steveinspain
pfm Member
I can cope with replacing valves every year or so and do have efficient speakers. It's something (ie own a hifi I really can't afford but makes me feel like I've reached the top of what's almost affordable) I have to do before I turn into my inlaws.
Well I'm new to ST ownership myself. I've owned a lot of amps over the decades and this is the amp that'll see me through to the grave. I wouldn't use it for 10-15 hours a day though. I imagine it might be too costly in electricity and decent valve replacements. It's more for those occasions when I want to listen to music, not just have it on in the background. Personally I'd use a Quad 303 for long hours of background music because it combines cool running, reliability, is easily fixed if it does go wrong and sounds very good.
As Alex S says there is no biasing necessary on an ST20. I haven't experienced any ground loop issues with mine and there's only a faint low hum from the speakers which I can't hear from any more than a metre away. Bear in mind though that being so aged, and thus having had components inside changed, or needing to be changed, I suspect very many ST20's won't perform at the same level in terms of reliability and sound quality.
As Alex S says there is no biasing necessary on an ST20. I haven't experienced any ground loop issues with mine and there's only a faint low hum from the speakers which I can't hear from any more than a metre away. Bear in mind though that being so aged, and thus having had components inside changed, or needing to be changed, I suspect very many ST20's won't perform at the same level in terms of reliability and sound quality.
Alex S
carbon based lifeform
This is probably very important. If you get one without exact known provenance be prepared for an expert to examine it and carry out work. Mine was rebuilt by Mike P and then further work carried out by GT so I'm confident.
steveinspain
pfm Member
Thanks for your input/help too.
Does anyone have any idea what one costs in terms of electricity used per hour/day?
Like both you and @Alex S say, buying one that's been properly overhauled is essential for me and peace of mind, even if it takes some time.
Tony L
Administrator
I think there might be a Watt reading upthread somewhere. The TL-12 Plus monos take 75 Watts each, so 150 the pair. I think the Stereo 20 is less, about 125 Watt (just the one mains transformer). Think of it as a couple of old tungsten light bulbs in real terms.
For comparison my old Pass Aleph 3 (a 30 Watt class A amp) used 250 Watt, a Quad 303 about 50 (the Quad will take more if driven hard).
steveinspain
pfm Member
Thank you Tony, that's not as bad as I was expecting.
I'll start looking...
toprepairman
pfm Member
depends on your rate but around 4/5pence/hr should cover it.
Barrymagrec
pfm Member
The power consumprion of a ST20 will be in the region of 125 watts as Tony says so about an eighth of a unit per hour, a bit under 4p an hour for most people in the UK (but going down a little on Monday).
steveinspain
pfm Member
Thank you both, I'll hold off buying one till after Monday then!
A option is to run a quad 303,306 or whatever ss amp u have...
Then use the st20 for extended listening when u are not going to get disturbed.
Makes u appreciate it even more and preserves valve life,as on and off is not best.
Also i keep volume low for the first 15 min and treat her like a classic bike on a cold start and feed in the volume...
The valves are cheap enough from ulkraine..
My favorite valve amp with els 57s,and Tannoys in the company of radford sta25s and quad IIs...
I use Mark Grant but could try Mogami of various numbers.
[/QUOTE]
Got fed up of interconnects being too short...
Bought a few metres of mogami and some discounted neutrink/
rean connectors.
Worked out silly cheap and have whatever length i desire and sounds fine in my ears...
Also switchcraft do a nice pair of angled rcas.....
[/QUOTE]
Got fed up of interconnects being too short...
Bought a few metres of mogami and some discounted neutrink/
rean connectors.
Worked out silly cheap and have whatever length i desire and sounds fine in my ears...
Also switchcraft do a nice pair of angled rcas.....
les24preludes
pfm Member
You don't have to be afraid of using valve amps long term. I have mine on 24/7 because all my sources go through my audio system - TV, internet etc. Before transistors valve amps did everything including making computers work for many, many years.
But as you say, you do have to check the components periodically. Resistors can drift a little and capacitors are worth swapping, but this would be a 5 year service as long as the components are good in the first place. A good rebuild is well worthwhile since there are better components available these days, and it does give you peace of mind.
The input valves will last for many years. The output EL84s should be checked periodically, say every 2 years if you use the amp a lot.
chiily
PFM Special Builder
I think I've found the perfect partner for my ST20, a pair of @James 's E-IXs. I've been in the office all day, sorting out the company books, and I've had the pleasure of my ST20 and the E-IXs playing along. Over the passed week I've been running the E-IXs with my DIY Stasis amp, it is a but too smooth and rounded. This morning I dragged the ST20 down from the semi-retirement shelf upstairs and with some cheap interconnects to the miniDSP flex on pre-amp duties with EQ flat, a mishmash of speaker wire to the E-IXs I've been enjoying every type of music I can throw at the audio combination.
I would have thought the ST20 was a tad underpowered for the E-IXs, but it does drive them to surprising volumes, not earth shattering, but plenty of life and depth to the music. And again, the ST20 is no pipe and slippers amp. I have just noticed that the input ECC83 (12AX7A) is made by RCA (red label), no idea where I bought that from...
PXL_20240329_213640312 by Garf Arf, on Flickr
PXL_20240329_213647017 by Garf Arf, on Flickr
Bob the zebra is enjoying the tunes too....
I would have thought the ST20 was a tad underpowered for the E-IXs, but it does drive them to surprising volumes, not earth shattering, but plenty of life and depth to the music. And again, the ST20 is no pipe and slippers amp. I have just noticed that the input ECC83 (12AX7A) is made by RCA (red label), no idea where I bought that from...
PXL_20240329_213640312 by Garf Arf, on FlickrPXL_20240329_213647017 by Garf Arf, on FlickrBob the zebra is enjoying the tunes too....
steveinspain
pfm Member
Has anyone here actually heard one of these valvepower amps?
With modern safety standards the plastic covers on modern electrolytic capacitors should be left in place. See my earlier post about replacing the power supply electrolytics and why you should leave the sleeves on the capacitors. Remember safety standards have changed significantly since the 1950s/60s.
Tony L
Administrator
If you were really picky about aesthetics a little filler and sanding on top would fill the dip prior to priming and painting. With a little effort you could get it looking original.
PS FWIW I’ve clearly not understood the issue here. The Stereo 20 chassis is ground. The signal return is ground. The schematic says it is ground. All of the black ground wires go back to a case screw on one of the big can cap mounting lugs. Everything continuity beeps to the earth pin on the mains plug anyway. Leak grounded the capacitor can, and very deliberately so by the looks of things. I was actually a bit worried by not doing so on my TL12 Plus rebuild, though left the F&T cap plastic skin on as I was mounting it internally and wanted to be sure it couldn’t short anywhere in any scenario even if it became loose (which it won’t!). As ever my aim is only to sympathetically restore. I have no interest in second-guessing or “improving” these classics.
PS FWIW I’ve clearly not understood the issue here. The Stereo 20 chassis is ground. The signal return is ground. The schematic says it is ground. All of the black ground wires go back to a case screw on one of the big can cap mounting lugs. Everything continuity beeps to the earth pin on the mains plug anyway. Leak grounded the capacitor can, and very deliberately so by the looks of things. I was actually a bit worried by not doing so on my TL12 Plus rebuild, though left the F&T cap plastic skin on as I was mounting it internally and wanted to be sure it couldn’t short anywhere in any scenario even if it became loose (which it won’t!). As ever my aim is only to sympathetically restore. I have no interest in second-guessing or “improving” these classics.
Barrymagrec
pfm Member
Exposed glass valves and a Bulgin main connector pretty much hits the buffers on modern safety standards anyway and these amplifiers were never intended to be on display , rather tucked away in a tasteful cabinet.
Common sense to fit your own circumstances and preferences is the way to go.
Common sense to fit your own circumstances and preferences is the way to go.