lebowski Posted August 14, 2020 Share Posted August 14, 2020 (edited) Hi all, hoping to get a few suggestions from you for replacement rectifier valves for my Weston Acoustics Topaz KT120. Looking for options from cheap, mid range and expensive. Currently running JAN cetron 5R4WGB which were fitted from new about 5 or 6 years ago. Edited August 14, 2020 by lebowski Add photos 2 Link to comment Share on other sites More sharing options...
unclekanus Posted August 14, 2020 Share Posted August 14, 2020 Brimar 5r4gy/CV717 RCA 5r4gy from the mid 40's. Twin rectangle getters are best. Two best options hands down. 2 Link to comment Share on other sites More sharing options...
xlr8or Posted August 14, 2020 Share Posted August 14, 2020 (edited) GZ34/5AR4 would be best to maximise plate voltage to the KT120. If you are heading in the EL34 direction larger voltage drops from AC to DC are recommended. Now for which one to use please look for late 1950's or very early 1960's f31 fat base Mullards from Blackburn. Edited August 14, 2020 by xlr8or 3 Link to comment Share on other sites More sharing options...
Cardiiiii Posted August 14, 2020 Share Posted August 14, 2020 Im using the Gold Lion GZ34 2 Link to comment Share on other sites More sharing options...
Luc Posted August 14, 2020 Share Posted August 14, 2020 Cabinets are looking a bit dated and I'm worried about Earle's amp being a dust magnet. I'd suggest ditch at least one of the cabinets(the left one thanks) and invest in some stillpoints and a Scandinavian Beech cabinet that's been scoured whitewash, to match the brickwork. The old Sansui cabinet look... it's meh these days. Ditch it. 1 Link to comment Share on other sites More sharing options...
Decky Posted August 14, 2020 Share Posted August 14, 2020 (edited) https://www.mojotone.com/amp-parts/TubeAccessories_5/Mojotone-Solid-State-Rectifier Edited August 14, 2020 by Decky Link to comment Share on other sites More sharing options...
Graywulf Posted August 14, 2020 Share Posted August 14, 2020 11 minutes ago, Decky said: https://www.mojotone.com/amp-parts/TubeAccessories_5/Mojotone-Solid-State-Rectifier Decky I'd be real careful with that type of rectifier, I found out to my own 'expense'. There's nothing wrong with them, per se. BUT I tried a pair in my VTA M-125 monoblocks. I fried two 6550's and a couple of components. Your amp may be different (obviously), but mine runs 4XKT88/6550 for 100watts+ (per block) 5AR4/GZ34 is the recommended, (but only 2 or 3 options in new production). There is no 'voltage sag' with these units and it 'took' my HT to 540v+, and I was using Russian 6550's. You certainly wont be drawing anything like the current draw limit running two of them. Most with my amps run the Weber solid state rectifier WZ68 (if they are driving the amps fairly hard) it has the same output as X2 GZ34's but more importantly has a resistor built in to reproduce voltage sag identical to the GZ34. Weber placed a 'disclaimer' on their site some while ago that these rectifiers are not intended for 'hifi' use, they've been used by the guys running Bob Latino's amps for yonks before that was put there. They think it may have to a 'disclaimer' against anyone trying to claim for any damage/failure etc. I'm running them quite comfortably on my amps, and have been for just over 2 yrs now. 1 Link to comment Share on other sites More sharing options...
Decky Posted August 14, 2020 Share Posted August 14, 2020 One would assume that people using valve amps with valve rectifiers would understand the advantages (cannot see any objective ones) and disadvantages (quite a few) of the said rectifiers. If they are used solely and deliberately to produce a voltage sag then I would probably define that as a misuse. Link to comment Share on other sites More sharing options...
unclekanus Posted August 14, 2020 Share Posted August 14, 2020 Earl's design choices aside, is an extra 50 or 60 vdc on the B+ and the subsequent changes in operating points on all the tubes going to make this amp sound better? 2 Link to comment Share on other sites More sharing options...
lebowski Posted August 14, 2020 Author Share Posted August 14, 2020 59 minutes ago, Luc said: Cabinets are looking a bit dated and I'm worried about Earle's amp being a dust magnet. I'd suggest ditch at least one of the cabinets(the left one thanks) and invest in some stillpoints and a Scandinavian Beech cabinet that's been scoured whitewash, to match the brickwork. The old Sansui cabinet look... it's meh these days. Ditch it. always appreciate your suggestions Luc. I am very much an old school type of guy, as you know so I’m just going to stick with this set up. Did try the Scandi look however it just didn’t work with the carpet. 3 Link to comment Share on other sites More sharing options...
Graywulf Posted August 14, 2020 Share Posted August 14, 2020 Just now, Decky said: One would assume that people using valve amps with valve rectifiers would understand the advantages (cannot see any objective ones) and disadvantages (quite a few) of the said rectifiers. If they are used solely and deliberately to produce a voltage sag then I would probably define that as a misuse. If it's defined as 'misuse'? I am not qualified to say, all I can do is relate my experience. If an amp is designed with a valve rectifier, then as far as my limited understanding is, the 'sag' of a valve rectifier is factored in? In the case for my amps, no sag, took the voltage on the outputs HT to the 'limit'? of the tubes and separate occasions I had the white/blue 'lightning flashes' inside the tubes. I can only 'repeat' as such what the 'tech' who went over the amps and repaired the components fried told me that in his opinion with modern production tubes, it allowed the HT to get to high for the tubes. I did not have, or since had, that particular fault using the Webers or a GZ34. I can understand his comment, in the past I had a Radford STA-100 an amplifier I regretted selling, still do, BUT it consumed modern tubes (mid 90's to early 2000's) with an appetite bordering on voracious, simply because to get 100 watts out of a pair of KT88's Arthur ran 600v on them, the only tubes then (and this is the era of golden dragon/shuggy chinese) were the 'real' Svetlana 6550's (which I understand had a higher voltage rating than a KT88) even so, it still chewed through them quite rapidly. Yet when purchased had a set of GE KT88's fitted that would have been at least 20yrs old... soft as heck, but still there. 2 Link to comment Share on other sites More sharing options...
Luc Posted August 14, 2020 Share Posted August 14, 2020 (edited) 7 minutes ago, lebowski said: always appreciate your suggestions Luc Persistence is my middle name but I realise this is basically a Sisyphian exercise. But if he was able to keep rolling it uphill then so can I. *Back to original Q. Have you asked Earle about upgrades? Edited August 14, 2020 by Luc Link to comment Share on other sites More sharing options...
Ihearmusic Posted August 14, 2020 Share Posted August 14, 2020 1 hour ago, Decky said: https://www.mojotone.com/amp-parts/TubeAccessories_5/Mojotone-Solid-State-Rectifier Operating point of the tubes (power and pre) are set taking into consideration the B+. Adding 30-50Vdc to an existing B+ is certainly going to mess up the operating points. Capacitor values in the power supply are also chosen for the type of rectification employed. Depending on the circuitry, changing to ss might give you problems instantly or down the track. 5 Link to comment Share on other sites More sharing options...
lebowski Posted August 14, 2020 Author Share Posted August 14, 2020 31 minutes ago, Luc said: Persistence is my middle name but I realise this is basically a Sisyphian exercise. But if he was able to keep rolling it uphill then so can I. *Back to original Q. Have you asked Earle about upgrades? I have asked Earle via text message however I’m not sure he would have received it as the number I have for him is about 10 years old. Link to comment Share on other sites More sharing options...
Luc Posted August 14, 2020 Share Posted August 14, 2020 Mark, he had some good advice with my Topaz re tubes. I lost his mobile number but via his site he got back to me reasonably quickly (for Earle) and yes I did preface my query with 'Bacon'...it does help. might be worth a shot maybe. 1 Link to comment Share on other sites More sharing options...
lebowski Posted August 15, 2020 Author Share Posted August 15, 2020 Thanks for recommendations so far. Where is best place/ site to buy valves at the moment? Link to comment Share on other sites More sharing options...
Graywulf Posted August 15, 2020 Share Posted August 15, 2020 1 hour ago, lebowski said: Thanks for recommendations so far. Where is best place/ site to buy valves at the moment? There are some reputable dealers on Epray, They are soon fairly obvious when you search for tubes. Otherwise the TubeDepot, Dougs tubes, the tube store.... But as I said earlier, for SS rectifier I will only use that Weber one now. 1 Link to comment Share on other sites More sharing options...
unclekanus Posted August 15, 2020 Share Posted August 15, 2020 (edited) I don't know if this is just a generic stock photo but if you get the tube pictured then this is a very good buy. Might be worth an inquiry. https://www.tubedepot.com/products/5r4gy Looks as though you can get 15% of your first order if you sign up for their newsletter. Edited August 15, 2020 by unclekanus Link to comment Share on other sites More sharing options...
unclekanus Posted August 15, 2020 Share Posted August 15, 2020 Another tube I just thought of is the 274b. Also a 2 amp rectifier and it isn't too far off in spec to a 5r4gy. Plenty of them being currently produced but the sticker shock on some of them is fairly savage. Link to comment Share on other sites More sharing options...
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