John's on point- that first cap is way too large for reliability, and doesn't get you much in return. If it were my amp, I'd drop the first cap to 100 uF or a little less, take the O/P B+ from the far side of the choke, then use a separate decoupling from the first cap (anything from an R-C to a regulator, depending on my ambitions) for the driver stage B+. That gets me smooth DC for the O/P stage, better reliability, and probably less P/S coupling between output and driver.
I agree with SY.
That first cap is too big for reliability.
If you have to add another socket for the extra GZ34, why not use a grunty diode like the EY/PY 500A, or 6CJ3/6CH3? Both are cheap, available, tough and reliable and have Ia (ave) of 440mA and 350mA respectively and a lot lower internal resistance, so lower voltage drop.
That first cap is too big for reliability.
If you have to add another socket for the extra GZ34, why not use a grunty diode like the EY/PY 500A, or 6CJ3/6CH3? Both are cheap, available, tough and reliable and have Ia (ave) of 440mA and 350mA respectively and a lot lower internal resistance, so lower voltage drop.
NO SILICON MAN?
Hi Joe,
Joe,you make it sound as if you just got sent to prison.
Some imaginary mindreading perhaps?
Joe,let's just say I'm Mr.Tube.
No semi conductors for me please,I hate them...for me they have no business in audio.
Then I see this Quicksilver amp,marvellous sound...but I see a twist...somebody did not play by the rules and put way too much of a burden on some tubes...
I think hard and hard and bingo I come up with a sollution or two.
One would be to put those diodes in.
You don't like the idea and then what?
You would still have to reduce the value of the filtercaps before the inductor as well and all will look like a big mess.
I'm not saying it can't be done elegantly.
It's just not worth it AND I'll bett you a big beer it is going to sound better the way you have it now.
Make that a big Belgian beer please,
Hi Joe,
Joe,you make it sound as if you just got sent to prison.
Some imaginary mindreading perhaps?
Joe,let's just say I'm Mr.Tube.
No semi conductors for me please,I hate them...for me they have no business in audio.
Then I see this Quicksilver amp,marvellous sound...but I see a twist...somebody did not play by the rules and put way too much of a burden on some tubes...
I think hard and hard and bingo I come up with a sollution or two.
One would be to put those diodes in.
You don't like the idea and then what?
You would still have to reduce the value of the filtercaps before the inductor as well and all will look like a big mess.
I'm not saying it can't be done elegantly.
It's just not worth it AND I'll bett you a big beer it is going to sound better the way you have it now.
Make that a big Belgian beer please,
Quicksilver Mods
Hello,
I'm a newbie here, stumbling over from the Audio Asylum. I own a pair of M60 and am very familiar with the QS design. Also, I have a very good rapport with Mike Sanders.
There is lots that can be done to these amps to either simply tweak or completely re- design specific rails. The improvemnt can be astonishing.
Yes the coupling caps on the phase splitter has been upgraded.
Looks like Mike is still using that OPT years later.
Have you checked the rails yet? Probably 460-500VDC
You are very lucky to get a pair of these-- lots of fun and listening enjoyment to be had.
Please feel free to ask any questions you have.
Regards,
Mitch
Hello,
I'm a newbie here, stumbling over from the Audio Asylum. I own a pair of M60 and am very familiar with the QS design. Also, I have a very good rapport with Mike Sanders.
There is lots that can be done to these amps to either simply tweak or completely re- design specific rails. The improvemnt can be astonishing.
Yes the coupling caps on the phase splitter has been upgraded.
Looks like Mike is still using that OPT years later.
Have you checked the rails yet? Probably 460-500VDC
You are very lucky to get a pair of these-- lots of fun and listening enjoyment to be had.
Please feel free to ask any questions you have.
Regards,
Mitch
Quicksilver Mods
Depending the the design of the power supply and the supply caps? THis is where the most improvent can be found.
Number and value of chokes. Ripple, LC filtering etc.
Hard to tell from the pic w/o zooming, but it looks like there is one choke feeding the B1+ rail and a cap to ground(47uf??), both off the main PSU supply cap probably 300uf?
bypassing the supply caps with a better ratio 1/100 makes a huge improvement in HF w/o any other tonal effects.
As for chassis wiring I recommend NOT touching that.
A simple upgrade w/large sonic improvement (some do frown upon) is to rewire the RCA input jack -> phase splitter AND ground with fine solid silver wire inserted into teflon tubing. Say #32-36!
Regards,
Mitch
Depending the the design of the power supply and the supply caps? THis is where the most improvent can be found.
Number and value of chokes. Ripple, LC filtering etc.
Hard to tell from the pic w/o zooming, but it looks like there is one choke feeding the B1+ rail and a cap to ground(47uf??), both off the main PSU supply cap probably 300uf?
bypassing the supply caps with a better ratio 1/100 makes a huge improvement in HF w/o any other tonal effects.
As for chassis wiring I recommend NOT touching that.
A simple upgrade w/large sonic improvement (some do frown upon) is to rewire the RCA input jack -> phase splitter AND ground with fine solid silver wire inserted into teflon tubing. Say #32-36!
Regards,
Mitch
SERIOUS OVERSIGHT
Hi,
Sorry to all involved,I completely overlooked this:
So the person who modded the amp has put the higher value in front of the choke?
Now,that doesn't make sense to me.
The comments from the fellow members now do,of course.
Joe,if space allows (or you can rewire) I'd rather put the higher value cap after the choke.
So the caps are the in reversed order:
1/330microF/500VDC
2/850microF/450VDC
You can also add a 0.22micoF good quality fimcap in // with the existing one over the (now) second cap.
Mitch,
Insulating silverwire with PTFE tubing is not going to stop it from oxidizing.
IMO better use PTFE factory insulated silverwire or,if you can find it Kapton (polyimide) silver wire throughout the signal path.
Again sorry about this,
Hi,
Sorry to all involved,I completely overlooked this:
So the person who modded the amp has put the higher value in front of the choke?
Now,that doesn't make sense to me.
The comments from the fellow members now do,of course.
Joe,if space allows (or you can rewire) I'd rather put the higher value cap after the choke.
So the caps are the in reversed order:
1/330microF/500VDC
2/850microF/450VDC
You can also add a 0.22micoF good quality fimcap in // with the existing one over the (now) second cap.
Mitch,
Insulating silverwire with PTFE tubing is not going to stop it from oxidizing.
IMO better use PTFE factory insulated silverwire or,if you can find it Kapton (polyimide) silver wire throughout the signal path.
Again sorry about this,
Wheezer/Mitch
Welcome
Thanks for the good replies. I'm sure you will add some valuable information and knowledge here.
Frank
As always I bow to your keen mind. So I need to switch the caps around now? Its a good thing these tube amps don't have a picture tube and a big red wire leading to it. I still have nightmares about pulling the wire off the tube when I was a young lad. I still will put plenty of room between myself and a Bendux Aviation Brand Television or any other TV. I'm still trying to find a diagram that will tell me what the socket numbers correspond to.
Frank, I'm still working on the schematic. I must admit that drawing schematic isn't my idea of fun.
I did however find a plastic part that looks like a transistor except that it has two leads on it and I haven't a clue what it is.
Joe
Welcome
Thanks for the good replies. I'm sure you will add some valuable information and knowledge here.
Frank
As always I bow to your keen mind. So I need to switch the caps around now? Its a good thing these tube amps don't have a picture tube and a big red wire leading to it. I still have nightmares about pulling the wire off the tube when I was a young lad. I still will put plenty of room between myself and a Bendux Aviation Brand Television or any other TV. I'm still trying to find a diagram that will tell me what the socket numbers correspond to.
Frank, I'm still working on the schematic. I must admit that drawing schematic isn't my idea of fun.
I did however find a plastic part that looks like a transistor except that it has two leads on it and I haven't a clue what it is.
Joe
Quicksilver Mods
A couple of schools of thought here.
The smaller cap first will help reduce ripple moreso than the larger. However, this would mean a pi filter xxuf......
A larger cap up front does reduce the need for an inductor, as well as help eat up ripple
THESE ARE COST VS. DESIGN ......
Reality is tubes like IRON AND LOTS OF IT.
IMO there is way too much uF.. 300 and two 850's..
THe more uf after around 800(total) causes a soft and floppy bass, in this size amp.It can also cause other funky things to happen.
Mike now uses one 750uf cap on the PSU.
I've had mine in for over a year and no sign of it.Perhaps the heat or the type of silver I used, A-M is my supplier.
I recently took apart a WBT crimp ferrul and the copper was blue in less than a year. so go figure.
A new tweak has arrived for this as lots of us like to make our own IC and terminate them.
Q-Dope, electronics stores have it and Allied elec. sells it too. Liquid polystyrene that's brushed on. Seals out the air!
A couple of schools of thought here.
The smaller cap first will help reduce ripple moreso than the larger. However, this would mean a pi filter xxuf......
A larger cap up front does reduce the need for an inductor, as well as help eat up ripple
THESE ARE COST VS. DESIGN ......
Reality is tubes like IRON AND LOTS OF IT.
IMO there is way too much uF.. 300 and two 850's..
THe more uf after around 800(total) causes a soft and floppy bass, in this size amp.It can also cause other funky things to happen.
Mike now uses one 750uf cap on the PSU.
Got that right.
I've had mine in for over a year and no sign of it.Perhaps the heat or the type of silver I used, A-M is my supplier.
I recently took apart a WBT crimp ferrul and the copper was blue in less than a year. so go figure.
A new tweak has arrived for this as lots of us like to make our own IC and terminate them.
Q-Dope, electronics stores have it and Allied elec. sells it too. Liquid polystyrene that's brushed on. Seals out the air!
QUICKSILVER
Hi,
Joe,
IMO,it does make a lot more sense.
But,before you start do make sure the caps are fully discharged.
Do NOT short them with a screwdriver or something or you may be in for a nasty surprise.
The IC you see may be a 7806 or something,the middle leg and body are ground so when it is bolted to the chassis they probably cut off the middle leg.
It probably provides regulated DC for the input tubes.
I'm guessing here though.
Mitch,
Interesting stuff!
Joe,
The input tubes are all the same internal layout (9A)* noval,the others I need to look up.
*
4+5 heater (9=center tap)
2+7 grid
1+6 plate
3+8 cathode
Cheers,
Hi,
Joe,
IMO,it does make a lot more sense.
But,before you start do make sure the caps are fully discharged.
Do NOT short them with a screwdriver or something or you may be in for a nasty surprise.
The IC you see may be a 7806 or something,the middle leg and body are ground so when it is bolted to the chassis they probably cut off the middle leg.
It probably provides regulated DC for the input tubes.
I'm guessing here though.
Mitch,
Interesting stuff!
Joe,
The input tubes are all the same internal layout (9A)* noval,the others I need to look up.
*
4+5 heater (9=center tap)
2+7 grid
1+6 plate
3+8 cathode
Cheers,
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