|
Search of All Forums Enter your search criteria. Click here for tips on using our search |
For Sale Ads |
1: K&K Audio / Lundahl Transformers, Stars in LL2765 Schematic (0.00)
Posted by jdrouin on 2021-05-07, 20:36:10 (45.28.146.203)
Hello, I'm about to wire up a pair of LL2765 and am wondering what the stars in the schematic mean, as I've never encountered that symbol in a transformer diagram before. Is it a phase dot indicator o .......
2: Tube DIY Asylum, Wright Mono 8 Schematic 6EM7-300B beta 0.2 (0.00)
Posted by jdrouin on 2017-11-07, 09:47:45 (72.222.112.165)
The amps in question were actually designed for the 6EM7, but the owner was using a 6DN7 to good effect. At any rate, here is the revised beta 0.2 6EM7-300B schematic. .......
3: MagneQuest/Peerless Forum, Wright Mono 8 Schematic 6EM7-300B beta 0.2 (0.00)
Posted by jdrouin on 2017-11-07, 09:44:48 (72.222.112.165)
I've had a chance to get back to this. Here's the updated 6EM7-300B schematic in beta 0.2, with parts list. .......
4: MagneQuest/Peerless Forum, WTB: TFA-204 (0.00)
Posted by jdrouin on 2017-10-19, 11:19:29 (72.222.112.165)
Hi Everyone, I've cleared it with Mike before posting that I'm looking for a pair of TFA-204. Please contact me directly or respond here if you have a pair to sell. Thanks, Jeff .......
5: MagneQuest/Peerless Forum, RE: Op points for 750R cathode resistor? (0.00)
Posted by jdrouin on 2017-10-18, 12:16:59 (72.222.112.165)
Thanks Palustris. I found out that the HV winding on the PT is 620VCT, so yes at 310V per side it runs the 300B at 2A3 voltages. I realize that the circuit is dated and that there are much better ways .......
6: Tube DIY Asylum, Mono 8 6DN7 (schematic attached) (0.00)
Posted by jdrouin on 2017-09-25, 09:00:56 (72.222.112.165)
Another Inmate was gracious enough to send pictures of the inside of his ca. 2001 Mono 8s with the 6DN7 input/driver tube. My rendering of the schematic is attached. Still stumped by that 750R cath .......
7: MagneQuest/Peerless Forum, Op points for 750R cathode resistor? (0.00)
Posted by jdrouin on 2017-09-25, 08:49:56 (72.222.112.165)
Thanks for the info, Mike. Now what's bugging me is the 750 ohm cathode resistor on the Mono 8's 300B tube. In order for that to work with the 60mA DC rating for the FS-030, it would need to be run at .......
8: SET Asylum, RE: Tracking down hum in Wright Sound Mono8 (0.00)
Posted by jdrouin on 2017-09-21, 08:17:14 (72.222.112.165)
Paging zplyonz: you mentioned taking pics of the inside of your Mono 8s. I've been trying to map the circuit. Would you mind PMing or emailing me the pics, or posting them here? Of course, I'll share .......
9: MagneQuest/Peerless Forum, Wright Mono 8 Schematic & MQ Iron (0.00)
Posted by jdrouin on 2017-09-15, 09:28:04 (72.222.112.165)
I'm posting this here because MQ used to supply iron for Wright Sound products and my question pertains, in part, to the amount of DC current that can reasonably be used in the FS-030. I've been br .......
10: Tube DIY Asylum, RE: Wright Mono 8 Schematic & Operating Points (0.00)
Posted by jdrouin on 2017-09-11, 15:51:13 (72.222.112.165)
I've had another go at reverse-engineering the schematic from recent internet sale pics, and this is what I've come up with so far (drawing attached). Yes, the choke is in the ground leg. What I ca .......
11: Tube DIY Asylum, RE: Wright Mono 8 Schematic & Operating Points (0.00)
Posted by jdrouin on 2017-03-31, 18:53:34 (72.192.68.101)
Thanks, Paul. Oh yes, I'm well aware of George's idiosyncrasies. Right now I'm modeling a circuit in LTSpice and PSUD2, based on a WPA 3.5 schematic that was reverse-engineered by an owner at diyaudio .......
12: Tube DIY Asylum, Wright Mono 8 Schematic & Operating Points (0.00)
Posted by jdrouin on 2017-03-31, 15:27:03 (72.192.68.101)
Does anyone have operating points or, even better, a schematic for the George Wright Mono 8 300B SET? I'm currently developing a 300B SET inspired by his WPA 3.5 circuit, which is the same as the Mono .......
13: Tubes Asylum, RE: Wright WLA12 / WLA12A Topology (0.00)
Posted by jdrouin on 2017-03-23, 13:52:11 (72.192.68.101)
"Driver is typically a cathode follower." Do you think this would be an AC or DC cathode follower in the WLA12? AC would have 100% feedback in the CF stage, whereas I gather DC would have no feedback, .......
14: Tubes Asylum, RE: Wright WLA12 / WLA12A Topology (0.00)
Posted by jdrouin on 2017-03-23, 11:08:14 (129.244.12.109)
I love George Wright stuff too. Many people would probably describe them as euphonic, but to me it just sounds so musical and vivid. It's hard to find used Wright components that haven't been altered, .......
15: Tubes Asylum, RE: Wright WLA12 / WLA12A Topology (0.00)
Posted by jdrouin on 2017-03-23, 11:00:11 (129.244.12.109)
OK, thanks. Very helpful. .......
16: Tubes Asylum, Wright WLA12 / WLA12A Topology (0.00)
Posted by jdrouin on 2017-03-21, 20:11:03 (72.192.68.101)
Does anyone know what topology was used in the George Wright WLA12/A line preamplifier? It uses a 6X5 rectifier, 6EM7 as a series high voltage regulator, and two 6SN7s for what his old website describ .......
17: MagneQuest/Peerless Forum, RE: First Simulation (0.00)
Posted by jdrouin on 2017-03-13, 18:06:45 (72.192.68.101)
Thanks, Gordon. Several members at diyaudio helped me figure out that the datasheet numbers for, say, plate voltage actually mean plate-to-cathode. So, the 350V operating point actually requires a .......
18: MagneQuest/Peerless Forum, RE: TFA-204 300B Operating Points (0.00)
Posted by jdrouin on 2017-03-12, 22:08:26 (72.192.68.101)
Thanks. I don't have the OPTs yet so I can't measure. I did however find a thread where Mike indicates the DCR for the TFA-204 is 140 ohm. I reposted it somewhere in the nest here, but the link is: ht .......
19: MagneQuest/Peerless Forum, RE: First Simulation (0.00)
Posted by jdrouin on 2017-03-12, 12:05:24 (72.192.68.101)
Learning more as I go along. I decided to set the voltage and frequency at the signal input source to 0 and then adjust the cathode resistor to 1K on the 300B to get an idle current of 60mA (plate .......
20: MagneQuest/Peerless Forum, First Simulation (0.00)
Posted by jdrouin on 2017-03-11, 14:42:36 (72.192.68.101)
After doing some more digging, I found a thread here where Mike indicated the DC series resistance of the TFA-204 primary is 140 ohm. Also, the previous LTSpice schematic contained an error. I thou .......
21: MagneQuest/Peerless Forum, RE: TFA-204 300B Operating Points (0.00)
Posted by jdrouin on 2017-03-10, 13:39:17 (72.192.68.101)
I've made a rudimentary model of the circuit in LTSpice, which I'm just starting to learn. This first attempt ignores the power supply from the schematic above, using DC voltage sources to drive th .......
22: MagneQuest/Peerless Forum, What's the Turns Ratio of the TFA-204? (0.00)
Posted by jdrouin on 2017-03-09, 20:10:37 (72.192.68.101)
I'm trying to model a circuit in LTSpice and the B+ is dropping way too much as it goes through the 3K primary of the TFA-204 to the plate of the 300B. Either I'm using the software incorrectly or 3Ko .......
23: MagneQuest/Peerless Forum, RE: TFA-204 300B Operating Points (0.00)
Posted by jdrouin on 2017-03-09, 18:50:31 (72.192.68.101)
Thanks, Mike. So, if you're saying a 350V/60mA op point is OK with the TFA-204, then I'll see what I can do with that. The more I read around, the more it seems George liked to go "by the book," choos .......
24: MagneQuest/Peerless Forum, RE: TFA-204 300B Operating Points (0.00)
Posted by jdrouin on 2017-03-07, 16:13:49 (72.192.68.101)
Thanks, triode3. I will keep these comments in mind, for sure. Right now I'm just interested in reproducing George's design accurately rather than modifying it, even though it uses a lot of unorthodox .......
25: MagneQuest/Peerless Forum, TFA-204 300B Operating Points (0.00)
Posted by jdrouin on 2017-03-07, 12:34:03 (129.244.12.109)
So, I'd like to breadboard a 6SN7 --> 300B SET circuit using Magnequest TFA-204 OPTs. It's a fairly well documented combination, but let me be up front that I'm trying to regain the sound of a pair .......
26: MagneQuest/Peerless Forum, RE: MQ OPTs for Tubelab SE 300b (0.00)
Posted by jdrouin on 2015-07-27, 09:30:26 (99.50.42.118)
Thanks, Paul and braubeat. I hadn't considered parafeed before, in part because I've never read about any TSE builders using it. I did a search and came up with one person who in fact used the EXO-003 .......
27: MagneQuest/Peerless Forum, RE: MQ OPTs for Tubelab SE 300b (0.00)
Posted by jdrouin on 2015-07-24, 10:14:36 (129.244.12.109)
Hi Mike, Sorry to put you on the spot there. It wasn't my intention. I just suck at delayed gratification and was getting hot to trot on this project. If you have any thoughts on what might work for t .......
28: MagneQuest/Peerless Forum, MQ OPTs for Tubelab SE 300b (0.00)
Posted by jdrouin on 2015-07-23, 10:46:42 (99.50.42.118)
Hello, I emailed Mike LaFevre a few days ago about OPTs for a Tubelab SE 300b build (http://tubelab.com/designs/tubelab-se/), but haven't heard back so I thought I'd post here hoping he might see it o .......
Found total of 28 records, Query: , Author: jdrouin in All Forums, Time: 0 sec.