crtexcnndrm99 Posted November 25, 2020 Share Posted November 25, 2020 45 minutes ago, mwhouston said: Godda link? https://bottlehead.com/product/moreplay-preamplifier-kit/ although I am suspicious of the true value for money for such ‘convenient’ kits... but what do I know! 1 Link to comment Share on other sites More sharing options...
andyr Posted November 25, 2020 Share Posted November 25, 2020 9 minutes ago, crtexcnndrm99 said: https://bottlehead.com/product/moreplay-preamplifier-kit/ although I am suspicious of the true value for money for such ‘convenient’ kits... but what do I know! Obviously SFA, Ash! At the price - I suggest that is value for money, for a tube preamp. However, I note: Output impedance is "less than 3.2Kohms " - that is high! (So not every power amp will be a good match.) Bandwidth is not great at the lower end: 23Hz to 45kHz, -1dB. Andy 1 Link to comment Share on other sites More sharing options...
mwhouston Posted November 25, 2020 Share Posted November 25, 2020 22 minutes ago, crtexcnndrm99 said: https://bottlehead.com/product/moreplay-preamplifier-kit/ although I am suspicious of the true value for money for such ‘convenient’ kits... but what do I know! You are aware this is preamp and not a HP driver. Link to comment Share on other sites More sharing options...
crtexcnndrm99 Posted November 25, 2020 Share Posted November 25, 2020 21 minutes ago, mwhouston said: You are aware this is preamp and not a HP driver. Definitely. Seeing the Crack made me interested in seeing what Bottlehead’s other offerings are. Apparently this Morelay is their latest product. Like their aesthetic 1 Link to comment Share on other sites More sharing options...
crtexcnndrm99 Posted November 25, 2020 Share Posted November 25, 2020 (edited) 24 minutes ago, andyr said: Obviously SFA, Ash! At the price - I suggest that is value for money, for a tube preamp. However, I note: Output impedance is "less than 3.2Kohms " - that is high! (So not every power amp will be a good match.) Bandwidth is not great at the lower end: 23Hz to 45kHz, -1dB. Andy Haha. Thanks Andy Edited November 25, 2020 by crtexcnndrm99 Link to comment Share on other sites More sharing options...
mwhouston Posted November 25, 2020 Share Posted November 25, 2020 50 minutes ago, crtexcnndrm99 said: https://bottlehead.com/product/moreplay-preamplifier-kit/ although I am suspicious of the true value for money for such ‘convenient’ kits... but what do I know! It works out to $550 Au. without any shipping chargers. How much was it to ship the Bottlehead? Link to comment Share on other sites More sharing options...
crtexcnndrm99 Posted November 25, 2020 Share Posted November 25, 2020 1 minute ago, mwhouston said: It works out to $550 Au. without any shipping chargers. How much was it to ship the Bottlehead? @barbz127 Link to comment Share on other sites More sharing options...
barbz127 Posted November 25, 2020 Share Posted November 25, 2020 12 minutes ago, mwhouston said: It works out to $550 Au. without any shipping chargers. How much was it to ship the Bottlehead? Cost ~80 USD to ship the crack. The crackatwoa is about ~$120 USD shipped and the mainline is ~$134 USD - these both appear to share the same frame as the moreplay 1 Link to comment Share on other sites More sharing options...
Ihearmusic Posted November 25, 2020 Share Posted November 25, 2020 3 hours ago, RankStranger said: Tried both. No change. I wonder if it’s a faulty transformer. Is that common? Is it a 50Hz hum or a 100Hz hum? 50Hz would be before rectification and it could be eddy currents introduced into the chassis. If possible you could move the transformer around to see whether proximity makes a difference. You might also want to try having the chassis earth closer to the IEC socket. Transformers are not likely to cause hum unless they have loose wingdings and/or are under rated and then it is more a mechanical noise. 1 1 Link to comment Share on other sites More sharing options...
aussievintage Posted November 25, 2020 Share Posted November 25, 2020 10 hours ago, crtexcnndrm99 said: https://bottlehead.com/product/moreplay-preamplifier-kit/ although I am suspicious of the true value for money for such ‘convenient’ kits... but what do I know! This not a conventional preamp. It mis-uses valves designed as power tubes, for low signal amplification. Not sure I agree this is a good idea, but is definitely a trend. I might have to lash one up on the workbench to have a listen for myself. You could tube roll all the similar power tubes. 2 Link to comment Share on other sites More sharing options...
mwhouston Posted November 25, 2020 Share Posted November 25, 2020 13 minutes ago, aussievintage said: This not a conventional preamp. It mis-uses valves designed as power tubes, for low signal amplification. Not sure I agree this is a good idea, but is definitely a trend. I might have to lash one up on the workbench to have a listen for myself. You could tube roll all the similar power tubes. You may have seen my preamp with antique (1920) low power power tubes, UX-171As. They are DHT so maybe there is a difference but the sound they produce is indescribable. I know Red has been experimenting with power tubes as preamp tube for a while. I was and am stunned by just how good they sound. https://retro-thermionic.blogspot.com/2020/04/mwh-1920s-ux-171a-tube-preamp.html 1 Link to comment Share on other sites More sharing options...
aussievintage Posted November 25, 2020 Share Posted November 25, 2020 22 minutes ago, mwhouston said: You may have seen my preamp with antique (1920) low power power tubes, UX-171As. They are DHT so maybe there is a difference but the sound they produce is indescribable. I know Red has been experimenting with power tubes as preamp tube for a while. I was and am stunned by just how good they sound. https://retro-thermionic.blogspot.com/2020/04/mwh-1920s-ux-171a-tube-preamp.html Yep, I remember us talking about it. I have all the bits, even a chassis, that I could build one with. I have so many projects in mind, I don't know what to build next Link to comment Share on other sites More sharing options...
Red MacKay Posted November 25, 2020 Share Posted November 25, 2020 Yes, even with all it's faults - I love my 10Y pre. I have thought about modding it - but no. Inspired by acg here, I am gathering all the goodies needed to make a new DHT pre - this time using a PX25. Same gain but way less plate resistance which is really important for good bandwidth. Just starting to scratch around with a circuit right now and contacted Mohan a couple of days back to enlist his help. After all - there needs to be at least one person involved that actually "knows" what he is doing. Mohan has a dislike for DHTs, but I will not be put off! A great read I discovered on the net last week was DHT Rob in Germany. A fellow crazy and a great read. Another mate recently received his custom 10Y pre from Japan. His circuit is completely different to mine and it has a 12BH7 as a driver tube for the 10Y for lower impedance and drive for the 10Y. Much better and more useful gain too. In reality, I only have a gain of about 1.3 with my 10Y and it regularly runs out of puff when you want Billy Idol to be going "more, more more!" The heater supplies on this Japanese unit and the B+ looks so much simpler than what I have done too. Maybe a case of KISS... I must get myself a spot in the hot seat at his place soon for a listen myself. The DHT signature is not for everyone, but to my ears they are in a listening SQ class of their own. 2 Link to comment Share on other sites More sharing options...
Red MacKay Posted November 25, 2020 Share Posted November 25, 2020 15 minutes ago, aussievintage said: I have all the bits, even a chassis, that I could build one with. I have so many projects in mind, I don't know what to build next ...Sounds like you have one right there to me. 2 Link to comment Share on other sites More sharing options...
crtexcnndrm99 Posted November 25, 2020 Share Posted November 25, 2020 45 minutes ago, Red MacKay said: Yes, even with all it's faults - I love my 10Y pre. I have thought about modding it - but no. Inspired by acg here, I am gathering all the goodies needed to make a new DHT pre - this time using a PX25. Same gain but way less plate resistance which is really important for good bandwidth. Just starting to scratch around with a circuit right now and contacted Mohan a couple of days back to enlist his help. After all - there needs to be at least one person involved that actually "knows" what he is doing. Mohan has a dislike for DHTs, but I will not be put off! A great read I discovered on the net last week was DHT Rob in Germany. A fellow crazy and a great read. Another mate recently received his custom 10Y pre from Japan. His circuit is completely different to mine and it has a 12BH7 as a driver tube for the 10Y for lower impedance and drive for the 10Y. Much better and more useful gain too. In reality, I only have a gain of about 1.3 with my 10Y and it regularly runs out of puff when you want Billy Idol to be going "more, more more!" The heater supplies on this Japanese unit and the B+ looks so much simpler than what I have done too. Maybe a case of KISS... I must get myself a spot in the hot seat at his place soon for a listen myself. The DHT signature is not for everyone, but to my ears they are in a listening SQ class of their own. Hoping to see a few more DHT pre builds by the sounds of it! Do you know what the name of the 10Y pre from Japan was? Link to comment Share on other sites More sharing options...
Red MacKay Posted November 26, 2020 Share Posted November 26, 2020 1 hour ago, crtexcnndrm99 said: Hoping to see a few more DHT pre builds by the sounds of it! Do you know what the name of the 10Y pre from Japan was? Otoman Laboratory. Sorry, no pics at this stage, but it's all on one chassis with a EL34 and 6SN7 as part of the reg circuit for the B+ and just one transformer and choke. Tango of course! 2 Link to comment Share on other sites More sharing options...
mwhouston Posted November 28, 2020 Share Posted November 28, 2020 Ive added a battery external test point. The shinny screw head is connected to the internal batteries and isolated from the Al enclosure. When on I meter between the test point and the earth of the RCAs. You only ever see half the total voltage as the RCA earth is 0V in the differential +/-9V PS. A fully charged battery will show 9V or a bit more at the test point. At a reading of 7V batteries require changing and are considered flat. With basic 9V inexpensive batteries you should get better than 50hours as the unit draws 10mA. With lithium’s, as I usually use, you get over 120hours. I buy packets of cheap lithium’s on eBay. Link to comment Share on other sites More sharing options...
aussievintage Posted November 28, 2020 Share Posted November 28, 2020 28 minutes ago, mwhouston said: Ive added a battery external test point. The shinny screw head is connected to the internal batteries and isolated from the Al enclosure. I had a similar problem with my battery powered variable-eq mono preamp. I ended up mounting the batteries on the outside of the case. I can measure them, and replace them easily. Used holder like this. The pins underneath just go through drilled holes into the case. 3 Link to comment Share on other sites More sharing options...
Guest Old Man Rubber Posted November 29, 2020 Share Posted November 29, 2020 Anyone got an idea what these might be? Probably PA or something but might be useful to convert to some kind of wacky horn driven hi-fi speaker? Link to comment Share on other sites More sharing options...
planet10 Posted November 29, 2020 Share Posted November 29, 2020 how big are they? dave Link to comment Share on other sites More sharing options...
simo8989 Posted November 29, 2020 Share Posted November 29, 2020 52 minutes ago, Old Man Rubber said: Anyone got an idea what these might be? Probably PA or something but might be useful to convert to some kind of wacky horn driven hi-fi speaker? 57 minutes ago, Old Man Rubber said: Anyone got an idea what these might be? Probably PA or something but might be useful to convert to some kind of wacky horn driven hi-fi speaker? It’s a Goodman’s Midax horn CONTENT Link to comment Share on other sites More sharing options...
simo8989 Posted November 29, 2020 Share Posted November 29, 2020 59 minutes ago, Old Man Rubber said: Anyone got an idea what these might be? Probably PA or something but might be useful to convert to some kind of wacky horn driven hi-fi speaker? Here you go they are very good vintage horns for hi fi. Link to comment Share on other sites More sharing options...
mwhouston Posted November 29, 2020 Share Posted November 29, 2020 (edited) 1 hour ago, Old Man Rubber said: Anyone got an idea what these might be? Probably PA or something but might be useful to convert to some kind of wacky horn driven hi-fi speaker? You may have some retro gems there. If they work all you need is some woofers for the first K and a suitable Xover. Edited November 29, 2020 by mwhouston Link to comment Share on other sites More sharing options...
Guest Old Man Rubber Posted November 29, 2020 Share Posted November 29, 2020 55 minutes ago, mwhouston said: You may have some retro gems there. If they work all you need is some woofers for the first K and a suitable Xover. I don't suppose there might be plans for such a thing, or a reasonable approach to designing something around them? Link to comment Share on other sites More sharing options...
mwhouston Posted November 29, 2020 Share Posted November 29, 2020 1 minute ago, Old Man Rubber said: I don't suppose there might be plans for such a thing, or a reasonable approach to designing something around them? Absolutely. PM if I can help. Link to comment Share on other sites More sharing options...
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