Luis,
Did you use 1/2 of a LL1667 per channel or did you use coils in series? I know you must have used one LL1667 per channel because you have monoblocks 🙂 but it is ofcourse possible that you did not use both coils.
Regards,
Bas
Did you use 1/2 of a LL1667 per channel or did you use coils in series? I know you must have used one LL1667 per channel because you have monoblocks 🙂 but it is ofcourse possible that you did not use both coils.
Regards,
Bas
Hi Bas,
I used the LL1667 in series as specified on the Lundahl PDF as single-end connection.
I saw that you also use it in your d3A 6C41C amp. Are you happy with the sound?
Best regards,
Luis.
I used the LL1667 in series as specified on the Lundahl PDF as single-end connection.
I saw that you also use it in your d3A 6C41C amp. Are you happy with the sound?
Best regards,
Luis.
Thanks Luis,
About the 6c41c...
I went from Mu-Stage d3a/6n1p to choke load triode wired d3a...and must say I like the choke loaded d3a a lot more! Yes...the sound is very good...does not have the dht magic yet...but sounds very good nevertheless.
Regards,
Bas
About the 6c41c...
I went from Mu-Stage d3a/6n1p to choke load triode wired d3a...and must say I like the choke loaded d3a a lot more! Yes...the sound is very good...does not have the dht magic yet...but sounds very good nevertheless.
Regards,
Bas
Compromised URL removed by ModerationDoes anyone know what determines the size of this cap 15uF here? Is it's function not just a bypass cap...and therefore a 100uF be suitable?
Last edited by a moderator:
Hi Thorsten,
I read somewhere that you advise newbies not to build such an amp because 300B's can blow up..
I am planning to build this design into my diyHifiSupply's LD+..
But I really don't understand the problems that could arise with DRD's...could I build it first with a capacitor between d3a and 300b grid to do a smoke test...and if it works remove the cap??
Regards,
Bas
I read somewhere that you advise newbies not to build such an amp because 300B's can blow up..
I am planning to build this design into my diyHifiSupply's LD+..
But I really don't understand the problems that could arise with DRD's...could I build it first with a capacitor between d3a and 300b grid to do a smoke test...and if it works remove the cap??
Regards,
Bas
Konnichiwa,
Actually, the DRD/Monkey principle is safe to build. I refer to split supply direct coupled amplifiers as "potentially 300B Graves".
BTW, I don't think the LD+ has the right supply voltages available, so this may be a non-starter...
Sayonara
Bas Horneman said:
Actually, the DRD/Monkey principle is safe to build. I refer to split supply direct coupled amplifiers as "potentially 300B Graves".
BTW, I don't think the LD+ has the right supply voltages available, so this may be a non-starter...
Sayonara
Yeah..you are right..I thought I could get away with the lower voltages..but...I'll go for d3a choke loaded I think.
Konnichiwa,
Lower supply voltages imply a reduction in power and a complete readjustement of the circuit.
For D3a choke loaded on an LD+ Chassis, look here:
http://www.jogis-roehrenbude.de/Leserbriefe/TH-Loesch-Amp/Th-Loesch-Amp.htm
This has got all the needed stuff, just adjust the input valve cathode resistor to suit the triode wired D3a.
Sayonara
Bas Horneman said:
Lower supply voltages imply a reduction in power and a complete readjustement of the circuit.
For D3a choke loaded on an LD+ Chassis, look here:
http://www.jogis-roehrenbude.de/Leserbriefe/TH-Loesch-Amp/Th-Loesch-Amp.htm
This has got all the needed stuff, just adjust the input valve cathode resistor to suit the triode wired D3a.
Sayonara
Hi all ,
I have built the DRD style amps, currently as 45s.
You can find bits of it over at "Audio round table, group build"
I used Lundel and James outputs, Jacks DRD chokes and the Lady Day style power transformer from DIY HI FI. If I am not mistaken , Thorsten had a big hand in it’s design.
This is a very flexible transformer. Between it’s multiple HV taps, buck boost taps, full or half wave and cap or choke input filters. There is a very wide range of voltages to play with.
Not to mention the clever filament secondary arrangement. Worth a look.
I first breadboarded these as a 45 amp with plans to run 2a3 and 300b as a series of post to ART.
I first set one up with a 6an4 driver , parts bin "fast rectifiers" and some honking big adjustable cathode resistors that could accommodate all 3 tubes. Dialed up the various voltages and had a listen . good. Build another .
Now one of the stated objectives of this project was to try some alternatives to AC heating But with this lash up. There is almost no hum. With my 96db/w speakers, I think what I hear is the diode switching noise. It has to be a very quiet night in N-town before this level of noise is heard.
I have been very busy at work and have not had a lot of time to play. I did toss a pair of 300’s in as a quick and dirty experiment but my heart was not in it. I did not have the time to do it properly and the 45’s were working well for me. I will get back to it as time permits.
In the mean time this is a very worthily configuration to consider…John
I have built the DRD style amps, currently as 45s.
You can find bits of it over at "Audio round table, group build"
I used Lundel and James outputs, Jacks DRD chokes and the Lady Day style power transformer from DIY HI FI. If I am not mistaken , Thorsten had a big hand in it’s design.
This is a very flexible transformer. Between it’s multiple HV taps, buck boost taps, full or half wave and cap or choke input filters. There is a very wide range of voltages to play with.
Not to mention the clever filament secondary arrangement. Worth a look.
I first breadboarded these as a 45 amp with plans to run 2a3 and 300b as a series of post to ART.
I first set one up with a 6an4 driver , parts bin "fast rectifiers" and some honking big adjustable cathode resistors that could accommodate all 3 tubes. Dialed up the various voltages and had a listen . good. Build another .
Now one of the stated objectives of this project was to try some alternatives to AC heating But with this lash up. There is almost no hum. With my 96db/w speakers, I think what I hear is the diode switching noise. It has to be a very quiet night in N-town before this level of noise is heard.
I have been very busy at work and have not had a lot of time to play. I did toss a pair of 300’s in as a quick and dirty experiment but my heart was not in it. I did not have the time to do it properly and the 45’s were working well for me. I will get back to it as time permits.
In the mean time this is a very worthily configuration to consider…John
- Status
- Not open for further replies.