Hold on there Philip, you've taken away the very simple ecc81 driver and now you want to make it complicated. I'd be very surprised is you could actually make the amp sound better than it already, er, did.
Then again, you found that lovely reference to turntable damping. I've eaten my hat already and I've got heartburn now.
Going back a couple of weeks, when you got rid of the ecc81 you were then driving the output pair from your WD pre? I'd have thought yes, okay it will work but would be weedy. Did it actually sound better and/or did you have to be close to the speakers, so to speak?
I've found a couple of 832s I'd forgotten I had so will probably put things together and use 6SN7 or 6J5 or something octal, at least, to drive the output pair. Oh, and I'll be using SS PSU this time - why be fernickety when these valves like to be driven hot?
832 TWEEKS
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#32
When the 300b amp gets its makeover i will use the 832a for a while to get a better impression.
The sound without the driver valve,and 832a seemed a bit "better",but the QQV valves gave a bit more volume without any quality loss.
What i really want is just a "bit" of gain to make the volume just 2.875 gnats louder !
ps make sure you use a CCT on the cathodes this time !
The sound without the driver valve,and 832a seemed a bit "better",but the QQV valves gave a bit more volume without any quality loss.
What i really want is just a "bit" of gain to make the volume just 2.875 gnats louder !
ps make sure you use a CCT on the cathodes this time !
The only thing necessary for the triumph of evil is for good men to do nothing.
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#33
As the 832a is coming in for a few mods i must address this "problem".
The original circuit had the input to 12AT7 grid (pin 2) from the wiper of a 100K pot.
As i use a preamp i take the input straight to pin 2, but should i have a grid leak resistor as well ?
If so is it 1M ?
PS just checked and it looks like i have fitted a 100K grid stopper from pin 2 to earth,do i need grid leak as well ?
The original circuit had the input to 12AT7 grid (pin 2) from the wiper of a 100K pot.
As i use a preamp i take the input straight to pin 2, but should i have a grid leak resistor as well ?
If so is it 1M ?
PS just checked and it looks like i have fitted a 100K grid stopper from pin 2 to earth,do i need grid leak as well ?
The only thing necessary for the triumph of evil is for good men to do nothing.
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G-Popz THE easy listening connoisseur. (Philip)
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#34
A tip for 832a users who may want to try QQV valves.
The Septar bases (sockets) are perfect for 832a but the QQV only just fit properly(pin length !) but the B7a are perfect for both,as the centre hole is big enough to let the QQV sit lower.
Just got some nice B7a off e-bay for when 832a is built into a proper box.
The Septar bases (sockets) are perfect for 832a but the QQV only just fit properly(pin length !) but the B7a are perfect for both,as the centre hole is big enough to let the QQV sit lower.
Just got some nice B7a off e-bay for when 832a is built into a proper box.
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
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andrew Ivimey
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#35
B7a eh! I didn't know that.
But it would be a shame to build your 832 into a box. As it is, it is a very successful inspiration.
But it would be a shame to build your 832 into a box. As it is, it is a very successful inspiration.
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#36
One day perhaps ?andrew Ivimey wrote:B7a eh! I didn't know that.
But it would be a shame to build your 832 into a box. As it is, it is a very successful inspiration.
Done the anode choke "mod" and fitted a 1M grid leak resistor.
Not sure if it's made any difference though as i haven't listened to 832a in the main system for a while.
One thing though,it certainly still sounds GOOD
Best PP amp in de Werld man !
The only thing necessary for the triumph of evil is for good men to do nothing.
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G-Popz THE easy listening connoisseur. (Philip)
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#38
As usual,i look forward to seeing/hearing your new amp Colin.
Best mod i ever did on 832a was the CC conversion ! Is that on your list ?
Best mod i ever did on 832a was the CC conversion ! Is that on your list ?
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#39
Philip,
It will be the pp amp featured on this thread:
http://www.audio-talk.co.uk/phpBB2/viewtopic.php?t=1109
I have ordered the interstage TX's from SP Wound and they have promised to wind them this week for me. So with some luck I'll get them next week.
I'm also still waiting on Danbury for my chokes and sourcing the components though I have some luvly american 807's courtesy of SteveS and a set of 4 russian jobbies to compare. If I can sourse 2 more Mullard 807's I can use the 2 I got from my workmate that started this project. I'm also hoping to use some mullard MV tubes in the power supply. Hence the amp will be named TOPPHAT. Geddit?
Simon has kindly loaned me a power supply TX and I shall initially be using the OPT's from my WAD 6550 amp for the breadboard mock up.
Nick will be fine tuning the design for me. What a wonderful man he is
It will be the pp amp featured on this thread:
http://www.audio-talk.co.uk/phpBB2/viewtopic.php?t=1109
I have ordered the interstage TX's from SP Wound and they have promised to wind them this week for me. So with some luck I'll get them next week.
I'm also still waiting on Danbury for my chokes and sourcing the components though I have some luvly american 807's courtesy of SteveS and a set of 4 russian jobbies to compare. If I can sourse 2 more Mullard 807's I can use the 2 I got from my workmate that started this project. I'm also hoping to use some mullard MV tubes in the power supply. Hence the amp will be named TOPPHAT. Geddit?
Simon has kindly loaned me a power supply TX and I shall initially be using the OPT's from my WAD 6550 amp for the breadboard mock up.
Nick will be fine tuning the design for me. What a wonderful man he is
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andrew Ivimey
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#40
um, er, um er ummmm Colin, that amp don't have interstages, does it!?!
Anyway PP 807s - My feeling is that 807s should sound rather like 6L6s and they are very nice valves.
Anticipating!
Anyway PP 807s - My feeling is that 807s should sound rather like 6L6s and they are very nice valves.
Anticipating!
#41
True with the SE amp that started the thread, but Nick persuaded me to go with this amp which does use interstage TX's. SE in with PP out.um, er, um er ummmm Colin, that amp don't have interstages, does it!?!
http://www.spwoundcomponents.co.uk/wp-c ... /pp002.pdf
EDIT
I should have mentioned we are using 807's instead of the 300b's and I think Nick has some other minor changes in mind to the original circuit. We are still intending using the 6C45pi though.
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andrew Ivimey
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#42
Aha! I've seen that one.
I have never heard a sweet sounding 6S45. My own conclusion on the little bugger is 'hard as nails'!
This is interesting for sure and are you suggesting that we can get quality transformers wound within a week?
Majestic has done that twice for me but I think I may have caught them while they had a lull in orders. Very good transformers, nevertheless!
I have never heard a sweet sounding 6S45. My own conclusion on the little bugger is 'hard as nails'!
This is interesting for sure and are you suggesting that we can get quality transformers wound within a week?
Majestic has done that twice for me but I think I may have caught them while they had a lull in orders. Very good transformers, nevertheless!
Last edited by andrew Ivimey on Fri Jan 16, 2009 2:02 pm, edited 1 time in total.
#43
This is one of the reasons why I am watching this project with interest, and it gives me a chance to see how the interstages behave as well.This is interesting for sure and are you suggesting that we can get quality transformers wound within a week?
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pre65
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#44
Now had a little time to listen to the modded 832a, and one track on my "New World" CD has surprised me.
"Try to remember" sounds very "open", the guitar sounds more "clear" and finger movements on the strings more "focused". Well i know what i mean !!
A very "listenable" sound.
In case of a DTB "bwainwave", "try to remember" is not the theme tune of the Alzheimer's association !!
"Try to remember" sounds very "open", the guitar sounds more "clear" and finger movements on the strings more "focused". Well i know what i mean !!
A very "listenable" sound.
In case of a DTB "bwainwave", "try to remember" is not the theme tune of the Alzheimer's association !!
The only thing necessary for the triumph of evil is for good men to do nothing.
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
Edmund Burke
G-Popz THE easy listening connoisseur. (Philip)
#45
Philip,
sorry if the last few posts are off topic. Not trying to steel your thread I'll start a new one when the build commences.
However, from your last posting it would appear the mods you have carried out have been worth the effort. Well done.
Andrew,
I ordered the TX's from SP before Christmas and the very nice man I spoke to said he would wind them for me the week beginning 6th Jan when they returned after the Christmas break. However, he has inbetween time received an order for a full set of TX's for the amp and intends to wind them at the same time as mine. Time will tell if they turn up next week. And then Nick will be doing some measurements of their performance to see just how good they are. This I will report in a new thread.
sorry if the last few posts are off topic. Not trying to steel your thread I'll start a new one when the build commences.
However, from your last posting it would appear the mods you have carried out have been worth the effort. Well done.
Andrew,
I ordered the TX's from SP before Christmas and the very nice man I spoke to said he would wind them for me the week beginning 6th Jan when they returned after the Christmas break. However, he has inbetween time received an order for a full set of TX's for the amp and intends to wind them at the same time as mine. Time will tell if they turn up next week. And then Nick will be doing some measurements of their performance to see just how good they are. This I will report in a new thread.