentode (C3g, D3a, 12GN7) or twin triode SRPP a la Bugle and cap couple it to the 45. Then you can try different drivers and the IT. Cap coupling is simpler to get right, the IT might give better performance but might be more tricky to get right.
If you go to a directly heated driver, whether a 4P1L pentode say or another triode, then you need to get the filament supply right as it will hum like a good 'un. Andrew L here has developed some boards and might still have some, or try Rod Coleman on DIY Audio, whose boards are also very good. Or lots of chokes and caps.
It might be that 4P1L pentode cap coupled to a 45 gives the best sound, say (I've no idea), but is only marginally better than a Bugle.
The power supply is important too. Try to at least go choke input, some swear by regulated, others don't. Lots of fun to be had
The beauty of DIY is that you can try a few things and see what works for you, as it probably won't be the same as what works for others. Start with something simple say an indirectly heated trioded pentode (C3g, D3a, 12GN7) or twin triode SRPP a la Bugle and cap couple it to the 45. Then you can try different drivers and the IT. Cap coupling is simpler to get right, the IT might give better performance but might be more tricky to get right.
If you go to a directly heated driver, whether a 4P1L pentode say or another triode, then you need to get the filament supply right as it will hum like a good 'un. Andrew L here has developed some boards and might still have some, or try Rod Coleman on DIY Audio, whose boards are also very good. Or lots of chokes and caps.
It might be that 4P1L pentode cap coupled to a 45 gives the best sound, say (I've no idea), but is only marginally better than a Bugle.
The power supply is important too. Try to at least go choke input, some swear by regulated, others don't. Lots of fun to be had
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IslandPink
- Amstrad Tower of Power
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#15
I'm a big fan of pentode drivers so would suggest trying the C3g in pentode mode into 45 if you have time. You can avoid a cathode by-pass cap on the driver , because there'll be plenty of gain ; so you get rid of two bass time constants - that from the by-pass cap, and also from the interstage . Just make sure the G2 is stabilised with a VR tube . On the other hand, what you were intending to do will also be very good 
"Once you find out ... the Circumstances ; then you can go out"