Re: Re: more details...
Which Fostex BLH?
I had a set of alnico Heresys and they were a joke. Fat, fat, bloated bottom end and very disjointed thru-out the entire range. I burned the boxes and sold the drivers to a guy in Hong Kong.
dave
tim614 said:
Which Fostex BLH?
I had a set of alnico Heresys and they were a joke. Fat, fat, bloated bottom end and very disjointed thru-out the entire range. I burned the boxes and sold the drivers to a guy in Hong Kong.
dave
Re: FORWARDNESS
This might be another thing to try. Right now I am using SS rectification and remembered that I also tried using a 5U4 in my 6EM7 amp and did not care for it due to softening of the sound and clarity, sort of like what adding the attenuator to it did. Must be why Alex designed it with tube rectification...
I wouldn't call it a clarity issue as both amps are very clear IMO. It just that after awhile, listening to the RH84 gets a little fatiguing whereas I could listen to the 6EM7 all day long without getting tired. Lastly, the 6EM7 amp seems to have a bit of "air" to it whereas the RH84 is just clean sounding. Subjective observations, I know, but this is what makes SE and full range speakers so special.
Alex Kitic said:
This might be another thing to try. Right now I am using SS rectification and remembered that I also tried using a 5U4 in my 6EM7 amp and did not care for it due to softening of the sound and clarity, sort of like what adding the attenuator to it did. Must be why Alex designed it with tube rectification...
I wouldn't call it a clarity issue as both amps are very clear IMO. It just that after awhile, listening to the RH84 gets a little fatiguing whereas I could listen to the 6EM7 all day long without getting tired. Lastly, the 6EM7 amp seems to have a bit of "air" to it whereas the RH84 is just clean sounding. Subjective observations, I know, but this is what makes SE and full range speakers so special.
Re: Re: Re: Re: more details...
Is that the Fostex recommended BLH? It isn't a very good example. I can understand why you weren't enamoured of it.
dave
tim614 said:
Is that the Fostex recommended BLH? It isn't a very good example. I can understand why you weren't enamoured of it.
dave
Re: Re: im also in the process of my second rh84
im still waiting on the PTX should be in soon.
the pic is layout im trying to work out, but im in the process of moving so dont have time to work on it yet until then i think i will start a new thread on the built.
Ty_Bower said:
im still waiting on the PTX should be in soon.
the pic is layout im trying to work out, but im in the process of moving so dont have time to work on it yet until then i think i will start a new thread on the built.
If you want the sound of tube rectification without doing all the nasty case work - try this. Place a 200R resistor in series with each rectifier - this should make them behave a bit more like valve rectifiers. Snub all your rectifiers + resistors with 0.1uf caps (rated at about 1000V - cheap ceramics should work). Snub across the secondary of the power transformer with something like a 0.1uf cap (1500V ceramic again). This should eliminate any ringing which can bleeed through to the power amp.
If you get a significant improvement then consider going over to valve rectification.
Shoog
If you get a significant improvement then consider going over to valve rectification.
Shoog
TUBE ROLLING AND PREAMPS (CHANGING)
I am not familiar with the Aikido preamp and would not want to insult anyone, but I am quite sure that the line stage of the RPA beats it sonically (a lot of diyers built the line stage, but I cannot recall the name Elvis gave it... I recall it was a SRPP preamp killer).
That is obviously the easiest solution to ascertain whether the forwardness comes from the amp or the combination 🙂
Frankly, to me there is no comparison between tube rectified and SS rectified. When you design something, you have to have an idea, then do a lot of math, thinking, and sims... in the end, you get a schematics that will work. BUT, to make it work you have to build it correctly, because hum or mistakes in the building can mar the result... Once it is built as it should, it works and shows whether all the effort was in vain or not. FINALLY, to obtain the best result one has to do component choices, tube rolling, etc... to make it sound at its best in the given room/system...
For instance, the RPA is depicted with an RCA 5Z4 rectifier, but I actually use it in my living room (change of apartment, change of room) with an RCA 5Y3 rectifier... not a slight difference, believe me. And, in this room I do not dare use 5R4 rectifiers on the amp, but actually 5U4 (also RCA...) to muffle the sound a bit because the room is very unforgiving... Luckily, I hope we shall finally buy this "final" apartment by the end of the summer and I'll finally have a decent living room to listen to music 😉 (again, since at the time the RH series was designed I had a nice relatively large living room... but the apartment was too small, particularly when we understood we were going to have twins...) 🙂
I am not familiar with the Aikido preamp and would not want to insult anyone, but I am quite sure that the line stage of the RPA beats it sonically (a lot of diyers built the line stage, but I cannot recall the name Elvis gave it... I recall it was a SRPP preamp killer).
That is obviously the easiest solution to ascertain whether the forwardness comes from the amp or the combination 🙂
Frankly, to me there is no comparison between tube rectified and SS rectified. When you design something, you have to have an idea, then do a lot of math, thinking, and sims... in the end, you get a schematics that will work. BUT, to make it work you have to build it correctly, because hum or mistakes in the building can mar the result... Once it is built as it should, it works and shows whether all the effort was in vain or not. FINALLY, to obtain the best result one has to do component choices, tube rolling, etc... to make it sound at its best in the given room/system...
For instance, the RPA is depicted with an RCA 5Z4 rectifier, but I actually use it in my living room (change of apartment, change of room) with an RCA 5Y3 rectifier... not a slight difference, believe me. And, in this room I do not dare use 5R4 rectifiers on the amp, but actually 5U4 (also RCA...) to muffle the sound a bit because the room is very unforgiving... Luckily, I hope we shall finally buy this "final" apartment by the end of the summer and I'll finally have a decent living room to listen to music 😉 (again, since at the time the RH series was designed I had a nice relatively large living room... but the apartment was too small, particularly when we understood we were going to have twins...) 🙂
Re: Re: Re: Re: Re: more details...
according to the guy i bough it from it was bulit within spec, i've also have heard several different BLH (fostex) from different people, all were not very special. i was very diapionted.
planet10 said:
according to the guy i bough it from it was bulit within spec, i've also have heard several different BLH (fostex) from different people, all were not very special. i was very diapionted.
I have always anticipated that the Fostex drivers would have a fairly bright analytical sound, rather in keeping with the Japanese style of music. I could be wrong though as I have never heard any in the flesh.
I found the European vintage alnico drivers to have lovely soft tones.
Shoog
I found the European vintage alnico drivers to have lovely soft tones.
Shoog
Re: TUBE ROLLING AND PREAMPS (CHANGING)
Sounds like I am at this point in time...
Hey guys, I think we have been hijacking this thread for awhile. Sorry about that. Well at least we had some bits and pieces of info that hopefully will help this guy down the road after he builds his first of many amps. Good luck and have fun...
Alex Kitic said:
Sounds like I am at this point in time...
Hey guys, I think we have been hijacking this thread for awhile. Sorry about that. Well at least we had some bits and pieces of info that hopefully will help this guy down the road after he builds his first of many amps. Good luck and have fun...
Re: Re: Re: Re: Re: Re: more details...
I built a BLH for the 4" Fostex. It's amazing how much bass (still not that much in the grand scheme) you can get out of a little low excursion driver. But I also found out that I'm not a fan of a full range BLH. I don't think it's the driver, per se. Admittedly, it's only one example, but based on playing around with damping, chamber size, etc., my impression is that it's the concept itself that is limited. There's a price to be payed for trying to get that bass from a driver that doesn't make much. There is a certain "horn" character that I can minimize, but never remove without subtracting bass too. It's more apparent on some music than other, but I guess that I'm sensitive to it. Now, if you are listening to chambered instruments, like strings, it fits right in. But with some voices, the "chamber" sound is there, and doesn't fit.
It's fine for my second system, used for background music. But I wouldn't be satisfied with it for serious listening.
Sheldon
tim614 said:
I built a BLH for the 4" Fostex. It's amazing how much bass (still not that much in the grand scheme) you can get out of a little low excursion driver. But I also found out that I'm not a fan of a full range BLH. I don't think it's the driver, per se. Admittedly, it's only one example, but based on playing around with damping, chamber size, etc., my impression is that it's the concept itself that is limited. There's a price to be payed for trying to get that bass from a driver that doesn't make much. There is a certain "horn" character that I can minimize, but never remove without subtracting bass too. It's more apparent on some music than other, but I guess that I'm sensitive to it. Now, if you are listening to chambered instruments, like strings, it fits right in. But with some voices, the "chamber" sound is there, and doesn't fit.
It's fine for my second system, used for background music. But I wouldn't be satisfied with it for serious listening.
Sheldon
Re: Re: Re: Re: Re: more details...
It isn't a very good example "how so?" please explain.
planet10 said:
It isn't a very good example "how so?" please explain.
Re: Re: Re: Re: Re: Re: more details...
It is not a very good design. If you can live with a BLH* there are better ones.
*(by its very nature, the bass in a BLH is delayed in time. The notes that are coming out of the horn started out out-of-phase and then travel the length of the horn. In a well designed horn, this will be (2n+1)/2 wavelengths (n=integer) at the highest frequencies and a 1/4 wl at the lowest frequencies, This really bothers some people, others have no problems with it)
dave
tim614 said:
It is not a very good design. If you can live with a BLH* there are better ones.
*(by its very nature, the bass in a BLH is delayed in time. The notes that are coming out of the horn started out out-of-phase and then travel the length of the horn. In a well designed horn, this will be (2n+1)/2 wavelengths (n=integer) at the highest frequencies and a 1/4 wl at the lowest frequencies, This really bothers some people, others have no problems with it)
dave
mach1 said:
Hi Mach1,
I also live in Brisbane and I'd like to talk to you about your RH84 build experiences. (I have a donor TC500A RtR.)
Please PM me.
Thanks
Doug
Maggie Turns RH84SE.
I'm exhilarated by the great sonics coming out of my humble Magnavox 196 BA re-wired to a RH84SE circuit.
Only changed the choke to a Hammond 10H@150mA.
Despite the original PT of 260-0-260v, with a B+ of 276v, it did'nt lose out much to my regular McIntosh MC-30 monobloc.
What surprised me most was how quite it is, not a hiss from my 101dB Altec 604-E! Incredible!
Can't beleive that 3 tiny-wimpy tubes can thump my Mac !?
Bass is a big "WOW". s
This first listen to a SET have totally changed my mentality of the low watters! I'm now confident enough to build a RH66 if I can find the schematics for it. Can make use of the quad of KT66 Gold Lion from the MC-30.
This hobby is fantastic and wish I could have taken up electronics instead of structural engineering, 40 yrs. ago.
Cheers!
Zekk
I'm exhilarated by the great sonics coming out of my humble Magnavox 196 BA re-wired to a RH84SE circuit.
Only changed the choke to a Hammond 10H@150mA.
Despite the original PT of 260-0-260v, with a B+ of 276v, it did'nt lose out much to my regular McIntosh MC-30 monobloc.
What surprised me most was how quite it is, not a hiss from my 101dB Altec 604-E! Incredible!
Can't beleive that 3 tiny-wimpy tubes can thump my Mac !?
Bass is a big "WOW". s
This first listen to a SET have totally changed my mentality of the low watters! I'm now confident enough to build a RH66 if I can find the schematics for it. Can make use of the quad of KT66 Gold Lion from the MC-30.
This hobby is fantastic and wish I could have taken up electronics instead of structural engineering, 40 yrs. ago.
Cheers!
Zekk
Thank you for the compliments! Frankly, they are quite in line with what other users have, more or less, attributed to the RH84.
If you are willing to build with KT66, the schematics already exists in the form of the RH807. Since the sub is the same for 807, KT66 and 6L6, you can build it with any of these tubes (or the 5881 for that matter).
You can find the schematics on my site, as well as my email address. If you have any questions on how to best build your RH66, let me know.
If you are willing to build with KT66, the schematics already exists in the form of the RH807. Since the sub is the same for 807, KT66 and 6L6, you can build it with any of these tubes (or the 5881 for that matter).
You can find the schematics on my site, as well as my email address. If you have any questions on how to best build your RH66, let me know.
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