SET amp owners thread
- Thread starter bonzo75
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Bergmann Modi with Odin, Reed 3P and FR64S on the separate tower.
Both Hørning OPTs are now in place and the stock OPTs are history. It´s been a productive day.
Picture of the first finnished amp with the Hørning opt under the dark red cover side by side with the standard amp.
Picture of the first finnished amp with the Hørning opt under the dark red cover side by side with the standard amp.
Difficult question all the time I haven’t tried all the carts on all arms but I used to have the Kuzma 4point and prefer the 3P over the 4point. The FR64S came in as my Koetsu did not work in any other (lighter) arm and it was first when I got a fairly heavy arm the Kortsu started to sing. I bought a B-60 from Leif and got a heavy Micro Seiki armboard for it and it excelled. It performed even better when Leif got me a heavy bronze nut. So mass on the FR64s with the Koetsu is a winning concept.
I used to have a Transfiguration Phoenix S on the Odin. It did not do it for me. A bit lifeless and dull, so the The Frog took its place. Works better and was all the time intended to be an every day allrounder.
They are all different arms obviously but the Reed is just musical and a fantastic arm. If I had to keep just one, I would probably keep the the 3P.
Kondo souga 2a3 Vs Kondo Gakuoh mk2 300b (new WE) Vs Kondo Kagura (RCA 211).
More details in a few days
More details in a few days
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Intensive weekend of listening with the Silvercore amp on the Horning speakers. Had several friends over last two weekends to join me (Acousticsguru, Christoph, Phonatix, and others not on WBF). Just did a lot of tube rolling of rectifiers and so far the three best that I own are the following:
1945 RCA 5R4GY Blackplate
Marconi (Canada) Blackplate 5U4G (not sure the year)
1955 Valvo metal base GZ34
Interestingly, the plate structure of the RCA and Marconi are VERY similar, despite being to different types of rectifiers. They are more similar visually than to other 5U4Gs. Sonically, they are much more similar to each other than the GZ34.
Will give a detailed analysis in due course…
Good!! You may notice that the value of the cap and resistor network required varies according to the tube. I imagine this aspect would make it really hard to actually know how the rectifier 'sounds' without adjusting these values. I also suspect that not getting this right might be why some amps have a bit of buzz in their noise floor. I also suspect that most people attribute that to something else.
I'm working on a 300b or UX-250 design for fun; this is one thing I'll be examining.
Basically, there are two factors in the low noise in tube rectifiers. 1. the resistance of the secondary winding of the mains transformer and the size of the charging capacitor(C) after the tube. the recommended resistance of the secondary winding(Rt red marked) is given in the data sheet of the tube rectifier.
Exsample
if the transformer has a lower impedance than recommended, charging current peaks can occur even if the charging capacitor size is observed. you know this hum.
In the worst case, it is a transformer with too little resistance and too large a charging capacitor. If you're not sure what the value of the transformer winding is, downsize a 60uf to 47uf charging capacitor. This does not affect the purity of the DC voltage with CLC filtering.
oh one more thing, tube rolling at this point with equal types is the worst thing you can do. it can go well or cause frustration and costs.
P.S
if you have a case, you can put a series resistor between the rectifier and the charging capacitor. please pay attention to the load capacity of the resistor P= U×I
Exsample
if the transformer has a lower impedance than recommended, charging current peaks can occur even if the charging capacitor size is observed. you know this hum.
In the worst case, it is a transformer with too little resistance and too large a charging capacitor. If you're not sure what the value of the transformer winding is, downsize a 60uf to 47uf charging capacitor. This does not affect the purity of the DC voltage with CLC filtering.
oh one more thing, tube rolling at this point with equal types is the worst thing you can do. it can go well or cause frustration and costs.
P.S
if you have a case, you can put a series resistor between the rectifier and the charging capacitor. please pay attention to the load capacity of the resistor P= U×I
My amp has 20uF cap. No worries... Plus I checked with the designer...5u4g, 5r4gy and 5ar4 should all work safely.
Depending on the B+ that's about all the current inrush those tubes can handle anyway. But the greater that input cap can be, the less amplitude the resulting sawtooth waveform will have. That is why I'm thinking that HEXFREDs can be a step forward since you can build a lower noise supply.
Both my SET amps use 5U4G/GZ34 tubes as rectifiers. I’ve only used new Russian tubes but would like to tube roll. How much are the RCA’s?
Try this in christofs amp made by mullard blackburn
Telefunken GZ34 nos / nib 1966 | Reverb Deutschland
Telefunken GZ34 from summer 66' . New old stock / nib. Tested and works great. You cannot find any better and more reliable GZ34 tube than old telefunkens. Please see photos for exact condition. Due to the nature of old item, no returns accepted. Comes very carefully packed with tracking. I ...
reverb.com
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I think I paid 85 each for them…but they are 5r4gys. My good 5u4g is Marconi. A metal base GZ34 is also awesome
Looks niceTry this in christofs amp made by mullard blackburn
Telefunken GZ34 nos / nib 1966 | Reverb Deutschland
Telefunken GZ34 from summer 66' . New old stock / nib. Tested and works great. You cannot find any better and more reliable GZ34 tube than old telefunkens. Please see photos for exact condition. Due to the nature of old item, no returns accepted. Comes very carefully packed with tracking. I ...
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